scholarly journals Atmospheric Response to Oceanic Cold Eddies West of Luzon in the Northern South China Sea

Atmosphere ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 255
Author(s):  
Haoya Liu ◽  
Shumin Chen ◽  
Weibiao Li ◽  
Rong Fang ◽  
Zhuo Li ◽  
...  
Keyword(s):  
Wind Speed ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Turbulent Heat ◽  
Sst Front ◽  
China Sea ◽  
Sst Anomalies

Using the compositing method, two kinds of sea surface temperature (SST) anomalies associated with mesoscale ocean eddies and their effects on the atmosphere over the northern South China Sea were investigated. We focused on Luzon cold eddies (LCEs), which form during the winter monsoon and occur repeatedly to the west of Luzon Island, where a SST front exists. Using satellite and reanalysis data, 20 LCEs from 2000–2016 were classified into two types according to their impact on the atmosphere. One type consisted of cold SST anomalies within the eddy interior; subsequent turbulent heat flux and surface wind speed decreased over the cold core, presenting a monopole pattern. The second type comprised SST anomalies on either side of the eddy, which mostly propagated along the SST front. For this type of LCEs, cyclonic eddy currents acting on the SST front led to the SST anomalies. They produced a dipole, with surface wind deceleration and acceleration over negative and positive SST anomalies, respectively, on either side of the eddy’s flank. Dynamically, for both types of LCE, a vertical mixing mechanism appeared to be responsible for the wind anomalies. Moreover, anomalous vertical circulations developed over the LCEs that extended over the whole boundary layer and penetrated into the free atmosphere, leading to an anomalous convective rain rate. Quantitatively, the surface wind speed changed linearly with SST; atmospheric anomalies related to LCEs explained 5%–14% of the total daily variance.

scholarly journals Factors for Interannual Variations of September–October Rainfall in Hainan, China

2013 ◽  
Vol 26 (22) ◽  
pp. 8962-8978 ◽  
Author(s):  
Xiao Feng ◽  
Renguang Wu ◽  
Jiepeng Chen ◽  
Zhiping Wen
Keyword(s):  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Maritime Continent ◽  
Central Pacific ◽  
China Sea ◽  
Anomaly Pattern ◽  
Sst Anomaly ◽  
Circulation Anomalies ◽  
Sst Anomalies

Abstract The present study investigates the year-to-year variations of September–October rainfall in Hainan, China, for the period 1965–2010. The dominant circulation anomalies feature a cyclone (an anticyclone) over the Indochina Peninsula and northern South China Sea, an anticyclone (a cyclone) over subtropical western North Pacific and lower-level convergence (divergence) over the Maritime Continent in the wet (dry) years. These circulation anomalies are responses to an east–west sea surface temperature (SST) anomaly pattern with negative (positive) SST anomalies in the equatorial central Pacific and positive (negative) SST anomalies around the Maritime Continent in the wet (dry) years. Although the SST anomaly pattern is similar (but with opposite anomaly), the SST signal in the equatorial central Pacific is more significant in the dry years than in the wet years. This difference indicates a larger case-to-case variability in the wet years than in the dry years. The large variability in the wet years is attributed to contributions of tropical cyclones (TCs) and intraseasonal oscillations (ISOs). There are more TCs impinging on Hainan and the TC tracks are closer to the island in the wet years than in the dry years. The rainfall shows large intraseasonal variations with periods of 10–20 and 30–60 days during September–October in the wet years. The 10–20-day ISO originates from the Maritime Continent, whereas the 30–60-day ISO develops over tropical Indian Ocean and propagates northeastward to northern South China Sea. In contrast, the ISO signal is much weaker in the dry years.

Analysis of Extreme Wind Speed Estimates in the Northern South China Sea

2020 ◽  
Vol 59 (10) ◽  
pp. 1625-1635
Author(s):  
Zhiduo Yan ◽  
Liang Pang ◽  
Sheng Dong
Keyword(s):  
Parameter Estimation ◽  
Wind Speed ◽  
South China Sea ◽  
South China ◽  
Northern South China Sea ◽  
Distribution Model ◽  
Wind Fields ◽  
China Sea ◽  
Extreme Wind ◽  
Extreme Wind Speed

AbstractAn increasing number of coastal and offshore structures have been built for coastal protection and marine development in recent years, and these marine structures need to be reasonably designed on the basis of wind speed. In this paper, extreme wind speed estimates are studied in detail by using the best-track datasets of northwestern Pacific Ocean tropical cyclones and ERA5 wind field data. The extreme wind speed fits by five distributions are compared using a blended sample of the wind fields from the ERA5 dataset and parametric wind data. The blend of wind fields improved the data accuracy and extreme value estimation reliability. In addition, the effects of the distribution model, data, threshold, and parameter estimation methods on the calculated results are discussed. The results show that the data had the greatest influences on probability prediction, followed by the distribution model and the parameter estimation method, with the threshold presenting the least influence. In this study, the reliability of the estimates was improved and the uncertainty of the results was analyzed, and the findings provide a wind speed design reference for the northern South China Sea.

scholarly journals Influence of SST Anomalies on Winter Turbulent Heat Fluxes in the Eastern Kuroshio–Oyashio Confluence Region

2014 ◽  
Vol 27 (24) ◽  
pp. 9349-9358 ◽  
Author(s):  
Shusaku Sugimoto
Keyword(s):  
Wind Speed ◽  
Air Temperature ◽  
Surface Wind ◽  
Surface Air Temperature ◽  
Surface Wind Speed ◽  
Heat Fluxes ◽  
Specific Humidity ◽  
Turbulent Heat ◽  
Confluence Region ◽  
Sst Anomalies

Abstract Variations in the turbulent heat flux (THF; the sum of the sensible and latent heat fluxes) in the eastern Kuroshio–Oyashio confluence region (EKOCR; 36°–40°N, 155°–160°E) were investigated over a period of 27 consecutive winters (December–February) from 1985/86 to 2011/12. The THF was calculated from a bulk formula using daily variables [surface wind speed, surface air specific humidity, surface air temperature, and sea surface temperature (SST)] of the objectively analyzed air–sea fluxes (OAFlux) dataset and bulk coefficients based on the Tropical Ocean and Global Atmosphere Coupled Ocean–Atmosphere Response Experiment (TOGA COARE) bulk flux algorithm 3.0. The winter THF over the EKOCR showed low-frequency variations, with larger THF values in the early 2000s and smaller values in the late 1990s and late 2000s. The heat release in the early 2000s was up to ~40% greater than that in the late 1990s and late 2000s. By performing experiments using combinations of daily raw data values and daily climatological data, the relative contributions of SST, surface air specific humidity, surface air temperature, and surface wind speed were quantitatively assessed in determining the THF over the EKOCR. Results showed that SST predominantly determines the THF: large amounts of heat are released during times of positive SST anomalies. By using Argo float (temperature–salinity) profiles of 2003–12 and a satellite altimetry dataset of 1992–2012, it was found that the warm–salty water transported by an occurrence of the Kuroshio bifurcation was responsible for the generation of positive SST anomalies in the EKOCR.

GEOPHYSICAL RESPONSE OF THE LIUHUA CARBONATE PLATFORM IN NORTHERN SOUTH CHINA SEA

2011 ◽  
Vol 31 (4) ◽  
pp. 105-112
Author(s):  
Guangxu ZHANG ◽  
Shiguo WU ◽  
Weilin ZHU ◽  
Hesheng SHI ◽  
Duanxin CHEN
Keyword(s):  
South China Sea ◽  
South China ◽  
Carbonate Platform ◽  
Northern South China Sea ◽  
China Sea
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