scholarly journals The Impact of the Mesoscale Ocean Variability on the Estimation of Tidal Harmonic Constants Based on Satellite Altimeter Data in the South China Sea

2021 ◽  
Vol 13 (14) ◽  
pp. 2736
Author(s):  
Qian Yu ◽  
Haidong Pan ◽  
Yanqiu Gao ◽  
Xianqing Lv
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Altimeter Data ◽  
Ocean Variability ◽  
China Sea ◽  
Tidal Harmonic ◽  
Before And After ◽  
Tidal Constituents ◽  
The Impact

The estimation accuracy of tidal harmonic constants is of great significance to maritime traffic and port construction. However, due to the long sampling period of satellite altimeters, tidal signals alias the mesoscale ocean frequencies. As a result, the harmonic analysis is affected by mesoscale environmental noise. In this study, the influence of the mesoscale ocean variability (MOV) on the estimation of tidal harmonic constants was quantified by analyzing 25 years of altimeter data from the Topex/Poseidon (T/P) and Jason satellites in the South China Sea (SCS). The results indicated that the absolute amplitude differences (AADs) of the eight major tidal constituents before and after the mesoscale variability correction (MVC) were generally within 10 mm, and most were within 6 mm. For the relative impact, M2, O1, and K1 were not obviously affected by the MOV because of their large amplitudes, and the AADs generally accounted for less than ±10% of the amplitudes. As a tidal constituent with amplitude less than 2 cm in the SCS, the amplitude of K2 was significantly affected by the MOV, with the ratios of the AADs to its own amplitudes ranging from −64.79% to 95.99% in space. In terms of phase, the K2 tide was most affected by the MOV: 63% of the data points before and after correction were over ±5°, and the maximum and minimum values were 86.46° and −176.27°, respectively. The absolute phase differences of other tidal constituents before and after the MVC were generally concentrated within ±5°. The impact of the MOV on the evolution of tidal amplitudes in the SCS was also explored. It was found that the MOV can cause pseudo-rapid temporal variations of tidal amplitudes in some regions of the SCS.

scholarly journals Characteristics of the South China Sea Monsoon from the Onset to Withdrawal before and after 1993/94

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhao Xiaofang ◽  
Wang Lijuan
Keyword(s):  
South China Sea ◽  
South China ◽  
Early Onset ◽  
Late Onset ◽  
Southern China ◽  
The South China Sea ◽  
Rain Belt ◽  
China Sea ◽  
Before And After ◽  
Onset Period

The characteristics and possible impact factors of the South China Sea summer monsoon (SCSSM) evolution from onset to withdrawal before and after 1993/94 are investigated using ERA-Interim, CPC rainfall, and OLR data. During the late-onset period of 1979–1993, the SCSSM was characterized by stronger onset intensity and a gradual withdrawal, resulting in a continuous, strong preflood season in Southern China and a slower rain-belt retreat from north to south China in September. In addition, the rain-belt in the Yangtze River basin persisted much longer during summer. However, during the early-onset period in 1994–2016, the SCSSM is associated with a weaker onset intensity and comparatively faster retreat. The advanced preflood season lasted intermittently throughout May and the whole eastern China precipitation lasted until October when it retreated rapidly, making the rain-belt in Southern China persist for an extended duration. Further analysis indicates that a strong modulation of SCS intraseasonal oscillation (ISO) on the SCSSM evolution is observed. There are two active low-frequency oscillations over the SCS in summer during the late-onset period but three during the early-onset period. The wet ISO in the Northwest Pacific propagating northwestward into the SCS and enhanced SCSSM ISO activity may contribute to the early onset and faster withdrawal after 1993/94. The effect of warm western Pacific sea surface temperatures (SST) on the SCSSM evolution is also discussed.

scholarly journals A simple predictive model for the eddy propagation trajectory in the South China Sea

2018 ◽  
Author(s):  
Jiaxun Li ◽  
Guihua Wang ◽  
Huijie Xue ◽  
Huizan Wang
Keyword(s):  
South China Sea ◽  
Predictive Model ◽  
South China ◽  
Forecast Accuracy ◽  
The South China Sea ◽  
Altimeter Data ◽  
Linear Regression Method ◽  
Mean Flow ◽  
The South ◽  
China Sea

Abstract. A novel predictive model is built for eddy propagation trajectory using the multiple linear regression method. This simple model has related various oceanic parameters to eddy propagation position changes in the South China Sea (SCS). These oceanic parameters mainly represent the effects of planetary β and mean flow advection on the eddy propagation. The performance of the proposed model is examined in the SCS based on twenty years of satellite altimeter data, and demonstrates its significant forecast skills over a 4-week forecast window comparing to the traditional persistence method. It is also found that the model forecast accuracy is sensitive to eddy polarity and forecast season.

scholarly journals Chinese Assertiveness in the South China Sea and Southeast Asian Responses

2011 ◽  
Vol 30 (2) ◽  
pp. 77-104 ◽  
Author(s):  
Carlyle A. Thayer
Keyword(s):  
South China Sea ◽  
South China ◽  
The United States ◽  
The Philippines ◽  
The South China Sea ◽  
Commercial Fishing ◽  
The South ◽  
China Sea ◽  
Asean Member ◽  
Before And After

This article reviews Chinese assertive behaviour towards the Philippines and Vietnam over South China Sea issues in 2011. The article compares and contrasts Chinese diplomatic behaviour in the period before and after the adoption by ASEAN member states and China of Guidelines for the Implementation the Declaration on Conduct of Parties in the South China Sea in July. In the first period China aggressively asserted its claims to sovereignty by interfering with commercial fishing and oil exploration activities of vessels operating in the Exclusive Economic Zones of Vietnam and the Philippines. Both states resisted Chinese actions. The Philippines allocated increased funding for defence modernization, lobbied ASEAN states and shored up its alliance with the United States. Vietnam too protested Chinese action and undertook symbolic steps to defend national sovereignty. In the second period all states moved to contain South China Sea tensions from affecting their larger bilateral relations. It remains to be seen, however, if proposed confidence building measures will ameliorate Chinese assertiveness.

Impact of assimilating altimeter data on eddy characteristics in the South China Sea

2020 ◽  
Vol 155 ◽  
pp. 101704
Author(s):  
J. Xie ◽  
M. De Vos ◽  
L. Bertino ◽  
J. Zhu ◽  
F. Counillon
Keyword(s):  
South China Sea ◽  
South China ◽  
The South China Sea ◽  
Altimeter Data ◽  
The South ◽  
China Sea ◽  
Eddy Characteristics
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