Effects of ENSO diversity and cold tongue bias on seasonal prediction of South China late spring rainfall

2021 ◽  
Author(s):  
Ronald Kwan Kit Li ◽  
Chi Yung Tam ◽  
Ngar Cheung Lau
Keyword(s):  
South China ◽  
Seasonal Prediction ◽  
Late Spring ◽  
Cold Tongue ◽  
Enso Diversity

scholarly journals Satellite observations of the small-scale cyclonic eddies in the western South China Sea

2014 ◽  
Vol 11 (9) ◽  
pp. 13515-13532
Author(s):  
F. Liu ◽  
S. Tang ◽  
C. Chen
Keyword(s):  
South China Sea ◽  
South China ◽  
Rotation Speed ◽  
Mesoscale Eddies ◽  
Small Scale ◽  
Western Boundary ◽  
Cold Tongue ◽  
China Sea ◽  
Western South China Sea ◽  
Offshore Transport

Abstract. High-resolution ocean color observation offers an opportunity to investigate the oceanic small-scale processes. In this study, The Medium Resolution Imaging Spectrometer (MERIS) daily 300 m data are used to study small-scale processes in the western South China Sea. It is indicated that the cyclonic eddies with horizontal scales of the order of 10 km are frequently observed during upwelling season of each year over 2004–2009. These small-scale eddies are generated in the vicinity of the southern front of the cold tongue, and then propagate eastward with a speed of approximately 12 cm s−1. This propagation speed is consistent with the velocity of the western boundary current. As a result, the small-scale eddies keep rotating high levels of the phytoplankton away from the coastal areas, resulting in the accumulation of phytoplankton in the interior of the eddies. The generation of the small-scale eddies may be associated with strengthening of the relative movement between the rotation speed of the anticylconic mesoscale eddies and the offshore transport. With the increases of the normalized rotation speed of the anticyclonic mesoscale eddies relative to the offshore transport, the offshore current become meander under the impacts of the anticyclonic mesoscale eddies. The meandered cold tongue and instability front may stimulate the generation of the small-scale eddies. Unidirectional uniform wind along cold tongue may also contribute to the formation of the small-scale eddies.

Sub-seasonal prediction of the 2008 extreme snowstorms over South China

2020 ◽  
Vol 55 (7-8) ◽  
pp. 1979-1994
Author(s):  
Lina Zheng ◽  
Yaocun Zhang ◽  
Anning Huang
Keyword(s):  
South China ◽  
Seasonal Prediction

Roles of tropical remote forcings on the South China Sea winter atmospheric and cold tongue variabilities

2021 ◽  
pp. 1-51
Author(s):  
Marvin Xiang Ce Seow ◽  
Yushi Morioka ◽  
Tomoki Tozuka
Keyword(s):  
Indian Ocean ◽  
South China Sea ◽  
South China ◽  
Tropical Indian Ocean ◽  
Internal Variability ◽  
Tropical Pacific ◽  
The South China Sea ◽  
Cold Tongue ◽  
China Sea ◽  
The Tropical Pacific

AbstractInfluences from the tropical Pacific and Indian Oceans, and atmospheric internal variability on the South China Sea (SCS) atmospheric circulation and cold tongue (CT) variability in boreal winter and the relative roles of remote forcings at interannual time scales are studied using observational data, reanalysis products, and coupled model experiments. In the observation, strong CT years are accompanied by local cyclonic wind anomalies, which are an equatorial Rossby wave response to enhanced convection over the warmer-than-normal western equatorial Pacific associated with La Niña. Also, the cyclonic wind anomalies are an atmospheric Kelvin wave response to diabatic cooling anomalies linked to both the decaying late fall negative Indian Ocean Dipole (IOD) and winter atmospheric internal variability. Partially coupled experiments reveal that both the tropical Pacific air-sea coupling and atmospheric internal variability positively contribute to the coupled variability of the SCS CT, while the air-sea coupling over the tropical Indian Ocean weakens such variabilities. The northwest Pacific anticyclonic wind anomalies that usually precede El Niño–Southern Oscillation-independent negative IOD generated under the tropical Indian Ocean air-sea coupling undermine such variabilities.

Drought in Late Spring of South China in Recent Decades

2006 ◽  
Vol 19 (13) ◽  
pp. 3197-3206 ◽  
Author(s):  
Xiaoge Xin ◽  
Rucong Yu ◽  
Tianjun Zhou ◽  
Bin Wang
Keyword(s):  
South China ◽  
Global Climate ◽  
Salient Feature ◽  
Late Spring ◽  
Central China ◽  
Interdecadal Change ◽  
The Tibetan Plateau ◽  
Spring Precipitation ◽  
Upper Troposphere ◽  
The North

Abstract Late spring (21 April–20 May) precipitation to the south of the Yangtze River in China along the East Asian front is a salient feature of the global climate. The present analysis reveals that during 1958–2000 South China (26°–31°N, 110°–122°E) has undergone a significant decrease in late spring precipitation since the late 1970s. The sudden reduction of the precipitation concurs with a notable cooling in the upper troposphere over the central China (30°–40°N, 95°–125°E). The upper-level cooling is associated with an anomalous meridional cell with descending motions in the latitudes 26°–35°N and low-level northerly winds over southeastern China (22°–30°N, 110°–125°E), causing deficient rainfall over South China. The late spring cooling in the upper troposphere over the central China is found to strongly link to the North Atlantic Oscillation (NAO) in the preceding winter. During winters with a positive NAO index, the upper-tropospheric cooling occurs first to the north of the Tibetan Plateau in early–middle spring, then propagates southeastward to central China in late spring. It is suggested that the interdecadal change of the winter NAO is the root cause for the late spring drought over South China in recent decades.

scholarly journals Satellite observations of the small-scale cyclonic eddies in the western South China Sea

2015 ◽  
Vol 12 (2) ◽  
pp. 299-305 ◽  
Author(s):  
F. Liu ◽  
S. Tang ◽  
C. Chen
Keyword(s):  
South China Sea ◽  
South China ◽  
Rotation Speed ◽  
Mesoscale Eddies ◽  
Small Scale ◽  
Western Boundary ◽  
Cold Tongue ◽  
China Sea ◽  
Western South China Sea ◽  
Offshore Transport

Abstract. High-resolution ocean color observations offer an opportunity to investigate the oceanic small-scale processes. In this study, the Medium Resolution Imaging Spectrometer (MERIS) daily 300 m data were used to study small-scale processes in the western South China Sea. It is indicated that the cyclonic eddies with horizontal scales of 10 km are frequently observed during the upwelling season of each year over the 2004–2009 period. These small-scale eddies were generated in the vicinity of the southern front of the cold tongue, and then propagated eastward with a speed of approximately 12 cm s−1. This propagation speed was consistent with the velocity of the western boundary current. As a result, the small-scale eddies kept the high levels of phytoplankton rotating away from the coastal areas, resulting in the accumulation of phytoplankton in the interior of the eddies. The generation of the small-scale eddies may be associated with strengthening of the relative movement between the rotation speed of the anticyclonic mesoscale eddies and the offshore transport. With the increases of the normalized rotation speed of the anticyclonic mesoscale eddies relative to the offshore transport, the offshore current became a meander under the impacts of the anticyclonic mesoscale eddies. The meandered cold tongue and instability front may stimulate the generation of the small-scale eddies. Unidirectional uniform wind along the cold tongue may also contribute to the formation of the small-scale eddies.

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