疏勒河流域极端降水特征分析

Characteristics of Extreme Precipitation in Shule River Basin

摘要: 疏勒河流域是我国河西走廊内陆河流域的重要组成部分。在全球气候变暖背景下，研究其极端降水特征变化对于了解西北内陆河流域生态水文过程以及对气候变化的响应均具有重要意义。本文以疏勒河流域4个气象站点1960~2012年逐日降水资料为基础，采用Mann-Kendall检验、Pettitt方法、气候倾向率、滑动平均和小波分析等方法，对研究区年降水总量、最大一天降水量的趋势变化、变点特征和周期特征进行分析，并对极端降水发生频次进行讨论。结果表明，近50多年来研究区玉门镇站、安西站和敦煌站年降水总量和最大一天降水量均呈波动上升趋势，上升幅度分别为3.0~5.3 mm/10a和0.7~1.0 mm/10a。各站点年降水总量序列基本存在11~13年长周期、6~7年中周期和2~4年短周期，短周期较为显著；最大一天降水量序列存在17~18年长周期、6~10年中周期和3~4年短周期，中周期和长周期较为显著。除马鬃山站以外，玉门镇站、安西站和敦煌站2000年以后极端降水发生频次明显增加，这与年降水总量和最大一天降水量变化趋势较为一致。

Abstract: Under the background of global warming, extreme climate events are proved to occur more frequently than before in most regions of China. Shule River basin, located in the Northwest of China, is one of the important parts of inland river basins in Hexi corridor. Studying the characteristics of extreme precipi-tation in Shule River basin is significant for better understanding the local eco-hydrological processes and its response to climate change. Based on the daily precipitation data from 1960 to 2012 at four me-teorological stations, the trends, change points and period features of the annual total precipitation (ATP) and the annual maximum precipitation for one day (AMP) over Shule River basin are investigated by means of Mann-Kendall test, Pettitt test, Climate trend rate, the five-year moving average method and Morlet wavelet analysis. In addition, the occurrence number of extreme precipitation over the study area is also discussed in this paper. Results show that, the increasing trends are found for the ATP and AMP series at Yumenzhen station, Anxi station and Dunhuang station with the climate trend rates of 3.0 - 5.3 mm/10a and 0.7 - 1.0 mm/10a. No significant change points are found for the ATP and AMP series with Pettitt test. Based on the wavelet analysis, the ATP series are found to have a long period of 11 - 13 years, a middle period of 6 - 7 years and a short period of 2 - 4 years, in which the short period shows more out-standing. The AMP series have a long period of 17 - 18 years, a middle period of 6 - 10 years, and a short period of 2 - 4 years, with more significant long and middle periods. The occurrence numbers of extreme precipitation at three stations (Yumenzhen, Anxi and Dunhuang stations) are found to have an increasing tendency after the year of 2000.