Journal articles on the topic 'Upwelling'
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1
Cury, Philippe, and Claude Roy. "Optimal Environmental Window and Pelagic Fish Recruitment Success in Upwelling Areas." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 4 (April 1, 1989): 670–80. http://dx.doi.org/10.1139/f89-086.
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Food availability and physical constraints such as turbulence are now considered as important factors that affect larval survival and pelagic fish recruitment. In Ekman-type upwelling, vertical advection, new inputs of nutrients and turbulence are linked to wind speed. According to the literature, food availability for larvae is related to biological dynamics (primary production) up to a point where the biological processes are disturbed by physical processes (turbulence generated by wind mixing). This limitation does not exist for non Ekman-type upwelling where upwelling intensity is not correlated with wind speed. We hypothesize that relations between annual recruitments and upwelling intensity are dome shaped in Ekman-type upwellings and linear for non Ekman-type upwellings. A statistical method is used to analyse the form of the relationships between recruitments and upwelling indices or wind mixing. The recruitment of the Peruvian anchoveta (Engraulis ringens), of the Pacific sardine (Sardinops sagax caerulea) and of the West African sardines and sardinellas are thereby examined. Results show that for Ekman-type upwelling the annual recruitment increases with upwelling intensity until wind speed reaches a value of roughly 5–6 m∙s−1 and decreases for higher values. For a non Ekman-type upwelling the relationship between recruitment and upwelling intensity is linear. These results confirm the existence of an optimal environmental window for recruitment.
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Troitskaya E.S., E. S., M. N. Shimaraev M.N., and I. A. Aslamov I.A. "Impact of climate change on occurrence and characteristics of coastal upwelling in Listvennichny Bay (Southern Baikal) from 1941 to 2023." Limnology and Freshwater Biology, no. 6 (2023): 261–74. http://dx.doi.org/10.31951/2658-3518-2023-a-6-261.
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The paper presents the results of analysis about relationship between climate changes and coastal upwellings in Listvennichny Bay (Southern Baikal) from 1941 to 2023. A decrease in both full and partial upwellings has been shown since the late 1950s. In addition, an increase in the proportion of upwelling events in August compared to other months during 1970-2023 were found. It also showed tendencies for longer upwelling durations and greater temperature drops during upwelling after 1970 compared to the previous period. Inferred from the analysis of the ERA5-Land data, it was determined that the cause of the observed changes was a global course of decreasing wind activity and a particular redistribution of the proportion of northerly and southwesterly winds in the Bay during the study period. Two cases of full and intermittent upwellings were described and compared. Possible ecological impacts on the Listvennichny Bay due to the combined effects of increasing anthropogenic pressure and less frequent upwellings have been hypothesized.
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Kowalewska-Kalkowska, Halina, and Marek Kowalewski. "Combining Satellite Imagery and Numerical Modelling to Study the Occurrence of Warm Upwellings in the Southern Baltic Sea in Winter." Remote Sensing 11, no. 24 (December 12, 2019): 2982. http://dx.doi.org/10.3390/rs11242982.
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Coastal upwelling involves an upward movement of deeper, usually colder, water to the surface. Satellite sea surface temperature (SST) observations and simulations with a hydrodynamic model show, however, that the coastal upwelling in the Baltic Sea in winter can bring warmer water to the surface. In this study, the satellite SST data collected by the advanced very high resolution radiometer (AVHRR) and the moderate-resolution imaging spectroradiometer (MODIS), as well as simulations with the Parallel Model 3D (PM3D) were used to identify upwelling events in the southern Baltic Sea during the 2010–2017 winter seasons. The PM3D is a three-dimensional hydrodynamic model of the Baltic Sea developed at the Institute of Oceanography, University of Gdańsk, Poland, in which parallel calculations enable high-resolution modelling. A validation of the model results with in situ observations and satellite-derived SST data showed the PM3D to adequately represent thermal conditions in upwelling areas in winter (91.5% agreement). Analysis of the frequency of warm upwellings in 12 areas of the southern Baltic Sea showed a high variability in January and February. In those months, the upwelling was most frequent, both in satellite imagery and in model results, off the Hel Peninsula (38% and 43% frequency, respectively). Upwelling was also frequent off the Vistula Spit, west of the Island of Rügen, and off the eastern coast of Skåne, where the upwelling frequency estimated from satellite images exceeded 26%. As determined by the PM3D, the upwelling frequency off VS and R was at least 25%, while off the eastern coast of Skåne, it reached 17%. The faithful simulation of SST variability in the winters of 2010–2017 by the high-resolution model used was shown to be a reliable tool with which to identify warm upwellings in the southern Baltic Sea.
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Silvestrova, K. P., S.A. Myslenkov 1,2,3,, and D. S. Repkov. "Wind upwelling forecast for the Russian Black Sea coast." Hydrometeorological research and forecasting 1 (March 30, 2022): 89–107. http://dx.doi.org/10.37162/2618-9631-2022-1-89-107.
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The paper presents a forecast system for wind Ekman upwelling for the Black Sea coast. The system is based on the calculation of the upwelling criterion, which depends on the wind speed and wind direction and the thickness of the upper mixed layer. The archived wind forecast was extracted from the COSMO-Ru07 model. The upwelling forecast with a lead time of 24–72 hours was calculated for three points off the Crimean coast for the period from May to November 2019. The quality of upwelling forecasts was assessed using in situ water temperature measurements in Balaklava, Foros, and Partenit. The comparison showed that 50% of the cases of a significant temperature drop for Foros and Balaklava are successfully predicted with a lead time of 48–72 hours. The cases of the significant temperature drop are rare in the study region, so the result is unsatisfactory. A part of cases that were not predicted by the system are probably downsurge upwellings or the horizontal advection of cold water. Keywords: upwelling, Black Sea, upwelling forecast, COSMO-Ru07, sea temperature
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Terada, Mio, Shoshiro Minobe, and Curtis Deutsch. "Mechanisms of Future Changes in Equatorial Upwelling: CMIP5 Intermodel Analysis." Journal of Climate 33, no. 2 (January 15, 2020): 497–510. http://dx.doi.org/10.1175/jcli-d-19-0128.1.
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AbstractThe future change in equatorial upwelling between 1971–2000 and 2071–2100 is investigated using data from 24 coupled climate models. The multimodel ensemble (MME) mean exhibits substantial equatorial upwelling decrease in the eastern Pacific and weaker decrease in the western Atlantic Ocean. The MME mean of upwelling change and intermodel variation of that are decomposed into distinct isopycnal and diapycnal components. In the Pacific, the diapycnal upwelling decreases near the surface, associated with a weakened Ekman pumping. The isopycnal upwelling decreases at depths of 75–200 m around the core of the Equatorial Undercurrent (EUC) due to flattening of the density layer in which it flows. Both the weakened Ekman pumping and the EUC flattening are induced by the locally weakened trade wind over the eastern Pacific basin. In the equatorial Atlantic, both the change in MME mean and the intermodel variation of upwellings are significantly related to the weakened trade wind and enhanced stratification, although these drivers are not independent. The results for the Pacific Ocean imply that future reduction in upwelling may have impacts at different depths by different mechanisms. In particular, the rapid warming of sea surface temperature in the eastern Pacific basin may be mainly caused by the near-surface diapycnal upwelling reduction rather than isopycnal upwelling reduction associated EUC flattening, which is important at deeper levels.
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Gaitán-Espitia, Juan Diego, Dustin Marshall, Sam Dupont, Leonardo D. Bacigalupe, Levente Bodrossy, and Alistair J. Hobday. "Geographical gradients in selection can reveal genetic constraints for evolutionary responses to ocean acidification." Biology Letters 13, no. 2 (February 2017): 20160784. http://dx.doi.org/10.1098/rsbl.2016.0784.
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Geographical gradients in selection can shape different genetic architectures in natural populations, reflecting potential genetic constraints for adaptive evolution under climate change. Investigation of natural pH/ p CO 2 variation in upwelling regions reveals different spatio-temporal patterns of natural selection, generating genetic and phenotypic clines in populations, and potentially leading to local adaptation, relevant to understanding effects of ocean acidification (OA). Strong directional selection, associated with intense and continuous upwellings, may have depleted genetic variation in populations within these upwelling regions, favouring increased tolerances to low pH but with an associated cost in other traits. In contrast, diversifying or weak directional selection in populations with seasonal upwellings or outside major upwelling regions may have resulted in higher genetic variances and the lack of genetic correlations among traits. Testing this hypothesis in geographical regions with similar environmental conditions to those predicted under climate change will build insights into how selection may act in the future and how populations may respond to stressors such as OA.
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Khlebnikov, D. V., A. Yu Ivanov, M. A. Evdoshenko, and S. K. Klimenko. "Manifestations of Upwellings in the Black Sea in Multisensor Remote Sensing Data." Исследования Земли из космоса 2023, no. 6 (November 1, 2023): 35–51. http://dx.doi.org/10.31857/s0205961423060052.
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The paper presents the results of a study of upwelling in the Black Sea in three marine areas: in the northeastern part of the sea, near the Tendrovskaya Spit and the Western Crimea, and off the coast of Turkey. They are based on the use of multi-sensor remote sensing data, namely ocean color scanners (MODIS, VIIRS, OLCI-a and OLCI-b), infrared radiometers (TIRS and AVHRR), as well as synthetic aperture radar (SAR) images acquired by spaceborne SARs. An integrated approach using practically only remote sensing data makes it possible to quite fully characterize the observed upwellings in the sea. In the active phase, upwelling, in addition to sea surface temperature (SST), is usually displayed both in the phytoplankton chlorophyll-a concentration (chlor-a) and in the sea surface roughness on the SAR images. In the analyzed cases, the duration of upwellings varied from 6 to 10 days, the SST differences in the upwelling zone were up to 8°С, and the concentrations of chlor-a were 5–6 times higher than the background values of 0.5–0.7 mg/m3. The maximum SST anomalies, which are about 8°C, were observed off the Turkish coast. As a result of the analysis, a dynamic relationship was revealed between the areas of low SST in the upwelling zone (compared to the sea waters surrounding this zone), sea surface roughness and chlor-a concentration. It is shown that in the case of using the full set of available remote sensing data, the observation, monitoring and study of upwelling does not present any fundamental difficulties.
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Yao, Zhongzhi, Wei Fan, Canbo Xiao, Tiancheng Lin, Yao Zhang, Yongyu Zhang, Jihua Liu, Zhujun Zhang, Yiwen Pan, and Ying Chen. "Numerical Studies on the Suitable Position of Artificial Upwelling in a Semi-Enclosed Bay." Water 12, no. 1 (January 8, 2020): 177. http://dx.doi.org/10.3390/w12010177.
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Ecological engineering by artificial upwelling is considered a promising way to improve water quality. Artificial upwelling could lift nutrient-rich bottom water to the surface, enhance seaweed growth and consequently increase nutrient removal from seawater. However, one of the major obstacles of the engineering application is to determine the suitable position of ecological engineering, which is critical for artificial upwelling’s performance. In this paper, potential artificial upwelling positions in a semi-closed bay are simulated by using the unstructured-grid Finite-Volume Coastal Ocean Model (FVCOM). The results show that the upwelling position with relative small tidal current and close to corner will be helpful to increasing nutrient concentration of surface water, and be appropriate to build the ecological engineering. With proper design of the ecological engineering, it is possible to have a noticeable impact in semi-closed bay. Thus, artificial upwelling has the potential to succeed as a promising way to alleviate the eutrophication.
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González-Dávila, Melchor, J. Magdalena Santana Casiano, and Francisco Machín. "Changes in the partial pressure of carbon dioxide in the Mauritanian–Cap Vert upwelling region between 2005 and 2012." Biogeosciences 14, no. 17 (August 31, 2017): 3859–71. http://dx.doi.org/10.5194/bg-14-3859-2017.
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Abstract. Coastal upwellings along the eastern margins of major ocean basins represent regions of large ecological and economic importance due to the high biological productivity. The role of these regions for the global carbon cycle makes them essential in addressing climate change. The physical forcing of upwelling processes that favor production in these areas are already being affected by global warming, which will modify the intensity of upwelling and, consequently, the carbon dioxide cycle. Here, we present monthly high-resolution surface experimental data for temperature and partial pressure of carbon dioxide in one of the four most important upwelling regions of the planet, the Mauritanian–Cap Vert upwelling region, from 2005 to 2012. This data set provides direct evidence of seasonal and interannual changes in the physical and biochemical processes. Specifically, we show an upwelling intensification and an increase of 0.6 Tg yr−1 in CO2 outgassing due to increased wind speed, despite increased primary productivity. This increase in CO2 outgassing together with the observed decrease in sea surface temperature at the location of the Mauritanian Cap Blanc, 21° N, produced a pH rate decrease of −0.003 ± 0.001 yr−1.
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Wolstencroft, Martin, and J. Huw Davies. "Breaking supercontinents; no need to choose between passive or active." Solid Earth 8, no. 4 (August 7, 2017): 817–25. http://dx.doi.org/10.5194/se-8-817-2017.
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Abstract. Much debate has centred on whether continental break-up is predominantly caused by active upwelling in the mantle (e.g. plumes) or by long-range extensional stresses in the lithosphere. We propose the hypothesis that global supercontinent break-up events should always involve both. The fundamental principle involved is the conservation of mass within the spherical shell of the mantle, which requires a return flow for any major upwelling beneath a supercontinent. This shallow horizontal return flow away from the locus of upwelling produces extensional stress. We demonstrate this principle with numerical models, which simultaneously exhibit both upwellings and significant lateral flow in the upper mantle. For non-global break-up the impact of the finite geometry of the mantle will be less pronounced, weakening this process. This observation should motivate future studies of continental break-up to explicitly consider the global perspective, even when observations or models are of regional extent.
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Hénin, Christian, and G. R. Cresswell. "Upwelling along the western barrier reef of New Caledonia." Marine and Freshwater Research 56, no. 7 (2005): 1005. http://dx.doi.org/10.1071/mf04266.
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Temperature decreases of up to 5°C at an automatic station at ~10 m depth at the outer reef of western New Caledonia signalled the occurrence of upwelling. The decreases are related to south-easterly wind events and they can take up to 5 days to develop. Successive wind events can depress the temperature for as much as 1 month. An upwelling shows in thermal satellite imagery as a band of cold water ~10 km wide and as long as several hundred kilometres just outside the reef. The cold water frequently spreads out to sea. The upwellings are more common in summer (October to March) than in winter. During lengthy periods of low wind speeds, the waters outside the reef appear to be overrun by warm water from farther north. The frequent occurrence of the warm water layer in the north may partly explain why upwellings are more common along the southern half of the reef. The entire lagoon cools in winter; most of the lagoon warms in summer, except at the southern end where the waters are cool, perhaps from tidal mixing.
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Hoetzel, S., L. M. Dupont, F. Marret, G. Jung, and G. Wefer. "Miocene–Pliocene stepwise intensification of the Benguela upwelling over the Walvis Ridge off Namibia." Climate of the Past Discussions 11, no. 3 (May 20, 2015): 1913–43. http://dx.doi.org/10.5194/cpd-11-1913-2015.
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Abstract. Upwelling is a significant part of the ocean circulation controlling largely the transport of cold waters to the surface and therefore influences ocean productivity and global climate. The Benguela Upwelling System (BUS) is one of the major upwelling areas in the world. Previous reconstructions of the BUS mainly focused on the onset and intensification in southern and central parts, but changes of the northern part have been rarely investigated in detail. Using the organic-walled dinoflagellate cyst record of ODP Site 1081 from the Late Miocene to the Pliocene we reconstruct and discuss the upwelling history on the Walvis Ridge with a special focus on the movement of the Angola–Benguela Front (ABF). We show that during the Late Miocene the Angola Current flowed southwards over the Walvis Ridge more frequently than today because the ABF was probably located further south as a result of a weaker meridional temperature gradient. A possible strengthening of the meridional gradient during the latest Miocene to early Pliocene in combination with uplift of south-western Africa intensified the upwelling along the coast and increased the upwelling's filaments over the Walvis Ridge. An intermediate period from 6.2 to 5.5 Ma is shown by the dominance of Habibacysta tectata, cysts of a cool-tolerant dinoflagellate known from the northern Atlantic, indicating changing oceanic conditions contemporaneous with the Messinian Salinity Crisis. From 4.4 Ma on, the upwelling signal got stronger again and waters were well-mixed and nutrient-rich. Also effects of Cunene River discharge into the South Atlantic are recorded since 4.4 Ma. Our results show a northward migration of the ABF and the initial stepwise intensification of the BUS.
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Mandal, Gagan, Shih-Yu Lee, and Jia-Yuh Yu. "The Roles of Wind and Sea Ice in Driving the Deglacial Change in the Southern Ocean Upwelling: A Modeling Study." Sustainability 13, no. 1 (January 2, 2021): 353. http://dx.doi.org/10.3390/su13010353.
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The Southern Ocean (SO) played a fundamental role in the deglacial climate system by exchanging carbon-rich deep ocean water with the surface. The contribution of the SO’s physical mechanisms toward improving our understanding of SO upwelling’s dynamical changes is developing. Here, we investigated the simulated transient SO atmosphere, ocean, and sea ice evolution during the last deglaciation in a fully coupled Earth system model. Our results showed that decreases in SO upwelling followed the weakening of the Southern Hemisphere surface westerlies, wind stress forcing, and Antarctic sea ice coverage from the Last Glacial Maximum to the Heinrich Stadial 1 and the Younger Dryas. Our results support the idea that the SO upwelling is primarily driven by wind stress forcing. However, during the onset of the Holocene, SO upwelling increased while the strength of the wind stress decreased. The Antarctic sea ice change controlled the salt and freshwater fluxes, ocean density, and buoyancy flux, thereby influencing the SO’s dynamics. Our study highlighted the dynamic linkage of the Southern Hemisphere westerlies, ocean, and sea ice in the SO’s latitudes. Furthermore, it emphasized that zonal wind stress forcing and buoyancy forcing control by sea ice together regulate the change in the SO upwelling.
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Newton, Alicia. "Upwelling displaced." Nature Geoscience 4, no. 9 (August 31, 2011): 580. http://dx.doi.org/10.1038/ngeo1257.
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Newton, Alicia. "Southern upwelling." Nature Geoscience 6, no. 12 (November 28, 2013): 989. http://dx.doi.org/10.1038/ngeo2031.
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Whitchurch, Amy. "Intraplate upwelling." Nature Geoscience 3, no. 2 (February 2010): 78. http://dx.doi.org/10.1038/ngeo768.
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Simpkins, Graham. "Humboldt upwelling." Nature Climate Change 8, no. 4 (April 2018): 272. http://dx.doi.org/10.1038/s41558-018-0135-8.
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Edelson, Steven, and Kai-Jye Lou. "Europe's upwelling." Science-Business eXchange 7, no. 7 (February 2014): 188. http://dx.doi.org/10.1038/scibx.2014.188.
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Wang, Li-Chiao, and Jia-Yuh Yu. "Dynamics of Upwelling Annual Cycle in the Equatorial Pacific Ocean." Sustainability 11, no. 18 (September 15, 2019): 5038. http://dx.doi.org/10.3390/su11185038.
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A recent work proposed a simple theory based on the framework of Zebiak–Cane (ZC) ocean model, and successfully characterized the equatorial Atlantic upwelling annual cycle as a combination of the local wind-driven Ekman upwelling and nonlocal wind-driven wave upwelling. In the present work, utilizing the same simple framework, we examined the fidelity of the upwelling Pacific annual cycle using observations and simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We demonstrated that the theoretical upwelling annual cycles generally match the original upwelling annual cycles in the equatorial Pacific in both observations and CMIP5 simulations. Therefore, this simple formulation can be used to represent the upwelling annual cycle in the equatorial Pacific. Observationally, the equatorial Pacific upwelling annual cycle is dominated by the local wind-driven Ekman upwelling, while the remote wave upwelling is confined near the eastern boundary with little contribution. In CMIP5 simulations, though the theoretical-reconstructed upwelling well-reproduces the original upwelling, the contribution is totally different compared to the observation. The wave upwelling serves as the main contributor instead of the Ekman upwelling. We further demonstrated that such discrepancy is attributable to the bias of the central to eastern equatorial thermocline depth patterns. This amplified, westward-shift wave upwelling weakened the impacts of the Ekman upwelling, and contributes to the entire Pacific equatorial upwelling annual cycle substantially. This implies that a realistic simulation of the equatorial Pacific upwelling annual cycle in models is very sensitive to the careful simulation of the equatorial thermocline depth annual evolutions.
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Bordbar, Mohammad Hadi, Volker Mohrholz, and Martin Schmidt. "Low confidence in multi-decadal trends of wind-driven upwelling across the Benguela Upwelling System." Earth System Dynamics 14, no. 5 (October 16, 2023): 1065–80. http://dx.doi.org/10.5194/esd-14-1065-2023.
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Abstract. Like other eastern boundary upwelling systems, in the Benguela Upwelling System, the upwelling along the coastline is primarily alongshore-wind-driven. In contrast, it is mainly driven by the wind stress curl farther offshore. The surface wind regime across the Benguela Upwelling System is strongly related to the South Atlantic Anticyclone that is believed to migrate poleward in response to anthropogenic global warming. Using the European Centre for Medium-Range Weather Forecasts ERA5 reanalysis for 1979–2021, we investigate multi-decadal changes in the South Atlantic Anticyclone and their impacts on coastal upwelling driven by alongshore winds, wind-stress-curl-driven upwelling within the coastal zone and total upwelling as the sum of both across the Benguela Upwelling System. Even though the detailed structure of surface wind over the coastal zone matters for both alongshore-wind-driven coastal upwelling and wind-stress-curl-driven upwelling, we show that it is not of major importance for the total amount of upwelled water. We found a robust connection between the anticyclone intensity and the zonally integrated wind-stress-curl-driven and total upwelling. However, such connection for the alongshore-wind-driven coastal upwelling is weak. The upwelling in the equatorward portion of the Benguela Upwelling System is significantly affected by the anticyclone intensity. In contrast, the poleward portion is also influenced by the meridional position of the anticyclone. In general, the impacts of the anticyclone on the local upwelling are more robust during the austral winter. The multi-decadal trend in the sea level pressure across the South Atlantic renders a considerable heterogeneity in space. However, this trend features a small signal-to-noise ratio and can be obscured by interannual to decadal climate variability. This view is further supported by the coastal and wind-stress-curl-driven upwelling in several upwelling cells showing hardly any significant multi-decadal trends.
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Abrahams, Amieroh, Robert W. Schlegel, and Albertus J. Smit. "A novel approach to quantify metrics of upwelling intensity, frequency, and duration." PLOS ONE 16, no. 7 (July 8, 2021): e0254026. http://dx.doi.org/10.1371/journal.pone.0254026.
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The importance of coastal upwelling systems is widely recognized. However, several aspects of the current and future behaviors of these systems remain uncertain. Fluctuations in temperature because of anthropogenic climate change are hypothesized to affect upwelling-favorable winds and coastal upwelling is expected to intensify across all Eastern Boundary Upwelling Systems. To better understand how upwelling may change in the future, it is necessary to develop a more rigorous method of quantifying this phenomenon. In this paper, we use SST data and wind data in a novel method of detecting upwelling signals and quantifying metrics of upwelling intensity, duration, and frequency at four sites within the Benguela Upwelling System. We found that indicators of upwelling are uniformly detected across five SST products for each of the four sites and that the duration of those signals is longer in SST products with higher spatial resolutions. Moreover, the high-resolution SST products are significantly more likely to display upwelling signals at 25 km away from the coast when signals were also detected at the coast. Our findings promote the viability of using SST and wind time series data to detect upwelling signals within coastal upwelling systems. We highlight the importance of high-resolution data products to improve the reliability of such estimates. This study represents an important step towards the development of an objective method for describing the behavior of coastal upwelling systems.
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Huang, Zhi, Jianyu Hu, and Weian Shi. "Mapping the Coastal Upwelling East of Taiwan Using Geostationary Satellite Data." Remote Sensing 13, no. 2 (January 6, 2021): 170. http://dx.doi.org/10.3390/rs13020170.
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Coastal upwelling is important for coastal ecosystems and the blue economy because of its large productivity and large potential for catching fish. However, coastal upwelling along the Taiwan east coast has received little attention from the research community. This study used five-year daily Himawari-8 geostationary satellite sea surface temperature data to map the coastal upwelling east of Taiwan during the summer monsoon season. We applied a semi-automatic image process technique based on the topographic position index for the quantitative upwelling mapping. The results show clear evidence of seasonal coastal upwelling along the entire Taiwan east coast, mainly under the influence of upwelling-favorable southwesterly/southerly winds. There are three broad upwelling centers along the Taiwan east coast: north, central, and south. The upwelling around the northern center has the longest upwelling season, lasting from May to September. The upwelling extents are larger between June and August during the height of the summer monsoon.
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Belmajdoub, Hanae, Khalid Minaoui, Anass El Aouni, Karim Hilmi, Rachid Saadane, and Abdellah Chehri. "A New Upwelling Index for the Moroccan Atlantic Coast for the Period between 1982–2021." Remote Sensing 15, no. 14 (July 8, 2023): 3459. http://dx.doi.org/10.3390/rs15143459.
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Being a component of the Eastern Boundary Upwelling (EBU) ecosystem, Morocco’s Atlantic coast presents high biological production throughout the year, with seasonal variations in upwelling dynamics. This characterization reflects the inherent nature of EBU’s ecosystems. In this work, we develop a novel methodology to compute a new upwelling index based on the analysis of sea surface temperature (SST) images. Our new upwelling index is not only simple to calculate but also efficient. Indeed, it is limited only to the upwelling region, which has allowed the improvement of the quantification and analysis of the seasonal and interannual variability of the upwelling dynamics. The new proposed upwelling index is based on the application of a recent segmentation method that allows for the monitoring of upwelling dynamics using satellite observations. The proposed upwelling index is applied to a 40-year database of weekly SST images covering the period from 1982 to 2021, and the results are used to analyze seasonal and interannual variations of the upwelling in the region.
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Vinayachandran, Puthenveettil Narayana Menon, Yukio Masumoto, Michael J. Roberts, Jenny A. Huggett, Issufo Halo, Abhisek Chatterjee, Prakash Amol, et al. "Reviews and syntheses: Physical and biogeochemical processes associated with upwelling in the Indian Ocean." Biogeosciences 18, no. 22 (November 23, 2021): 5967–6029. http://dx.doi.org/10.5194/bg-18-5967-2021.
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Abstract. The Indian Ocean presents two distinct climate regimes. The north Indian Ocean is dominated by the monsoons, whereas the seasonal reversal is less pronounced in the south. The prevailing wind pattern produces upwelling along different parts of the coast in both hemispheres during different times of the year. Additionally, dynamical processes and eddies either cause or enhance upwelling. This paper reviews the phenomena of upwelling along the coast of the Indian Ocean extending from the tip of South Africa to the southern tip of the west coast of Australia. Observed features, underlying mechanisms, and the impact of upwelling on the ecosystem are presented. In the Agulhas Current region, cyclonic eddies associated with Natal pulses drive slope upwelling and enhance chlorophyll concentrations along the continental margin. The Durban break-away eddy spun up by the Agulhas upwells cold nutrient-rich water. Additionally, topographically induced upwelling occurs along the inshore edges of the Agulhas Current. Wind-driven coastal upwelling occurs along the south coast of Africa and augments the dynamical upwelling in the Agulhas Current. Upwelling hotspots along the Mozambique coast are present in the northern and southern sectors of the channel and are ascribed to dynamical effects of ocean circulation in addition to wind forcing. Interaction of mesoscale eddies with the western boundary, dipole eddy pair interactions, and passage of cyclonic eddies cause upwelling. Upwelling along the southern coast of Madagascar is caused by the Ekman wind-driven mechanism and by eddy generation and is inhibited by the Southwest Madagascar Coastal Current. Seasonal upwelling along the East African coast is primarily driven by the northeast monsoon winds and enhanced by topographically induced shelf breaking and shear instability between the East African Coastal Current and the island chains. The Somali coast presents a strong case for the classical Ekman type of upwelling; such upwelling can be inhibited by the arrival of deeper thermocline signals generated in the offshore region by wind stress curl. Upwelling is nearly uniform along the coast of Arabia, caused by the alongshore component of the summer monsoon winds and modulated by the arrival of Rossby waves generated in the offshore region by cyclonic wind stress curl. Along the west coast of India, upwelling is driven by coastally trapped waves together with the alongshore component of the monsoon winds. Along the southern tip of India and Sri Lanka, the strong Ekman transport drives upwelling. Upwelling along the east coast of India is weak and occurs during summer, caused by alongshore winds. In addition, mesoscale eddies lead to upwelling, but the arrival of river water plumes inhibits upwelling along this coast. Southeasterly winds drive upwelling along the coast of Sumatra and Java during summer, with Kelvin wave propagation originating from the equatorial Indian Ocean affecting the magnitude and extent of the upwelling. Both El Niño–Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) events cause large variability in upwelling here. Along the west coast of Australia, which is characterized by the anomalous Leeuwin Current, southerly winds can cause sporadic upwelling, which is prominent along the southwest, central, and Gascoyne coasts during summer. Open-ocean upwelling in the southern tropical Indian Ocean and within the Sri Lanka Dome is driven primarily by the wind stress curl but is also impacted by Rossby wave propagations. Upwelling is a key driver enhancing biological productivity in all sectors of the coast, as indicated by enhanced sea surface chlorophyll concentrations. Additional knowledge at varying levels has been gained through in situ observations and model simulations. In the Mozambique Channel, upwelling simulates new production and circulation redistributes the production generated by upwelling and mesoscale eddies, leading to observations of higher ecosystem impacts along the edges of eddies. Similarly, along the southern Madagascar coast, biological connectivity is influenced by the transport of phytoplankton from upwelling zones. Along the coast of Kenya, both productivity rates and zooplankton biomass are higher during the upwelling season. Along the Somali coast, accumulation of upwelled nutrients in the northern part of the coast leads to spatial heterogeneity in productivity. In contrast, productivity is more uniform along the coasts of Yemen and Oman. Upwelling along the west coast of India has several biogeochemical implications, including oxygen depletion, denitrification, and high production of CH4 and dimethyl sulfide. Although weak, wind-driven upwelling leads to significant enhancement of phytoplankton in the northwest Bay of Bengal during the summer monsoon. Along the Sumatra and Java coasts, upwelling affects the phytoplankton composition and assemblages. Dissimilarities in copepod assemblages occur during the upwelling periods along the west coast of Australia. Phytoplankton abundance characterizes inshore edges of the slope during upwelling season, and upwelling eddies are associated with krill abundance. The review identifies the northern coast of the Arabian Sea and eastern coasts of the Bay of Bengal as the least observed sectors. Additionally, sustained long-term observations with high temporal and spatial resolutions along with high-resolution modelling efforts are recommended for a deeper understanding of upwelling, its variability, and its impact on the ecosystem.
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Shi, Weian, Zhi Huang, and Jianyu Hu. "Using TPI to Map Spatial and Temporal Variations of Significant Coastal Upwelling in the Northern South China Sea." Remote Sensing 13, no. 6 (March 11, 2021): 1065. http://dx.doi.org/10.3390/rs13061065.
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Based on Himawari-8 Sea Surface Temperature (SST) data and the semi-automatic Topographic Position Index (TPI)-based mapping method, this study maps the significant coastal upwelling in the northern South China Sea (NSCS). The results show that the Minnan coastal upwelling mainly occurs within 100 km off the south coast of Fujian; the Yuedong coastal upwelling appears to the east of Pearl River Estuary, limited to the area shallower than 40 m; and the Qiongdong coastal upwelling occurs most frequently in the area shallower than 75 m off the east coast of Hainan Island. Based on the results, this paper quantitatively describes the temporal and spatial variations of upwelling duration, influence area, upwelling SST anomaly, and chlorophyll-a (Chl-a) increase. Different coastal upwelling regions in the NSCS are significantly different in characteristics. The Qiongdong coastal upwelling has the longest duration and occurs most frequently, the Yuedong coastal upwelling has the largest influence area and Chl-a increase, and the Minnan coastal upwelling is quite strong in the NSCS.
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Utama, Alifka F., Arif Maulana, Dini Alfany, Candrasa Surya Dharma, and Gentio Harsono. "Pemetaan Kriteria Upwelling di Wilayah Kepulauan Karimata Menggunakan Parameter Suhu Permukaan Laut dan Klorofil-A pada Bulan Mei 2023." Jurnal Hidrografi Indonesia 5, no. 2 (January 25, 2024): 99–104. http://dx.doi.org/10.62703/jhi.v5i2.26.
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Perairan Karimata merupakan perairan tropis yang berada dalam wilayah Negara Kesatuan Republik Indonesia. Sehingga dengan adanya sinar matahari sepanjang tahun, produktivitas penghasil organisme di perairan tersebut dapat terus berlanjut. Produktivitas yang berkelanjutan dengan memproduksi organisme di perairan menyediakan sumber makanan bagi ikan dan organisme lainnya. Perairan Karimata mempunyai potensi sebagai daerah upwelling. Dengan memetakan sebaran wilayah upwelling tentunya memberikan jalan bagi para pelaku sektor perikanan responsif laut untuk mengidentifikasi wilayah yang potensial sebagai daerah penangkapan ikan. Penelitian ini bertujuan untuk memetakan kriteria upwelling di Wilayah Kepulauan Karimata pada bulan Mei 2023 dengan menggunakan parameter suhu permukaan laut dan konsentrasi klorofil-a untuk mengidentifikasi dan memetakan wilayah upwelling beserta kriterianya. Penelitian ini bersifat deskriptif eksploratif dengan menggunakan variabel suhu permukaan laut dan konsentrasi klorofil-a yang diolah melalui metode overlay pada perangkat lunak. Sebaran wilayah upwelling diperoleh dengan kriteria upwelling sangat kuat, upwelling kuat, upwelling sedang, dan upwelling lemah. Berdasarkan hasil pemetaan, wilayah yang dekat dengan daratan mempunyai kriteria upwelling yang sangat kuat sehingga menunjukkan tingkat produktivitas air yang sangat tinggi dibandingkan wilayah lain dalam pemetaan.
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Leng, Jin Ying, Jia Wang Chen, Hao Cai Huang, Shan Lin, Ming Zhou Liu, and Jun Bo Liu. "Impact of Structure Design of Artififical Upwelling Tube." Applied Mechanics and Materials 496-500 (January 2014): 547–50. http://dx.doi.org/10.4028/www.scientific.net/amm.496-500.547.
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Deep ocean water (DOW) is cold, nutrient-rich and pathogen-free water, which can be transported to the surface by upwelling. Upwelling can change the temperature and nutrient distribution of the surrounding water, hence improves the marine ecological environment and the marine primary productivity. Two lake experiments were accomplished in Qiandao Lake .The first experiment was done with hard PVC upwelling tube, while in the second experiment , the upwelling tubes with different diameters (0.5 m, 1 m, 1.5 m and 2 m) were made of nylon ,which are supported by rings. It can be concluded that upwelling ratio (the ratio of water volume flow rate and air volume flow rate) of the hard PVC upwelling tube was higher than that of soft nylon upwelling tube, and in condition of soft nylon upwelling tube, upwelling ratio of 1 m diameter tube was higher than that of others, providing important guidance for the next sea trial.
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Zhang, Caiyun. "Responses of Summer Upwelling to Recent Climate Changes in the Taiwan Strait." Remote Sensing 13, no. 7 (April 3, 2021): 1386. http://dx.doi.org/10.3390/rs13071386.
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The response of a summer upwelling system to recent climate change in the Taiwan Strait has been investigated using a time series of sea surface temperature and wind data over the period 1982–2019. Our results revealed that summer upwelling intensities of the Taiwan Strait decreased with a nonlinear fluctuation over the past four decades. The average upwelling intensity after 2000 was 35% lower than that before 2000. The long-term changes in upwelling intensities show strong correlations with offshore Ekman transport, which experienced a decreasing trend after 2000. Unlike the delay effect of canonical ENSO events on changes in summer upwelling, ENSO Modoki events had a significant negative influence on upwelling intensity. Strong El Niño Modoki events were not favorable for the development of upwelling. This study also suggested that decreased upwelling could not slow down the warming rate of the sea surface temperature and would probably cause the decline of chlorophyll a in the coastal upwelling system of the Taiwan Strait. These results will contribute to a better understanding of the dynamic process of summer upwelling in the Taiwan Strait, and provide a sound scientific basis for evaluating future trends in coastal upwelling and their potential ecological effects.
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Bui, Hong Long, and Minh Thu Phan. "Upwelling phenomenon in the marine regions of Southern Central of Vietnam: a review." Tạp chí Khoa học và Công nghệ Biển 22, no. 2 (June 21, 2022): 103–22. http://dx.doi.org/10.15625/1859-3097/17231.
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Upwelling is an oceanographic phenomenon that involves the physical process and contributes to changes in chemistry, biology, and natural resources. So, systematically, it is the particular ecosystems of whole marine regions with the upwelling. The strong upwelling waters in South Central Regions of Vietnam have uncertain features of the East Vietnam Sea (Bien Dong) and special characteristics of a coastal upwelling area, recorded in international scientific papers in the twentieth century. Their first signals were discovered in the early 1930s through conceptual ideas. The upwelling phenomenon is officially confirmed by scientific results of marine investigations of the NAGA Expedition (1959–1961). The paper aims to review and discuss the physical from Vietnamese investigation and results since 1990s. The following factors are the most contributing to forming and developing the strong upwelling in Southern Central Waters: (1) Influence scale (Mezo- and micro-scale); (2) Forming causes and developing mechanism of upwelling phenomenon, such as monsoon, morphography, shoreline, and western boundary current system of the East Vietnam Sea; (3) Influence of the water-mass from Mekong River on the upwelling area; (4) Ecological environmental consequences; (5) Impacts of the atmospheric-oceanic interaction processes on the western EVS on upwelling. Additionally, the review has targeted findings of upwelling phenomenon mainly in Vietnamese waters based on remote sensing analysis and reanalysis data series to simulate their forming, mechanizing, fluctuating models and the impacts of upwelling in the EVS on resources and ecosystems. The coupled atmosphere-ocean models resulted the upwelling mechanisms and formation. The long-time series of upwelling phenomenon (Macroscale) were evaluated by remote sensing and reanalyzed data series. It is also providing the supplementing and detailing causes and mechanisms of upwelling formation; impacts and interactions of upwelling on marine physics and hydrodynamics (ocean vortexes, seawater temperature), biochemical (nutrients, plankton organisms), and resources (fish, seafood). Within the framework of strong upwelling waters in the Southern Central Regions (Vietnam), the review has not only mentioned partly clarified scientific results but also indicates the limitations and challenges which were faced and encountered in the forecasters of upwelling phenomena in the future.
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Langlet, D., L. Y. Alleman, P. D. Plisnier, H. Hughes, and L. André. "Mn seasonal upwellings recorded in Lake Tanganyika mussels." Biogeosciences Discussions 3, no. 5 (September 22, 2006): 1453–71. http://dx.doi.org/10.5194/bgd-3-1453-2006.
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Abstract. Biogenic productivity of Lake Tanganyika is highly dependent on seasonal upwellings of anoxic deep waters. We investigated the shell of freshwater bivalve Pleiodon spekii as a geochemical archive of these periodic hydrological changes tuned by the monsoon regime. The results of a 2-years-long geochemical survey of the coastal waters performed on the dissolved and particulate fractions were put in perspective against laser ablation ICP-MS profiles of Mn in five aragonitic shells from the same lake location. Skeletal Mn profiles in 3 shells are very similar and dominated by episodic peaks that matched the Mn increase recorded in surface waters during the 2002 upwelling, while a shell collected during 2003 dry season detect both 2002 and 2003 upwelling events. Larger shells showing an extremely reduced growth display more than 8Mn peaks suggesting at least an 8 years record of seasonal changes in water composition.
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Chang, Yu-Lin, Lie-Yauw Oey, Chau-Ron Wu, and Hung-Fu Lu. "Why Are There Upwellings on the Northern Shelf of Taiwan under Northeasterly Winds?" Journal of Physical Oceanography 40, no. 6 (June 1, 2010): 1405–17. http://dx.doi.org/10.1175/2010jpo4348.1.
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Abstract Upwellings are observed on the northern shelf of Taiwan during northeasterly winds. Analytical and realistic numerical models are used to explain how vertical motions are created by divergence and convergence produced by wind acting on the vorticity field of two strong jets: the Kuroshio and the Taiwan Warm Current. The seaward increase in cyclonic vorticity near the Kuroshio’s western edge favors a stronger Ekman transport away from the jet, producing upwelling at the shelfbreak under a northeasterly wind. A similar mechanism for generating vertical motions is found across the Taiwan Warm Current. The numerical model results indicate that the vorticity effects can account for up to 30%–50% of the total variation in the surface Ekman transport. Except during summer’s weak southwesterlies, northeasterly wind is dominant over the East China Sea, suggesting that the vorticity effects may be prominent in the observed shelfbreak upwelling in nonsummer months.
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Liu, Sihai, Qibin Lao, Xin Zhou, Guangzhe Jin, Chunqing Chen, and Fajin Chen. "Impacts of Marine Heatwave Events on Three Distinct Upwelling Systems and Their Implications for Marine Ecosystems in the Northwestern South China Sea." Remote Sensing 16, no. 1 (December 28, 2023): 131. http://dx.doi.org/10.3390/rs16010131.
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Under global warming, the frequency and intensity of marine heatwaves are increasing. However, the inhibition of atmospheric-forcing marine heatwaves (AMHW) on upwelling and their impacts on marine ecosystems remain poorly understood. To address this issue, the satellite sea surface temperature and reanalysis data during 1998–2021 were analyzed in three distinct upwelling systems, in the northwestern South China Sea. The results showed that the coastal tide-induced upwelling in the west (W) of Hainan Island is primarily suppressed by enhanced stratification during the AMHW events, since the coastal tide-induced upwelling is insensitive to wind weakening. Contrarily, the wind-driven upwelling in the east (E) and northeast (NE) of Hainan Island are jointly regulated by wind and stratification during the AMHW. Specifically, the AMHW events have a stronger inhibitory effect on the upwelling and phytoplankton growth in the NE than that in the E. The causes could be the following: (1) the background upwelling in the NE region is stronger than in the E; thus, the NE region has a higher susceptibility to the wind weakening; (2) the wind-driven upwelling begins to be suppressed by AMHW when the high-pressure system is aligned with the coastline of the upwelling. In the NE region, the location of the high-pressure center during the occurrence of AMHW is positioned in closer proximity to the upwelling area. Moreover, the inhibitory effect of wind weakening and stratification enhancing on upwelling changes with the development of the AMHW. Before and during the mature phase of AMHW, stratification and wind jointly inhibit upwelling and phytoplankton growth, while a shift to stratification-dominated (>85%) occurs during the decline phase. This study suggests that MHW has a great impact on the upwelling ecosystem, especially the wind-driven upwelling, which should be given high attention under global warming (with increasing MHW events in the future).
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Balaji, Durairaj, Ravi Bhushan, and Laxman Singh Chamyal. "Variations of the Somali upwelling since 18.5 ka BP and its relationship with southwest monsoon rainfall." Climate of the Past 14, no. 9 (September 20, 2018): 1331–43. http://dx.doi.org/10.5194/cp-14-1331-2018.
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Abstract. Somali upwelling history has been reconstructed for the last 18.5 ka BP based on biogenic silica fluxes estimated from a sediment core retrieved from the western Arabian Sea. Surface winds along the east African coast during the southwest monsoon (SWM) cause the Somali upwelling; thus, the intensity of this upwelling has been related to the variability of the SWM. Biogenic silica flux variation suggests periodic weakening and strengthening of the Somali upwelling. Weakened upwelling during the 18.5–15 ka BP period and strengthened upwelling during the Bølling–Allerød (15–12.9 ka BP) suggest the onset of the SWM. The Younger Dryas (12.9–11.7 ka BP) is marked by reduced upwelling strength, with an intensification of the Somali upwelling observed at the beginning of the Holocene and a further decline at 8 ka BP. The increase in the upwelling strength recorded since 8 ka BP suggests SWM strengthening during the latter part of the Holocene. A comparison of upwelling variations with the SWM precipitation record demonstrates a reversal in the relationship between the strength of the Somali upwelling and SWM rainfall at the beginning of the Holocene. This observed shift has been attributed to the variation in the SWM strength due to the latitudinal shift of the intertropical convergence zone (ITCZ) associated with changes in moisture sources.
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Tristianto, Galih, Sri Yulina Wulandari, Agus Anugroho Dwi Suryoputro, Gentur Handoyo, and Muhammad Zainuri. "Studi Variabilitas Upwelling di Laut Banda." Indonesian Journal of Oceanography 3, no. 1 (March 31, 2021): 25–35. http://dx.doi.org/10.14710/ijoce.v3i1.9764.
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Laut Banda adalah sebuah cekungan perairan (basin) yang terletak di Kepulauan Maluku, Indonesia. Laut Banda memiliki karakteristik oseanografi yang menarik karena dikelilingi pulau-pulau dan juga selat sebagai jalur perlintasan Arlindo. Sirkulasi dan karakteristik massa air di Laut Banda dipengaruhi kuat oleh angin monsun. Variasi nilai arah dan kecepatan angin monsun berdampak terhadap kejadian coastal upwelling. Tujuan penelitian untuk mengetahui variabilitas upwelling di Laut Banda dan mengetahui hubungan antar parameter upwelling (indeks upwelling,SPL, dan klorofil-a). Penelitian ini menggunakan data komposit bulanan dari satelit Aqua-MODIS level 3 untuk data SPL dan klorofil-a,data angin reanalisis ECMWF,tahun 2003-2019. Hasil penelitian menunjukkan upwelling di Laut Banda terjadi pada periode April-Oktober dengan puncaknya di bulan Agustus. Rata-rata indeks upwelling mencapai 1.86 m3/s. Dampak kejadian upwelling dapat diidentifikasi melalui SPL yang lebih dingin dan konsentrasi klorofil-a tinggi. Nilai SPL mencapai 26.79 oC dan konsentrasi klorofil-a adalah 0.614 mg/m3. Hubungan SPL terhadap indeks upwelling memiliki koefisien korelasi (r=-0.707). Hubungan konsentrasi klorofil-a terhadap indeks upwelling memiliki koefisien korelasi (r=0.661).
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Liu, Xiuping, Ningdong Xie, Jiaqian Li, Mohan Bai, Biswarup Sen, and Guangyi Wang. "Potential Contribution of Coastal Upwelling to Carbon Sink through Interaction between Cyanobacteria and Microbial Eukaryotes." Water 14, no. 19 (October 1, 2022): 3097. http://dx.doi.org/10.3390/w14193097.
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Upwelling, a common oceanographic event, can make great contributions, directly or indirectly, to deep ocean carbon sequestration. However, the extent of its contribution indirectly depends on the composition of microbial communities and the interactions between bacterioplankton and other microorganisms. This study provides insights into the influence of upwelling on bacterioplankton at the whole community level and predicts their potential functional profiles. The α diversity of the bacterial community exhibited no significant differences between the upwelling area and non-upwelling area, while the community composition varied clearly in different habitats. Proteobacteria, Cyanobacteria, Bacteroidota, Firmicutes, and Actinobacteria were the five dominant phyla in all of the habitats. The proportions of members of Firmicutes were increased whereas Cyanobacteria were reduced in upwelling water. However, the percentage of Cyanobacteria was enhanced in the upwelling deep water. Functional genes that are involved in signal transductions, which belong to environmental information processing, were more active in upwelling surface water than in the other habitats. Closer and more complex relationships between bacterioplankton and microbial eukaryotes were found in the upwelling area, which altered with the variation of the external environmental conditions. Cyanobacteria showed a positive correlation with microbial eukaryotes in upwelling deep water. Combined with the high proportions of Cyanobacteria in upwelling deep water, this might be strong evidence that Cyanobacteria contribute to a deep ocean carbon sink. Overall, our study reveals the impacts of upwelling on the bacterial community composition, metabolic functions, and microbial interactions, which are significant to further understanding the carbon sink effects of upwelling.
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Satar, Muhammad Naim, Mohd Fadzil Akhir, Zuraini Zainol, and Jing Xiang Chung. "Upwelling in Marginal Seas and Its Association with Climate Change Scenario—A Comparative Review." Climate 11, no. 7 (July 18, 2023): 151. http://dx.doi.org/10.3390/cli11070151.
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After Bakun proposed his hypothesis in 1990 regarding upwelling under climate change, researchers conducted intensive studies to obtain the trends, current status, and future predictions of upwelling. Numerous studies have mainly focused on four major upwelling areas, which are part of the Eastern Boundary Upwelling System (EBUS). However, despite its importance, little attention has been given to the marginal seas upwelling areas such as the South China Sea (SCS), Arabian Sea, Baltic Sea, and other small-scale upwelling locations. Here, we combined several published studies to develop a new synthesis describing climate change impacts on these areas. There had been uncertainty regarding the intensification of upwelling, depending on the locations, data type, and method used. For the SCS, Vietnam and the northern SCS showed intensifying upwelling trends, while the Taiwan Strait showed a decreasing trend. Separate studies in eastern Hainan and the Arabian Sea (Somali and Oman) showed contrasting results, where both increasing and decreasing trends of upwelling had been recorded. Like the SCS, the Baltic Sea showed different results for different areas as they found negative trends along the Polish, Latvian and Estonian, and positive trends along the Swedish coast of the Baltic Sea and the Finnish coast of the Gulf of Finland. While small scales upwelling in La Guajira and southern Java showed increasing and decreasing trends, respectively. All of these limited studies suggest that researchers need to conduct a lot more studies, including the future projection of upwelling, by using climate models to develop a new understanding of how the upwelling in the SCS responds to climate change.
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Dunstall, T. G., J. C. H. Carter, B. P. Monroe, G. T. Haymes, R. R. Weiler, and G. J. Hopkins. "Influence of Upwellings, Storms, and Generating Station Operation on Water Chemistry and Plankton in the Nanticoke Region of Long Point Bay, Lake Erie." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 7 (July 1, 1990): 1434–45. http://dx.doi.org/10.1139/f90-162.
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Storms and upwellings resulted in significant alterations to the aquatic environment in the Long Point Bay region of Lake Erie, contributing to short-term variability in water chemistry and plankton. Both storms and upwellings resulted in nutrient enrichment (filtered reactive phosphorus, total inorganic nitrogen, reactive silicates and organic nitrogen) in lake surface waters during the period of lake warming, prior to mid-August. Storms and upwellings also differentially affected the distributions of specific zooplankton taxa in the lake surface stratum. The most prominent effect was the increased abundance of Diacyclops bicuspidatus thomasi during upwellings, particularly towards shore. The once-through cooling process of the generating station also affected zooplankton distributions, most notably that of D. bicuspidatus thomasi, with a nearshore increase in abundance that was similar to the influence exerted by upwelling.
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Brandt, Peter, Gaël Alory, Founi Mesmin Awo, Marcus Dengler, Sandrine Djakouré, Rodrigue Anicet Imbol Koungue, Julien Jouanno, Mareike Körner, Marisa Roch, and Mathieu Rouault. "Physical processes and biological productivity in the upwelling regions of the tropical Atlantic." Ocean Science 19, no. 3 (May 11, 2023): 581–601. http://dx.doi.org/10.5194/os-19-581-2023.
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Abstract. In this paper, we review observational and modelling results on the upwelling in the tropical Atlantic between 10∘ N and 20∘ S. We focus on the physical processes that drive the seasonal variability of surface cooling and the upward nutrient flux required to explain the seasonality of biological productivity. We separately consider the equatorial upwelling system, the coastal upwelling system of the Gulf of Guinea and the tropical Angolan upwelling system. All three tropical Atlantic upwelling systems have in common a strong seasonal cycle, with peak biological productivity during boreal summer. However, the physical processes driving the upwelling vary between the three systems. For the equatorial regime, we discuss the wind forcing of upwelling velocity and turbulent mixing, as well as the underlying dynamics responsible for thermocline movements and current structure. The coastal upwelling system in the Gulf of Guinea is located along its northern boundary and is driven by both local and remote forcing. Particular emphasis is placed on the Guinea Current, its separation from the coast and the shape of the coastline. For the tropical Angolan upwelling, we show that this system is not driven by local winds but instead results from the combined effect of coastally trapped waves, surface heat and freshwater fluxes, and turbulent mixing. Finally, we review recent changes in the upwelling systems associated with climate variability and global warming and address possible responses of upwelling systems in future scenarios.
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Xiao, Teng, Jiajun Feng, Zhongfeng Qiu, Rong Tang, Aibo Zhao, Kapo Wong, Jin Yeu Tsou, and Yuanzhi Zhang. "Remote-Sensing Estimation of Upwelling-Frequent Areas in the Adjacent Waters of Zhoushan (China)." Journal of Marine Science and Engineering 12, no. 7 (June 27, 2024): 1085. http://dx.doi.org/10.3390/jmse12071085.
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Upwelling, which mixes deep and surface waters, significantly enhances the productivity of surface waters and plays a critical role in marine ecosystems, especially in key fishing areas like Zhoushan. This study utilized merged sea surface temperature data and an upwelling edge detection algorithm based on temperature gradients to analyze the characteristics of upwelling in Zhoushan and the Yangtze River Estuary over the past 28 years. The results indicate that upwelling in Zhoushan begins in April, peaks in July, gradually weakens, and disappears by October. The phenomenon is most pronounced during the summer months (June to August), with significant spatial distribution differences in April and September. Notably, high probability values of upwelling centers and core areas are mainly concentrated near Ma’an Island, Zhongjieshan Island, and Taohua Island. In these areas, upwelling remains stable during the summer, forming a unique “footprint” distribution pattern, and these are also the locations of the Zhoushan National Marine Ranch. From April to August, the extent of the upwelling area gradually decreases and stabilizes. These findings emphasize the frequent upwelling activity around Zhoushan and its significant contribution to the formation of local fisheries. Additionally, considering that the formation of natural upwelling in the East China Sea depends on the southern monsoon, the study suggests establishing artificial upwelling systems during periods unfavorable for natural upwelling, based on high probability areas, to enhance fishery yields and support the development of local fisheries.
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Li, Yuhui, Yun Qiu, Jianyu Hu, Cherry Aung, Xinyu Lin, and Yue Dong. "Springtime Upwelling and Its Formation Mechanism in Coastal Waters of Manaung Island, Myanmar." Remote Sensing 12, no. 22 (November 18, 2020): 3777. http://dx.doi.org/10.3390/rs12223777.
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Multisource satellite remote sensing data and the World Ocean Atlas 2018 (WOA18) temperature and salinity dataset have been used to analyze the spatial distribution, variability and possible forcing mechanisms of the upwelling off Manaung Island, Myanmar. Signals of upwelling exist off the coasts of Manaung Island, in western Myanmar during spring. It appears in February, reaches its peak in March and decays in May. Low-temperature (<28.3 °C) and high-salinity (>31.8 psu) water at the surface of this upwelling zone is caused by the upwelling of seawater from a depth below 100 m. The impact of the upwelling on temperature is more significant in the subsurface layer than that in the surface layer. In contrast, the impact of the upwelling on salinity in the surface layer is more significant. Further research reveals that the remote forcing from the equator predominantly induces the evolution of the upwelling, while the local wind forcing also contributes to strengthen the intensity of the upwelling during spring.
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Yi, X., B. Hünicke, N. Tim, and E. Zorita. "The relationship between Arabian Sea upwelling and Indian monsoon revisited." Ocean Science Discussions 12, no. 6 (November 6, 2015): 2683–704. http://dx.doi.org/10.5194/osd-12-2683-2015.
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Abstract. Studies based on upwelling indices (sediment records, sea-surface temperature and wind) suggest that upwelling along the western coast of Arabian Sea is strongly affected by the Indian summer monsoon (ISM). In order to examine this relationship directly, we employ the vertical water mass transport produced by the eddy-resolving global ocean simulation STORM driven by meteorological reanalysis over the last 61 years. With its very high spatial resolution (10 km), STORM allows us to identify characteristics of the upwelling system. We analyze the co-variability between upwelling and meteorological and oceanic variables from 1950 to 2010. The analyses reveal high interannual correlations between coastal upwelling and along-shore wind-stress (r=0.73) as well as with sea-surface temperature (r0.83). However, the correlation between the upwelling and the ISM is small and other factors might contribute to the upwelling variability. In addition, no long-term trend is detected in our modeled upwelling time series.
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Ismail, Hassan Ebrahiem, Johannes Jacobus Agenbag, Stephanie de Villiers, and Bhekumusa Jabulani Ximba. "Relation between Upwelling Intensity and the Variability of Physical and Chemical Parameters in the Southern Benguela Upwelling System." International Journal of Oceanography 2015 (February 8, 2015): 1–8. http://dx.doi.org/10.1155/2015/510713.
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The extent to which wind-driven seasonal upwelling cycles manifest in surface ocean temperature and nutrient variability along a monitoring line in the Southern Benguela upwelling system was investigated. Monitoring conducted monthly over a six-year period shows that surface temperature and nutrient concentrations exhibit very poor seasonality and weak correlation with the upwelling index. This is, despite clear evidence for spatial inshore-offshore gradients in temperature, nutrients, and chlorophyll, consistent with an upwelling regime. The upper ocean temperature gradient shows a much better correspondence to the upwelling index but at the same time demonstrates that surface heating, and not vertical mixing related to upwelling, controls the upper ocean temperature gradient. The results suggest that remote sensing techniques would be inadequate tools to monitor upwelling events in the Southern Benguela. Also, the incidence of phytoplankton blooms is more likely triggered by stratified conditions associated with surface heating than relaxation of upwelling winds.
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Sukresno, Bambang, Denarika Jatisworo, and Denny Wijaya Kusuma. "ANALISIS MULTILAYER VARIABILITAS UPWELLING DI PERAIRAN SELATAN JAWA." Jurnal Kelautan Nasional 13, no. 1 (April 2, 2018): 15. http://dx.doi.org/10.15578/jkn.v1i1.6619.
Full textAbstract:
Variabilitas upwelling di perairan selatan Jawa telah diidentifikasi. Analisis multilayer dilakukan dengan menggunakan data ARGO Float. Variabilitas suhu permukaan laut (SPL) dan klorofil-a (klor-a) dianalisis dengan menggunakan data satelit MODIS Aqua. Pengaruh El Nino Southern Oscillation (ENSO) terhadap upwelling dilakukan dengan menggunakan indeks Oceanic Nino Index (ONI), sedangkan pengaruh Indian Ocean Dipole (IOD) direpresentasikan dengan menggunakan indeks Dipole Mode Index (DMI). Dari hasil penelitian diketahui bahwa ENSO mempengaruhi intensitas upwelling. Pada periode el nino intensitas upwelling mengalami peningkatan yang diikuti oleh penurunan SPL dan naiknya konsentrasi klor-a, sebaliknya pada periode la nina terjadi penurunan intensitas upwelling yang diikuti naiknya SPL dan turunnya konsentrasi klor-a. Peningkatan intensitas upwelling juga terdeteksi pada saat terjadi periode IOD positif, sedangkan penurunan intensitas upwelling terjadi pada periode IOD negatif.
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Bai, Peng, Pei Liang Li, Yan Zhen Gu, and Ke Jian Wu. "Interaction between Upwelling and Internal Tide in the East Qiongzhou Strait Areas." Advanced Materials Research 1092-1093 (March 2015): 1160–64. http://dx.doi.org/10.4028/www.scientific.net/amr.1092-1093.1160.
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An upwelling event that occurred off the east Hainan Island coast in summer 2010 is captured by processing the Moderate Resolution Imaging Spectroradiometer (MODIS) sea surface temperature (SST) data. High resolution Regional Ocean Model System (ROMS) is employed to study this upwelling event, and is proved to provide good reproduction of this upwelling event by comparing ROMS SST with MODIS SST. It is detected that internal tide generated and interacted with the upwelling in the east Qiongzhou Strait areas. The upwelling and the internal tide modulated each other: the uplift of the isopycnal due to the fluctuation of the internal tide enhanced the upwelling; in another aspect, the upwelling changed the background stratification which is sufficient to control the amount of barotropic-to-baroclinic energy conversion and the preferred direction of baroclinic energy flux [21].
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ZHABIN, I. A., and N. B. LUK’YANOVA. "IMPACT OF WIND-DRIVEN UPWELLING AND AMUR RIVER DISCHARGE ON THE THERMOHALINE WATER STRUCTURE OFF THE NORTHEASTERN COAST OF SAKHALIN." Meteorologiya i Gidrologiya, no. 9 (September 2022): 32–41. http://dx.doi.org/10.52002/0130-2906-2022-9-32-41.
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The impact of the wind-driven upwelling and the Amur River discharge on the thermohaline water structure off the northeastern coast of Sakhalin was analyzed using hydrographic data аnd satellite information on the sea surface temperature distribution. The interaction of upwelling water and the coastal current depends on wind conditions and the Amur river runoff. Coastal upwelling develops at relatively low river runoff values (summer low water). The increase in the Amur River discharge during the summer flood enhances the interaction of the upwelling and the coastal buoyancy current. The Amur river runoff flows directly along the shore, which tears cold upwelling water off the coast. The advection of the cold upwelling water from the coast towards the open sea increases with the consecutive alternation of upwelling and downwelling events.
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Abalos, M., W. J. Randel, and E. Serrano. "Variability in upwelling across the tropical tropopause and correlations with tracers in the lower stratosphere." Atmospheric Chemistry and Physics Discussions 12, no. 7 (July 31, 2012): 18817–51. http://dx.doi.org/10.5194/acpd-12-18817-2012.
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Abstract. Temporal variability of the upwelling near the tropical tropopause on daily to annual timescales is investigated using three different estimates computed from the ERA-Interim reanalysis. These include upwelling archived by the reanalysis, plus estimates derived from thermodynamic and momentum balance calculations. Substantial variability in upwelling is observed on both seasonal and sub-seasonal time scales, and the three estimates show reasonably good agreement. Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing the calculated upwelling estimates with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Statistically significant correlations between upwelling, temperatures and tracers are also found for sub-seasonal timescales, demonstrating the importance of upwelling in forcing transient variability in the lower tropical stratosphere.
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Abalos, M., W. J. Randel, and E. Serrano. "Variability in upwelling across the tropical tropopause and correlations with tracers in the lower stratosphere." Atmospheric Chemistry and Physics 12, no. 23 (December 4, 2012): 11505–17. http://dx.doi.org/10.5194/acp-12-11505-2012.
Full textAbstract:
Abstract. Temporal variability of the upwelling near the tropical tropopause on daily to annual timescales is investigated using three different estimates computed from the ERA-Interim reanalysis. These include upwelling archived by the reanalysis, plus estimates derived from thermodynamic and momentum balance calculations. Substantial variability in upwelling is observed on both seasonal and sub-seasonal timescales, and the three estimates show reasonably good agreement. Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing the calculated upwelling estimates with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Statistically significant correlations between upwelling, temperatures and tracers are also found for sub-seasonal timescales, demonstrating the importance of upwelling in forcing transient variability in the lower tropical stratosphere.
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Bode, Antonio, Angel F. Lamas, and Carmen Mompeán. "Effects of Upwelling Intensity on Nitrogen and Carbon Fluxes through the Planktonic Food Web off A Coruña (Galicia, NW Spain) Assessed with Stable Isotopes." Diversity 12, no. 4 (March 25, 2020): 121. http://dx.doi.org/10.3390/d12040121.
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The input of new nutrients by upwelling in shelf waters, and the associated carbon and nitrogen fluxes, can be traced by their stable isotope signatures in organic matter. Here, we analyze the relationships between upwelling intensity and natural abundance of stable carbon and nitrogen isotopes in seston, sedimented particles, and four plankton size fractions (200 to 5000 µm) sampled monthly during 2010 and 2011 in a seasonal upwelling ecosystem. Upwelling modified the seasonal warming stratification by introducing cold and nutrient-rich waters in subsurface layers, enhancing chlorophyll-a and diatom abundance. Seston and sedimented particles were enriched in heavy nitrogen (but not carbon) isotopes linearly with upwelling intensity, indicating a primary effect of upwelling on phytoplankton production. In contrast, all plankton fractions were enriched in heavy carbon isotopes with upwelling, mainly due to the consumption of diatoms. These results confirm the differential effect of upwelling on nitrogen and carbon fluxes in the plankton food web. Direct effects of the new nitrogen inputs on phytoplankton are less evident with the increase of plankton size as nitrogen is repeatedly recycled, while the enriched carbon of plankton suggests the consumption of diatoms during upwelling. We provide linear equations to assess the influence of changes in upwelling intensity on nitrogen and carbon fluxes in seston and plankton in this ecosystem, as well as to estimate reference baseline values for food web studies.
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Tim, N., E. Zorita, and B. Hünicke. "Decadal variability and trends of the Benguela upwelling system as simulated in a high-resolution ocean simulation." Ocean Science 11, no. 3 (June 30, 2015): 483–502. http://dx.doi.org/10.5194/os-11-483-2015.
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Abstract. Detecting the atmospheric drivers of the Benguela upwelling systems is essential to understand its present variability and its past and future changes. We present a statistical analysis of a high-resolution (0.1°) ocean-only simulation driven by observed atmospheric fields over the last 60 years with the aim of identifying the large-scale atmospheric drivers of upwelling variability and trends. The simulation is found to reproduce well the seasonal cycle of upwelling intensity, with a maximum in the June–August season in North Benguela and in the December–February season in South Benguela. The statistical analysis of the interannual variability of upwelling focuses on its relationship to atmospheric variables (sea level pressure, 10 m wind, wind stress). The relationship between upwelling and the atmospheric variables differ somewhat in the two regions, but generally the correlation patterns reflect the common atmospheric pattern favouring upwelling: southerly wind/wind stress, strong subtropical anticyclone, and an ocean–land sea level pressure gradient. In addition, the statistical link between upwelling and large-scale climate variability modes was analysed. The El Niño–Southern Oscillation and the Antarctic Oscillation exert some influence on austral summer upwelling velocities in South Benguela. The decadal evolution and the long-term trends of simulated upwelling and of ocean-minus-land air pressure gradient do not agree with Bakun's hypothesis that anthropogenic climate change should generally intensify coastal upwelling.
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Tim, N., E. Zorita, and B. Hünicke. "Decadal variability and trends of the Benguela Upwelling System as simulated in a high-resolution ocean simulation." Ocean Science Discussions 12, no. 2 (March 9, 2015): 403–47. http://dx.doi.org/10.5194/osd-12-403-2015.
Full textAbstract:
Abstract. Detecting the atmospheric drivers of the Benguela Upwelling Systems is essential to understand its present variability and its past and future changes. We present a statistical analysis of an ocean-only simulation driven by observed atmospheric fields over the last decades with the aim of identifying the large-scale atmospheric drivers of upwelling variability and trends. The simulation is found to reproduce well the seasonal cycle of upwelling intensity, with a maximum in the June-to-August season in North Benguela and in the December-to-February season in South Benguela. The statistical analysis of the interannual variability of upwelling focuses on its relationship to atmospheric variables (sea level pressure, 10 m-wind, wind stress). The relationship between upwelling and the atmospheric variables differ somewhat in the two regions, but generally, the correlation patterns reflect the common atmospheric pattern favoring upwelling: southerly wind/wind stress, strong subtropical anticyclone, and an ocean-land sea level pressure gradient. In addition, the statistical link between upwelling and large-scale climate variability modes was analyzed. The El Niño Southern Oscillation and the Antarctic Oscillation exert some influence on austral summer upwelling velocities in South Benguela. The decadal evolution and the long-term trends of upwelling and of ocean-minus-land air pressure gradient do not agree with Bakun's hypothesis that anthropogenic climate change should generally intensify coastal upwelling.