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1
Wermter, Joseph, Stephen Noble, and Brian Viner. "Impacts of the Thermal Gradient on Inland Advecting Sea Breezes in the Southeastern United States." Atmosphere 13, no. 7 (June 22, 2022): 1004. http://dx.doi.org/10.3390/atmos13071004.
Повний текст джерелаАнотація:
Sea breezes are frequently observed in the South Carolina/Georgia region of the Southeastern United States (SEUS) and can reach upwards of 150km inland. This region is unique among the places frequently affected by sea breeze due to it being a continental location with relatively flat topography. The thermal gradient between land and water environments is a factor in introducing the sea breeze, but its role in the inland extent of sea breeze propagation isn’t as well known. We investigate the role of the thermal gradient in previously catalogued sea breeze events observed at the Savannah River Site (SRS) by taking differences of temperature measurements at inland and coastal weather stations for the days that the events occurred. We saw that the temperature differences for those days were much higher than in the non-sea breeze days during the mornings and afternoon. Numerical models were also used to conduct a sensitivity study on a sea breeze case, using simple modifications of the temperature gradient. We found that while the modifications did not stop the generation of a sea breeze circulation, the extent of the inland propagation was dependent on the magnitude of the thermal gradient.
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You, Cheng, Jimmy Chi-Hung Fung, and Wai Po Tse. "Response of the Sea Breeze to Urbanization in the Pearl River Delta Region." Journal of Applied Meteorology and Climatology 58, no. 7 (July 2019): 1449–63. http://dx.doi.org/10.1175/jamc-d-18-0081.1.
Повний текст джерелаАнотація:
AbstractThe Pearl River delta (PRD) region has undergone rapid urbanization since the 1980s, which has had significant effects on the sea-breeze circulation in this region. Because the sea breeze plays an important role in pollutant transportation and convective initiation in the PRD region, it is meaningful to study the effects of urbanization on the sea breeze. In this study, three numerical experiments were conducted from 2 June to 31 August 2010 with land-use data from 1988, 1999, and 2010. For each simulation, characteristics of the sea breeze such as the start time, end time, intensity, height, pumping ability, and inland penetration distance were quantified. By comparing the characteristics of the sea breeze in these simulations, its response to urbanization was quantified. The results show that urbanization enhances the duration, height, and intensity of the sea breeze but blocks its inland penetration. One physical mechanism is proposed to dynamically elucidate the response of the sea breeze to urbanization. Because the urban area in the PRD region is concentrated near the coast, urbanization imposes a positive heating gradient on the coastal region and a negative heating gradient on the region farther inland. The positive heating gradient may intensify the sea breeze, and the negative heating gradient may prevent the sea breeze from propagating farther inland.
3
Zheng, Xiaoxue, Yan Tao, Zhongqiang Wang, Chen Ma, Hong He, and Xiuqin Yin. "Soil macro-fauna respond to environmental variations along a coastal-inland gradient." PeerJ 8 (July 14, 2020): e9532. http://dx.doi.org/10.7717/peerj.9532.
Повний текст джерелаАнотація:
Varied environmental conditions in coastal-inland zones tend to influence soil faunal communities. However, few studies have focused on the responses of soil fauna to environmental variations along the coastal-inland gradient. In order to better understand the aforementioned responses, a total of 80 soil macro-faunal samples were collected at the five different distances from the coastline of China’s Bohai Bay. The results revealed that the compositions, structural characteristics and diversity of the soil macro-fauna varied among the different habitats. With the increases in the distance from the sea, the individual density, richness and diversity levels of the soil macro-fauna all first increased and then decreased. The individual density, richness and diversity values were all at their maximum at 30 km from the sea. The Edge effect promoted unique and rare soil macro-faunal taxa. Formicidae, Curculionidae and Aphodiidae were found to be the edge taxa. Agelenidae, Liocranidae and Nematocera were considered to be indicator taxa of severe sea effects. Paradoxosomatidae was an indicator taxon of slight effects. Overall, the environmental variations along the coastal-inland gradient were found to have the potential to affect the soil macro-faunal communities, and the different taxa of the soil macro-fauna responded to those variations in different ways. This study further revealed the processes and mechanisms of the sea influencing the soil macro-faunal communities, which had been caused by the coastal-inland gradient. The results of this study also provided a theoretical basis for developing future biodiversity guidelines for coastal ecosystems.
4
Yu, Xiaojie, Xinyu Guo, and Hidetaka Takeoka. "Fortnightly Variation in the Bottom Thermal Front and Associated Circulation in a Semienclosed Sea." Journal of Physical Oceanography 46, no. 1 (January 2016): 159–77. http://dx.doi.org/10.1175/jpo-d-15-0071.1.
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AbstractSummer hydrographic data from 1971 to 2000 demonstrate the presence of bottom cold water (BCW) and a bottom thermal front around the BCW in a semienclosed sea in the Seto Inland Sea of Japan. The horizontal gradient of water temperature across the bottom front was larger in neap tide than in spring tide, which is the opposite the pattern observed in the fortnightly variations in other areas (e.g., the Irish Sea). A numerical model for the Inland Sea reproduced the presence of BCW and a bottom front as well as the same fortnightly variation in the horizontal gradient of water temperature across the bottom front as in observational data. Being the same BCW as those in other areas, the presence of BCW in the Inland Sea is also caused by spatial variation in tidal mixing. The intensification of the bottom front in neap tide in the Inland Sea results from a combination of tidal mixing and horizontal advection of warm water to the BCW. The presence of a bottom residual current in the direction across the bottom front results in the horizontal advection of warm water to the BCW, and its fortnightly variation is responsible for the fortnightly variation of the bottom front in the Inland Sea. The presence of the BCW induces a surface cyclonic circulation in the direction approximately along the bottom front; the intensification and weakening of the bottom front with the spring–neap tidal cycle, combined with the fortnightly variation in the bottom boundary layer thickness, produce a slightly stronger surface cyclonic circulation in neap tide than in spring tide.
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Molinet, Carlos, Carlos A. Moreno, Edwin J. Niklitschek, Manira Matamala, Mónica Neculman, Alejandra Arévalo, José Codjambassis, Patricio Diaz, and Manuel Diaz. "Reproduction of the sea urchin Loxechinus albus across a bathymetric gradient in the Chilean Inland Sea." Revista de biología marina y oceanografía 47, no. 2 (August 2012): 257–72. http://dx.doi.org/10.4067/s0718-19572012000200008.
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LOHAR, D., B. CHAKRAVARTY, and B. Pal. "Sensitivity studies on the air flow characteristics In Kharagpur using a meso-scale model." MAUSAM 44, no. 4 (January 1, 2022): 329–36. http://dx.doi.org/10.54302/mausam.v44i4.3903.
Повний текст джерелаАнотація:
A three-dimensional hydrostatic model has been employed for the study of sea breeze circulations over south West Bengal with special reference to an inland station Kharagpur (22°.21' N, 87° 19'E). A series of sensitivity experiments have been performed to stress the Importance of differential heating on circulation over south West Bengal during pre-monsoon period. It is found that due to differential heating rate between land and sea surfaces, sea breezes can penetrate to the inland station Kharagpur and beyond even in case of moderate gradient wind. Surface observations at Kharagpur and pilot balloon observation at nearby station Kalaikunda are used to compare the model results. The onset of sea breezes, variation of the air temperature and humidity are In fairly good agreement whereas It over estimates the depth of the circulation and cannot predict the variation of the late morning hours surface wind.
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RAO, D. VENKATESWARA. "The speed and some other features of the sea-breeze Front at Madras." MAUSAM 6, no. 3 (December 3, 2021): 233–42. http://dx.doi.org/10.54302/mausam.v6i3.4479.
Повний текст джерелаАнотація:
The speed with which the sea breeze advances inland at Madras under various meteorological conditions and Its dependence on the time of onset and depth of penetration are discussed in this paper, utilising the records for the year 1945 and 1946 of autographic instruments at three stations located at different distances from the coast. A velocity of 10-15 mph, a south southeasterly direction of the resultant wind, the months April to September and a time of onset during the early afternoon are favoured most by the sea breeze at Madras. The average speed of the sea- breeze front is found to be 37 mph. It is accelerated with depth of penetration inland independently of the wind speed. It varies with the hour of onset of the sea-breeze, being lowest during the epoch of maximum temperature. The variation of the ratio of the speed inland to that near the coast with time of onset and direction of the on-shore wind is investigated. The results are explained on t he basis of the temperature gradient and its variation with distance inland. The mean temperature drop and vapour pressure rise caused by the sea-breeze for different times of incidence and magnitudes of wind velocity in the various months have also been studied. The changes are maximum in the proximity of the epoch of maximum temperature and in the month of July in the year. The results of this study would help in anticipating with sufficient accuracy and sufficiently in advance for aviation needs the time of onset of the sea-breeze and the accompanying meteorological changes at the airfield at Meenambakkam given the time of incidence and the direction of the on shore wind earlier at a point closer to the coast.
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Yoshikado, Hiroshi. "Intense Summer Heat in Tokyo and Its Suburban Areas Related with Variation in the Synoptic-Scale Pressure Field: A Statistical Analysis." Journal of Applied Meteorology and Climatology 52, no. 9 (September 2013): 2065–74. http://dx.doi.org/10.1175/jamc-d-12-0315.1.
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AbstractIntense summer heat in Tokyo, Japan, and its suburban areas between 1990 and 2010 was statistically analyzed. Sample days were selected from among days with a sea breeze and sufficient sunshine duration, because sea breeze is the dominant summertime meteorological system in the region. Excess in the daily maximum temperature of an inland urban site in Tokyo over a site facing the outer sea where the sea breeze originates was selected as a key index. A comparison of a group of days for which the temperature excess was large with an opposing group of days for which it was small revealed a distinct difference in diurnal wind variations: persistent southwesterly winds overwhelmed the sea breeze in areas facing the outer sea in the former case, whereas in the latter case a diurnal sea-breeze cycle was typically observed in those areas as well as in the inland areas. This difference could furthermore be connected to differences in the pressure gradient in the region, that is, differences in the synoptic-scale pressure field. As a result, slight shifts in the pressure field affect urban heat, suggesting that, in addition to general warming, changes in the pressure field resulting from future climate change can be of great importance.
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Khodzher, T. V., L. P. Golobokova, E. Yu Osipov, Yu A. Shibaev, V. Ya Lipenkov, O. P. Osipova, and J. R. Petit. "Spatial–temporal dynamics of chemical composition of surface snow in East Antarctica along the Progress station–Vostok station transect." Cryosphere 8, no. 3 (May 19, 2014): 931–39. http://dx.doi.org/10.5194/tc-8-931-2014.
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Abstract. In January of 2008, during the 53rd Russian Antarctic Expedition, surface snow samples were taken from 13 shallow (0.7 to 1.5 m depth) snow pits along the first tractor traverse from Progress to Vostok stations, East Antarctica. Sub-surface snow/firn layers are dated from 2.1 to 18 yr. The total length of the coast to inland traverse is more than 1280 km. Here we analysed spatial variability of concentrations of sulphate ions and elements and their fluxes in the snow deposited within the 2006–2008 time interval. Anions were analysed by high-performance liquid chromatography (HPLC), and the determination of selected metals, including Na, K, Mg, Ca and Al, was carried out by mass spectroscopy with atomization by induced coupled plasma (ICP-MS). Surface snow concentration records were examined for trends versus distance inland, elevation, accumulation rate and slope gradient. Na shows a significant positive correlation with accumulation rate, which decreases as distance from the sea and altitude increase. K, Ca and Mg concentrations do not show any significant relationship either with distance inland or with elevation. Maximal concentrations of these elements with a prominent Al peak are revealed in the middle part of the traverse (500–600 km from the coast). Analysis of element correlations and atmospheric circulation patterns allow us to suggest their terrestrial origin (e.g. aluminosilicates carried as a continental dust) from the Antarctic nunatak areas. Sulphate concentrations show no significant relationship with distance inland, elevation, slope gradient and accumulation rate. Non-sea salt secondary sulphate is the most important contribution to the total sulphate budget along the traverse. Sulphate of volcanic origin attributed to the Pinatubo eruption (1991) was revealed in the snow pit at 1276 km (depth 120–130 cm).
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Lebassi, Bereket, Jorge González, Drazen Fabris, Edwin Maurer, Norman Miller, Cristina Milesi, Paul Switzer, and Robert Bornstein. "Observed 1970–2005 Cooling of Summer Daytime Temperatures in Coastal California." Journal of Climate 22, no. 13 (July 1, 2009): 3558–73. http://dx.doi.org/10.1175/2008jcli2111.1.
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Abstract This study evaluated 1950–2005 summer [June–August (JJA)] mean monthly air temperatures for two California air basins: the South Coast Air Basin (SoCAB) and the San Francisco Bay Area (SFBA). The study focuses on the more rapid post-1970 warming period, and its daily minima temperature Tmin and maxima temperature Tmax values were used to produce average monthly values and spatial distributions of trends for each air basin. Additional analyses included concurrent SSTs, 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) sea level coastal pressure gradients, and GCM-downscaled average temperature Tave values. Results for all 253 California National Weather Service (NWS) Cooperative Observer Program (COOP) sites together showed increased Tave values (0.23°C decade−1); asymmetric warming, as Tmin values increase faster than Tmax values (0.27° versus 0.04°C decade−1) and thus decreased daily temperature range (DTR) values (0.15°C decade−1). The spatial distribution of observed SoCAB and SFBA Tmax values exhibited a complex pattern, with cooling (−0.30°C decade−1) in low-elevation coastal areas open to marine air penetration and warming (0.32°C decade−1) in inland areas. Results also showed that decreased DTR values in the basins arose from small increases at inland sites (0.16°C decade−1) combined with large decreases (−0.58°C decade−1) at coastal sites. It is also possible that some of the current observed temperature trends could be associated with low-frequency decadal variability, expected even with a constant radiative forcing. Previous studies suggest that cooling JJA Tmax values in coastal California were a result of increased irrigation, coastal upwelling, or cloud cover. The current hypothesis is that they arise (as a possible “reverse reaction”) from the global warming of inland areas, which results in increased sea-breeze flow activity. GCM model Tave warming decreased from 0.13°C decade−1 at inland sites to 0.08°C decade−1 in coastal areas. Sea level pressure increased in the Pacific high and decreased in the thermal low. The corresponding gradient thus showed a trend of 0.04 hPa 100 km−1 decade−1, supportive of the hypothesis of increased sea-breeze activity.
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Guo, Qiaona, Yahui Zhang, Zhifang Zhou, and Zili Hu. "Transport of Contamination under the Influence of Sea Level Rise in Coastal Heterogeneous Aquifer." Sustainability 12, no. 23 (November 25, 2020): 9838. http://dx.doi.org/10.3390/su12239838.
Повний текст джерелаАнотація:
This paper provided for the first time an experimental study on the influence of sea level rise on transport of contamination in the heterogeneous unconfined aquifer of the coastal zone. The experiments were conducted using the tank, considering the difference between sea level and inland head 1 cm for Case 1 and 2 cm for Case 2. Observed data were validated using the numerical model, which matched well with the toe length of seawater wedge and the shape of the contaminant plume. The results showed that the observed and simulated values of Cl− concentration at the sampling points increased sharply at the initial time, and then they increased slowly and tended to be stable. The seawater wedge migrated inland with time under the effects of the hydraulic gradient toward the inland and the density difference between saltwater and freshwater. The steady state length of the 50% isoline of the seawater wedge was 167 cm in Case 2, which was larger than that of Case 1. The maximum area of plume in Case 2 was 0.13 m2, larger than that in Case 1, which indicated that the velocity of diffusion of the contaminant plume increased as the sea level increased. As the velocity of diffusion increased, the time for pollutant migration to the intersection between seawater and freshwater became shorter. The maximum area and vertical depth of pollutant plume were sensitive to the hydraulic conductivity, dispersivity, and contamination concentration. The infiltration depth and range of the contaminant plume in the heterogeneous aquifer were greater than those in the homogeneous aquifer of the actual beach.
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Gremmen, N. J. M., A. H. L. Huiskes, and J. W. Francke. "Epilithic macrolichen vegetation of the Argentine Islands, Antarctic Peninsula." Antarctic Science 6, no. 4 (December 1994): 463–71. http://dx.doi.org/10.1017/s0954102094000702.
Повний текст джерелаАнотація:
Classification of 162 sample plots of lichen vegetation from the Argentine Islands region, Antarctica, yielded two main groups, the Usnea complex and the Mastodia-Rinodina complex, comprising four and six subordinate communities, respectively. Communities of the Usnea complex typically occur in inland sites with steep slopes, characterized by low chloride, ammonia and phosphate concentrations. Communities of the Mastodia-Rinodina complex occur close to the shore and in areas occupied by birds, where concentrations of chloride, ammonia and phosphate were relatively high. Within each vegetation complex species composition is related to factors indicating nutrient status (chloride and ammonia concentration, distance from the sea), as well as to variables indicating different microclimatic conditions (elevation, aspect, exposure, moisture, and gradient). In canonical correspondence analyses of the data a large part of species variation could not be explained by the environmental variables studied (elevation, gradient, slope aspect, distance from the sea, direction of the sea, presence of guano, exposure, moisture, chloride, ammonia, phosphate and nitrate concentrations). It is suggested that temporal variability in mineral concentrations and the lack of information on differences in length of the growing season at the sample sites are, to a large extent, responsible for this.
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Muir Wood, Robert, and William Bateman. "Uncertainties and constraints on breaching and their implications for flood loss estimation." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 363, no. 1831 (June 15, 2005): 1423–30. http://dx.doi.org/10.1098/rsta.2005.1576.
Повний текст джерелаАнотація:
Around the coasts of the southern North Sea, flood risk is mediated everywhere by the performance of natural and man-made flood defences. Under the conditions of extreme surge with tide water levels, the performance of the defences determines the extent of inland flooding. Sensitivity tests reveal the enormous increase in the volume of water that can pass through a defence once breaching is initiated, with a 1 m reduction in sill elevation doubling the loss. Empirical observations of defence performance in major storm surges around the North Sea reveal some of the principal controls on breaching. For the same defence type, the maximum size and depth of a breach is a function of the integral of the hydraulic gradient across the defence, which is in turn determined by the elevation of the floodplain and the degree to which water can continue to flow inland away from the breach. The most extensive and lowest floodplains thereby ‘generate’ the largest breaches. For surges that approach the crest height, the weaker the protection of the defence, the greater the number of breaches. Defence reinforcement reduces both the number and size of the breaches.
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Cuxart, J., M. A. Jiménez, M. Telišman Prtenjak, and B. Grisogono. "Study of a Sea-Breeze Case through Momentum, Temperature, and Turbulence Budgets." Journal of Applied Meteorology and Climatology 53, no. 11 (November 2014): 2589–609. http://dx.doi.org/10.1175/jamc-d-14-0007.1.
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AbstractA simulation with the Méso-NH model over the island of Mallorca, Spain, has been made in a case of synoptic high pressure (5 June 2010) that allowed the development of sea breezes (SB) in the three main basins of the island. The results compare well to the available observations and are qualitatively very close to a previous idealized study with no synoptic forcing made by Ramis and Romero in 1995. The temporal and spatial structure of the SB in the southeastern basin is analyzed with the use of the momentum, temperature, and turbulence kinetic energy budgets provided by the numerical model. Five stages of evolution from before dawn to after sunset are discussed, identifying the main physical mechanisms at play. The morning land heating warms the land and the air over it until an air temperature gradient is created and a marine flow accelerates inland, dragged by turbulence in the low layers. The upper part of the inland current and the layers just above are dominated by compensatory motions, which oppose the corresponding pressure gradient at these levels. These mechanisms last while the SB is active, with significant effects from the local topography, and they decrease in intensity as sunset approaches. This relatively simple case has been used to check the goodness of two analytical models of the SB that perform relatively well because they use turbulence as a surrogate for the missing advection terms in the layers above 200 m. These models are formulated here in a more consistent manner in the turbulence parameterization than were the original propositions.
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Del Vecchio, Silvia, Edy Fantinato, Mauro Roscini, Alicia T. R. Acosta, Gianluigi Bacchetta, and Gabriella Buffa. "The germination niche of coastal dune species as related to their occurrence along a sea–inland gradient." Journal of Vegetation Science 31, no. 6 (May 25, 2020): 1112–21. http://dx.doi.org/10.1111/jvs.12899.
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Kehrwald, Natalie M., William D. McCoy, Jeanne Thibeault, Stephen J. Burns та Eric A. Oches. "Paleoclimatic implications of the spatial patterns of modern and LGM European land-snail shell δ18O". Quaternary Research 74, № 1 (липень 2010): 166–76. http://dx.doi.org/10.1016/j.yqres.2010.03.001.
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AbstractThe oxygen isotopic composition of land-snail shells may provide insight into the source region and trajectory of precipitation. Last glacial maximum (LGM) gastropod shells were sampled from loess from Belgium to Serbia and modern land-snail shells both record δ18O values between 0‰ and − 5‰. There are significant differences in mean fossil shell δ18O between sites but not among genera at a single location. Therefore, we group δ18O values from different genera together to map the spatial distribution of δ18O in shell carbonate. Shell δ18O values reflect the spatial variation in the isotopic composition of precipitation and incorporate the snails' preferential sampling of precipitation during the warm season. Modern shell δ18O decreases in Europe along a N–S gradient from the North Sea inland toward the Alps. Modern observed data of isotopes in precipitation (GNIP) demonstrate a similar trend for low-altitude sites. LGM shell δ18O data show a different gradient with δ18O declining toward the ENE, implying a mid-Atlantic source due to increased sea ice and a possible southern displacement of the westerly jet stream. Balkan LGM samples show the influence of a Mediterranean source, with δ18O values decreasing northward.
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Arnup, Sarah J., and Michael J. Reeder. "The Diurnal and Seasonal Variation of the Northern Australian Dryline." Monthly Weather Review 135, no. 8 (August 1, 2007): 2995–3008. http://dx.doi.org/10.1175/mwr3455.1.
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Abstract The diurnal and seasonal variations of the northern Australian dryline are examined by constructing climatologies of low-level dynamic and thermodynamic variables taken from the high-resolution Australian Bureau of Meteorology’s Limited Area Prediction Scheme (LAPS) forecasts from 2000 to 2003. The development of the dryline is analyzed within the framework of the frontogenesis function applied to the mixing ratio and the airstream diagnostics of Cohen and Schultz. A case study of 12–13 October 2002 illustrating the airmass boundaries over the Australian region is also examined. Daytime surface heating produces sea-breeze circulations around the coast and a large inland heat trough that extends east–west along northern Australia. At night, air parcels accelerate toward low pressure, increasing convergence and deformation within the heat trough. This sharpens the moisture gradient across the tropical and continental airmass boundary into a dryline. This is different than the dryline of the Great Plains in the United States, which generally weakens overnight. The Australian dryline is strongest in spring just poleward of the Gulf of Carpentaria, where the moisture gradient across the heat trough is enhanced by the coast, and the axis of dilatation is closely aligned with mixing ratio isopleths. The dryline is weakest in winter, when the heat trough is weak. The LAPS 3-h forecasts are in good agreement with observations obtained from the Automatic Weather Station network. The 3-h forecasts capture the observed diurnal and seasonal cycle of the airmass boundaries. However, the sea-breeze circulation and ageostrophic flow into the surface heat trough is limited by the model resolution. The LAPS 3-h forecasts may therefore underestimate the nocturnal intensification of the dryline, especially since the inland moisture content is overestimated.
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Lo, Jeff C. F., Alexis K. H. Lau, Fei Chen, Jimmy C. H. Fung, and Kenneth K. M. Leung. "Urban Modification in a Mesoscale Model and the Effects on the Local Circulation in the Pearl River Delta Region." Journal of Applied Meteorology and Climatology 46, no. 4 (April 1, 2007): 457–76. http://dx.doi.org/10.1175/jam2477.1.
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Abstract The Pearl River Delta (PRD) region, located in the southern part of Guangdong Province in China, is one of the most rapidly developing regions in the world. The evolution of local and regional sea-breeze circulation (SBC) is believed to be responsible for forming meteorological conditions for high air-pollution episodes in the PRD. To understand better the impacts of urbanization and its associated urban heat island (UHI) on the local- and regional-scale atmospheric circulations over PRD, a number of high-resolution numerical experiments, with different approaches to treat the land surface and urban processes, have been conducted using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5). The results show that an accurate urban land-use dataset and a proper urban land-use parameterization are critical for the mesoscale model to capture the major features of the observed UHI effect and land–sea-breeze circulations in the PRD. Stronger UHI in the PRD increases the differential temperature gradient between urbanized areas and nearby ocean surface and hence enhances the mesoscale SBC. The SBC front consequently penetrates farther inland to overcome the prevailing easterly flow in the western part of inland Hong Kong. Additional sensitivity studies indicate that further industrial development and urbanization will strengthen the daytime SBC as well as increase the air temperature in the lowest 2 km of the atmosphere.
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Curtis, Chris J., Jan Kaiser, Alina Marca, N. John Anderson, Gavin Simpson, Vivienne Jones, and Erika Whiteford. "Spatial variations in snowpack chemistry, isotopic composition of NO<sub>3</sub><sup>−</sup> and nitrogen deposition from the ice sheet margin to the coast of western Greenland." Biogeosciences 15, no. 2 (January 29, 2018): 529–50. http://dx.doi.org/10.5194/bg-15-529-2018.
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Abstract. The relative roles of anthropogenic nitrogen (N) deposition and climate change in causing ecological change in remote Arctic ecosystems, especially lakes, have been the subject of debate over the last decade. Some palaeoecological studies have cited isotopic signals (δ(15N)) preserved in lake sediments as evidence linking N deposition with ecological change, but a key limitation has been the lack of co-located data on both deposition input fluxes and isotopic composition of deposited nitrate (NO3−). In Arctic lakes, including those in western Greenland, previous palaeolimnological studies have indicated a spatial variation in δ(15N) trends in lake sediments but data are lacking for deposition chemistry, input fluxes and stable isotope composition of NO3−. In the present study, snowpack chemistry, NO3− stable isotopes and net deposition fluxes for the largest ice-free region in Greenland were investigated to determine whether there are spatial gradients from the ice sheet margin to the coast linked to a gradient in precipitation. Late-season snowpack was sampled in March 2011 at eight locations within three lake catchments in each of three regions (ice sheet margin in the east, the central area near Kelly Ville and the coastal zone to the west). At the coast, snowpack accumulation averaged 181 mm snow water equivalent (SWE) compared with 36 mm SWE by the ice sheet. Coastal snowpack showed significantly greater concentrations of marine salts (Na+, Cl−, other major cations), ammonium (NH4+; regional means 1.4–2.7 µmol L−1), total and non-sea-salt sulfate (SO42−; total 1.8–7.7, non-sea-salt 1.0–1.8 µmol L−1) than the two inland regions. Nitrate (1.5–2.4 µmol L−1) showed significantly lower concentrations at the coast. Despite lower concentrations, higher precipitation at the coast results in greater net deposition for NO3− as well as NH4+ and non-sea-salt sulfate (nss-SO42−) relative to the inland regions (lowest at Kelly Ville 6, 4 and 3; highest at coast 9, 17 and 11 mol ha−1 a−1 of NO3−, NH4+ and nss-SO42− respectively). The δ(15N) of snowpack NO3− shows a significant decrease from inland regions (−5.7 ‰ at Kelly Ville) to the coast (−11.3 ‰). We attribute the spatial patterns of δ(15N) in western Greenland to post-depositional processing rather than differing sources because of (1) spatial relationships with precipitation and sublimation, (2) within-catchment isotopic differences between terrestrial snowpack and lake ice snowpack, and (3) similarities between fresh snow (rather than accumulated snowpack) at Kelly Ville and the coast. Hence the δ(15N) of coastal snowpack is most representative of snowfall in western Greenland, but after deposition the effects of photolysis, volatilization and sublimation lead to enrichment of the remaining snowpack with the greatest effect in inland areas of low precipitation and high sublimation losses.
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You, Cheng, and Jimmy Chi-Hung Fung. "Characteristics of the Sea-Breeze Circulation in the Pearl River Delta Region and Its Dynamical Diagnosis." Journal of Applied Meteorology and Climatology 58, no. 4 (April 2019): 741–55. http://dx.doi.org/10.1175/jamc-d-18-0153.1.
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AbstractThe Pearl River delta (PRD) region has experienced rapid economic development since the 1980s and has become one of the world’s largest industrial zones and metropolitan areas. Previous studies have shown that the sea-breeze circulation can contribute to pollutant transportation and convective initiation, so it is useful to study the dynamic structure of the sea-breeze circulation in the PRD region. Many researchers have focused on the effects of environmental factors, such as topography, urbanization, and background wind, on the sea breeze, but most focused only on case studies and did not quantify the characteristics of the sea-breeze circulation climatologically. In this study, a sea-breeze identification metric was defined to identify sea-breeze events from WRF simulation data of 2012 and quantify their characteristics, including their start time, end time, strength, height, frequency, pumping ability, and inland-penetrating distance. The results indicate that this method works well to identify and quantify the sea-breeze events of 2012. It is found that the solenoid term, the largest positive contributor to vorticity acceleration, is mostly modulated by the temperature gradient. Therefore, the frontogenesis of the sea-breeze front is discussed in this study. The result shows that offshore background wind that increases frontogenesis is favorable to the development of the sea breeze, but it also prevents it from propagating vertically and horizontally.
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Hamasaki, Koji, Akito Taniguchi, Yuya Tada, Richard A. Long, and Farooq Azam. "Actively Growing Bacteria in the Inland Sea of Japan, Identified by Combined Bromodeoxyuridine Immunocapture and Denaturing Gradient Gel Electrophoresis." Applied and Environmental Microbiology 73, no. 9 (March 2, 2007): 2787–98. http://dx.doi.org/10.1128/aem.02111-06.
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ABSTRACT A fundamental question in microbial oceanography concerns the relationship between prokaryote diversity and biogeochemical function in an ecosystem context. We combined bromodeoxyuridine (BrdU) magnetic bead immunocapture and PCR-denaturing gradient gel electrophoresis (BUMP-DGGE) to examine phylotype-specific growth in natural marine assemblages. We also examined a broad range of marine bacterial isolates to determine their abilities to incorporate BrdU in order to test the validity of the method for application to diverse marine assemblages. We found that 27 of 29 isolates belonging to different taxa could incorporate BrdU. BUMP-DGGE analysis revealed phylogenetic affiliations of DNA-synthesizing, presumably actively growing bacteria across a eutrophic to mesotrophic transect in the Inland Sea of Japan. We found that the BrdU-incorporating (growing) communities were substantially different from the total communities. The majority (34/56) of phylotypes incorporated BrdU and were presumably growing, and these phylotypes comprised 10 alphaproteobacteria, 1 betaproteobacterium, 11 gammaproteobacteria, 11 Cytophaga-Flavobacterium-Bacteroides group bacteria, and 1 unclassified bacterium. All BrdU-responsive alphaproteobacteria were members of the Rhodobacterales, suggesting that such bacteria were dominant in the growing alphaproteobacterial populations in our samples. The BrdU-responsive gammaproteobacteria belonged to the Oceanospirillales, the SAR86 cluster, the Pseudomonadales, the Alteromonadales, and the Vibrionales. Thus, contemporaneous cooccurrence of diverse actively growing bacterial taxa was a consistent pattern in our biogeochemically varied study area.
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Koyama, Asuka, and Tatsuya Ide. "Coastal habitats across sea-to-inland gradient sustain endangered coastal plants and Hymenoptera in coastal dune ecosystems of Japan." Biodiversity and Conservation 29, no. 14 (October 15, 2020): 4073–90. http://dx.doi.org/10.1007/s10531-020-02065-8.
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Burn, C. R. "Cryostratigraphy, paleogeography, and climate change during the early Holocene warm interval, western Arctic coast, Canada." Canadian Journal of Earth Sciences 34, no. 7 (July 1, 1997): 912–25. http://dx.doi.org/10.1139/e17-076.
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Botanical and cryostratigraphic records from northwest Canada indicate that the climate of the early Holocene was considerably warmer than today: tree line was over 100 km farther north; and a thaw unconformity, dating from 8000 14C years BP, formed at the base of an active layer 2.5 times thicker than at present. Numerous thermokarst-lake basins formed in the preceding millennia. Both the botanical and cryostratigraphic indices described are products of summer conditions. Previous reconstructions of early Holocene climate have not assessed the significance of paleocoastal location on the seasonality and extent of apparent climate warming. At present, there is a steep gradient in growing-season conditions between cooler sites on the Beaufort Sea coast and warmer, inland locations. Winter conditions are more uniform because both sea and land are snow-covered. Coastal retreat in the region has been rapid, due to sea level rising over a gently sloping shelf containing readily erodible sediments. The coastline has moved about 100 km southward during the Holocene. The increasing proximity to the coast, through time, of points currently within 100 km of the sea may account for between one and two thirds of the cooling in summer climate experienced there since the mid-Holocene.
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Comarazamy, Daniel E., Jorge E. González, Jeffrey C. Luvall, Douglas L. Rickman, and Robert D. Bornstein. "Climate Impacts of Land-Cover and Land-Use Changes in Tropical Islands under Conditions of Global Climate Change." Journal of Climate 26, no. 5 (February 27, 2013): 1535–50. http://dx.doi.org/10.1175/jcli-d-12-00087.1.
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Abstract Land-cover and land-use (LCLU) changes have significant climate impacts in tropical coastal regions with the added complexity of occurring within the context of a warming climate. The individual and combined effects of these two factors in tropical islands are investigated by use of an integrated mesoscale atmospheric modeling approach, taking the northeastern region of Puerto Rico as the test case. To achieve this goal, an ensemble of climate simulations is performed, combining two LCLU and global warming scenarios. Reconstructed agricultural maps and sea surface temperatures form the past (1955–59) scenario, while the present (2000–04) scenario is supported with high-resolution remote sensing LCLU data. Here, the authors show that LCLU changes produced the largest near-surface (2-m AGL) air temperature differences over heavily urbanized regions and that these changes do not penetrate the boundary layer. The influence of the global warming signal induces a positive inland gradient of maximum temperature, possibly because of increased trade winds in the present climatology. These increased winds also generate convergence zones and convection that transport heat and moisture into the boundary layer. In terms of minimum temperatures, the global warming signal induces temperature increases along the coastal plains and inland lowlands.
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Wong, Martin L. M., and Johnny C. L. Chan. "Modeling the Effects of Land–Sea Roughness Contrast on Tropical Cyclone Winds." Journal of the Atmospheric Sciences 64, no. 9 (September 1, 2007): 3249–64. http://dx.doi.org/10.1175/jas4027.1.
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Abstract The fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) is used to simulate tropical cyclone (TC) wind distribution near landfall. On an f plane at 15°N, the effects of the different surface roughness between the land and sea on the wind asymmetry is examined under a strong constraint of a dry atmosphere and time-invariant axisymmetric mass fields. The winds are found to adjust toward a steady state for prelandfall (50, 100, and 150 km offshore), landfall, and postlandfall (50, 100, and 150 km inland) TC positions. The TC core is asymmetric even when it lies completely offshore or inland. The surface (10 m) wind asymmetry at the core for pre- (post) landfall position is apparently related to the acceleration (deceleration) of the flow that has just moved over the sea (land) as a response to the sudden change of surface friction. For prelandfall TC positions, the resulted strong surface inflow to the left and front left (relative to the direction pointing from sea to land) also induces a tangential (or total) wind maxima at a smaller radius, about 90° downstream of the maximum inflow, consistent with the absolute angular momentum advection (or work done by pressure). The surface maximum wind is of similar magnitude as the gradient wind. There is also a small region of weak outflow just inside the wind maxima. For postlandfall TC positions, inflow is weakened to the right and rear right associated with the onshore flow. Both onshore and offshore flows affect the surface wind asymmetry of the core in the landfall case. Above the surface and near the top of the planetary boundary layer (PBL), the wind is also asymmetric and a strongly supergradient tangential wind is primarily maintained by vertical advection of the radial wind. Much of the steady-state vertical structure of the asymmetric wind is similar to that forced by the motion-induced frictional asymmetry, as found in previous studies. The associated asymmetry of surface and PBL convergences has radial dependence. For example, the landfall case has stronger PBL convergence to the left for the 0–50-km core region, due to the radial inflow, but to the right for the 100–500-km outer region, due to the tangential wind convergence along the coastline. The strong constraint is then removed by considering an experiment that includes moisture, cumulus heating, and the free adjustments of mass fields. The TC is weakening and the sea level pressure has a slightly wavenumber-1 feature with larger gradient wind to the right than to the left, consistent with the drift toward the land. The asymmetric features of the wind are found to be very similar to those in the conceptual experiments.
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Kokhia, Mzia S., and Sergei I. Golovatch. "A checklist of the millipedes of Georgia, Caucasus (Diplopoda)." ZooKeys 741 (March 7, 2018): 35–48. http://dx.doi.org/10.3897/zookeys.741.20042.
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The diplopod fauna of Georgia, Transcaucasia, is very rich given the country’s relatively small territory, presently comprising 95 species from 42 genera, 12 families, and seven orders. Most of the Diplopoda known from Georgia are subendemics (39 species, or 38%), shared with one or more neighbouring countries, but another 33 species (33%) are strict endemics, nearly all highly localized, including 12 presumed troglobites. Several genera are likewise endemic to Georgia, including a few troglobionts. Within Georgia, the fauna of the western part (= Colchis) is particularly rich and diverse, the faunas of the central and eastern parts of the country growing increasingly depauperate inland and apparently following a rather gradual climatic aridisation gradient from west (the Black Sea coast) to east (Armenia and Azerbaijan). Much more work to include alpine and cave environments is required in order to reveal and refine the real diversity of Georgia’s Diplopoda.
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Rios-López, Neftalí. "Effects of increased salinity on tadpoles of two anurans from a Caribbean coastal wetland in relation to their natural abundance." Amphibia-Reptilia 29, no. 1 (2008): 7–18. http://dx.doi.org/10.1163/156853808783431451.
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Abstract Many amphibians depend on wetland ecosystems for reproduction and survival, and coastal wetlands are not the exception. Recent advances on climate change research predict a reduction in land cover of coastal wetlands due to sea-level rise in response to global warming. Although this scenario will contribute to further amphibian population declines worldwide the impacts of sea-level rise and its related salt water intrusion on anuran assemblages in coastal wetlands remain largely unknown. I documented patterns of abundance of the native Caribbean white-lipped frog (Leptodactylus albilabris) and the introduced marine toad (Bufo marinus) along an inland-to-coastal salinity gradient in Puerto Rico. In addition, I investigated the effects of increasing salinity on larval growth and survival to metamorphosis in L. albilabris and B. marinus in laboratory experiments. In the field, relative abundance of adults of L. albilabris decreased with increasing salinity, while B. marinus showed the opposite pattern. Laboratory experiments with L. albilabris and B. marinus revealed that percentage of larvae surviving to metamorphosis in both species was greatly reduced in 22-25% seawater (8 ppt), which is within salinity levels found in their natural distribution. In this salinity level, the native L. albilabris showed ∼100% metamorphosis failure while the introduced B. marinus showed ∼60% metamorphosis failure. The reduction in metamorphosis was due to high mortality in L. albilabris and was accompanied with morphological abnormalities in B. marinus. Tadpoles of only L. albilabris reared for four weeks showed significant weight loss at 8 ppt, but showed no difference in length. These results suggest that anuran tadpoles may be living near their physiological limit for salinity in the studied wetland. Conservation implications are profound, however, as salt water intrusion and urban encroaching inland may result in anuran population replacement, from native species to introduced species in this wetland.
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González, Eva, Nico Deus, Jörg Elbracht, M. Azizur Rahman, and Helga Wiederhold. "Current and future state of groundwater salinization of the northern Elbe-Weser region." Grundwasser 26, no. 4 (November 11, 2021): 343–56. http://dx.doi.org/10.1007/s00767-021-00496-w.
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AbstractSalinization of the upper aquifer of the northern Elbe-Weser region almost extends to the surface. Chloride content exceeds 250 mg/l and the groundwater is therefore, according to the German Drinking Water Ordinance, not suitable as drinking water. The chloride content in the aquifer originates from early flooding with seawater which occurred during the Holocene sea level rise. Depth and extent of the salinization were mapped by airborne electromagnetic surveys and validated by groundwater analyses. In the transition zone between the marshlands and geest areas, the fresh-saline groundwater interface falls to a depth of > −175 m NHN. Due to the extensive drainage of the marshlands, seepage of fresh groundwater is impeded. Instead, an upconing of the fresh-saline groundwater interface appears due to an upwardly directed hydraulic gradient. Due to climate change, chloride concentrations will increase along the coastlines. Further inland, a decrease of chloride content in near-surface groundwater will occur.
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Rada, F., G. Goldstein, A. Orozco, M. Montilla, O. Zabala, and A. Azocar. "Osmotic and Turgor Relations of Three Mangrove Ecosystem Species." Functional Plant Biology 16, no. 6 (1989): 477. http://dx.doi.org/10.1071/pp9890477.
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The water relations of three mangrove ecosystem species, Rhizophora mangle, Conocarpus erectus and Coccoloba uvifera were investigated in an intertidal zone of the Venezuelan coast. The influence of a salinity gradient (from seashore to inland) and seasonal fluctuations in salinity were studied. Daily courses of leaf water and osmotic potentials and other water relations characteristics were estimated from pressure-volume curves. All species exhibited a decrease in osmotic potential of leaf tissues during the dry season when salinity levels increased in ground water. This osmotic adjustment was due to changes in either the symplasmic water fraction, the osmotically active solutes in leaf cells, or both. Changes in cell wall elasticity were also observed. The cell walls were more rigid during the dry season in all three species. Rhizophora mangle, the species that grows closest to the sea, had much more rigid cell walls than the other two species. The adaptive significance of these mechanisms for turgor maintenance and water uptake in mangrove habitats is discussed.
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Wang, Jun-Jian, Yi Jiao, Robert C. Rhew, and Alex T. Chow. "Haloform formation in coastal wetlands along a salinity gradient at South Carolina, United States." Environmental Chemistry 13, no. 4 (2016): 745. http://dx.doi.org/10.1071/en15145.
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Environmental contextNatural haloform emissions contribute to stratospheric ozone depletion but there are major unknown or underestimated sources of these gases. This study demonstrates that soil and water at tidal wetlands are important haloform sources, and emissions peak at the forest–marsh transition zone. The low-lying forested wetlands of the south-eastern United States that are facing sea-level rise and seawater intrusion may become hotspots for haloform emission. AbstractSoil haloform emissions are sources of reactive halogens that catalytically deplete ozone in the stratosphere but there are still unknown or underestimated haloform sources. The >200000ha of low-lying tidal freshwater swamps (forests and marshes) in the south-eastern United States could be haloform (CHX3, X=Cl or Br) sources because sea-level rise and saltwater intrusion bring halides inland where they mix with terrestrial humic substances. To evaluate the spatial variation along the common forest–marsh salinity gradient (freshwater wetland, oligohaline wetland and mesohaline saltmarsh), we measured chloroform emissions from in situ chambers and from laboratory incubations of soil and water samples collected from Winyah Bay, South Carolina. The in situ and soil-core haloform emissions were both highest in the oligohaline wetland, whereas the aqueous production was highest in mesohaline saltmarsh. The predominant source shifted from sediment emission to water emission from freshwater wetland to mesohaline saltmarsh. Spreading out soil samples increased soil haloform emission, suggesting that soil pores can trap high amounts of CHCl3. Soil sterilisation did not suppress CHCl3 emission, indicating the important contribution of abiotic soil CHCl3 formation. Surface wetland water samples from eight locations along a salinity gradient with different management practices (natural v. managed) were subjected to radical-based halogenation by Fenton-like reagents. Halide availability, organic matter source, temperature and light irradiation were all found to affect the radical-based abiotic haloform formation from surface water. This study clearly indicates that soil and water from the studied coastal wetlands are both haloform sources, which however appear to have different formation mechanisms.
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Medeiros, Luiz Eduardo, Gilberto Fisch, Paulo Iriart, Felipe Denardin Costa, Dionnathan Willian Oliveira, and Daniel Schuch. "PADRÕES DE VENTO A NÍVEL DE SUPERFÍCIE PARA REGIÃO DA COSTA NORTE DO BRASIL." Ciência e Natura 38 (July 20, 2016): 383. http://dx.doi.org/10.5902/2179460x21574.
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The atmospheric flow near the surface and in the planetary boundary layer (PBL) are investigated for the coastal part of Maranhão state. Near the coast in the PBL the flow is predominantly from the northeast quadrant with its meridional component increasing during the day and being from north-northeast and decreasing during the course of the night to be from east-northeast at early morning. The result of this is a small counterclockwise rotation but with no flow reversals. Through an analysis of extensive radiosonde data it is found that the flow above the PBL is predominantly southeasterly for the region. It is consequence of the outflow from the descending branch of the large-scale circulation of the Hadley cell. For stations further inland the flow is from approximately northeast during period between morning to noon but rotating clockwise to become from southeast-east (SEE) sector at early evening. The clockwise rotation continues in the afternoon and the wind becomes from south, and later southwest when in the evening it quickly becomes from north. The wind rotation during this period is mainly determined by an oscillating surface pressure gradient-force. During the night the local surface wind tendency is not controlled by the gradient-force probably because the air has to go against higher terrain and negative buoyancy becomes an important force of the momentum balance. The oscillating surface pressure-gradient-force is a response to a sea-breeze circulation. In the coast, we speculate that the flow does not reverse its meridional component because the surface pressure-gradient point south there for most of the time.
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Liu, Xiaoming, and Menghua Wang. "Deriving VIIRS High-Spatial Resolution Water Property Data over Coastal and Inland Waters Using Deep Convolutional Neural Network." Remote Sensing 13, no. 10 (May 17, 2021): 1944. http://dx.doi.org/10.3390/rs13101944.
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The Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-orbiting Partnership (SNPP) satellite has been a reliable source of ocean color data products, including five moderate (M) bands and one imagery (I) band normalized water-leaving radiance spectra nLw(λ). The spatial resolutions of the M-band and I-band nLw(λ) are 750 m and 375 m, respectively. With the technique of convolutional neural network (CNN), the M-band nLw(λ) imagery can be super-resolved from 750 m to 375 m spatial resolution by leveraging the high spatial resolution features of I1-band nLw(λ) data. However, it is also important to enhance the spatial resolution of VIIRS-derived chlorophyll-a (Chl-a) concentration and the water diffuse attenuation coefficient at the wavelength of 490 nm (Kd(490)), as well as other biological and biogeochemical products. In this study, we describe our effort to derive high-resolution Kd(490) and Chl-a data based on super-resolved nLw(λ) images at the VIIRS five M-bands. To improve the network performance over extremely turbid coastal oceans and inland waters, the networks are retrained with a training dataset including ocean color data from the Bohai Sea, Baltic Sea, and La Plata River Estuary, covering water types from clear open oceans to moderately turbid and highly turbid waters. The evaluation results show that the super-resolved Kd(490) image is much sharper than the original one, and has more detailed fine spatial structures. A similar enhancement of finer structures is also found in the super-resolved Chl-a images. Chl-a filaments are much sharper and thinner in the super-resolved image, and some of the very fine spatial features that are not shown in the original images appear in the super-resolved Chl-a imageries. The networks are also applied to four other coastal and inland water regions. The results show that super-resolution occurs mainly on pixels of Chl-a and Kd(490) features, especially on the feature edges and locations with a large spatial gradient. The biases between the original M-band images and super-resolved high-resolution images are small for both Chl-a and Kd(490) in moderately to extremely turbid coastal oceans and inland waters, indicating that the super-resolution process does not change the mean values of the original images.
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Sun, Youn-Jong, and Atsuhiko Isobe. "Lagrangian H/U3 Values Computed around Fronts Using a Fine-Resolution Numerical Model and Ferryboat-Monitored SST Dataset." Journal of Physical Oceanography 38, no. 11 (November 1, 2008): 2575–86. http://dx.doi.org/10.1175/2008jpo3839.1.
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Abstract Front locations are identified as the local maximum of the sea surface temperature gradient revealed in the continuously ferryboat-monitored data in the Seto Inland Sea, Japan. In addition, Simpson and Hunter’s H/U3 values, where H is the water depth and U is the tidal-current amplitude, are computed at each cell using a fine-resolution, finite-volume ocean model to find the values at the fronts (i.e., Eulerian critical H/U3 values). Moreover, Lagrangian critical H/U3 values are computed using the same model in conjunction with particle-tracking experiments in which the particle’s H/U3 values saved along their trajectories are all averaged at each cell. In comparison with the Eulerian H/U3 values, it is revealed that the standard deviation of the Lagrangian critical values considerably reduces, especially for the fronts near straits. This accurate estimate of the critical H/U3 values shows that critical values depend on the tidal-current amplitude at the front locations. The dependency of critical H/U3 values on the tidal-current amplitude is likely due to dependency of the efficiency factor for vertical mixing in the original Simpson and Hunter formula on the amplitude. It is suggested that the efficiency factor for vertical mixing must be small (large) at locations with the large (small) tidal-current amplitude.
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Job, Thomas, Dan Penny, Bree Morgan, Quan Hua, Patricia Gadd, and Atun Zawadzki. "Multi-stage Holocene evolution of the River Murray Estuary, South Australia." Holocene 31, no. 1 (October 8, 2020): 50–65. http://dx.doi.org/10.1177/0959683620961487.
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The River Murray Estuary, South Australia exhibits a morphology typical of a wave-dominated estuary and comprises two large, shallow central basin lakes – Lakes Alexandrina and Albert. Contested interpretations of the estuary’s limnological history and uncertainty surrounding the sustainability of current basin water usage practice warrant a robust investigation into how the system has evolved. Here we combine lithostratigraphic, geochemical and sedimentological evidence from a transect of sediment cores to reconstruct the sediment infill history of the system. We uncover multiple stages of sediment infill over the history of the system, associated with (1) the low gradient morphology of the estuary and lower river channel, (2) the mid- to late-Holocene sea-level regression and (3) anthropogenic modifications to the fluvio-estuarine system. We show that while estuarine conditions in the system were fully established during the mid-Holocene highstand (~6.4 kyr BP), central basin facies sedimentation was focussed further inland before prograding with the lowering of base level and shifting of tidal influence as sea-level fell. Central basin facies sedimentation within northern Lake Albert occurred from 5.4 to 4.0 cal kyr BP at ~0.25 cm yr-1. The uppermost accumulation of this unit was eroded by continued reduction in base level until sea-level regression concluded at 3.5 cal kyr BP. Barrage and weir installation (1940 CE) re-initiated and expanded central basin facies sedimentation in the estuary (~0.32 cm yr-1). Recently deposited sediments exhibit geochemical markers of increased trophy and more frequent acid sulfate soil acidification, exposing human impacts on the estuary.
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Chen, Pan, Yan Zhang, Xiaojing Zhu, and Changhu Lu. "Distribution of crabs along a habitat gradient on the Yellow Sea coast after Spartina alterniflora invasion." PeerJ 7 (April 16, 2019): e6775. http://dx.doi.org/10.7717/peerj.6775.
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The effects of Spartina alterniflora invasion on macrobenthos have long been of concern; however, there is currently no unified conclusion regarding these effects. Most studies on crabs focus on one species or limited habitat types, and assessments of the community-level effects of S. alterniflora invasion considering multiple species and habitat types have rarely been conducted. In this study, we sampled crabs along a habitat gradient from the shoreline to inland areas on the Yellow Sea coast, including the mudflat, S. alterniflora marsh, Suaeda salsa marsh and Phragmites australis marsh. A total of 10 crab species were found among all habitats, with five species in the mudflat, six species in S. alterniflora marsh, seven species in S. salsa marsh and four species in P. australis marsh. The Shannon index values for the crab communities were similar between S. alterniflora marsh and S. salsa marsh, and these values were significantly higher than those for the mudflat and P. australis marsh. However, the total biomass of crabs was highest in the mudflat, and Metaplax longipes, Philyra pisum and Macrophthalmus dilatatus exclusively preferred the mudflat. The analysis of principal components and similarities showed that the crab community structure in S. alterniflora marsh was most similar to that in S. salsa marsh, while the crab community structure in the mudflat was most different from that in the other habitat types. Our results demonstrate that the distribution of crabs varies across a habitat gradient after S. alterniflora invasion and that the crab community in S. alterniflora marsh is slightly different from that associated with the local vegetation but shows a large difference from that in the mudflat. This study indicates that some crab species may have adapted to habitat containing alien S. alterniflora, while other crab species reject this new marsh type. The effects of the distribution of crabs after S. alterniflora invasion on the regional ecosystem need further study in the future.
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Becagli, Silvia, Marco Proposito, Silvia Benassai, Roberto Gragnani, Olivier Magand, Rita Traversi, and Roberto Udisti. "Spatial distribution of biogenic sulphur compounds (MSA, nssSO42–) in the northern Victoria Land–Dome C–Wilkes Land area, East Antarctica." Annals of Glaciology 41 (2005): 23–31. http://dx.doi.org/10.3189/172756405781813384.
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AbstractDuring the 1992–2002 Antarctic expeditions, in the framework of the International Trans-Antarctic Expedition (ITASE) project, about 600 sites were sampled (superficial snow, snow pits and firn cores) along traverses in the northern Victoria Land–Dome C–Wilkes Land region. The sites were characterized by different geographical (distance from the sea, altitude) and climatological (annual mean accumulation rate, temperature) conditions and were affected by air masses from different marine sectors (Ross Sea, Pacific Ocean). Mean anion and cation contents were calculated at each site, in order to evaluate the spatial distribution of chemical impurities in snow. Here we discuss the distribution of non-sea-salt sulphate (nssSO42–) and of methanesulphonic acid (MSA) mainly originating from atmospheric oxidation of biogenic dimethyl sulphide; these compounds play a key role in climate control processes by acting as cloud condensation nuclei. The spatial distribution of nssSO42– and MSA is discussed as a function of distance from the sea, altitude and accumulation rate. Depositional fluxes of nssSO42– and MSA decrease as a function of distance from the sea, with a higher gradient in the first 200km step. There is an analogous trend with the site altitude, and the first 1600m step is relevant in determining the nssSO42– and MSA content in snow. The nssSO42–/MSA ratio depends on the distance from the sea and the biogenic source strength. At coastal sites, where biogenic inputs are dominant, this ratio is ~2. As biogenic input decreases (low MSA content) inland, the ratio increases, indicating the presence of alternative sources of nssSO42– (crustal, volcanic background) or advection of low-latitude air masses. By plotting total flux as a function of accumulation rate, dry depositional contributions were evaluated for nssSO42– and MSA in the Ross Sea and Pacific Ocean sectors. Non-sea-salt sulphate wet deposition prevails at sites where the accumulation rate (expressed as water equivalent) is higher than 70 kgm–2 a–1 (Ross Sea sector) or 370 kgm–2 a–1 (Pacific Ocean sector). MSA threshold values in these sectors are respectively 90 and 220 kgm–2 a–1.
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Kante, Ibrahima Kalil, Daouda Badiane, Saïdou Moustapha Sall, Abdoulaye Deme, and Arona Diedhiou. "Comparative Study of the West African Continental, Coastal, and Marine Atmospheric Profiles during the Summer of 2006." International Journal of Geophysics 2012 (2012): 1–14. http://dx.doi.org/10.1155/2012/603949.
Повний текст джерелаАнотація:
We used sounding data of the Multidisciplinary Analysis of the African Monsoon experience in summer 2006 at continental and coastal sites of West Africa, respectively, to analyze the vertical profiles of relative humidity, temperature, dew point, and speed and wind direction for the JJAS rainy period. The vertical gradient method is applied to the profiles of some thermodynamic parameters estimated from sounding data to do a comparative study of the structure and thermal properties, moisture, and static stability of the atmospheric boundary layer of inland, coastal, and marine sites to show consistent differences related to geographic factors. In vertical profiles of relative humidity, the intensity is higher in Dakar than in Niamey particularly in the core of the season. There are dry intrusions in the low levels at the beginning and end of the season in Dakar, which do not exist in Niamey. The mixing layer on the continent during the day can reach a height greater than 1100 m, and the inversion layer height can exceed 1700 m. Therefore, the maximum thickness of the boundary layer is observed on the continent during the day, while at night the marine boundary layer is the thickest. The diurnal evolution shows that the mixing layer thickness decreases during the night over the continent but increases at the coast and at sea. In the night at the continental site there is a division of the mixing layer with a consistent residual mixing layer. Continental boundary layer is more unstable during the day, while at night it is the marine boundary layer that is more unstable than the coastal and inland ones.
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Du, Yu, and Guixing Chen. "Heavy Rainfall Associated with Double Low-Level Jets over Southern China. Part I: Ensemble-Based Analysis." Monthly Weather Review 146, no. 11 (October 30, 2018): 3827–44. http://dx.doi.org/10.1175/mwr-d-18-0101.1.
Повний текст джерелаАнотація:
Abstract Heavy rainfall occurred at both the inland frontal zone and coastal warm sector in southern China during 10–11 May 2014, which is a typical pattern in the early-summer rainy season. To clarify the key factors controlling the rainfall, we conduct an ensemble-based analysis using the operational global ensemble forecasts from ECMWF. The forecasts of frontal (warm sector) rainfall have a relatively small (large) spread and a small (large) bias of ensemble-mean amount, suggesting an obvious difference in the predictability. It is shown that double low-level jets (LLJs) in the southwesterly moist flow play a significant role in the heavy rainfall over southern China. The inland frontal rainband is closely related to the synoptic-system-related low-level jet (SLLJ) with maximum wind speed at 850–700 hPa, especially for its meridional wind component. The more intense cold front is accompanied by the stronger southwesterly SLLJ on the adjacent south side, favoring more precipitation near the front. The warm-sector heavy rainfall, a few hundred kilometers away from the front, is associated with the boundary layer jet (BLJ) at 925 hPa. The southerly BLJ occurs over the northern region of the South China Sea and reaches its maximum wind speed in the early morning. The variations of the BLJ are mainly induced by the surface low and related upper-level short-wave trough upstream. The large pressure gradient to the southeast of the surface low can accelerate the BLJ by increasing the geostrophic winds. The diurnal cycle of the low-level winds, seen in the climatology, also contributes in part to the development of the BLJ at night.
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Stešević, Danijela, Nada Bubanja, Danka Caković, Nejc Jogan, Milica Luković, and Urban Šilc. "Synecology of Cutandia maritima (L.) Barbey, a rare psammophytic species along the Montenegrin Coast (East Adriatic Coast)." Hacquetia 16, no. 2 (December 20, 2017): 181–87. http://dx.doi.org/10.1515/hacq-2017-0002.
Повний текст джерелаАнотація:
AbstractCutandia maritima is a circum-Mediterranean species that inhabits sandy dunes along the coast line. It is fairly frequent on the western Adriatic coast but fairly rare and possibly even non-native in the east. In Croatia, it was discovered in 1990 in Crnika Bay on the island of Rab, which was considered until 2005 to be the only site on the eastern Adriatic coast from the Gulf of Trieste in the north to Corfu in the south. In 2009, the species was briefly reported for Velika plaža (Long Beach) in Ulcinj (Montenegro) but without details about the habitat type and synecology. The aim of this paper is thus to provide a deeper insight into the ecology and synecology of C. maritima in the eastern Adriatic part of the distribution area. On Velika plaža in Ulcinj, the species was found along the whole sea-inland gradient of sand dunes, in various types of vegetation: [1210] - annual vegetation of drift lines, [2110] - embryonic shifting dunes, [2120] - shifting dunes with Ammophila arenaria (white dunes), [2220] - dunes with Euphorbia terracina, [2130*] - fixed coastal dunes with herbaceous vegetation (grey dunes), and also [2190] - humid dune slacks.
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Wang, Yifeng, Robert G. Way, Jordan Beer, Anika Forget, Rosamond Tutton, and Meredith C. Purcell. "Significant underestimation of peatland permafrost along the Labrador Sea coastline in northern Canada." Cryosphere 17, no. 1 (January 10, 2023): 63–78. http://dx.doi.org/10.5194/tc-17-63-2023.
Повний текст джерелаАнотація:
Abstract. Northern peatlands cover approximately four million km2, and about half of these peatlands are estimated to contain permafrost and periglacial landforms, like palsas and peat plateaus. In northeastern Canada, peatland permafrost is predicted to be concentrated in the western interior of Labrador but is assumed to be largely absent along the Labrador Sea coastline. However, the paucity of observations of peatland permafrost in the interior, coupled with traditional and ongoing use of perennially frozen peatlands along the coast by Labrador Inuit and Innu, suggests a need for re-evaluation of the reliability of existing peatland permafrost distribution estimates for the region. In this study, we develop a multi-stage consensus-based point inventory of peatland permafrost complexes in coastal Labrador and adjacent parts of Quebec using high-resolution satellite imagery, and we validate it with extensive field visits and low-altitude aerial photography and videography. A subset of 2092 wetland complexes that potentially contained peatland permafrost were inventoried, of which 1119 were classified as likely containing peatland permafrost. Likely peatland permafrost complexes were mostly found in lowlands within 22 km of the coastline, where mean annual air temperatures often exceed +1 ∘C. A clear gradient in peatland permafrost distribution exists from the outer coasts, where peatland permafrost is more abundant, to inland peatlands, where permafrost is generally absent. This coastal gradient may be attributed to a combination of climatic and geomorphological influences which lead to lower insolation, thinner snowpacks, and poorly drained, frost-susceptible materials along the coast. The results of this study suggest that existing estimates of permafrost distribution for southeastern Labrador require adjustments to better reflect the abundance of peatland permafrost complexes to the south of the regional sporadic discontinuous permafrost limit. This study constitutes the first dedicated peatland permafrost inventory for Labrador and provides an important baseline for future mapping, modelling, and climate change adaptation strategy development in the region.
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Deetz, Konrad, Heike Vogel, Peter Knippertz, Bianca Adler, Jonathan Taylor, Hugh Coe, Keith Bower, et al. "Numerical simulations of aerosol radiative effects and their impact on clouds and atmospheric dynamics over southern West Africa." Atmospheric Chemistry and Physics 18, no. 13 (July 11, 2018): 9767–88. http://dx.doi.org/10.5194/acp-18-9767-2018.
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Abstract. Southern West Africa (SWA) is undergoing rapid and significant socioeconomic changes associated with a massive increase in air pollution. Still, the impact of atmospheric pollutants, in particular that of aerosol particles, on weather and climate in this region is virtually unexplored. In this study, the regional-scale model framework COSMO-ART is applied to SWA for a summer monsoon process study on 2–3 July 2016 to assess the aerosol direct and indirect effect on clouds and atmospheric dynamics. The modeling study is supported by observational data obtained during the extensive field campaign of the project DACCIWA (Dynamics–Aerosol–Chemistry–Cloud Interactions in West Africa) in June–July 2016. As indicated in previous studies, a coastal front is observed that develops during daytime and propagates inland in the evening (Atlantic inflow). Increasing the aerosol amount in COSMO-ART leads to reduced propagation velocities with frontal displacements of 10–30 km and a weakening of the nocturnal low-level jet. This is related to a subtle balance of processes related to the decrease in near-surface heating: (1) flow deceleration due to reduced land–sea temperature contrast and thus local pressure gradient, (2) reduced turbulence favoring frontal advance inland and (3) delayed stratus-to-cumulus transition of 1–2 h via a later onset of the convective boundary layer. The spatial shift of the Atlantic inflow and the temporal shift of the stratus-to-cumulus transition are synergized in a new conceptual model. We hypothesize a negative feedback of the stratus-to-cumulus transition on the Atlantic inflow with increased aerosol. The results exhibit radiation as the key player governing the aerosol affects on SWA atmospheric dynamics via the aerosol direct effect and the Twomey effect, whereas impacts on precipitation are small.
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Oda, Ryoko, and Manabu Kanda. "Observed Sea Surface Temperature of Tokyo Bay and Its Impact on Urban Air Temperature." Journal of Applied Meteorology and Climatology 48, no. 10 (October 1, 2009): 2054–68. http://dx.doi.org/10.1175/2009jamc2163.1.
Повний текст джерелаАнотація:
Abstract Sea surface temperature (SST) and air temperature were measured in situ in Tokyo Bay. These measurements were made with high spatial and temporal resolutions between November 2006 and September 2007. The analysis of these data revealed 1) the seasonal and diurnal variations of SST and air temperature, and 2) the physical process by which Tokyo Bay lowers urban air temperature in summer. The following were the major findings obtained: 1) the diurnal amplitude of SST was as large as 5.5°C; 2) abrupt increases of SST occurred at the head and mouth of the bay that were due to heated water discharge and the Kuroshio, respectively; 3) the values of the satellite-based objectively analyzed SSTs were higher than those of the in situ SSTs, especially in winter; 4) the relationship between SST and air temperature was classified into three seasonal modes—winter, transient, and summer—and each mode was associated with the seasonal stability condition of the near-surface water; 5) the strong southwesterly wind over the bay in summer decreased the SST mainly because of increased turbulent mixing at the water surface, thereby increasing downward sensible heat flux up to −100 W m−2; 6) the lower SSTs in summer lowered the air temperature, but only for the urban atmosphere near the coast, and no effect was detected at 20 km inland; and 7) the horizontal gradient of air temperature over the land intensified with increasing wind speed.
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Hill, Philip R. "Late Quaternary sequence stratigraphy of the Mackenzie Delta." Canadian Journal of Earth Sciences 33, no. 7 (July 1, 1996): 1053–74. http://dx.doi.org/10.1139/e96-081.
Повний текст джерелаАнотація:
The Late Wisconsinan and Holocene sequence stratigraphy of the Mackenzie Delta provides insights into the glacial history of the region. The base of the described succession is a hummocky regional reflector interpreted to be a flooding surface formed immediately after retreat of glacial ice from the Mackenzie Trough. Above this flooding surface, two progradational parasequences are present. The first, assigned to the transgressive systems tract, is correlated with the Tutsieta Lake readvance of the ice sheet at approximately 13 000 BP. A flooding surface forming the upper boundary of this parasequence extends inland to at least Inuvik, developing as a response to glacial retreat and early Holocene relative sea level rise. The second parasequence of Holocene deltaic deposits is assigned to the highstand systems tract and is characterized by progressive progradation of the delta into the Mackenzie Trough to a position seaward of the present delta coastline. A distinct reduction in gradient of the most recent delta clinoforms is consistent with other data suggesting regional transgression and is interpreted to represent the development of a healing-phase wedge. The reasons for this recent transgression are not clear, because relative sea level rise has decreased and sediment supply probably increased over the last 2000 years. Transgression may be related to decreased efficiency of channels, increased trapping of sediments by thermokarst lakes, overspill of the delta across the eastern margin of the valley, and (or) progressively greater exposure to wave action as the delta became less sheltered by the confines of the glacial valley.
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Weinmann, Anna E., and Susan T. Goldstein. "Landward-directed Dispersal of Benthic Foraminiferal Propagules At Two Shallow-water Sites in the Doboy Sound Area (Georgia, U.S.A.)." Journal of Foraminiferal Research 47, no. 4 (October 1, 2017): 325–36. http://dx.doi.org/10.2113/gsjfr.47.4.325.
Повний текст джерелаАнотація:
Abstract Transport of foraminiferal propagules is an important mode of dispersal in benthic foraminifera. Known to occur from tidal marshes and estuaries to deep-water environments, the former are particularly vulnerable to ongoing climate change. Because rising sea levels can have profound implications on local salinity and associated faunal compositions, transport of foraminiferal propagules within these environments can be crucial for local assemblages to respond to changing conditions. Here we focus on a shallow-water environment in southeastern Georgia to evaluate whether propagule transport occurs evenly or whether it shows a predominant direction, such as land- or seaward. Two sites were sampled in the Doboy Sound area: the southern tip of Sapelo Island and a site on the North River located approximately 10 km inland. We applied the propagule method using the fine fraction of the sediments that contains the propagule bank. Experimental conditions in the laboratory included three temperatures (18, 24 and 30°C) and three salinities (15, 25 and 35) to simulate a range of environments that might trigger the growth of various foraminiferal species. While adult in situ assemblages of both sites were at least partly influenced by the adjacent salt marshes, experimentally grown assemblages were dominated by mudflat, estuarine or more open marine species. Thus, propagule transport from the more terrestrial side of the assemblage gradient is limited, while propagules of more marine species can be transported far into the extensive estuarine system of the study area, where they can remain viable within the local propagule banks. Results provide important insights into possible changes in foraminiferal assemblages with rising sea-level on the Georgia coast.
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Rahn, David A., René D. Garreaud, and José A. Rutllant. "The Low-Level Atmospheric Circulation near Tongoy Bay–Point Lengua de Vaca (Chilean Coast, 30°S)." Monthly Weather Review 139, no. 11 (November 1, 2011): 3628–47. http://dx.doi.org/10.1175/mwr-d-11-00059.1.
Повний текст джерелаАнотація:
Abstract Strong southerly, terrain parallel winds often occur along the coast of north-central Chile (25°–35°S) embedded in the marine atmospheric boundary layer and the lower part of the capping temperature inversion. Their offshore structure and variability have received considerable attention because of the effect on open-ocean processes and connection with the southeast Pacific cloud layer. Mesoscale low-level circulations linked to the coastal topography (e.g., coastal jets and sea breeze) are less studied in Chile, but are particularly relevant as they alter the upper-ocean circulation and the cloud pattern in the nearshore strip. Surface, radiosonde, and airborne meteorological observations near point Lengua de Vaca (LdV)–Tongoy Bay (TB) at 30°S are used alongside numerical modeling to understand the local circulation near a prominent upwelling center. Most observations were gathered during the Variability of the American Monsoon Systems (VAMOS) Ocean–Cloud–Atmosphere–Land Study Chilean Upwelling Experiment (VOCALS-CUpEx) during two weeks in late spring 2009. The regional topography resembles other major capes, but south of TB and east of LdV there is a low (100–300 m), dry marine terrace bounded by high elevation at the coast (~600 m) and farther inland. Coastal soundings 25 km upstream of LdV revealed a southerly wind maximum near the surface and another at 900 m separated by a destabilized layer, deviating from the two-layer model often applied to coastal flow. In the morning a shallow sea breeze penetrates from TB to the marine terrace, but is overridden by southerly flow in the afternoon. Furthermore, between 400 and 900 m, warm continental air is advected from over the marine terrace creating a residual boundary layer over TB. Concurrent with slower changes offshore, the low-level warming over TB leads to a marked cross-shore pressure gradient enhancing the coastal jet just north of LdV.
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Jiang, Zhina, Da-Lin Zhang, Rudi Xia, and Tingting Qian. "Diurnal Variations of Presummer Rainfall over Southern China." Journal of Climate 30, no. 2 (January 2017): 755–73. http://dx.doi.org/10.1175/jcli-d-15-0666.1.
Повний текст джерелаАнотація:
In this study, the presummer diurnal cycle of rainfall (DCR) over southern China is examined using the merged 0.1°-resolution gridded hourly rain gauge and satellite rainfall dataset and the National Centers for Environmental Prediction Final Global Analysis during April to June of 2008–2015. Results show pronounced diurnal variations in rainfall amount, frequency, and intensity over southern China, with substantially different amplitudes from southwestern to southeastern China, and from the pre- to postmonsoon-onset period. Southwestern China often encounters significant nocturnal-to-morning rainfall under the influence of enhanced nocturnal low-level southwesterly winds. Southeastern China is dominated by afternoon rainfall, as a result of surface heating, likely aided by local topographical lifting. Both the pre- and postmonsoon-onset periods exhibit two diurnal rainfall peaks: one in the early morning and the other in the late afternoon. But the latter shows the two peaks with nearly equal amplitude whereas the former displays a much larger early morning peak than that in the late afternoon. Three propagating modes accounting for the presummer DCR are found: (i) an eastward- or southeastward-propagating mode occurs mostly over southwestern China that is associated with enhanced transport of warm and moist air from tropical origin and the induced low-level convergence, (ii) a quasi-stationary mode over southeastern China appears locally in the warm sector with weak-gradient flows, and (iii) an inland-propagating mode occurs during the daytime in association with sea breezes along the southern coastal regions, especially evident throughout the postmonsoon-onset period.
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Rolf Olsen, J., Vikram M. Mehta, and Harvey Hill. "Incorporating decadal climate variability information in the operation and design of water infrastructure." Water Policy 23, S1 (December 1, 2021): 232–49. http://dx.doi.org/10.2166/wp.2021.267.
Повний текст джерелаАнотація:
Abstract The high thermal and mechanical inertia of the oceans results in slow changes in sea surface temperatures (SSTs). Changes in SSTs, in turn, can impact atmospheric circulation including water vapor transport, precipitation, and temperatures throughout the world. The Pacific Decadal Oscillation (PDO), the tropical Atlantic SST gradient variability, and the West Pacific Warm Pool are patterns of natural climate variability that tend to persist over decadal time periods. There are current efforts to produce decadal climate predictions, but there is limited understanding if this information can be used in water resources management. Understanding the current state of decadal climate variability (DCV) phenomena and the probability of persisting in that state may be useful information for water managers. This information could improve forecasts that aid operations and short-term planning for reservoir management, domestic and industrial water supplies, flood risk management, energy production, recreation, inland navigation, and irrigation. If conditions indicate a higher likelihood of drought, reservoir managers could reduce flood storage space and increase storage for conservation purposes. Improved forecasts for irrigation could result in greater efficiencies by shifting crops and rotational crop patterns. The potential benefits of using a forecast must be balanced against the risk of damages if the forecast is wrong. Seasonal forecasts using DCV information could also be used to inform drought triggers. If DCV indices indicate that the climate has a higher probability of dry conditions, drought contingency plans could be triggered earlier. Understanding of DCV phenomena could also improve long-range water resources planning. DCV can manifest itself in relatively short-term hydrologic records as linear trends that complicate hydrologic frequency analysis, which has traditionally assumed that hydrologic records are stationary.
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Yan, Jinfeng, Ruiming Xiao, Fenzhen Su, Jinbiao Bai, and Feixue Jia. "Impact of Port Construction on the Spatial Pattern of Land Use in Coastal Zones Based on CLDI and LUT Models: A Case Study of Qingdao and Yantai." Remote Sensing 13, no. 16 (August 6, 2021): 3110. http://dx.doi.org/10.3390/rs13163110.
Повний текст джерелаАнотація:
Ports are an important type of land use in coastal cities, and the development of ports has a significant influence on the spatial pattern of land use in port cities. However, the research focusing on economic indicators hardly reflects the process of changes in the spatial distribution of land development in coastal port cities. This paper introduces a spatial association rule method to establish a coastline and land development intensity (CLDI) model and land use transfer (LUT) model in the vertical direction of coastal zones to mine the association rules between shoreline change and land development intensity along the sea–land gradient in the Qingdao and Yantai coastal zones and to explore the important land development sequence patterns. The results showed that, in the early stage of regional development, the land development intensity decreased from sea to land. In the later stage, as the industry transferred to nearby towns, the land units with extremely strong and strong levels started to move to the end or middle of the sequence. With the improvement of the urban construction level, the simple LUT pattern sequence that increased building land through the occupation of cultivated land and forestland was replaced gradually by complex sequences with multiple components. The relationship between land development and distance from the port showed that the areas with strong land development intensity gradually moved from coastal to inland areas over time. Port shipping has a profound influence on port city land use patterns. Industrial transfer drives the development of surrounding towns during the metaphase. This trend was used to build a second port to realize the division of transportation capacity, as the old port’s carrying capacity tended to become saturated. This paper revealed the general changes in the important land use patterns in port areas through a comparative study of the Qingdao and Yantai port areas and the differences among different geographical locations and development processes. This study provides a reference for the rational planning of coastal zone spatial layouts and provides a model basis for the analysis of the spatial structure of coastal zones. This information can be used to coordinate the relationship between ports and cities and promote the sustainable development of coastal zones.
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Davis, W. Jackson, Peter J. Taylor, and W. Barton Davis. "The Origin and Propagation of the Antarctic Centennial Oscillation." Climate 7, no. 9 (September 17, 2019): 112. http://dx.doi.org/10.3390/cli7090112.
Повний текст джерелаАнотація:
The Antarctic Centennial Oscillation (ACO) is a paleoclimate temperature cycle that originates in the Southern Hemisphere, is the presumptive evolutionary precursor of the contemporary Antarctic Oscillation (AAO), and teleconnects to the Northern Hemisphere to influence global temperature. In this study we investigate the internal climate dynamics of the ACO over the last 21 millennia using stable water isotopes frozen in ice cores from 11 Antarctic drill sites as temperature proxies. Spectral and time series analyses reveal that ACOs occurred at all 11 sites over all time periods evaluated, suggesting that the ACO encompasses all of Antarctica. From the Last Glacial Maximum through the Last Glacial Termination (LGT), ACO cycles propagated on a multicentennial time scale from the East Antarctic coastline clockwise around Antarctica in the streamline of the Antarctic Circumpolar Current (ACC). The velocity of teleconnection (VT) is correlated with the geophysical characteristics of drill sites, including distance from the ocean and temperature. During the LGT, the VT to coastal sites doubled while the VT to inland sites decreased fourfold, correlated with increasing solar insolation at 65°N. These results implicate two interdependent mechanisms of teleconnection, oceanic and atmospheric, and suggest possible physical mechanisms for each. During the warmer Holocene, ACOs arrived synchronously at all drill sites examined, suggesting that the VT increased with temperature. Backward extrapolation of ACO propagation direction and velocity places its estimated geographic origin in the Southern Ocean east of Antarctica, in the region of the strongest sustained surface wind stress over any body of ocean water on Earth. ACO period is correlated with all major cycle parameters except cycle symmetry, consistent with a forced, undamped oscillation in which the driving energy affects all major cycle metrics. Cycle period and symmetry are not discernibly different for the ACO and AAO over the same time periods, suggesting that they are the same climate cycle. We postulate that the ACO/AAO is generated by relaxation oscillation of Westerly Wind velocity forced by the equator-to-pole temperature gradient and propagated regionally by identified air-sea-ice interactions.
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Neiman, Paul J., F. Martin Ralph, Allen B. White, David D. Parrish, John S. Holloway, and Diana L. Bartels. "A Multiwinter Analysis of Channeled Flow through a Prominent Gap along the Northern California Coast during CALJET and PACJET." Monthly Weather Review 134, no. 7 (July 1, 2006): 1815–41. http://dx.doi.org/10.1175/mwr3148.1.
Повний текст джерелаАнотація:
Abstract Experimental observations from coastal and island wind profilers, aircraft, and other sensors deployed during the California Land-falling Jets Experiment of 1997/98 and the Pacific Land-falling Jets Experiment of 2000/01–2003/04 were combined with observations from operational networks to document the regular occurrence and characteristic structure of shallow (∼400–500 m deep), cold airstreams flowing westward through California’s Petaluma Gap from the Central Valley to the coast during the winter months. The Petaluma Gap, which is the only major air shed outlet from the Central Valley, is ∼35–50 km wide and has walls extending, at most, a modest 600–900 m above the valley floor. Based on this geometry, together with winter meteorological conditions typical of the region (e.g., cold air pooled in the Central Valley and approaching extratropical cyclones), this gap is predisposed to generating westward-directed ageostrophic flows driven by along-gap pressure differences. Two case studies and a five-winter composite analysis of 62 gap-flow cases are presented here to show that flows through the Petaluma Gap significantly impact local distributions of wind, temperature, precipitation, and atmospheric pollutants. These gap flows preferentially occur in pre-cold-frontal conditions, largely because sea level pressure decreases westward along the gap in a stably stratified atmosphere in advance of approaching cold-frontal pressure troughs. Airstreams exiting the Petaluma Gap are only several hundred meters deep and characterized by relatively cold, easterly flow capped by a layer of enhanced static stability and directional vertical wind shear. Airborne air-chemistry observations collected offshore by the NOAA P-3 aircraft illustrate the fact that gap-flow events can transport pollutants from inland to the coast, and that they can contribute to coastally blocked airstreams. The strongest gap-flow cases occur when comparatively deep midtropospheric troughs approach the coast, while the weak cases are tied to anticyclonic conditions aloft. Low-level cold-frontal pressure troughs approaching the coast are stronger and possess a greater along-gap pressure gradient for the strong gap-flow cases. These synoptic characteristics are dynamically consistent with coastal wind profiler observations of stronger low-level gap flow and winds aloft, and greater rainfall, during the strong gap-flow events. However, gap flow, on average, inhibits rainfall at the coast.