scholarly journals Evapotranspiration on Natural and Reclaimed Coral Islands in the South China Sea

2021 ◽  
Vol 13 (6) ◽  
pp. 1110
Author(s):  
Shengsheng Han ◽  
Suxia Liu ◽  
Shi Hu ◽  
Xianfang Song ◽  
Xingguo Mo
Keyword(s):  
Remote Sensing ◽  
Land Use ◽  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Water Dynamics ◽  
The South ◽  
China Sea ◽  
Land Use Types ◽  
Coral Islands

Studies of evapotranspiration on remote tropical coral islands are important to explore and sustain scarce freshwater resources. However, there is a significant knowledge gap between research to evaluate evapotranspiration based on remote sensing methods and the influences of different land use types on water dynamics on reclaimed coral islands. This study applied the remote-sensing-based Vegetation Interfaces Processes (VIP-RS) model to estimate actual evapotranspiration (ETa) on Zhaoshu Island, Yongxing Island, and Yongshu Island in the South China Sea from 2016 to 2019. The results showed that the average annual ETa of Zhaoshu Island, Yongxing Island, and Yongshu Island was 685 mm, 530 mm, and 210 mm, respectively. Annual transpiration (Ec) and soil evaporation (Es) exhibited similar patterns on the natural islands; however, Es controlled the water consumption on the reclaimed islands. Water dynamics exhibited seasonal fluctuations due to the uneven distribution of precipitation (PRP). However, ETa of the natural islands was higher than PRP in the dry season, indicating vegetation has to absorb water from the groundwater to sustain growth. The results also agreed with the analysis of dominant driving factors based on partial correlation analysis, which demonstrated that the Normalized Difference Vegetation Index (NDVI) is the most important factor that influences ETa, while relative humidity (RH) controlled the bare land or sparsely vegetated areas on the reclaimed islands. The setting of different land use types showed that vegetation and built-up or hardened roads took control of evapotranspiration and rainwater collection, respectively, which play important roles in water dynamics on corals islands. The evaluation of ETa based on a remote-sensing-based model overcame the difficulty in fieldwork observation, which improves the certainty and accuracy at a spatial scale. In addition, it gave us a new reference to protect and manage scarce freshwater resources properly.

References to the Coral Islands in Huang Zhong’s Hai yu 海語

2019 ◽  
Vol 23 (1) ◽  
pp. 39-72 ◽  
Author(s):  
Roderich Ptak
Keyword(s):  
South China Sea ◽  
Present Article ◽  
South China ◽  
The South China Sea ◽  
The Other ◽  
The South ◽  
China Sea ◽  
English Translations ◽  
History Of ◽  
Coral Islands

Abstract There are many studies on the history of the islands in the South China Sea. The present article looks at the references to these islands in one source, Huang Zhong’s 黄衷 Hai yu 海語 (preface 1536). This mainly concerns two entries in that work. One entry bears the title Wanli shitang 萬里石塘, the other is called Wanli changsha 萬里長沙. The article presents English translations of these entries together with detailed comments. These comments are necessary because both entries contain several terms and passages that are difficult to understand. The comments investigate questions related to the geography and other phenoma of this area. This involves citations from contemporary sources as well as from some earlier and later works. In that sense the article may classify as a long philological note, or a collection of glosses, on a particular aspect described in one important mid-Ming text.

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 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.

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