Academic literature on the topic 'Atmospheric circulation Pacific area'
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Journal articles on the topic "Atmospheric circulation Pacific area"
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Nakamura, Mototaka, and Toru Miyama. "Impacts of the Oyashio Temperature Front on the Regional Climate." Journal of Climate 27, no. 20 (October 7, 2014): 7861–73. http://dx.doi.org/10.1175/jcli-d-13-00609.1.
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Abstract Impacts of a sea surface temperature front (SSTF) in the northwestern Pacific Ocean on the large-scale summer atmospheric state in the region are examined with a regional atmospheric circulation model developed at the International Pacific Research Center. Ensemble simulation experiments with various SSTF strengths and positions show that an SSTF does have strong impacts on the summer atmospheric circulation in the region. A meridional shift in the position of the SSTF generally shifts the tropospheric jet and brings temperature anomalies in the area affected by the shift.
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Hoell, Andrew, and Chris Funk. "The ENSO-Related West Pacific Sea Surface Temperature Gradient." Journal of Climate 26, no. 23 (December 2013): 9545–62. http://dx.doi.org/10.1175/jcli-d-12-00344.1.
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El Niño–Southern Oscillation (ENSO) events are accompanied by an anomalous zonal sea surface temperature (SST) gradient over the west Pacific Ocean, defined here as the west Pacific SST gradient (WPG). The WPG is defined as the standardized difference between area-averaged SST over the central Pacific Ocean (Niño-4 region) and west Pacific Ocean (0°–10°N, 130°–150°E). While the direction of the WPG follows ENSO cycles, the magnitude of the gradient varies considerably between individual El Niño and La Niña events. In this study, El Niño and La Niña events are grouped according to the magnitude of the WPG, and tropical SST, circulations, and precipitation are examined for the period 1948–2011. Until the 1980s the WPG showed little trend as the west and central Pacific warmed at similar rates; however, the west Pacific has recently warmed faster than the central Pacific, which has resulted in an increased WPG during La Niña events. The temporal evolution and distribution of tropical Pacific SST as well as the near-surface tropical Pacific zonal wind, divergence, and vertical velocity are considerably different during ENSO events partitioned according to the strength of the WPG. Modifications to the tropical circulation, resulting in changes to Indo– west Pacific precipitation, are linked to strong and consistent circulation and precipitation modifications throughout the Northern Hemisphere during winter.
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Gradov, Viacheslav S., Irina V. Borovko, and Vladimir N. Krupchatnikov. "IMPACT OF ARCTIC SEA ICE REDUCTION ON ATMOSPHERIC CIRCULATION PATTERNS." Interexpo GEO-Siberia 4, no. 1 (May 21, 2021): 103–10. http://dx.doi.org/10.33764/2618-981x-2021-4-1-103-110.
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This paper focuses on the effect of sea ice melting under the effect of the mechanism of decreasing albedo of dry and wet ice and snow on the structure of atmospheric circulation. In particular, the Impact on storm tracks in the Pacific and Atlantic Oceans is analyzed. Extreme weather events are usually associated with atmospheric blocking conditions. Blocking is such meteorological conditions in which a large anticyclonic atmospheric vortex is observed over an area for several days. The Molteni-Tibaldi blocking criterion and the magnitude of the local anticyclonic wave activity (LAWA) are used to estimate the number of blockings. Extreme values of LAWA may indicate the presence of atmospheric blockings. As a result, there is a weakening and eastward shift of Atlantic storm trajectories. There is almost no influence on the Pacific storm tracks.
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Jia, XiaoJing, Hai Lin, June-Yi Lee, and Bin Wang. "Season-Dependent Forecast Skill of the Leading Forced Atmospheric Circulation Pattern over the North Pacific and North American Region*." Journal of Climate 25, no. 20 (April 9, 2012): 7248–65. http://dx.doi.org/10.1175/jcli-d-11-00522.1.
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Abstract Multimodel ensemble (MME) seasonal forecasts are analyzed to evaluate numerical model performance in predicting the leading forced atmospheric circulation pattern over the extratropical Northern Hemisphere (NH). Results show that the time evolution of the leading tropical Pacific sea surface temperature (SST)-coupled atmospheric pattern (MCA1), which is obtained by applying a maximum covariance analysis (MCA) between 500-hPa geopotential height (Z500) in the extratropical NH and SST in the tropical Pacific Ocean, can be predicted with a significant skill in March–May (MAM), June–August (JJA), and December–February (DJF) one month ahead. However, most models perform poorly in capturing the time variation of MCA1 in September–November (SON) with 1 August initial condition. Two possible reasons for the models’ low skill in SON are identified. First, the models have the most pronounced errors in the mean state of SST and precipitation along the central equatorial Pacific. Because of the link between the divergent circulation forced by tropical heating and the midlatitude atmospheric circulation, errors in the mean state of tropical SST and precipitation may lead to a degradation of midlatitude forecast skill. Second, examination of the potential predictability of the atmosphere, estimated by the ratio of the total variance to the variance of the model forecasts due to internal dynamics, shows that the atmospheric potential predictability over the North Pacific–North American (NPNA) region is the lowest in SON compared to the other three seasons. The low ratio in SON is due to a low variance associated with external forcing and a high variance related to atmospheric internal processes over this area.
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Nobre, Paulo, Marta Malagutti, Domingos F. Urbano, Roberto A. F. de Almeida, and Emanuel Giarolla. "Amazon Deforestation and Climate Change in a Coupled Model Simulation." Journal of Climate 22, no. 21 (November 1, 2009): 5686–97. http://dx.doi.org/10.1175/2009jcli2757.1.
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Abstract The effects of Amazon deforestation on climate change are investigated using twin numerical experiments of an atmospheric general circulation model (AGCM) with prescribed global sea surface temperature and the same AGCM coupled to an ocean GCM (CGCM) over the global tropics. An ensemble approach is adopted, with 10-member ensemble averages of a control simulation compared with perturbed simulations for three scenarios of Amazon deforestation. The latest 20 yr of simulation from each experiment are analyzed. Local surface warming and rainfall reduction are simulated by both models over the Amazon basin. The coupled model presented a rainfall reduction that is nearly 60% larger compared to its control run than those obtained by the AGCM. The results also indicated that both the fraction of the deforested area and the spatial continuity of the vegetated area might be important for modulating global climate variability and change. Additionally, significant remote atmospheric responses to Amazon deforestation scenarios are detected for the coupled simulations, which revealed global ocean and atmosphere circulation changes conducive to enhanced ocean–atmosphere variability over the Pacific Ocean. This, in turn, is interpreted as a manifestation of enhanced El Niño–Southern Oscillation (ENSO) activity over the Pacific and a positive feedback contributing to the extra rainfall reduction over the Amazon on the coupled simulations.
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Hu, Zeng-Zhen, Arun Kumar, Bhaskar Jha, Jieshun Zhu, and Bohua Huang. "Persistence and Predictions of the Remarkable Warm Anomaly in the Northeastern Pacific Ocean during 2014–16." Journal of Climate 30, no. 2 (January 2017): 689–702. http://dx.doi.org/10.1175/jcli-d-16-0348.1.
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In this work, the evolution and prediction of the persistent and remarkable warm sea surface temperature anomaly (SSTA) in the northeastern Pacific during October 2013–June 2016 are examined. Based on experiments with an atmospheric model, the possible contribution of SSTAs in different ocean basins to the atmospheric circulation anomalies is identified. Further, through verifying the real-time forecasts, current capabilities in predicting such an extreme warm event with a state-of-the-art coupled general circulation model are assessed. During the long-lasting warm event, there were two warm maxima in the area-averaged SSTA around January 2014 and July 2015, respectively. The warm anomaly originated at the oceanic surface and propagated downward and reached about 300 m. Model experiments forced by observed SST suggest that the long persistence of the atmospheric anomalies in the northeastern Pacific as a whole may be partially explained by SST forcing, particularly in the tropical Pacific Ocean associated with a persistent warm SSTA in 2014/15 and an extremely strong El Niño in 2015/16, via its influence on atmospheric circulation over the North Pacific. Nevertheless, it was a challenge to predict the evolution of this warm event, especially for its growth. That is consistent with the fact that the SSTAs in extratropical oceans are largely a consequence of unpredictable atmospheric variability.
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Lim, Won-Il, and Kyong-Hwan Seo. "Physical–Statistical Model for Summer Extreme Temperature Events over South Korea." Journal of Climate 32, no. 6 (February 26, 2019): 1725–42. http://dx.doi.org/10.1175/jcli-d-18-0201.1.
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AbstractExtreme temperature events have a significant impact on human life and property. Since the Korean Peninsula is affected by the high variability of the East Asian summer monsoon system, it is difficult to predict extreme temperature events skillfully. Here, we construct an empirical model to investigate the interannual variation of the frequency of summer extreme temperature events over South Korea by identifying predictors (explanatory variables) from ocean boundary conditions. The selected explanatory variables are sea surface temperature anomalies (SSTAs) over the North Atlantic, the western North Pacific, and the eastern North Pacific. The cross-validated correlation skill of the statistical model constructed using a 23-yr dataset is estimated to be 0.77. A common feature that all three explanatory variables contain is the development of an anticyclonic circulation anomaly over the Korean Peninsula. The North Atlantic SSTA predictor acts as a forcing mechanism for the generation of Rossby wave trains downstream, developing an anticyclonic circulation anomaly in the lower and upper troposphere over the Korean Peninsula. The western North Pacific (WNP) warm SSTA predictor induces a cyclonic circulation anomaly over the WNP and an anticyclonic circulation anomaly over the Korean Peninsula, resembling the Pacific–Japan teleconnection mechanism that represents the northward Rossby wave propagation over the western Pacific. Through air–sea interaction, the tripolar SSTA pattern in the eastern North Pacific representing the North Pacific gyre oscillation induces two opposite precipitation anomalies in the equatorial Maritime Continent and the Philippine Sea. These diabatic anomalies excite northward-propagating Rossby waves that form a cyclonic circulation anomaly in the WNP area and an anticyclonic anomaly over the Korean Peninsula.
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Šácha, Petr, Friederike Lilienthal, Christoph Jacobi, and Petr Pišoft. "Influence of the spatial distribution of gravity wave activity on the middle atmospheric dynamics." Atmospheric Chemistry and Physics 16, no. 24 (December 21, 2016): 15755–75. http://dx.doi.org/10.5194/acp-16-15755-2016.
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Abstract. Analysing GPS radio occultation density profiles, we have recently pointed out a localised area of enhanced gravity wave (GW) activity and breaking in the lower stratosphere of the east Asian–northwestern Pacific (EA/NP) region. With a mechanistic model of the middle and upper atmosphere, experiments are performed to study the possible effect of such a localised GW breaking region on large-scale circulation and transport and, more generally, a possible influence of the spatial distribution of gravity wave activity on middle atmospheric dynamics.The results indicate the important role of the spatial distribution of GW activity for polar vortex stability, formation of planetary waves and for the strength and structure of zonal-mean residual circulation. Furthermore, a possible effect of a zonally asymmetric GW breaking in the longitudinal variability of the Brewer–Dobson circulation is analysed. Finally, consequences of our results for a variety of research topics (e.g. sudden stratospheric warming, atmospheric blocking, teleconnection patterns and a compensation mechanism between resolved and unresolved drag) are discussed.
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Chen, Tsing-Chang, Harryvan Loon, Kuang-Der Wu, and Ming-Cheng Yen. "Changes in the Atmospheric Circulation over the North Pacific-North America Area since 1950." Journal of the Meteorological Society of Japan. Ser. II 70, no. 6 (1992): 1137–46. http://dx.doi.org/10.2151/jmsj1965.70.6_1137.
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Meehl, Gerald A., Julie M. Arblaster, and Johannes Loschnigg. "Coupled Ocean–Atmosphere Dynamical Processes in the Tropical Indian and Pacific Oceans and the TBO." Journal of Climate 16, no. 13 (July 1, 2003): 2138–58. http://dx.doi.org/10.1175/2767.1.
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Abstract The transitions (from relatively strong to relatively weak monsoon) in the tropospheric biennial oscillation (TBO) occur in northern spring for the south Asian or Indian monsoon and northern fall for the Australian monsoon involving coupled land–atmosphere–ocean processes over a large area of the Indo-Pacific region. Transitions from March–May (MAM) to June–September (JJAS) tend to set the system for the next year, with a transition to the opposite sign the following year. Previous analyses of observed data and GCM sensitivity experiments have demonstrated that the TBO (with roughly a 2–3-yr period) encompasses most ENSO years (with their well-known biennial tendency). In addition, there are other years, including many Indian Ocean dipole (or zonal mode) events, that contribute to biennial transitions. Results presented here from observations for composites of TBO evolution confirm earlier results that the Indian and Pacific SST forcings are more dominant in the TBO than circulation and meridional temperature gradient anomalies over Asia. A fundamental element of the TBO is the large-scale east–west atmospheric circulation (the Walker circulation) that links anomalous convection and precipitation, winds, and ocean dynamics across the Indian and Pacific sectors. This circulation connects convection over the Asian–Australian monsoon regions both to the central and eastern Pacific (the eastern Walker cell), and to the central and western Indian Ocean (the western Walker cell). Analyses of upper-ocean data confirm previous results and show that ENSO El Niño and La Niña events as well as Indian Ocean SST dipole (or zonal mode) events are often large-amplitude excursions of the TBO in the tropical Pacific and Indian Oceans, respectively, associated with anomalous eastern and western Walker cell circulations, coupled ocean dynamics, and upper-ocean temperature and heat content anomalies. Other years with similar but lower-amplitude signals in the tropical Pacific and Indian Oceans also contribute to the TBO. Observed upper-ocean data for the Indian Ocean show that slowly eastward-propagating equatorial ocean heat content anomalies, westward-propagating ocean Rossby waves south of the equator, and anomalous cross-equatorial ocean heat transports contribute to the heat content anomalies in the Indian Ocean and thus to the ocean memory and consequent SST anomalies, which are an essential part of the TBO.
Dissertations / Theses on the topic "Atmospheric circulation Pacific area"
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Johnson, Gregory Conrad. "Near-equatorial deep circulation in the Indian and Pacific Oceans /." Thesis, Woods Hole, Mass. : Woods Hole Oceanographic Institution, 1990. http://hdl.handle.net/1912/2637.
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Thesis (Ph. D.)--Woods Hole Oceanographic Institution and Massachusetts Institute of Technology, 1990.Funding was provided by the Office of Naval Research and a Secretary of the Navy Graduate Fellowship in Oceanography. References : p. 117-121.
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Mechem, David B. "Organized layer overturning in mesoscale convective systems over the western Pacific warm pool /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/10059.
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Robinson, Dennis P. "Diagnostic studies of extratropical intraseasonal variability in the northern hemisphere." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-04102006-125331/.
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Thesis (Ph. D.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2006.Dickinson, Robert, Committee Member ; Black, Robert, Committee Chair ; Cunnold, Derek, Committee Member ; Fu, Rong, Committee Member ; Knox, John, Committee Member.
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Widlansky, Matthew Johnson. "Variability of the South Pacific Convergence Zone and its influence on the general atmospheric circulation." Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19766.
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Intense atmospheric convection associated with the South Pacific Convergence Zone (SPCZ) significantly impacts basin-scale circulation patterns over the Pacific. We explore dynamical processes which foster changes in convection along the convergence zone. These forcings include strong moisture convergence and accumulation of wave energy in the boundary layer, as well as dynamical instability associated with moderate cross-equatorial wind bursts. A focus is applied to observing the dominant modes of variability on synoptic to intraseasonal timescales using a combination of satellite observations and NCEP reanalysis data. Accumulation of energy, due to negative stretching deformation, occurs with both tropical and extratropical modes suggesting that the SPCZ is an artifact of wide ranging modes. Signals of the dominant modes (inferred from fields of outgoing longwave radiation: OLR) are isolated using bandpass filtering techniques, which are then mapped in space and time using Principal Components from Empirical Orthogonal Function analyses.
Variability of convective systems in the SPCZ is found to be significantly correlated with changes in the regional Hadley Circulation and the Pacific Walker cell. This co-variability presents the possibility of important teleconnection routes between the tropical West and East Pacific, as well as with the mid-latitude regions of the Northern and Southern Hemispheres. We test these interaction hypotheses by developing composites of the circulation patterns using dates of maximum convection events (regions of minimum OLR) in the SPCZ. Intensities of the large-scale circulations are measured using observations of stream function mass fluxes. Results suggest that deep convection maxima (minima) are associated with an increase (decrease) in the Walker Circulation. It is also illustrated how off-equatorial convection anomalies in the subtropical portion of the SPCZ may induce changes to the Hadley Circulation. Interactions with the zonal (Walker) and meridional (Hadley) circulations appear to have important consequences on the ability for wave energy to propagate through the tropical Pacific atmosphere. Examples include Northern Hemisphere cross-equatorial teleconnections through the Westerly Wind Duct in the upper branch of the Walker circulation and Rossby wave trains in the SPCZ, which may be partially governed by characteristics of the regional Hadley circulation.
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Malevich, S. B., and C. A. Woodhouse. "Pacific sea surface temperatures, midlatitude atmospheric circulation, and widespread interannual anomalies in western U.S. streamflow." AMER GEOPHYSICAL UNION, 2017. http://hdl.handle.net/10150/625050.
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Widespread droughts can have considerable impact on western United States (U.S.) streamflow but causes related to moisture delivery processes are not yet fully understood. Here we examine western U.S. streamflow records to identify robust leading modes of interannual variability and their links to patterns of ocean and atmospheric circulation. The leading mode of streamflow variability, a pattern of west-wide streamflow anomalies, accounts for approximately 50% of variability and is associated with persistent high-pressure anomalies related to ridges off the Pacific North American coast. The second mode of variability accounts for approximately 25% of variability and is associated with ocean and atmospheric conditions in the tropical Pacific. Our results suggest that the leading mode of streamflow variability in the western U.S. is more strongly associated with internally driven midlatitude atmospheric variability than equatorial Pacific sea surface temperatures.
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De, Szoeke Simon P. "Evolution of the cross-equatorial atmospheric boundary layer in the east Pacific : observations and models /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/10083.
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Tonin, Hemerson E., and hemer tonin@flinders edu au. "Atmospheric freshwater sources for eastern Pacific surface salinity." Flinders University. Chemistry, Physics and Earth Sciences, 2006. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20061031.080144.
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The remarkable salinity difference between the upper Pacific and Atlantic Oceans is often explained through net export of water vapour across Central America. To investigate this mechanism a study of salinity signals in the Equatorial Pacific Ocean current system was made looking at responses to fresh water input from two sources (local versus remote - Atlantic Ocean) as well as a combination of the two. Statistical analyses (Empirical Orthogonal Functions, Single Value Decomposition and Wavelet analysis) were used to split the main sources of the atmospheric freshwater input into local and remote contributions and to quantify both contributions. The remote source was assumed to have been transported over Central America from the Atlantic Ocean as an atmospheric freshwater flux, whereas the local source originated in the Pacific Ocean itself. The analysis suggests that 74% of the total variance in precipitation over the tropical eastern Pacific is due to water vapour transport from the Atlantic. It also demonstrates strong influence of ENSO events, with maximum correlation at a two months time lag. During La Ni�a periods the precipitation variance is more closely related to water vapour transport across Central America (the remote source), while during El Ni�o periods it is more closely related to the water vapour transport by Southerly winds along the west coast of South America (the local source). The current and temperature fields provided by the Modular Ocean Model (version 2) were used to study the changes in the salinity field when freshwater was added to or removed from the model. ECMWF ERA-40 data taken from the ECMWF data server was used to determine the atmospheric flux of freshwater at the ocean surface, in the form of evaporation minus precipitation (E-P). The Mixed Layer Depth (MLD) computed from temperature and salinity fields determines to what depth the salinity's dilution/concentration takes place for every grid point. Each MLD was calculated from the results of the previous time step, and the water column was considered well mixed from the surface to this depth. The statistical relationships were used to reconstruct the precipitation over the tropical eastern Pacific. A numerical ocean model, which uses currents and temperature from a global ocean model and is forced by precipitation, was used to study the ocean's response to either the remote or the local source acting in isolation. Through time lag correlation analysis of the sea surface salinity anomalies produced by the variation in the reconstructed precipitation fields, it is found that the anomaly signals of salinity propagate westward along the Equator at a rate of approximately 0.25 m.s-1 (6.1 degrees per month).
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Zaunbrecher, Laura Katharine. "Coral records of radiocarbon variability in the central tropical pacific during the last millennium." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28272.
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Thesis (M. S.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2009.Committee Chair: Kim Cobb; Committee Member: Annalisa Bracco; Committee Member: Ellery Ingall; Committee Member: Jean Lynch-Stieglitz; Committee Member: Yuhang Wang.
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Taylor, Stephen V. "Northerly surface wind events over the eastern North Pacific Ocean spatial distribution, seasonality, atmospheric circulation, and forcing /." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3237552.
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Thesis (Ph. D.)--University of California, San Diego, 2006.Title from first page of PDF file (viewed December 12, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 126-133).
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Norris, Joel R. "Interannual variability in cloudiness, sea surface temperature, and atmospheric circulation over the midlatitude North Pacific during summer." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/10050.
Full textBooks on the topic "Atmospheric circulation Pacific area"
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Murray, Chapman, and Prothero R. Mansell, eds. Circulation in population movement: Substance and concepts from the Melanesian case. London: Routledge & Kegan Paul, 1985.
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Tibaldi, Stefano, and Franco Molteni. Atmospheric Blocking in Observation and Models. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.611.
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The atmospheric circulation in the mid-latitudes of both hemispheres is usually dominated by westerly winds and by planetary-scale and shorter-scale synoptic waves, moving mostly from west to east. A remarkable and frequent exception to this “usual” behavior is atmospheric blocking. Blocking occurs when the usual zonal flow is hindered by the establishment of a large-amplitude, quasi-stationary, high-pressure meridional circulation structure which “blocks” the flow of the westerlies and the progression of the atmospheric waves and disturbances embedded in them. Such blocking structures can have lifetimes varying from a few days to several weeks in the most extreme cases. Their presence can strongly affect the weather of large portions of the mid-latitudes, leading to the establishment of anomalous meteorological conditions. These can take the form of strong precipitation episodes or persistent anticyclonic regimes, leading in turn to floods, extreme cold spells, heat waves, or short-lived droughts. Even air quality can be strongly influenced by the establishment of atmospheric blocking, with episodes of high concentrations of low-level ozone in summer and of particulate matter and other air pollutants in winter, particularly in highly populated urban areas.Atmospheric blocking has the tendency to occur more often in winter and in certain longitudinal quadrants, notably the Euro-Atlantic and the Pacific sectors of the Northern Hemisphere. In the Southern Hemisphere, blocking episodes are generally less frequent, and the longitudinal localization is less pronounced than in the Northern Hemisphere.Blocking has aroused the interest of atmospheric scientists since the middle of the last century, with the pioneering observational works of Berggren, Bolin, Rossby, and Rex, and has become the subject of innumerable observational and theoretical studies. The purpose of such studies was originally to find a commonly accepted structural and phenomenological definition of atmospheric blocking. The investigations went on to study blocking climatology in terms of the geographical distribution of its frequency of occurrence and the associated seasonal and inter-annual variability. Well into the second half of the 20th century, a large number of theoretical dynamic works on blocking formation and maintenance started appearing in the literature. Such theoretical studies explored a wide range of possible dynamic mechanisms, including large-amplitude planetary-scale wave dynamics, including Rossby wave breaking, multiple equilibria circulation regimes, large-scale forcing of anticyclones by synoptic-scale eddies, finite-amplitude non-linear instability theory, and influence of sea surface temperature anomalies, to name but a few. However, to date no unique theoretical model of atmospheric blocking has been formulated that can account for all of its observational characteristics.When numerical, global short- and medium-range weather predictions started being produced operationally, and with the establishment, in the late 1970s and early 1980s, of the European Centre for Medium-Range Weather Forecasts, it quickly became of relevance to assess the capability of numerical models to predict blocking with the correct space-time characteristics (e.g., location, time of onset, life span, and decay). Early studies showed that models had difficulties in correctly representing blocking as well as in connection with their large systematic (mean) errors.Despite enormous improvements in the ability of numerical models to represent atmospheric dynamics, blocking remains a challenge for global weather prediction and climate simulation models. Such modeling deficiencies have negative consequences not only for our ability to represent the observed climate but also for the possibility of producing high-quality seasonal-to-decadal predictions. For such predictions, representing the correct space-time statistics of blocking occurrence is, especially for certain geographical areas, extremely important.
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Behera, Swadhin, and Toshio Yamagata. Climate Dynamics of ENSO Modoki Phenomena. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.612.
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The El Niño Modoki/La Niña Modoki (ENSO Modoki) is a newly acknowledged face of ocean-atmosphere coupled variability in the tropical Pacific Ocean. The oceanic and atmospheric conditions associated with the El Niño Modoki are different from that of canonical El Niño, which is extensively studied for its dynamics and worldwide impacts. A typical El Niño event is marked by a warm anomaly of sea surface temperature (SST) in the equatorial eastern Pacific. Because of the associated changes in the surface winds and the weakening of coastal upwelling, the coasts of South America suffer from widespread fish mortality during the event. Quite opposite of this characteristic change in the ocean condition, cold SST anomalies prevail in the eastern equatorial Pacific during the El Niño Modoki events, but with the warm anomalies intensified in the central Pacific. The boreal winter condition of 2004 is a typical example of such an event, when a tripole pattern is noticed in the SST anomalies; warm central Pacific flanked by cold eastern and western regions. The SST anomalies are coupled to a double cell in anomalous Walker circulation with rising motion in the central parts and sinking motion on both sides of the basin. This is again a different feature compared to the well-known single-cell anomalous Walker circulation during El Niños. La Niña Modoki is the opposite phase of the El Niño Modoki, when a cold central Pacific is flanked by warm anomalies on both sides.The Modoki events are seen to peak in both boreal summer and winter and hence are not seasonally phase-locked to a single seasonal cycle like El Niño/La Niña events. Because of this distinction in the seasonality, the teleconnection arising from these events will vary between the seasons as teleconnection path will vary depending on the prevailing seasonal mean conditions in the atmosphere. Moreover, the Modoki El Niño/La Niña impacts over regions such as the western coast of the United States, the Far East including Japan, Australia, and southern Africa, etc., are opposite to those of the canonical El Niño/La Niña. For example, the western coasts of the United States suffer from severe droughts during El Niño Modoki, whereas those regions are quite wet during El Niño. The influences of Modoki events are also seen in tropical cyclogenesis, stratosphere warming of the Southern Hemisphere, ocean primary productivity, river discharges, sea level variations, etc. A remarkable feature associated with Modoki events is the decadal flattening of the equatorial thermocline and weakening of zonal thermal gradient. The associated ocean-atmosphere conditions have caused frequent and persistent developments of Modoki events in recent decades.
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Kucharski, Fred, and Muhammad Adnan Abid. Interannual Variability of the Indian Monsoon and Its Link to ENSO. Oxford University Press, 2017. http://dx.doi.org/10.1093/acrefore/9780190228620.013.615.
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The interannual variability of Indian summer monsoon is probably one of the most intensively studied phenomena in the research area of climate variability. This is because even relatively small variations of about 10% to 20% from the mean rainfall may have dramatic consequences for regional agricultural production. Forecasting such variations months in advance could help agricultural planning substantially. Unfortunately, a perfect forecast of Indian monsoon variations, like any other regional climate variations, is impossible in a long-term prediction (that is, more than 2 weeks or so in advance). The reason is that part of the atmospheric variations influencing the monsoon have an inherent predictability limit of about 2 weeks. Therefore, such predictions will always be probabilistic, and only likelihoods of droughts, excessive rains, or normal conditions may be provided. However, even such probabilistic information may still be useful for agricultural planning. In research regarding interannual Indian monsoon rainfall variations, the main focus is therefore to identify the remaining predictable component and to estimate what fraction of the total variation this component accounts for. It turns out that slowly varying (with respect to atmospheric intrinsic variability) sea-surface temperatures (SSTs) provide the dominant part of the predictable component of Indian monsoon variability. Of the predictable part arising from SSTs, it is the El Niño Southern Oscillation (ENSO) that provides the main part. This is not to say that other forcings may be neglected. Other forcings that have been identified are, for example, SST patterns in the Indian Ocean, Atlantic Ocean, and parts of the Pacific Ocean different from the traditional ENSO region, and springtime snow depth in the Himalayas, as well as aerosols. These other forcings may interact constructively or destructively with the ENSO impact and thus enhance or reduce the ENSO-induced predictable signal. This may result in decade-long changes in the connection between ENSO and the Indian monsoon. The physical mechanism for the connection between ENSO and the Indian monsoon may be understood as large-scale adjustment of atmospheric heatings and circulations to the ENSO-induced SST variations. These adjustments modify the Walker circulation and connect the rising/sinking motion in the central-eastern Pacific during a warm/cold ENSO event with sinking/rising motion in the Indian region, leading to reduced/increased rainfall.
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George C. Marshall Space Flight Center., ed. Tropical Pacific moisture variability: Its detection, synoptic structure and consequences in the general circulation. College Station, TX: Dept. of Meteorology, Texas A&M University, 1990.
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United States. National Aeronautics and Space Administration., ed. South Pacific convergence zone and global-scale circulations: Final report for 20 July 1987 - 19 July 1991. [Washington, DC: National Aeronautics and Space Administration, 1991.
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Twining, David S. The relationship of precipitation in the western United States to variations in the outgoing long-wave radiation field over the tropical Pacific: The role of the mid-latitude circulation. 1995.
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Prothero, R. Mansell, and Murray Chapman. Circulation in Population Movement: Substance and Concepts from the Melanesian Case. Taylor & Francis Group, 2013.
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Circulation in Population Movement: Substance and Concepts from the Melanesian Case. Taylor & Francis Group, 2012.
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The Law The Law Library. Fisheries of the Exclusive Economic Zone off Alaska - Pacific Cod Allocations in the Bering Sea and Aleutian Islands Management Area (US National Oceanic and Atmospheric Administration Regulation) (NOAA) (2018 Edition). Independently Published, 2019.
Find full textBook chapters on the topic "Atmospheric circulation Pacific area"
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Cayan, Daniel R., and David H. Peterson. "The Influence of North Pacific Atmospheric Circulation on Streamflow in the West." In Aspects of Climate Variability in the Pacific and the Western Americas, 375–97. Washington, D. C.: American Geophysical Union, 2013. http://dx.doi.org/10.1029/gm055p0375.
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Ojrzyńska, Hanna, Maciej Kryza, Kinga Wałaszek, Mariusz Szymanowski, Małgorzata Werner, and Anthony J. Dore. "High-Resolution Dynamical Downscaling of ERA-Interim Using the WRF Regional Climate Model for the Area of Poland. Part 2: Model Performance with Respect to Automatically Derived Circulation Types." In Geoinformatics and Atmospheric Science, 69–92. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-66092-9_5.
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Hultberg, H., and M. Ferm. "Measurements of Atmospheric Deposition and Internal Circulation of Base Cations to a Forested Catchment Area." In Acid Reign ’95?, 2235–40. Dordrecht: Springer Netherlands, 1995. http://dx.doi.org/10.1007/978-94-007-0864-8_60.
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Luterbacher, J., and E. Xoplaki. "500-year Winter Temperature and Precipitation Variability over the Mediterranean Area and its Connection to the Large-scale Atmospheric Circulation." In Mediterranean Climate, 133–53. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-642-55657-9_7.
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Garreaud, René D., and Patricio Aceituno. "Atmospheric Circulation and Climatic Variability." In The Physical Geography of South America. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195313413.003.0010.
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Regional variations in South America’s weather and climate reflect the atmospheric circulation over the continent and adjacent oceans, involving mean climatic conditions and regular cycles, as well as their variability on timescales ranging from less than a few months to longer than a year. Rather than surveying mean climatic conditions and variability over different parts of South America, as provided by Schwerdtfeger and Landsberg (1976) and Hobbs et al. (1998), this chapter presents a physical understanding of the atmospheric phenomena and precipitation patterns that explain the continent’s weather and climate. These atmospheric phenomena are strongly affected by the topographic features and vegetation patterns over the continent, as well as by the slowly varying boundary conditions provided by the adjacent oceans. The diverse patterns of weather, climate, and climatic variability over South America, including tropical, subtropical, and midlatitude features, arise from the long meridional span of the continent, from north of the equator south to 55°S. The Andes cordillera, running continuously along the west coast of the continent, reaches elevations in excess of 4 km from the equator to about 40°S and, therefore, represents a formidable obstacle for tropospheric flow. As shown later, the Andes not only acts as a “climatic wall” with dry conditions to the west and moist conditions to the east in the subtropics (the pattern is reversed in midlatitudes), but it also fosters tropical-extratropical interactions, especially along its eastern side. The Brazilian plateau also tends to block the low-level circulation over subtropical South America. Another important feature is the large area of continental landmass at low latitudes (10°N–20°S), conducive to the development of intense convective activity that supports the world’s largest rain forest in the Amazon basin. The El Niño–Southern Oscillation phenomenon, rooted in the ocean-atmosphere system of the tropical Pacific, has a direct strong influence over most of tropical and subtropical South America. Similarly, sea surface temperature anomalies over the Atlantic Ocean have a profound impact on the climate and weather along the eastern coast of the continent. In this section we describe the long-term annual and monthly mean fields of several meteorological variables.
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Whiteman, C. David. "Atmospheric Scales of Motion and Atmospheric Composition." In Mountain Meteorology. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195132717.003.0010.
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Weather phenomena occur over a very broad range of scales of space and time, from the global circulation systems that extend around the earth’s circumference to the small eddies that cause cigarette smoke to swirl and mix with clear air. Each circulation can be described in terms of its approximate horizontal diameter and lifetime. Large-scale weather systems, such as hemispheric wave patterns called Rossby waves, monsoons, high and low pressure centers, and fronts, are called synopticscale weather systems. Temperature, humidity, pressure, and wind measurements collected simultaneously all over the world are used to analyze and forecast the evolution of these systems, which have diameters greater than 200 km (125 mi) and lifetimes of days to months. Mesoscale weather events include diurnal wind systems such as mountain wind systems, like breezes, sea breezes, thunderstorms, and other phenomena with horizontal scales that range from 2 to 200 km (1 to 125 mi) and lifetimes that range from hours to days. Mesoscale meteorologists use networks of surface- based instruments, balloon-borne sounding systems, remote sensing systems (e.g., radar, lidar, and sodar), and aircraft to make observations on these scales. Microscale meteorology focuses on local or small-scale atmospheric phenomena with diameters below 2 km (1 mi) and lifetimes from seconds to hours, including gusts and turbulence, dust devils, thermals, and certain cloud types. Microscale studies are usually confined to the layer of air from the earth’s surface to an altitude where surface effects become negligible (approximately 1000 feet or 300 m at night and 5000 feet or 1500 m during the day). A fourth and less rigorously defined term, the regional scale, denotes circulations and weather events occurring on horizontal scales from 500 to 5000 km (310 to 3100 mi). The regional scale is thus smaller than synoptic scale, but larger than mesoscale. The term is often used to describe events that occur within more or less homogeneous physiographic provinces (e.g., the Pacific Northwest region). Major mountain ranges impact the weather on the synoptic scale. They anchor large-scale pressure systems in the Northern Hemisphere, cause low and high pressure weather systems to form, and produce large-scale seasonal wind systems in Asia and North America.
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Kousky, Vernon E., and Gerald D. Bell. "Causes, Predictions, and Outcomes of El Niño 1997-1998." In El Niño, 1997-1998. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780195135510.003.0008.
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One of the most prominent aspects of our weather and climate is its variability. This variability ranges over many time and space scales, from small-scale weather phenomena such as wind gusts, localized thunderstorms, and tornadoes, to larger-scale weather features such as fronts and storms and to prolonged climate features such as droughts, floods, and fluctuations occurring on multiseasonal, multiyear, and multidecade time scales. Some examples of these longer time-scale fluctuations include abnormally hot and dry summers, abnormally cold and snowy winters, a series of abnormally mild or exceptionally severe winters, and even a mild winter followed by a severe winter. In general, the longer time-scale variations are often associated with changes in the atmospheric circulation that encompass areas far larger than a particular affected region. At times, these persistent circulation features affect vast parts of the globe, resulting in abnormal temperature and precipitation patterns in many areas. During the past several decades, scientists have discovered that important aspects of interannual variability in global weather patterns are linked to a naturally occurring phenomenon known as the El Niño / Southern Oscillation (ENSO) cycle. The heart of ENSO lies in the tropical Pacific, where there is strong coupling between variations in ocean surface temperatures and the circulation of the overlying atmosphere. The terms El Niño and La Niña represent opposite extremes of the ENSO cycle, and they cause very different rainfall outcomes, as illustrated in Figure 2-1. Before describing the oceanic and atmospheric characteristics of the ENSO cycle, it is necessary to describe the average climatic conditions and how they vary throughout the year. Interannual climate variability is often measured by comparing the observed conditions to the long-term mean conditions. The mean state of the tropical Pacific Ocean is identified by both its surface and its subsurface characteristics, each of which exhibits considerable evolution across the eastern half of the tropical Pacific during the course of the year. Throughout the year, the ocean surface is warmest in the west and coldest in the east. The largest difference between the two regions is observed during September and October, when temperatures in the eastern Pacific reach their annual minimum.
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Tuck, Adrian F. "Initial Survey of Observations." In Atmospheric Turbulence. Oxford University Press, 2008. http://dx.doi.org/10.1093/oso/9780199236534.003.0005.
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The observations are our starting point in this book, having been obtained from research aircraft in the last two decades. Justification for this approach can be found in Section 1.3 and by noting that there are no known analytical solutions to the Navier–Stokes equation, preventing the possibility of a priori prediction of the atmosphere’s turbulent structure. We note the pioneering power spectral analysis of wind, temperature, and ozone from commercial Boeing 747 aircraft (Nastrom and Gage 1985) and the more recent data from Airbus 340 aircraft under the aegis of the MOZAIC programme (Marenco et al. 1998). Multifractal analysis was first applied to observations from an IL-12 aircraft in the tropics (Chigirinskaya et al. 1994) and has been applied to a large body of observations taken from ER- 2, WB57F, DC-8, and G4 aircraft, with dropsondes from the last of these; Chapters 2, 4 and 5 are largely devoted to the results. Many of these data were obtained in the lower stratosphere from the ER-2 in the course of investigating ozone loss in both Arctic and Antarctic regions, where there exists a reasonably well-defined, durable circulation system offering clear dynamical, chemical, and radiative signatures. A more climate-driven imperative exists to investigate the tropical upper troposphere and lower stratosphere, largely pursued with the WB57F. The recent G4 and dropsonde data were acquired in the troposphere over the eastern Pacific Ocean, in the course of investigating northern hemisphere winter storms there. The utility of balloons and then, 120 years later, from 1903, of powered aircraft for exploring atmospheric properties, were immediately obvious. The Second World War saw aircraft attaining stratospheric altitudes, revealing a very dry lower stratosphere with westerly winds in winter and easterlies in summer, with accumulation of high ozone abundances in polar regions (Brewer 1944; Dobson et al. 1945; Brewer et al. 1948; Brewer 1949; Murgatroyd and Clews 1949; Bannon et al. 1952).
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Goodin, Douglas G. "Introductory Overview." In Climate Variability and Ecosystem Response in Long-Term Ecological Research Sites. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195150599.003.0022.
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Timescale is the organizing framework of this volume. In various sections, we consider the effects of climate variability on ecosystems at timescales ranging from weeks or months to centuries. In part III, we turn our attention to interdecadal-scale events. The timescales we consider are not absolutely defined, but for our purposes we define the interdecadal scale to encompass effects occurring with recurring cycles generally ranging from 10 to 50 years. A recurring theme in many of the chapters in this section is the effect on ecosystem response of teleconnection patterns associated with recognized quasi-periodic atmospheric circulation modes. These circulation modes include the well-known El Niño– Southern Oscillation (ENSO) phenomenon, which is generally thought to recur at shorter, interdecadal timescales but also includes some longer-term periodicities. Several other climate variability modes, including the Pacific North American index (PNA), North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), and North Pacific index (NP) also show strong interdecadal scale signatures and figure prominently in the chapters of part III. McHugh and Goodin begin the section by examining the climate record at several North American LTER sites for evidence of interdecadal-scale fluctuation. They note that interdecadal-scale contributions to climate variability can best be described in terms of two types of variation: (1) discontinuities in mean value, and (2) the presence of trends in the data. Evaluation of interdecadal periodicities in LTER data is complicated by the relatively short time series of observations available. McHugh and Goodin approach the problem mainly through the use of power spectrum analysis, a widely used tool for evaluating the periodicity in a time series of data. Principal components analysis is used to decompose the time series of growing-season climate data for each of the LTER sites into their principal modes of variability. These modes are then subjected to power spectrum analysis to evaluate the proportions of the variance in the data occurring at various timescales. McHugh and Goodin’s results suggest that significant effects on precipitation and temperature at interdecadal timescales are uncommon in these data, although significant periodicities at both shorter and longer frequencies do emerge from the data (a finding of relevance to other sections of this volume).
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Furley, Peter A. "Tropical Forests of the Lowlands." In The Physical Geography of South America. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780195313413.003.0017.
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Most of South America lies within the tropics, and lowland tropical ecosystems make up the majority of its landscapes. Although there is great concern for the Amazon ecosystem, the largest of the world’s tropical forests, there are many other fascinating and in some cases more endangered types of lowland forest. Such forests may be defined as lying below 1,000 m above sea level, although it is difficult to set arbitrary limits (Hartshorn, 2001). The two main lowland moist evergreen forests are the Hylea (a term coined by Alexander von Humboldt to denote rain forests of the Amazon Basin) and the much smaller Chocó forest on the Pacific coast between Panama and Ecuador. Two related yet distinctive types of forest are the Mata Atlântica or Atlantic moist evergreen forest and the Mata Decidua or dry deciduous forest, including the caatinga woodland, which is both deciduous and xerophytic (Rizzini et al., 1988). The latter two formations are among the most threatened of all South American forests. Lowland forests vary from dense and multilayered to open and single-layered, from evergreen to deciduous, and from flooded or semi-aquatic to near-arid. Tree heights range from 30 to 40 m with emergent trees reaching over 50 m, to forests where the tallest trees barely attain 20 m (Harcourt and Sayer, 1996; Solorzano, 2001). However, because of its extent and importance, Amazonia will form the principal focus of this chapter. Amazonia covers a vast area (>6 × 106 km2) and contains some 60% of the world’s remaining tropical forest. The Amazon and Orinoco basins influence not only regional climates and air masses, but also atmospheric circulation patterns both north and south of the Equator. The sheer size and diversity of Amazonia exhausts a normal repertoire of grandiose adjectives. The Amazon may or may not be the longest river in the world but it is by far the greatest in terms of discharge, sending around one fifth of the world’s fresh water carried by rivers to the oceans(see chapter 5; Eden, 1990; Sioli, 1984). The drainage basin is twice as large as any other of the world’s catchments.
Conference papers on the topic "Atmospheric circulation Pacific area"
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Alotaibi, Fahad M., Faisel M. Al-Dossari, Fahad M. Al-Majed, Ali M. Al-Hajri, and Talal A. Al-Zahrani. "Berri Increment Novel Waste Heat Recovery System." In SPE Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210714-ms.
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Abstract Berri Crude Increment Project (currently in the Execution phase) will install a new oil processing facility. As part of the project, a new thermal hot oil system will be provided to heat the crude oil for the desalting and stabilization process to meet the product specifications. This heating is primarily achieved through three hot oil heaters (furnaces) fueled by natural gas in a closed heating circulation system. The objective is to maximize the energy utilization and efficiency of the oil processing facility by integrating the waste heat of the plant turbines’ exhaust with the plant process heating network. The project added in the scope a waste heat recovery system as part of the hot oil loop to recover the energy and maximize the plant’s efficiency. The waste heat recovery consists of heat exchangers mounted on the plant combustion gas turbines to recover the exhaust heat and supply it to the plant heat demand. These turbines are fueled by natural gas to drive the water injection pumps at the facility. This design enhancement will minimize fuel gas burning in the hot oil heaters to supply the required process heating, and will reduce combustion product emissions from the hot oil heaters’ stacks to atmosphere. The anticipated benefits are as follows:Recover energy of up to 75 MW that represent 50% of the total heating duty.Optimize lifecycle cost through Savings by reducing fuel gas burning by 50%.Reduce greenhouse gases emissions by minimizing the hot oil heaters’ fuel gas consumption.Improve equipment and plant efficiency (10% turndown of process heating can be achieved).Minimize single point of failure through the increase of plant availability with flexible process heating design. This energy integrated design is one of a kind among conventional oil and gas surface facilities with very high energy recovery capability. The facility is expected to recover 50% of its total thermal duty needed by processes through efficient energy utilization. In addition, substantial environmental advantages are foreseen by reducing the plant combustion effluents. This is important for a processing facility located in an area that is considered a hub of several marine and environmental initiatives of Saudi Aramco.
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Zhen, Han, Fengjie Yang, Tao Jiang, Yong Qing Li, and Liqing Lei. "Monitoring and analysis of atmospheric environment by remote sensing in mining area." In Asia-Pacific Symposium on Remote Sensing of the Atmosphere, Environment, and Space, edited by Upendra N. Singh, Huanling Hu, and Gengchen Wang. SPIE, 1998. http://dx.doi.org/10.1117/12.319517.
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Muhammad, Faraz Khan, Zahid Mohammed Karajagi, Surya Pallapothu, Hafez Mohamed, Pierre Klem, and Umar Arshad. "Engineered Reinforced Composite Mat Pills to Effectively Combat Losses While Drilling in Qatar." In IADC/SPE Asia Pacific Drilling Technology Conference. SPE, 2021. http://dx.doi.org/10.2118/201030-ms.
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Abstract Drilling into fractures and fissures in carbonate reservoirs with lateral pore pressure variations is a major challenge. Accurately predicting and managing fracture initiation and fracture closure pressure is not practically feasible in naturally fractured carbonate rocks. Local fracture closure pressure (FCP, minimum in situ stress) around fractures are much lower than the mean value of FCP for the area, as observed in the Al Shaheen field. Drilling operators are experiencing massive lost circulation resulting in potential formation damage; and cost overruns. To address these lost circulation instances, modern lost circulation pills must be implemented. Drilling through the natural fractures within parts of the Shuaiba limestone reservoir usually results in significant drilling fluid losses, up to 50 m3/h. Lateral pore pressure variation causes dynamic inflow conditions within the wellbore, which make plugging fractures difficult. In addressing these lost circulation challenges, various approaches were previously used, notably reducing the hydrostatic pressure of fluids column, utilizing lighter weight drilling fluids, reducing the penetration of fluids into fractures with the use of various lost circulation materials, and the use of thixotropic cement slurries and lightweight high-solids-content cement slurries. Conventional lost circulation treatments provided very limited success under these conditions. An engineered composite fiber-based lost circulation pill with an innovative blend of fibers and sized solids to bridge and plug thief zones has been developed to address these lost circulation challenges. This pill was designed to be pumped through either a dummy bottomhole assembly (BHA) or through bypass circulation ports above the BHA with total flow area of 1.571 in2. These pills have been successfully used to mitigate losses while drilling as well as to achieve an incremental equivalent static density up to 144 kg/m3 to drill and cement the section. An impermeable grid created by this system was able to withstand the additional pressures. As a result, all the wells treated with these pills in the field were successfully drilled and cemented. After establishing the field specific guidelines over 2 years, continuous success was replicated in other wells for all the operator's rigs in Qatar.
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Sur, Shakya, Ahmed Mahmoud, Ali Ebrahimi Khabbazi, Elan Pavlov, and Amy M. Bilton. "Computational Modeling and Field Evaluation of an Innovative Solar Updraft Aeration System for Aquaculture in the Developing World." In ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-59572.
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Throughout the Asia Pacific region, fish farming is a vital and growing source of food security and economic activity. Since 1970, aquaculture has maintained an average annual growth rate of 8.7% in the region. Currently, almost 90% of global aquaculture production currently takes place in Asia Pacific and over 20 million people are employed in the sector. This growth has been associated with a large increase in family-run backyard aquaculture and integrated agriculture-aquaculture reservoirs in areas like rural Vietnam. However, yields in those rural ponds have typically been low. This is largely due to lack of aeration systems, which introduce oxygen into the pond water and allow for greater stocking densities, healthier fish, and greater yields. Aeration systems typically are not employed in these remote communities due to high capital costs, lack of access to reliable electricity, and prohibitive maintenance costs. To address this need, a low-cost solar-thermal aeration system for implementation in resource-constrained settings was devised. The system consists of a metallic solar collector and a heat transfer column, which induces convective circulation in the water by dissipating heat to the cooler, deeper layers of the pond. As a result of the circulation produced by the device, oxygen generated by phytoplankton at the top of the pond is distributed throughout the water column, preventing oxygen losses to the atmosphere due to surface supersaturation and increasing the overall pond oxygen content. This paper presents the system models developed to validate the concept, including a Computational Fluid Dynamics (CFD) model and a diel Dissolved Oxygen (DO) simulation model. These models, when used in conjunction, can estimate the increase in DO to be expected by the introduction of passive aeration device. These models were tailored to represent two target test ponds in Bac Ninh, Vietnam. To calibrate the models, instrumentation measured relevant parameters including DO and water temperatures at various depths, wind speed, ambient air temperature, and solar irradiance. A description of the mechanical design, construction and installation of two full-scale prototypes is then discussed, and field results for the first month post-implementation are analyzed. The model and experimental results indicate that the device can improve the DO content at deep levels of the ponds (i.e. oxygen-depleted regions) and has the potential to improve aquaculture productivity in resource-constrained settings.
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Kharol, Shailesh Kumar, and K. V. S. Badarinath. "Characterization of atmospheric aerosols over urban area using ground-based measurements and satellite data: a case study over Hyderabad, India." In Asia-Pacific Remote Sensing Symposium, edited by Si-Chee Tsay, Teruyuki Nakajima, Ramesh P. Singh, and R. Sridharan. SPIE, 2006. http://dx.doi.org/10.1117/12.697867.
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Zhang, Wenxing, Daren Lu, and Pucai Wang. "Measurement and analysis of atmospheric aerosol optical thickness and Angstrom exponent of 1998-2000 over the Beijing area." In Third International Asia-Pacific Environmental Remote Sensing Remote Sensing of the Atmosphere, Ocean, Environment, and Space, edited by Hung-Lung Huang, Daren Lu, and Yasuhiro Sasano. SPIE, 2003. http://dx.doi.org/10.1117/12.467539.
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Demetrashvili, Demuri, Vepkhia Kukhalashvili, Diana Kvaratskhelia, and Aleksandre Surmava. "MARINE FORECAST FOR THE EASTERNMOST PART OF THE BLACK SEA." In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b1/v3/50.
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Modelling and forecasting of dynamic processes and distribution of various substances of anthropogenic and natural origin in coastal and shelf zones of the seas and oceans are of great interest due to the high anthropogenic load of these zones. The aim of this paper is to present some examples of modelling and short-term forecasting of dynamic fields – the current, temperature and salinity in the easternmost Black Sea covering Georgian sector of the Black Sea and adjacent water area using a high-resolution regional model of the Black Sea dynamics. The z-level regional model is based on a full system of ocean hydro-thermodynamics equations and is nested in the basin-scale model of the Black Sea dynamics of Marine Hydrophysical Institute (Sevastopol). To solve the model equation system, a numerical algorithm based on the splitting method is used. Calculations show that circulation processes in the easternmost water area of the Black Sea are characterized by a permanent alternation of different circulation modes with the formation of mesoscale and submesoscale eddies throughout the year, which significantly affect the formation of thermohaline fields; atmospheric wind forcing substantially determines not only the peculiarities of the sea surface horizontal circulation, also the vertical structure of the current field.
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Evstigneeva, Natalia, Natalia Evstigneeva, Sergey Demyshev, and Sergey Demyshev. "NUMERICAL SIMULATION OF MESO- AND SUBMESOSCALE FEATURES OF THE NORTH-WESTERN BLACK SEA SHELF CIRCULATION USING HIGH SPATIAL RESOLUTION." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.31519/conferencearticle_5b1b943490dd49.54668884.
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A numerical experiment on reconstruction of currents was conducted with real atmospheric forcing data in autumn period of 2007 on the basis of Marine hydrophysical institute (MHI) hydrodynamic model, which was adapted to the coastal area of the Black Sea with an open boundary (north-western shelf). A high resolution (horizontal grid 500500 m and 44 verti-cal layers from 1 m to 49 m) and detailed bathymetry with resolution ~1.6 km were used in the calculation. A higher spatial resolution allowed to get a detailed mesoscale and sub-mesoscale structure of currents in the upper and deep layers of the north-western shelf and to obtain quantitative and qualitative characteristics of the eddies and jets more accurately in comparison with previous calculations.
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Evstigneeva, Natalia, Natalia Evstigneeva, Sergey Demyshev, and Sergey Demyshev. "NUMERICAL SIMULATION OF MESO- AND SUBMESOSCALE FEATURES OF THE NORTH-WESTERN BLACK SEA SHELF CIRCULATION USING HIGH SPATIAL RESOLUTION." In Managing risks to coastal regions and communities in a changing world. Academus Publishing, 2017. http://dx.doi.org/10.21610/conferencearticle_58b4316337b1b.
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A numerical experiment on reconstruction of currents was conducted with real atmospheric forcing data in autumn period of 2007 on the basis of Marine hydrophysical institute (MHI) hydrodynamic model, which was adapted to the coastal area of the Black Sea with an open boundary (north-western shelf). A high resolution (horizontal grid 500500 m and 44 verti-cal layers from 1 m to 49 m) and detailed bathymetry with resolution ~1.6 km were used in the calculation. A higher spatial resolution allowed to get a detailed mesoscale and sub-mesoscale structure of currents in the upper and deep layers of the north-western shelf and to obtain quantitative and qualitative characteristics of the eddies and jets more accurately in comparison with previous calculations.
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Panicker, Philip K., and Amani Magid. "Microwave Plasma Gasification for the Restoration of Urban Rivers and Lakes, and the Elimination of Oceanic Garbage Patches." In ASME 2016 10th International Conference on Energy Sustainability collocated with the ASME 2016 Power Conference and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/es2016-59632.
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This review paper describes techniques proposed for applying microwave-induced plasma gasification (MIPG) for cleaning rivers, lakes and oceans of synthetic and organic waste pollutants by converting the waste materials into energy and useful raw materials. Rivers close to urban centers tend to get filled with man-made waste materials, such as plastics and paper, gradually forming floating masses that further trap biological materials and animals. In addition, sewage from residences and industries, as well as rainwater runoff pour into rivers and lakes carrying solid wastes into the water bodies. As a result, the water surfaces get covered with a stagnant, thick layer of synthetic and biological refuse which kill the fish, harm animals and birds, and breed disease-carrying vectors. Such destruction of water bodies is especially common in developing countries which lack the technology or the means to clean up the rivers. A terrible consequence of plastic and synthetic waste being dumped irresponsibly into the oceans is the presence of several large floating masses of garbage in the worlds’ oceans, formed by the action of gyres, or circulating ocean currents. In the Pacific Ocean, there are numerous debris fields that have been labeled the Great Pacific Garbage Patch. These patches contain whole plastic litters as well as smaller pieces of plastic, called microplastics, which are tiny fragments that were broken down by the action of waves. These waste products are ingested by animals, birds and fishes, causing death or harm. Some of the waste get washed ashore on beaches along with dead marine life. The best solution for eliminating all of the above waste management problems is by the application of MIPG systems to convert solid waste materials and contaminated water into syngas, organic fuels and raw materials. MIPG is the most efficient form of plasma gasification, which is able to process the most widest range of waste materials, while consuming only about a quarter of the energy released from the feedstock. MIPG systems can be scaled in size, power rating and waste-treatment capacity to match financial needs and waste processing requirements. MIPG systems can be set up in urban locations and on the shores of the waterbody, to filter and remove debris and contaminants and clean the water, while generating electric power to feed into the grid, and fuel or raw materials for industrial use. For eliminating the pelagic debris fields, the proposed design is to have ships fitted with waste collector and filtration systems that feeds the collected waste materials into a MIPG reactor, which converts the carbonaceous materials into syngas (H2 + CO). Some of the syngas made will be used to produce the electric power needed for running the plasma generator and onboard systems, while the remainder can be converted into methanol and other useful products through the Fischer-Tropsch process. This paper qualitatively describes the implementation schemes for the above processes, wherein MIPG technology will be used to clean up major waste problems affecting the earth’s water bodies and to convert the waste into energy and raw materials in a sustainable and environmentally friendly manner, while reducing the dependence on fossil fuels and the release of carbon dioxide and methane into the atmosphere.