遂宁市各季节降水与干旱研究

本文利用1961~2010年月降水资料,采用小波分析方法对遂宁市近50年来降水不同时间尺度进行分析。揭示了该地区降水变化的多时间尺度变化特征,并对未来降水进行预估,同时从天气学原理出发分析造成春旱和夏、伏旱的环流背景和机制,结果表明:遂宁市降水3~5a左右时间尺度的周期震荡最显著;夏季降水和年降水具有相同的变化规律;小波系数出现最大值的后1~2年干旱容易发生。春季冷空气和南支槽都偏弱的情况下,遂宁市容易出现较为严重的春旱;盛夏,西太平洋副高偏强加之西风带明显偏北的时候,遂宁市容易出现严重的伏旱。 

Seasonal Precipitation and Drought Research in Suining Area in Central Sichuan

Based on the analysis of different time scales of precipitation in the past 50 years using the wavelet analysis method in Suining area with the annual and monthly rainfall data from 1961 to 2010.The paper reveals the multi-time scales characteristic of the precipitation changes in the region,and predicts future precipitation and circulation background and mechanism analysis caused by spring drought and summer drought by using the synoptic principle.It shows that there are obvious periodic oscillation of 3-5a for spring,summer and annual precipatation.Summer precipitation and annual precipitation have the same variation,which infers annual precipitation of 2011~2014 will be less than normal level in Suining area.Drought tends to happen 1 or 2 years after the maximum of wavelet coefficient.If spring cold air and southern branch trough are slightly weaker,severe spring dnceght tends to happen in Suiming area.In the summer,when the West Pacific subtropical high is slightly stronger than normal years and westerlies' position is significantly northward,severe summer drought tends to happen.