基于PDSI的甘肃省干旱时空变化特征分析

Temporal and Spatial Variation Feature Analysis of Drought in Gansu Province Based on PDSI Method

针对甘肃省旱灾频繁、危害大的现状,开展了干旱时空变化特征分析。选取甘肃省境内的30个气象台站1951—2010年的月降水量、月平均风速、日最高温度、日最低温度、日照时数、日平均水汽压、可能日照时数等资料,基于帕默尔干旱指数(PDSI),采用Mann-Kendall非参数检验法对干旱时空变化特征进行研究。结果表明:全省旱情呈现微弱缓解的趋势;20世纪50年代、70年代、90年代及21世纪前10 a的中后期干旱状况明显加重,20世纪60年代、80年代干旱状况有所缓解。对中等干旱、严重干旱和极端干旱的可能发生频次和空间分布进行分析,发现全省旱情地域差别较大,总体呈现"两头重、中间轻"的特点。

Aimed at the Present situation of frequent drought and huge damage in Gansu Province,temporal and spatial variation features of drought were analyzed in the paper. On the basis of the monthly precipitation,monthly average wind speed,daily maximum temperature,daily minimum temperature,sunshine hours,daily average water vapor pressure and probably sunshine hours of each month in 50 meteorological stations in Gansu Province during the period of 1951 to 2010 and based on Palmer Drought Severity Index （PDSI）method,temporal and spatial variation characteris-tics of the drought were analyzed by using Mann-Kendall nonparametric test analysis. The results show that the drought trend is weakly relieved in Gansu Province in recent years;the drought situations were significantly worsened in 1950s,1970s,1990s and 2000s,while the drought situations were relieved in 1960s and 1980s. The frequency and spatial distribution of medium drought,serious drought and extreme drought were analyzed, which shows that the regional drought is more different in the whole province with the characteristics of“the two ends are heavy and the middle is light”.