吉林省四平地区近50年区域旱涝变化特征

应用国家气候中心下发的吉林省四平市5站的逐日降水资料对四平市进行旱涝等级划分,主要应用线性趋势法和小波分析法对其特征进行分析,根据旱涝指标Z指数对旱涝指数W指数进行运算。结果分析得出:W指数存在较弱的下降趋势,并且阶段性特征变化明显,W指数计算得出严重旱年与降水距平百分率有很好的对应关系;54年四季旱涝年数差异较大,各季存在旱涝交替、连旱或连涝的特征;年W指数以3.68·10a~(-1)的速度递减,春季和冬季W旱涝指数以3.89·10a~(-1)和10.183·10a~(-1)的速率增加,均通过0.05水平的显著性检验,呈现增加趋势,夏季和秋季W旱涝指数呈现递减趋势。从小波分析结果得出各季节震荡周期不同并且特征显著。

Variation of drought and flood frequency in Siping region in the past 50 years

Based on the calculation of the drought-flood index (Z index, W index) with the daily precipitation data of 5 meterological stations, the variation of drought-flood in Siping region was analyzed by the linear trend method and wavelet analysis method. The results showed that the W index data was in a weak downward trend in the Siping during the past 54 years, and exhibited alternating drought and flooding. The extreme drought year of W index corresponded to the precipitation anomaly year. These two had consistency and W index might well reflect the flood/drought rules of Siping region. The drought parameter W tends to decreased at a rate of 3.68·10a^-1, while it tends to increased significantly at the rate of 3.89·10a^-1 in spring, and 10.183·10a^-1 in winter. Each season has a different oscillation period and distinguished feature according to the result of the wavelet analysis method.