【摘要】 干旱是全球范围内影响最广的自然灾害,近年来,华北地区几乎每年都有不同程度的干旱发生,旱情持续时间长,影响范围广,作物受旱程度十分严重,甚至出现连年干旱情况,影响较为巨大。依据1998—2017年气象降水资料,计算标准化降水指数(SPI),采用SPI栅格化处理和时间序列相结合的方法从SPI的年、月时序变化和空间尺度的季节性干旱演变分析了华北地区这20年的干旱时空变化特征。结果表明:(1)华北地区1998—2017年干旱发生频繁,在年与年之间发生干旱的程度和范围有所不同;(2)干旱主要发生在春、夏、秋3个季节,春、夏旱发生频率较高;(3)河南、山西、山东部分地区春旱较为严重,华北地区夏旱面积最广。更多还原

【Abstract】 Drought is the most severe natural disaster on a global scale. In recent years, almost every year, there are different degrees of drought in north China. The drought lasts for a long time, the scope of impact is wide, the degree of drought in crops is very serious, and even droughts occur in successive years. Based on the meteorological precipitation data from 1998 to 2017, this paper calculated the standardized precipitation index(SPI), and used the combination of SPI rasterization and time series to analyze the annual and monthly time series of SPI and the seasonal drought evolution of spatial scale. The characteristics of the spatio-temporal changes in the region over the past 20 years were analyzed. The results showed that:(1) the drought occurred frequently in north China from 1998 to 2017, and the degree and extent of drought were different between years;(2) the drought mainly occurred in spring, summer and autumn, and the frequencies of spring and summer drought were higher;(3) the spring drought in Henan, Shanxi and Shandong was more serious. The area suffering from summer drought in north China is large.更多还原