scholarly journals Remote sensing observations of winter phytoplankton blooms southwest of the Luzon Strait in the South China Sea

1999 ◽  
Vol 191 ◽  
pp. 43-51 ◽  
Author(s):  
DL Tang ◽  
IH Ni ◽  
DR Kester ◽  
FE Müller-Karger
Keyword(s):  
Remote Sensing ◽  
South China Sea ◽  
South China ◽  
Luzon Strait ◽  
The South China Sea ◽  
The South ◽  
Phytoplankton Blooms ◽  
China Sea

scholarly journals Feasibility of reconstructing the basin–scale sea surface partial pressure of carbon dioxide from sparse in situ observations over the South China Sea

2020 ◽  
Author(s):  
Guizhi Wang ◽  
Samuel S. P. Shen ◽  
Yao Chen ◽  
Yan Bai ◽  
Huan Qin ◽  
...  
Keyword(s):  
Remote Sensing ◽  
South China Sea ◽  
Partial Pressure ◽  
South China ◽  
The South China Sea ◽  
Sea Surface ◽  
High Pco2 ◽  
The South ◽  
China Sea ◽  
Basin Scale

Abstract. Sea surface partial pressure of CO2 (pCO2) data with high spatial-temporal resolution are important in studying the global carbon cycle and assessing the oceanic carbon uptake capacity. However, the observed sea surface pCO2 data are usually limited in spatial and temporal coverage, especially in marginal seas. This study provides an approach to reconstruct the complete sea surface pCO2 field in the South China Sea (SCS) with a grid resolution of 0.5º × 0.5º over the period of 2000–2017 using both remote-sensing derived pCO2 and observed pCO2. Empirical orthogonal functions (EOFs) were computed from the remote sensing derived pCO2. Then, a multilinear regression was applied to the observed pCO2 as the response variable with the EOFs as the explanatory variables. EOF1 explains the general spatial pattern of pCO2 in the SCS. EOF2 shows the pattern influenced by the Pearl River plume on the northern shelf and slope. EOF3 is consistent with the pattern influenced by coastal upwelling along the north coast of the SCS. The reconstructions always agree with observations. When pCO2 observations cover a sufficiently large area, the reconstructed fields successfully display a pattern of relatively high pCO2 in the mid-and-southern basin. The rate of sea surface pCO2 increase in the SCS is 2.383 μatm per year based on the spatial average of the reconstructed pCO2 over the period of 2000–2017. All the data for this paper are openly and freely available at PANGAEA under the link https://doi.pangaea.de/10.1594/PANGAEA.921210 (Wang et al., 2020).

scholarly journals Spatio-Temporal Variations of Winter Phytoplankton Blooms Northwest of the Luzon Island in the South China Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Hui Gao ◽  
Hui Zhao ◽  
Guoqi Han ◽  
Changming Dong
Keyword(s):  
South China Sea ◽  
South China ◽  
Linear Regression Analysis ◽  
The South China Sea ◽  
Ekman Transport ◽  
Wind Component ◽  
Ekman Pumping ◽  
The South ◽  
Phytoplankton Blooms ◽  
China Sea

Phytoplankton is a key component of marine ecosystems. Winter phytoplankton blooms are frequently observed northwest of Luzon Island in the South China Sea. In this study, with the multi-satellite merged ocean color remote sensing data from November 1999 to February 2015, we examine the spatial and temporal changes of chlorophyll-a (Chl-a) concentration and further investigate its response to physical environment parameters including wind speed, Ekman transport, Ekman pumping velocity, sea surface temperature, and sea level anomalies in the region northwest of Luzon Island. The main factors affecting the distribution of Chl-a are discussed by using the partial correlation analysis and multiple stepwise linear regression analysis. The results show that centers of winter Chl-a blooms northwest of Luzon Island often occur near 119.5°E, 19.5°N. The significant multiple correlation (r = 0.76, p < 0.01) between Chl-a and oceanic conditions indicates that both the wind component parallel to the coastline and the wind stress curls enhance the winter upwelling in the study area, consistent with previous studies. A novel finding in the present study is that the winter bloom center is located north of the upwelling center, attributed to the advection effect of the northward background coastal flow.

scholarly journals Observed Near-Inertial Waves in the Northern South China Sea

2021 ◽  
Vol 13 (16) ◽  
pp. 3223
Author(s):  
Bing Yang ◽  
Po Hu ◽  
Yijun Hou
Keyword(s):  
Remote Sensing ◽  
South China Sea ◽  
South China ◽  
Mesoscale Eddies ◽  
Relative Vorticity ◽  
The South China Sea ◽  
Inertial Waves ◽  
The South ◽  
China Sea ◽  
Maximum Value

Characteristics of near-inertial waves (NIWs) induced by the tropical storm Noul in the South China Sea are analyzed based on in situ observations, remote sensing, and analysis data. Remote sensing sea level anomaly data suggests that the NIWs were influenced by a southwestward moving anticyclonic eddy. The NIWs had comparable spectral density with internal tides, with a horizontal velocity of 0.14–0.21 m/s. The near-inertial kinetic energy had a maximum value of 7.5 J/m3 and propagated downward with vertical group speed of 10 m/day. Downward propagation of near-inertial energy concentrated in smaller wavenumber bands overwhelmed upward propagation energy. The e-folding time of NIWs ranged from 4 to 11 days, and the larger e-folding time resulted from the mesoscale eddies with negative vorticity. Modified by background relative vorticity, the observed NIWs had both red-shifted and blue-shifted frequencies. The upward propagating NIWs had larger vertical phase speeds and wavelengths than downward propagating NIWs. There was energy transfer from the mesoscale field to NIWs with a maximum value of 8.5 × 10−9 m2 s−3 when total shear and relative vorticity of geostrophic currents were commensurate. Our results suggest that mesoscale eddies are a significant factor influencing the generation and propagation of NIWs in the South China Sea.

Weakening of the Kuroshio Intrusion into the South China Sea over the Past Two Decades

2013 ◽  
Vol 26 (20) ◽  
pp. 8097-8110 ◽  
Author(s):  
Feng Nan ◽  
Huijie Xue ◽  
Fei Chai ◽  
Dongxiao Wang ◽  
Fei Yu ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Luzon Strait ◽  
The South China Sea ◽  
Negative Trend ◽  
Kuroshio Intrusion ◽  
The South ◽  
China Sea ◽  
The Past ◽  
The Kuroshio

Abstract Inferred from the satellite and in situ hydrographic data from the 1990s and 2000s, the Kuroshio intrusion into the South China Sea (SCS) had a weakening trend over the past two decades. Associated with the weakened Kuroshio intrusion, the Kuroshio loop and eddy activity southwest of Taiwan became weaker, whereas the water above the salinity minimum became less saline in the northern SCS. The sea surface height southwest of Taiwan increased at a slower rate compared to other regions of the SCS because of the weakened Kuroshio intrusion. Simulations using the Regional Ocean Modeling System (ROMS) Pacific model show that the strength of the Kuroshio intrusion into the SCS decreased from 1993 to 2010 with a negative trend, −0.24 sverdrups (Sv) yr−1 (1 Sv ≡ 106 m3 s−1), in the total Luzon Strait transport (LST). Although wind-induced Ekman transport through the Luzon Strait became weaker, the magnitude at 0.001 Sv yr−1 was too small to compensate for the negative trend of the LST. On the other hand, the piling up of the water induced by monsoon winds was an important mechanism for changing the pressure gradient across the Luzon Strait and eventually affecting the LST. The sea level gradient between the western Pacific and the SCS had a negative trend, −0.10 cm yr−1, corresponding to a negative trend in the geostrophic transport at −0.20 Sv yr−1. The Kuroshio transport east of Luzon Island also had a negative trend, which might also be linked to the weakening Kuroshio intrusion.

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