广西夏季风变异的某些前期征兆与机理分析

SOME EARLIER STAGE CHARACTERISTICS AND MECHANISM ANALYSIS OF GUANGXI SUMMER MONSOON ANOMALY

利用拉萨站 1月份地面气温资料、 4月份赤道东西太平洋海表温度资料和南半球海冰和气旋的资料 ,分析高原热异常、赤道太平洋东西海温梯度异常以及南极海冰变化对广西夏季风变异的影响机理 ,并提出具体的“涝线”和“旱线”概念 ,为季风变异造成的旱涝天气预报提供一些有物理意义的因子指标。

Guangxi is situated in subtropical monsoon region .The prevailing southwestern wind during summer monsoon is caused by cross-equatorial flow from southern hemisphere, which is affected by terrain and β effect. The flood and drought in Guangxi during flood season due to summer monsoon anomaly gives great impact on local agriculture, industry and social life . It is a complex scientific question. The effects of the heating anomaly in Tibetan plateau, the sea surface temperature gradient anomaly over the equatorial Pacific and Antarctic sea ice anomaly on the summer monsoon anomaly in Guangxi are analyzed with the data of surface temperature in January in Lasa, equatorial east-west pacific SST in April and Antarctic sea ice.It is introduced the conception of “flood line” and “drought line”, which correspond to the Jannary temperature anomaly(+1°C and -1°C) in Lasa, the difference in temperature between eastern and western pacific SST (2°C and 1°C),and the number of low latitude cyclones in southern hemisphere (50 and 30) respectively .The results of the study can be used as predictive factors for long-range flood and drought forecasting during flood season in Guangxi.