关键词: 东北地区, 夏季干旱, 风险评估, 风险区划

Abstract:

Since the Northeast China is an important commodity grain base, the persistent drought events become a serious threat to food production in this area. Now the loss of grain caused by the drought is up to or even more than 10 billion YUAN each year. Due to the significant decrease of river runoff in the periods of drought and the over-exploitation of the groundwater, the situation of gradual deterioration of ecological environment in Northeast China has happened, the drought become a serious challenge in sustainable development of social economic and ecological environment. The study of the cause and its risk assessment of drought in Northeast China are of very important for the reduction of losses in drought disaster, and also important for providing scientific and technological support in the fight against droughts. Based on the daily mean temperature and precipitation data in Northeast China , and considering the influence of summer precipitation on food production, a summer drought index is defined by the use of K index, the space-time variation of summer drought is then investigated. The summer precipitation variation coefficient, the risk index and the risk probability of summer drought are calculated and analyzed. The comprehensive risk index is defined based on four indicators, i.e. the variation coefficient of summer precipitation, the frequency of summer drought, the risk index and risk probability of summer drought, the comprehensive risk division of summer drought is also conducted. Results show that: summer drought in Northeast China is more serious in the west than that in the east. The summer drought in Northeast China is get into the frequently-occurring stage since the 1990′s.The southwest of Heilongjiang Province, the west of Jilin Province and the west of Liaoning Province are the driest regions and they are the high-risk areas of summer drought, the north and east parts of Heilongjiang Province, the central of Jilin and Liaoning Province are the lower risks areas of summer drought, the south-central of Heilongjiang Province, the east of Jilin Province and the southeast of Liaoning Province are the low risk areas. Defensive measures should be taken in the high-risk and the higher risk areas, by promoting the agricultural drought resistant technology vigorously, taking grater efforts on the climate prediction, strengthing the construction of drought resistance so as to reduce the summer drought loss in Northeast China.

Key words: Northeast China, summer drought, risk evaluation, risk division