丽水不同等级降水日数多时间尺度变化特征

The Multi-time-scale Characteristics of Different Level Precipitation Days in Lishui

为了解不同等级降水日数变化特征,更好地为农业生产服务,根据丽水市1953—2011年逐日降水量资料,在对不同等级降水日数进行年、月趋势分析的基础上,运用Mann-Kendall检验对显著降水事件进行趋势变化和突变转折的研究,从而探讨不同等级降水日数在多时间尺度上的变化特征。结果表明:近59年来,丽水市总降水日数呈明显的下降趋势,气候倾向率达到-3.70d/10a,其中小雨日数占总雨日的72.6%,下降趋势同样通过99%显著性检验。暴雨日为缓慢增加态势,其他等级降水日数表现为减少,但不显著。Mann-Kendall检测得出:雨日表现为"先增加,后减少"的变化趋势,2002年是雨日由缓慢减少转为急剧下降的突变点。

In order to understand the different level precipitation days and better services for agricultural production, according to the daily precipitation data from 1953 to 2011 in Lishui, and based on the study of annual and monthly trend of different levels of precipitation events, the author used Mann-Kendall test to study the time-frequency characteristics and abrupt change of significant precipitation events, in order to further explore the multi-time-scale characteristics of different level precipitation days in Lishui. The results showed： the total precipitation days had a significant decreasing trend at -3.70 d/10 a in Lishui over the past 59 years, and the light rain days accounted for 72.6% of total precipitation days, and its decreasing trend passed the 99% significance test. At the same time, torrential rain days had increased slowly, and the other levels of precipitation days showed a decreasing trend, but not obvious. The results of Mann-Kendall test showed that the precipitation days increased at first, and then decreased, its abrupt change occurred in 2002.