新疆塔城地区1961—2021年季节性干旱演变特征

利用塔城地区9个国家气象观测站1961—2021年逐月降水资料,基于标准化降水量指数(SPI)运用最小二乘法和Mann-Kendall检验等方法分析塔城地区干旱时空分布特征。结果表明：(1)年尺度上,塔城地区干旱发生频率为30.37%,轻旱发生最多,中旱次之；2/3站点SPI呈显著增大趋势,年站次比和干旱强度呈显著减小趋势,干旱程度有所减轻,在1987年之后塔城干旱程度整体偏轻。(2)季节尺度上,夏、秋、冬季在1980年代中期发生干旱减轻的突变,且秋季和冬季分别在2002年和1997年达到显著。(3)在影响范围方面,各季以局域性和全域性干旱为主,全域性干旱发生频率介于20～30%之间；在干旱强度方面,各季轻度干旱发生频率最高,中度以上干旱发生频率介于33～38%之间。(4)近60a塔城地区季节性干旱呈现影响范围缩小,强度减弱的变化趋势,尤其是冬季干旱站次比和干旱强度分别以-7.79%.(10a)-1^和-0.11.(10a)-1^的倾向率显著减小,干旱减轻趋势在四季中最为显著。

Recently 60 years characteristics of seasonal drought in Tacheng,Xinjiang

Drought is one of the main natural disasters in Tacheng area, which lasts for a long time and has a wide impact on agricultural production and social economy. Based on monthly precipitation data of 9 national meteorological observation stations in Tacheng area from 1961 to 2021, and by using standardized precipitation index (SPI) and adopting least Squares and Mann-Kendall test, the spatial-temporal distribution characteristics of seasonal drought were analyzed on frequency of drought, drought impact range and intensity. The results can be shown as follows: (1) The annual frequency of drought are 30.37% in Tacheng area, with light drought occurs frequently, secondly medium drought; SPI can be shown a significant increase trend for 2/3 stations, and the percentage of frequency and drought intensity are significantly decreasing, and after 1987 the drought degree is relatively light. (2) On the seasonal scale, in summer, autumn and winter the abrupt changes of SPI appears in Mid 1980s, and the abrupt changes show significant in 2002 and 1997. (3) In terms of the affected range, local droughts and widespread droughts happen frequently, and frequency of widespread droughts is between 20% and 30% in each season. In terms of drought intensity, There got the highest number of light droughts, secondly medium drought which appearing frequency is between 33% and 38%. (4) In the past 60 years, the seasonal drought has shown a trend of decreasing on influence range and intensity. Especially in winter, the percentage drought and drought intensity have decreased significantly at the rates of -7.79%.(10a)_-¹ and -0.11.(10a)_-¹, and the lighten trend of drought is the most significant in the four seasons.