1961-2010年锡林浩特地区夏季降水量特征的小波分析

The wavelet analysis of summer precipitation characteristics in Xilinhot from 1961 to 2010

运用墨西哥帽函数(Mexican Hat Function)小波分析方法对锡林浩特地区50年来夏季降水量进行了小波分析。结果表明,夏季降水量在不同时间尺度上的周期变化不同,在较大时间尺度上振荡平缓,在较小时间尺度上振荡剧烈。夏季降水量周期振荡的第1~4主周期分别为30年、27年、24年和21年,夏季降水量多少和周期变化对年降水量产生一定影响。该区夏季降水量在30年以上较大时间尺度上存在7~15年的周期变化;在15年时间尺度上存在明显的10年左右的周期变化;在9年时间尺度上存在2~9年的周期变化;在3年以下较小时间尺度上周期振荡明显加强,无稳定周期,降水存在明显的不确定性。降水量的多少是决定草地植被生长状况和营养成分积累及含量的主要原因之一。

Using the wavelet analysis method with Mexican Hat Function,the characteristics of summer precipitation in Xilinhot from 1961 to 2010was analyzed.The results showed that the cycle of summer precipitation varied with timescales which supported by weak oscillation with larger timescale and volatile oscillation with smaller timescale.The first,second,third and fourth main period of summer precipitation periodic oscillation was 30,27,24 and 21years,respectively.The summer precipitation and periodic changes had an impact on annual precipitation.For the summer precipitation,the cycle was 7to 15 year for the timescale with more than 30 years,the cycle was10 years for a 15 year timescale and the cycle was 2to 9years for a 9year timescale.For the timescale with less than 3years,the periodic oscillation significantly strengthened,the cycle was shorter and unstable,and the precipitation was obviously uncertain.The precipitation was the key factor to determine the grassland vegetation growth status and nutrient accumulation and content.