福建省极端降水时空变化特征及其环流因素分析

Spatio-temporal change characteristics and circulation causes of extreme precipitation in Fujian Province

利用福建省22个气象观测站1961-2013年逐日降水量实测资料,应用趋势分析法、Mann-Kendall突变分析法、小波分析法、点值法和相关分析法,分析了极端降水的时空变化特征及其环流因素。研究结果表明:(1)在时间尺度上,福建省极端降水整体上表现出增加的趋势,其中SDII、R50mm和CWD存在明显的突变现象,突变时间分别在1994年左右、1995年左右和1998年左右;各极端降水指数普遍存在着2~3a、6~8a的短周期和10~12a的中周期;(2)在空间尺度上,极端降水受海陆位置、纬度位置影响存在明显的空间差异,具体表现为PRCPTOT变化趋势由东部沿海向西部内陆减小;(3)随着季节变换,影响或登陆福建省台风数、副热带高压带的强度引发明显的环流季节变化对福建省极端降水产生重要影响,福建省在850hPa和1000hPa位势高度差值均存在负的低值中心,有利于极端降水事件的发生。研究结果为未来福建省的极端气候变化趋势预测、福建农业气象灾害影响预估、决策提供参考。

Extreme precipitation is an important aspect of climate change. Fujian Province is often affected by extreme precipitation events such as typhoons and severe convective weather and it is critical to research changes in extreme precipitation events in Fujian with respect to global warming. This study analyzed the spatio-temporal change in extreme precipitation in Fujian and circulation causes using trend analysis, Mann-Kendall abrupt change analysis, wavelet analysis, Point-Measured methods and correlational analysis. We used daily precipitation of 22 meteorological observation stations in Fujian from 1961 to 2013. We found that extreme precipitation increased. The SDII, R5Omm and CWD indices experienced obvious abrupt changes around 1994, 1995 and 1998, respectively. The period of oscillation of each extreme precipitation index was similar, including 2-3 years, 6-8 years short-cycle and 10-12 years middle-cycle at large. Extreme precipitation had obvious spatial differences. PRCPTOT revealed a decreasing trend from the eastern coast to western inland. Extreme precipitation was influenced by the location of land and sea, terrain and latitude. Circulation seasonal variation in the number of Fujian Province Typhoons, and the intensity and location of the Subtropical High affected extreme precipitation in Fujian. There was a negative low value center in the geopotential height difference of 850hPa and the 1000hPa over Fujian, which promoted the occurrence of extreme precipitation events. These findings provide a scientific reference for further our understanding and predicting trends in extreme climate in the future and estimates and decision-making of agro-meteorological hazard influence in Fujian.