云南高原岩溶区极端降水变化规律研究

利用云南高原岩溶区9个气象站1960-2017年逐日降水量数据,通过MATLAB软件计算了6个极端降水指数,基于反距离加权插值、线性倾向估计、Mann-Kendall突变检验以及Morlet连续小波变换等技术方法,探讨了云南高原岩溶区极端降水的演化规律。结果表明:云南高原岩溶区1960-2017年各极端降水指数中,CDD、RX1day、RX5day、SDII主要呈缓慢的上升趋势,CWD呈显著的下降趋势,PRCPTOT整体减少趋势不显著;1960-2017年间仅有CDD和PRCPTOT发生了显著突变,突变年份分别为2006年以及2000年,其余4个指数CWD、RX1day、RX5day、SDII无明显突变现象;各极端降水指数周期性震荡较为明显,CDD、CWD、RX1day、RX5day分别存在28~30a、26~30a、27~30a、27~30a的主周期,SDII与PRCPTOT在27~30a时间尺度上周期最为明显;1960-2017年云南高原岩溶区各极端降水指数空间差异较为明显,除CDD表现为由南向北逐渐递增趋势外,其余5个指数表现为由北向南逐渐递增的相反趋势;1960-2017年间,CDD、CWD、RX1day、RX5day以及SDII均与PRCPTOT呈一致的极显著正相关,相关系数均达0.98以上。极端降水的这些变化可为未来岩溶水资源管理、生态环境建设等方面提供参考。

Study on the variation characteristics of extreme precipitation events of karst area in Yunnan Plateau

Using the daily precipitation data from nine meteorological stations in the karst area of the Yunnan Plateau from 1960 to 2017, six extreme precipitation indexes were calculated by MATLAB. Based on inverse distance weighted interpolation, linear tendency estimation, Mann-Kendall abrupt change test and Morlet continuous wavelet transform, we explored the evolution of extreme precipitation events in the karst area of the Yunnan plateau. The results showed that among the extreme precipitation indexes in the karst area of the Yunnan plateau from 1960 to 2017, CDD, RX1day, RX5day, and SDII mainly showed a slow upward trend, CWD showed a significant downward trend, and the overall decrease of PRCPTOT was not significant. Only CDD and PRCPTOT had undergone significant abrupt changes in this period, which happened in 2006 and 2000, whereas the remaining four indexes CWD, RX1day, RX5day, and SDII had no obvious abrupt changes. The periodic fluctuations of each extreme precipitation index were obvious, manifested as major cycles of 28-30 a, 26-30 a, 27-30 a, and 27-30 a for CDD, CWD, RX1day, and RX5day, respectively. In comparison, SDII and PRCPTOT are most obvious at the 27-30 a scale. The spatial differences of extreme precipitation indexes in the karst area of the Yunnan Plateau from 1960 to 2017 were obvious. All the indexes increased from north to south with the exception of CDD showing the oposite trend. From 1960-2017, CDD, CWD, RX1day, RX5day, and SDII all had a very significant positive correlation with PRCPTOT, with the correlation coefficient of 0.98 and above. These changes of extreme precipitation events can provide some reference for future karst water resources management and ecological environment construction.