scholarly journals Key Environmental Factors for Rapid Intensification of the South China Sea Tropical Cyclones

2021 ◽  
Vol 8 ◽  
Author(s):  
Yao Chen ◽  
Si Gao ◽  
Xun Li ◽  
Xinyong Shen
Keyword(s):  
South China Sea ◽  
Tropical Cyclones ◽  
South China ◽  
Vertical Wind Shear ◽  
Onset Time ◽  
The South China Sea ◽  
Rapid Intensification ◽  
The South ◽  
Translation Speed ◽  
China Sea

Forecasting rapid intensification (RI) of the South China Sea (SCS) tropical cyclones (TCs) remains an operational challenge, mainly owing to the incomplete understanding of its physical mechanisms. Based on TC best-track data, atmospheric analysis data, and sea surface temperature data, this study compares temporal evolution characteristics of environmental conditions from the previous 24 h to the onset time for RI and non-RI TCs in the SCS during 2000–2018, and then identifies key factors for RI of the SCS TCs using the box difference index and stepwise regression. A combination of strong divergence in the upper troposphere and strong convergence in the boundary layer, weak deep-layer vertical wind shear, fast storm translation speed, and high TC intensification potential (i.e., maximum potential intensity minus current intensity) north of the storm center at the previous 24 h are favorable for RI of the SCS TCs, and their importance for RI is in descending order. The results may shed light on operational forecasting of rapid intensification of the SCS TCs.

scholarly journals The Association of Typhoon Intensity Increase with Translation Speed Increase in the South China Sea

2020 ◽  
Vol 12 (3) ◽  
pp. 939
Author(s):  
Ya-Ting Chang ◽  
I-I Lin ◽  
Hsiao-Ching Huang ◽  
Yi-Chun Liao ◽  
Chun-Chi Lien
Keyword(s):  
South China Sea ◽  
South China ◽  
Vertical Wind Shear ◽  
The South China Sea ◽  
Intensity Increase ◽  
The South ◽  
Translation Speed ◽  
Speed Increase ◽  
China Sea ◽  
Typhoon Intensity

Tropical cyclone (TC) translation speed is an important parameter. In the context of TC–ocean interaction, faster translation speed can contribute to less TC-induced ocean cooling and thus enables more air–sea enthalpy flux supply to favor TC intensification. In 2018, Kossin published an interesting paper in Nature, reporting a global slow-down of TC translation speed since the 1950s. However, upon close inspection, in the last two decades, TC translation speed actually increased over the western North Pacific (WNP) and neighboring seas. Thus, we are interested to see which sub-region in the WNP and neighboring seas had the largest increase during the last two decades, and whether such increases contribute to TC intensification. Our results found statistically significant translation speed increases (~0.8 ms−1 per decade) over the South China Sea. Ruling out other possible factors that may influence TC intensity (i.e., changes in atmospheric vertical wind shear, pre-TC sea surface temperature or subsurface thermal condition), we suggest, in this research, the possible contribution of TC translation speed increases to the observed TC intensity increases over the South China Sea in the last two decades (1998–2017).

scholarly journals Estimate of Ocean Mixed Layer Deepening after a Typhoon Passage over the South China Sea by Using Satellite Data

2013 ◽  
Vol 43 (3) ◽  
pp. 498-506 ◽  
Author(s):  
Jiayi Pan ◽  
Yujuan Sun
Keyword(s):  
South China Sea ◽  
Surface Temperature ◽  
Mixed Layer ◽  
South China ◽  
The South China Sea ◽  
Temperature Profiles ◽  
The South ◽  
Translation Speed ◽  
China Sea ◽  
Sst Cooling

Abstract The ocean responses to Typhoon Cimaron, which influenced the South China Sea (SCS) from 1 to 8 November 2006, are analyzed. Based on satellite-observed sea surface temperature (SST) and climatological temperature profiles in the SCS, mixed layer deepening, an important parameter characterizing turbulent mixing and upwelling driven by strong typhoon winds, is derived. Corresponding to the SST drop of 4.4°C on 3 November 2006, the mixed layer deepened by 104.5 m relative to the undisturbed depth of 43.2 m, which is consistent with a simulation result from a mixed layer model. Furthermore, baroclinic geostrophic velocity and vorticity are calculated from the surface temperature gradient caused by the typhoon. The negative vorticity, associated with the typhoon cooling, indicated an anticyclonic baroclinic circulation strongest at the base of the mixed layer and at the depth of 50 m, the geostrophic speed reached as high as 0.2 m s−1. Typhoon Cimaron proceeded slowly (1.7 m s−1) when it was making a southwestward turn on 3 November 2006, resulting in a subcritical condition with a Froude number (the ratio of typhoon translation speed to first baroclinic mode speed) of 0.6 around the maximum SST drop location and facilitating high SST cooling and mixed layer deepening because of the absence of inertial-gravity waves in the wake of the typhoon. Comparison of Argo buoy data with the climatological temperature suggests that the average uncertainty in the mixed layer deepening estimation caused by the difference between Argo and climatological temperature profiles is less than 10 m.

Blended wind fields for wave modeling of tropical cyclones in the South China Sea and East China Sea

2018 ◽  
Vol 71 ◽  
pp. 20-33 ◽  
Author(s):  
Zhuxiao Shao ◽  
Bingchen Liang ◽  
Huajun Li ◽  
Guoxiang Wu ◽  
Zhaohui Wu
Keyword(s):  
South China Sea ◽  
Tropical Cyclones ◽  
East China Sea ◽  
South China ◽  
The South China Sea ◽  
East China ◽  
The South ◽  
Wind Fields ◽  
Wave Modeling ◽  
China Sea
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