scholarly journals Relation of the South China Sea Precipitation Variability to Tropical Indo-Pacific SST Anomalies during Spring-to-Summer Transition

2014 ◽  
Vol 27 (14) ◽  
pp. 5451-5467 ◽  
Author(s):  
Wenting Hu ◽  
Renguang Wu ◽  
Yong Liu
Keyword(s):  
South China Sea ◽  
South China ◽  
Rainfall Variability ◽  
Walker Circulation ◽  
Tropical Indian Ocean ◽  
Atmospheric Model ◽  
Additional Contribution ◽  
China Sea ◽  
Rainfall Variation ◽  
Sst Anomalies

Abstract The present study investigates the relationship of South China Sea (SCS) precipitation to tropical Indo-Pacific sea surface temperature (SST) during April–June (AMJ), which is the transition season from spring to summer. It is revealed that SCS rainfall anomalies in AMJ are influenced by SST anomalies in the equatorial Pacific (EP), tropical Indian Ocean (TIO), and western North Pacific (WNP). Three types of SST-influenced cases are obtained based on different combinations of SST anomalies in the above three regions. When same-sign EP and TIO SST anomalies are accompanied by opposite WNP SST anomalies, both anomalous cross-equatorial flows from the southwestern TIO induced by negative SST anomalies there and an anomalous Walker circulation forced by negative EP SST anomalies contribute to enhanced convection over the SCS and the surrounding regions with additional contribution from positive WNP SST anomalies via a Rossby wave–type response. In the cases of combined effects of EP and WNP SST anomalies, above-normal SST in the WNP is a direct cause of above-normal SCS rainfall though the WNP SST anomalies are induced by EP SST forcing. In the cases of combined impacts of TIO and EP SST anomalies, the accompanying coastal Sumatra SST anomalies contribute to the SCS rainfall variability via an anomalous cross-equatorial vertical circulation. The negative SST anomalies near the Sumatra coast induce descent over the southeastern TIO and ascent over the SCS and WNP. Model experiments with an atmospheric model confirm the impacts of southern TIO and EP SST anomalies on AMJ rainfall variation over the SCS.

scholarly journals Tracking the Detrital Zircon Provenance of Early Miocene Sediments in the Continental Shelf of the Northwestern South China Sea

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 752
Author(s):  
Ce Wang ◽  
Letian Zeng ◽  
Yaping Lei ◽  
Ming Su ◽  
Xinquan Liang
Keyword(s):  
South China Sea ◽  
Continental Shelf ◽  
South China ◽  
Detrital Zircon ◽  
Early Miocene ◽  
Sediment Provenance ◽  
Additional Contribution ◽  
Lower Miocene ◽  
Paleogeographic Reconstruction ◽  
China Sea

Sediment provenance studies have become a major theme for source-to-sink systems and provide an important tool for assessing paleogeographic reconstruction, characterizing the depositional system, and predicting reservoir quality. The lower Miocene is an important stratigraphic unit for deciphering sediment evolution in the continental shelf of the northwestern South China Sea, but the provenance characteristics of this strata remain unclear. In this study, detrital zircon U-Pb geochronology and Lu-Hf isotopes from the lower Miocene Sanya Formation in the Yinggehai-Song Hong Basin were examined to study the provenance and its variation in the early Miocene. U-Pb dating of detrital zircons yielded ages ranging from Archean to Cenozoic (3313 to 39 Ma) and displayed age distributions with multiple peaks and a wide range of εHf(t) values (from −27.2 to +8.5). Multi-proxy sediment provenance analysis indicates that the Red River system was the major source for the sediments in the northern basin, with additional contribution from central Vietnam, and the Hainan played the most important role in contributing detritus to the eastern margin of the basin in the middle Miocene. This paper highlights the provenance of early Miocene sediments and contributes to paleogeographic reconstruction and reservoir evaluation.

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 South China Sea hydrological changes and Pacific Walker Circulation variations over the last millennium

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Hong Yan ◽  
Liguang Sun ◽  
Delia W. Oppo ◽  
Yuhong Wang ◽  
Zhonghui Liu ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Walker Circulation ◽  
Last Millennium ◽  
China Sea ◽  
Hydrological Changes

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.

scholarly journals Two Distinctive Processes for Abnormal Spring to Summer Transition over the South China Sea

2017 ◽  
Vol 30 (23) ◽  
pp. 9665-9678 ◽  
Author(s):  
Renguang Wu ◽  
Zhuoqi He
Keyword(s):  
South China Sea ◽  
South China ◽  
North Pacific ◽  
Western North Pacific ◽  
The South China Sea ◽  
The South ◽  
Maritime Continent ◽  
China Sea ◽  
Tropical Western North Pacific ◽  
Sst Anomalies

The period from April to June signifies the transition from spring to summer over the South China Sea (SCS). The present study documents two distinct processes for abnormal spring to summer transition over the SCS. One process is related to large-scale sea surface temperature (SST) anomalies in the tropical Indo-Pacific region. During spring of La Niña decaying years, negative SST anomalies in the equatorial central Pacific (ECP) and the southwestern tropical Indian Ocean (TIO) coexist with positive SST anomalies in the tropical western North Pacific. Negative ECP SST anomalies force an anomalous Walker circulation, negative southwestern TIO SST anomalies induce anomalous cross-equatorial flows from there, and positive tropical western North Pacific SST anomalies produce a Rossby wave–type response to the west. Together, they contribute to enhanced convection and an anomalous lower-level cyclone over the SCS, leading to an advanced transition to summer there. The other process is related to regional air–sea interactions around the Maritime Continent. Preceding positive ECP SST anomalies induce anomalous descent around the Maritime Continent, leading to SST increase in the SCS and southeast TIO. An enhanced convection region moves eastward over the south TIO during spring and reaches the area northwest of Australia in May. This enhances descent over the SCS via an anomalous cross-equatorial overturning circulation and contributes to further warming in the SCS. The SST warming in turn induces convection over the SCS, leading to an accelerated transition to summer. Analysis shows that the above two processes are equally important during 1979–2015.

Signals of the South China Sea summer rainfall variability in the Indian Ocean

2015 ◽  
Vol 46 (9-10) ◽  
pp. 3181-3195 ◽  
Author(s):  
Zhuoqi He ◽  
Renguang Wu ◽  
Weiqiang Wang
Keyword(s):  
Indian Ocean ◽  
South China Sea ◽  
South China ◽  
Rainfall Variability ◽  
Summer Rainfall ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
The Indian Ocean

scholarly journals Evaluating the Bias of South China Sea Summer Monsoon Precipitation Associated with Fast Physical Processes Using a Climate Model Hindcast Approach

2019 ◽  
Vol 32 (14) ◽  
pp. 4491-4507 ◽  
Author(s):  
Wei-Ting Chen ◽  
Chien-Ming Wu ◽  
Hsi-Yen Ma
Keyword(s):  
South China Sea ◽  
Summer Monsoon ◽  
South China ◽  
Climate Model ◽  
Atmospheric Model ◽  
Climate Simulation ◽  
Physical Processes ◽  
Local Circulation ◽  
China Sea ◽  
Onset Period

Abstract The present study aims to identify the precipitation bias associated with the interactions among fast physical processes in the Community Atmospheric Model, version 5 (CAM5), during the abrupt onset of the South China Sea (SCS) summer monsoon, a key precursor of the overall East Asia summer monsoon (EASM). The multiyear hindcast approach is utilized to obtain the well-constrained synoptic-scale horizontal circulation each year during the onset period from the years 1998 to 2012. In the pre-onset period, the ocean precipitation over the SCS is insufficiently suppressed in CAM5 hindcasts and thus weaker land–ocean precipitation contrasts. This is associated with the weaker and shallower convection simulated over the surrounding land, producing weaker local circulation within the SCS basin. In the post-onset period, rainfall of the organized convection over the Philippine coastal ocean is underestimated in the hindcasts, with overestimated upper-level heating. These biases are further elaborated as the underrepresentation of the convection diurnal cycle and coastal convection systems, as well as the issue of precipitation sensitivity to environmental moisture during the SCS onset period. The biases identified in hindcasts are consistent with the general bias of the EASM in the climate simulation of CAM5. The current results highlight that the appropriate representation of land–ocean–convection interactions over coastal areas can potentially improve the simulation of seasonal transition over the monsoon regions.

scholarly journals Interdecadal Difference of Interannual Variability Characteristics of South China Sea SSTs Associated with ENSO

2015 ◽  
Vol 28 (18) ◽  
pp. 7145-7160 ◽  
Author(s):  
Yali Yang ◽  
Shang-Ping Xie ◽  
Yan Du ◽  
Hiroki Tokinaga
Keyword(s):  
Indian Ocean ◽  
South China Sea ◽  
South China ◽  
El Niño ◽  
El Nino ◽  
Tropical Indian Ocean ◽  
Easterly Wind ◽  
China Sea ◽  
Sst Warming ◽  
The Indian Ocean

Abstract The correlation between sea surface temperature (SST) and El Niño–Southern Oscillation (ENSO) persists into post-ENSO September over the South China Sea (SCS), the longest correlation in the World Ocean. Slow modulations of this correlation are analyzed by using the International Comprehensive Ocean–Atmosphere Dataset (ICOADS). ENSO’s influence on SCS SST has experienced significant interdecadal changes over the past 138 years (1870–2007), with a double-peak structure correlation after the 1960s compared to a single-peak before the 1940s. According to the ENSO correlation character, the analysis period is divided into four epochs. In epoch 3, 1960–83, the SST warming and enhanced precipitation over the southeastern tropical Indian Ocean, rather than the Indian Ocean basinwide warming, induce easterly wind anomalies and warm up the SCS in the summer following El Niño. Besides the Indian Ocean effect, during epochs 2 (1930–40) and 4 (1984–2007), the Pacific–Japan (PJ) pattern of atmospheric circulation anomalies helps sustain the SCS SST warming through summer (June–August) with easterly wind anomalies. The associated increase in shortwave radiation and decrease in upward latent heat flux cause the SCS SST warming to persist into the summer. Meanwhile, the rainfall response around the SCS to ENSO shows interdecadal variability, with stronger variability after the 1980s. The results suggest that both the remote forcing from the tropical Indian Ocean and the PJ pattern are important for the ENSO teleconnection to the SCS and its interdecadal modulations.

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