Page 165 - 《高原气象》2021年第5期

高 原 气 象 40 卷
1126

Variation and Precursory Signals of Persistent Rainstorm during the

First Rainy Season in Guangdong Province from 1961 to 2019

1
1
YU Lingling ，JI Zhongping ，MAI Jianhua 2
（1. Guangdong Meteorological Observatory，Guangzhou 510080，Guangdong，China；
2. Zhongshan Meteorological Service，Zhongshan 528400，Guangdong，China）

Abstract：In order to improve the short-term climate prediction ability of precipitation concentration period and
rainfall during the first rainy season in Guangdong Province，the variation characteristics of persistent rainstorm
days in recent 59 years，the precursory signals in the atmospheric circulation and SST field in pre-winter，and the
physical mechanism were studied by using wavelet analysis，correlation analysis and other methods. The results
show that：（1）there were 108 persistent rainstorm processes，and 398 persistent rainstorm days during the first
rainy season in Guangdong in recent 59 years. Most of persistent rainstorm processes occurred from May to
June，and long-lasting torrential rain reaching or exceeding 10 days mainly occurred in June. The number of per‐
sistent rainstorm days exhibited quasi 2-，7-and 12-year periodic oscillations；（2）The precursory signals in pre-
winter over the atmospheric circulation affecting the more（less）number of persistent rainstorm days were stron‐
ger ridge（trough）in European（45°N-60°N，0°-30°E）and stronger trough（ridge）in northwest Asia and mid-
Asia（30°N-50°N，50°E-70°E）and its north at 500 hPa，and the stronger（weaker）southerly in northern SCS
（18°N-22°N，107°E-120°E）at 850 hPa. They affected the number of persistent rainstorm days in the first
rainy season by mainly adjusting the strength of the East Asian Trough and the wind over northern SCS in the lat‐
er stage.（3）The SST in pre-winter in the central North Pacific（15°N-30°N，170°E-160°W）was the key SST
region affecting the number of persistent rainstorm days in the first rainy season in Guangdong Province. They
had a good inverse relationship on the periodic scale of 4~8 years and 8~18 years. It affected the number of per‐
sistent rainstorm days in the first rainy season in Guangdong Province by influencing the later atmospheric circu‐
lation.
Key words：Persistent rainstorm in the first rainy season；precursor signal；key region of atmospheric circula‐
tion in pre-winter；key region of SST in pre-winter