Abstract:

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.

Key words: drought')">

drought, Heilongjiang Province, [WTBX]SPI[WTBZ], spatialtemporal characteristic