基于 SPI 干旱指数的海口市干旱变化特征研究

根据海口市 8 个雨量站 1970- 2012 年的逐日降雨资料, 采用降雨平均和 SP I( 标准化降水指数)平均两种不 同的 SPI 处理方案计算了三个时间尺度( 3、6、12 个月) 的 S PI 值。将两种处理方案在不同时间尺度上计算所得 的干旱情况与实际干旱情况做了比较, 选择适用于海口市干旱评估的处理方案, 应用 M ann2Kendall 检验, Morlet 小波分析方法分析了海口市 1970- 2012 年间各季节的干旱变化趋势和年干旱变化周期。结果显示: 降雨平均方 案更适用于评估海口市的干旱情况; 海口市不同程度的干旱发生频率高达 56% , 多发生在春、秋两季, 频率分别 为 51% 和 41% , 秋季特旱发生频率为 14% ; 海口市整体干旱有加重趋势且秋季加重趋势明显; 海口市干旱具有 13 a 左右的第一主周期, 4 a 和 22 a 的第二、三周期。研究结果可为海口市干旱评估和预报以及制定抗旱减灾措施 提供参考。 Acco rding to the daily r ainfall data of the eight rainfall statio ns in Haiko u City fr om 1970 t o 2012, w e used two differ2 ent SPI pro cessing schemes, ( 1) SPI calculated from all2station av erag ed precipitation ( pr ecipitatio n2mean) and ( 2) mean o f all SPI calculated fr om pr ecipitatio n at indiv idual stations ( S PI2mean) , to ca lculate t he SPI v alues at 32, 62and 122month sca les. We compar ed the droug ht situat ion reflect ed by the t wo schemes at each month scale with the actual dr ought situatio n and selected the suitable scheme fo r dro ug ht evaluation in H aikou City. We used the Mann2Kenda ll test and Mo rlet w avelet analysis method to analy ze the chang e trend and the cycle o f dro ug ht change in H aikou City from 1970 to 2012. The results show ed that pr ecipi2 tat ion2mean is mo re suitable to ev aluate the dro ug ht situation in H aikou. Fr om 1970 to 2012, the o ccurrence frequency of dr oughts of differ ent degr ees in H aikou City w as as high as 56% , especially in spring and autumn, w here the fr equency w as 51% and 41% respectively . T he o ccurr ence fr equency o f extr eme dr oughts in autumn was 14% . The g ener al dro ug ht situatio n in Haiko u Cit y w as ag g ravating , and the t rend w as especially o bv ious in autumn. T he dro ug ht in Haiko u had a first main cycle of about 13 years, a second main cy cle o f 4 y ears, and a third main cycle of 22 y ears. The r esults can pro vide a r efer ence for dr ought evaluat ion and fo recast ing and the dev elo pment of dro ug ht relief measur es in H aikou City . 国家自然科学基金( 51621096)