scholarly journals Statistical Analysis of Mesovortices During The First Rainy Season In South China

2021 ◽  
Author(s):  
Ying Tang ◽  
Xin Xu ◽  
Yuanzhao Chen ◽  
Xunlai Chen ◽  
Jiahao Liang ◽  
...  
Keyword(s):  
South China ◽  
Rainy Season ◽  
Vertical Wind Shear ◽  
Guangdong Province ◽  
Statistical Characteristics ◽  
Pearl River Delta Region ◽  
Late Afternoon ◽  
Vapor Flux ◽  
Early Evening ◽  
Northern Guangdong

Abstract Based on the Doppler radar observation and reanalysis data, the statistical characteristics of mesovortices (MVs) during the first rainy season (April–June) in South China from 2017 to 2019 are studied, including their spatio-temporal distributions, structural features and favorable environmental conditions. The results show that the MVs usually exhibit short lifetime, among which about 70% last for less than 30 minutes. The intensity and horizontal scale of the MVs are proportional to their lifetime. Long-lived MVs have larger horizontal scales and stronger intensities than short-lived ones. The MVs are mainly observed over the Pearl River Delta region, followed by the western Guangdong province, but relatively fewer in both eastern and northern Guangdong province. The uneven spatial distribution of the MVs is closely related to the differences of environment conditions over South China. The monsoonal south-westerlies, water vapor flux, atmospheric instability and vertical wind shear over southwest Guangdong are significantly larger than those in other regions, which are favorable for the formation of MVs. The occurrence frequencies of MVs in central and southern parts of Guangdong display similar diurnal variations, reaching the peak during the late afternoon and early evening, while dropping to the minimum overnight. However, the situation is opposite in northern Guangdong, with the peak overnight and the minimum during the late afternoon and early evening.

Hydrogeochemistry and geothermometry of geothermal waters from the Pearl River Delta region, South China

Geothermics ◽  
2021 ◽  
Vol 96 ◽  
pp. 102164
Author(s):  
Zheng-An Wei ◽  
Haibing Shao ◽  
Ling Tang ◽  
Bin Deng ◽  
Hailong Li ◽  
...  
Keyword(s):  
South China ◽  
Pearl River Delta ◽  
River Delta ◽  
Pearl River ◽  
Pearl River Delta Region ◽  
Delta Region ◽  
Geothermal Waters ◽  
The Pearl River Delta ◽  
The Pearl River

Spatiotemporal computing of cold wave characteristic in recent 52 years: a case study in Guangdong Province, South China

2015 ◽  
Vol 79 (2) ◽  
pp. 1257-1274 ◽  
Author(s):  
Wei Liu ◽  
Si-yu Huang ◽  
Dan Li ◽  
Chong-yang Wang ◽  
Xia Zhou ◽  
...  
Keyword(s):  
South China ◽  
Guangdong Province ◽  
Cold Wave ◽  
Wave Characteristic

scholarly journals A 7-Year Climatology of Warm-Sector Heavy Rainfall over South China during the Pre-Summer Months

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 914
Author(s):  
Tao Chen ◽  
Da-Lin Zhang
Keyword(s):  
South China ◽  
Heavy Rainfall ◽  
Large Scale ◽  
Convective Available Potential Energy ◽  
Potential Temperature ◽  
Vertical Wind Shear ◽  
Precipitable Water ◽  
Atmospheric Parameter ◽  
Low Level ◽  
Warm Sector

In view of the limited predictability of heavy rainfall (HR) events and the limited understanding of the physical mechanisms governing the initiation and organization of the associated mesoscale convective systems (MCSs), a composite analysis of 58 HR events over the warm sector (i.e., far ahead of the surface cold front), referred to as WSHR events, over South China during the months of April to June 2008~2014 is performed in terms of precipitation, large-scale circulations, pre-storm environmental conditions, and MCS types. Results show that the large-scale circulations of the WSHR events can be categorized into pre-frontal, southwesterly warm and moist ascending airflow, and low-level vortex types, with higher frequency occurrences of the former two types. Their pre-storm environments are characterized by a deep moist layer with >50 mm column-integrated precipitable water, high convective available potential energy with the equivalent potential temperature of ≥340 K at 850 hPa, weak vertical wind shear below 400 hPa, and a low-level jet near 925 hPa with weak warm advection, based on atmospheric parameter composite. Three classes of the corresponding MCSs, exhibiting peak convective activity in the afternoon and the early morning hours, can be identified as linear-shaped, a leading convective line adjoined with trailing stratiform rainfall, and comma-shaped, respectively. It is found that many linear-shaped MCSs in coastal regions are triggered by local topography, enhanced by sea breezes, whereas the latter two classes of MCSs experience isentropic lifting in the southwesterly warm and moist flows. They all develop in large-scale environments with favorable quasi-geostrophic forcing, albeit weak. Conceptual models are finally developed to facilitate our understanding and prediction of the WSHR events over South China.

scholarly journals Cause Analysis on Eastward Movement of Southwest China Vortex and Its Induced Heavy Rainfall in South China

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Yongren Chen ◽  
Yueqing Li ◽  
Tianliang Zhao
Keyword(s):  
South China ◽  
Heavy Rainfall ◽  
Southwest China ◽  
Dominant Role ◽  
Vertical Wind Shear ◽  
Heavy Rain ◽  
Convective Systems ◽  
Rainfall Occurrence ◽  
Positive Vorticity ◽  
Upper Level Jet

The movement of southwest China vortex (SWV) and its heavy rainfall process in South China had been investigated during June 11–14, 2008. The results show that under the steering of upper-level jet (ULJ) and mid-level westerly trough, SWV moved eastward from southern Sichuan Plateau, across eastern Yunnan-Guizhou Plateau to South China, forming an obvious heavy rain belt. SWV developed in the large storm-relative helicity (SRH) environment, as environmental wind field continuously transferred positive vorticity to it to support its development. The thermodynamic structures of distinctive warm (cold) advections in front (rear) of the SWV movement are also important factors for the SWV evolutions with a southwest low-level jet (LLJ) and vertical wind shear. SWV development was associated with the distributions of negative MPV1 (the barotropic item of moist potential vorticity) and positive MPV2 (the baroclinic item of it). The MPV1 and MPV2 played the dominant role in the formation and the evolution of SWV, respectively. The mesoscale convective systems (MCSs) frequently occurred and persisted in water vapor convergence areas causing the severe heavy rainfall. The areas of high moist helicity divergence and heavy rainfall are consistent, and the moist helicity divergence could be a good indicator for heavy rainfall occurrence.

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