The Experts below are selected from a list of 140079 Experts worldwide ranked by ideXlab platform
Jiaxin Wang - One of the best experts on this subject based on the ideXlab platform.
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Impact of Low-Pressure Systems on winter heavy air pollution in the northwest Sichuan Basin, China
Atmospheric Chemistry and Physics, 2018Co-Authors: Guicai Ning, Shigong Wang, Steve Hung Lam Yim, Ziwei Shang, Jinyan Wang, Jiaxin WangAbstract:Abstract. The cities of Chengdu, Deyang, and Mianyang in the northwest Sichuan Basin are part of a rapidly developing urban agglomeration adjoining the eastern slopes of the Tibetan Plateau. Heavy air pollution events have frequently occurred over these cities in recent decades, but the effects of meteorological conditions on these pollution events are unclear. We explored the effects of weather Systems on winter heavy air pollution from 1 January 2006 to 31 December 2012 and from 1 January 2014 to 28 February 2017. A total of 10 heavy air pollution events occurred during the research period and 8 of these took place while the region was affected by a dry Low-Pressure System at 700 hPa. When the urban agglomeration was in front of the Low-Pressure System and the weather conditions were controlled by a warm southerly air fLow, a strong temperature inversion appeared above the atmospheric boundary layer acting as a lid. Forced by this strong inversion layer, the local secondary circulation was confined to the atmospheric boundary layer, and the horizontal wind speed in the Lower troposphere was Low. As a result, vertical mixing and horizontal dispersion in the atmosphere were poor, favoring the formation of heavy air pollution events. After the Low-Pressure System had transited over the region, the weather conditions in the urban agglomeration were controlled by a dry and cold air fLow from the northwest at 700 hPa. The strong inversion layer gradually dissipated, the secondary circulation enhanced and uplifted, and the horizontal wind speed in the Lower troposphere also increased, resulting in a sharp decrease in the concentration of air pollutants. The strong inversion layer above the atmospheric boundary layer induced by the Low-Pressure System at 700 hPa thus played a key role in the formation of heavy air pollution during the winter months in this urban agglomeration. This study provides scientific insights for forecasting heavy air pollution in this region of China.
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Impact of Low-Pressure Systems on winter heavy air pollution in the northwest Sichuan Basin, China
2018Co-Authors: Guicai Ning, Shigong Wang, Steve Hung Lam Yim, Ziwei Shang, Jinyan Wang, Jiaxin WangAbstract:Abstract. The cities of Chengdu, Deyang, and Mianyang in the northwest Sichuan Basin are part of a rapidly developing urban agglomeration adjoining the eastern slopes of the Tibetan Plateau. Heavy air pollution events have frequently occurred over the cities in recent decade, but the effects of meteorological conditions on these pollution events are unclear. We explored the effects of weather Systems on winter heavy air pollution from 1 January 2006 to 31 December 2012 and from 1 January 2014 to 28 February 2017. Ten heavy air pollution events occurred during the research period and eight of these took place while the region was affected by a dry Low-Pressure System at 700 hPa. When the urban agglomeration was in front of the Low-Pressure System and the weather conditions were controlled by a warm southerly air fLow, and a strong temperature inversion appeared above the atmospheric boundary layer acting as a lid. Forced by this strong inversion layer, the local secondary circulation was confined within the atmospheric boundary layer and the horizontal wind speed in the Lower troposphere was Low. As a result, vertical mixing and horizontal dispersion in the atmosphere were poor, favoring the formation of heavy air pollution events. After the Low-Pressure System had transited over the region, the weather conditions in the urban agglomeration were controlled by a dry and cold air fLow from the northwest at 700 hPa. The strong inversion layer gradually dissipated, the secondary circulation enhanced and uplifted, and the horizontal wind speed in the Lower troposphere also increased, resulting in a sharp decrease in the concentration of air pollutants. The strong inversion layer above the atmospheric boundary layer induced by the Low-Pressure System at 700 hPa thus played a key role in the formation of heavy air pollution during the winter months in this urban agglomeration. This study provides scientific insights for forecasting heavy air pollution in this region of China.
Takeshi Tamura - One of the best experts on this subject based on the ideXlab platform.
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modeling ocean cryosphere interactions off adelie and george v land east antarctica
Journal of Climate, 2017Co-Authors: Kazuya Kusahara, Hiroyasu Hasumi, Alexander D Fraser, Shigeru Aoki, Keishi Shimada, G D Williams, R A Massom, Takeshi TamuraAbstract:AbstractOcean–cryosphere interactions along the Adelie and George V Land (AGVL) coast are investigated using a coupled ocean–sea ice–ice shelf model. The dominant feature of the Mertz Glacier Tongue (MGT), located at approximately 145°E, was a highly productive winter coastal polynya System, until its calving in February 2010 dramatically changed the regional “icescape.” This study examines the annual mean, seasonal, and interannual variabilities of sea ice production; basal melting of the MGT; ice shelves, large icebergs, and fast ice; Dense Shelf Water (DSW) export; and bottom water properties on the continental slope and rise, and assesses the impacts of the calving event. The interannual variability of the winter coastal polynya regime is dominated by the regional offshore winds and air temperature, which are linked to activity of the Amundsen Sea Low Pressure System. This is the main driver of the interannual variability of DSW exported from the AGVL region. The calving event led to a decrease in sea...
Fabien Desbiolles - One of the best experts on this subject based on the ideXlab platform.
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role of ocean mesoscale structures in shaping the angola Low Pressure System and the southern africa rainfall
Climate Dynamics, 2020Co-Authors: Fabien Desbiolles, Emma Howard, Ross C Blamey, Rondrotiana Barimalala, Neil C G Hart, C J C ReasonAbstract:Southern African climate is under the influence of both tropical and subtropical Systems which result in a complex region where important interactions co-exist over a large spectrum of spatiotemporal scales. The Angola Low (AL), situated on boundary between tropical and subtropical southern Africa, has been diagnosed as a key driver of moisture distribution in the region on daily to seasonal time scales. It has been demonstrated that the AL Pressure System is sensitive to the dynamics of the neighbouring oceans, but to date no study has considered the model resolution of air–sea interactions required to simulate this sensitivity. Using sensitivity experiments with a regional atmospheric model, which differ only in the mesoscale sea surface temperature (SST) forcing characteristics (either the full spectrum of SST variability or only its large-scale components are included), we first quantify the importance of SST gradients on the AL strength and variability. The results suggest that the mesoscale SST variability of the Angola–Benguela Frontal Zone (ABFZ) plays a key role in AL activity, particularly during the late summer. Synoptic-scale tropical Lows, which form the AL, are automatically detected, and the results suggest more extreme events occur when the model is forced by mesoscale SSTs (everywhere and in the ABFZ area only). The rainfall resulting from those events suggests that tropical-Low episodes are associated with nearly 15% of the total rain in Angola and Namibia. The link between AL dynamics and wet spells is also discussed, with the former showing a different spatial pattern as well as frequency when the ocean is fully resolved.
Katja Lohmann - One of the best experts on this subject based on the ideXlab platform.
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importance of heat transport and local air sea heat fluxes for barents sea climate variability
Journal of Geophysical Research, 2010Co-Authors: Anne Britt Sando, Jan Even Øie Nilsen, Katja LohmannAbstract:[1] An isopycnic coordinate ocean model has been used to investigate the importance of different mechanisms on the Barents Sea climate variability for the period 1948–2006 Observed and simulated time series from the Kola Section are used to evaluate the model, and the model captures both the temperature and its variability. Based on lagged correlations between different climatological time series, it is shown here that heat transport through the Barents Sea Opening and solar heat flux are about equally important to the climate variability in the Barents Sea. The heat transport has greater potential of predictability due to a relatively long time lag. Furthermore, the non-solar and the net heat flux variability is governed by fluctuations in the oceanic heat content. All time series considered important for the Barents Sea climate variability show significant correlation to the North Atlantic Oscillation (NAO) pattern on a decadal time scale. As the associated Low Pressure System in the Nordic Seas moves eastward from 1948–1977 to 1978–2006, the correlation between NAO and heat transports into the Barents Sea becomes higher.
R A Massom - One of the best experts on this subject based on the ideXlab platform.
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modeling ocean cryosphere interactions off adelie and george v land east antarctica
Journal of Climate, 2017Co-Authors: Kazuya Kusahara, Hiroyasu Hasumi, Alexander D Fraser, Shigeru Aoki, Keishi Shimada, G D Williams, R A Massom, Takeshi TamuraAbstract:AbstractOcean–cryosphere interactions along the Adelie and George V Land (AGVL) coast are investigated using a coupled ocean–sea ice–ice shelf model. The dominant feature of the Mertz Glacier Tongue (MGT), located at approximately 145°E, was a highly productive winter coastal polynya System, until its calving in February 2010 dramatically changed the regional “icescape.” This study examines the annual mean, seasonal, and interannual variabilities of sea ice production; basal melting of the MGT; ice shelves, large icebergs, and fast ice; Dense Shelf Water (DSW) export; and bottom water properties on the continental slope and rise, and assesses the impacts of the calving event. The interannual variability of the winter coastal polynya regime is dominated by the regional offshore winds and air temperature, which are linked to activity of the Amundsen Sea Low Pressure System. This is the main driver of the interannual variability of DSW exported from the AGVL region. The calving event led to a decrease in sea...
