基于SPI的黑龙江省干旱时空特征分析

利用黑龙江省10个气象站点1953—2015年逐日降水数据,计算不同尺度下的标准化降水指数(SPI),并结合游程理论分析黑龙江省干旱的时空演变特征。结果表明:降水仍是黑龙江省干旱的主要影响因素;黑龙江省干旱夏季和秋季呈增强趋势,SPI变化速率分别为每10 a下降0.029、0.135,春旱和冬旱呈缓解趋势,速率为每10 a上升0.061、0.074,年SPI变化速率为每10 a下降0.044;黑龙江省20世纪60年代中后期~70年代末,干旱较为频繁,且干旱的持续时间长、干旱程度大、干旱强度大,出现了1974—1980年的连续干旱期,80年代~90年代中期较为正常,90年代末及之后,干旱频率及其持续时间、程度、强度呈增加趋势;干旱事件的持续时间从西北向东南呈增加—减少趋势,黑龙江省中部的干旱事件持续时间最长。

Spatial-temporal characteristics of drought in Heilongjiang Province based on standardized precipitation index

As one of the major grain-producing provinces,Heilongjiang Province,China is susceptible to suffering from drought risk.Drought happened much more frequently in recent years.Only a few studies focused on drought in the study area at present and most of them paid more attention to the frequency and degree of drought than the changes of the spatial-temporal characteristics of drought events.The changes of drought and the spatial-temporal characteristics of drought events in Heilongjiang Province were showed based on daily precipitation data from 1953 to 2015 by different scales of Standardized Precipitation Index (SPI),combined with Run-length theory.The results showed that precipitation,compared with temperature,has been the main factor related to drought.The research indicated that the SPI is an effective index for assessing drought conditions in Heilongjiang Province.The trend of summer drought and autumn drought was increased,while the trend of winter drought and spring drought was decreased.The summer SPI and autumn SPI were decreased with average rates of 0.029 and 0.135 per ten years respectively,while the spring SPI and winter SPI were increased with average rates of 0.061 and 0.074 per ten years separately.Annual SPI was decreased with an average rate of 0.044 per ten years.From the middle of 1960s to the late 1970s,drought in Heilongjiang Province happened frequently.The duration of drought events was long.The degree of drought was big and the intensity of drought was high.A consecutive drought period occurred in the years from 1974 to 1980.During this time period,droughts happened at a higher frequency and for a longer duration.The situation was comparatively normal from 1980s to the middle of 1990s.The duration,the severity and the intensity of drought events showed an increasing trend from the late 1990s.From the Northwest to the Southeast,the duration of drought events was decreased after the first increase.This study could make contribution to monitoring and assessment of drought.And it could be used in guidelines of water resource management and agricultural production.