Drought evolution characteristics and attribution analysis in northeast China

Drought disaster costs the most economic losses among natural disasters in the worldwide, which not only affects food production, but also be related with the rational utilization of water resources. As an important commodity grain production and reserve base, the northeast of China has been seriously threatened by drought disaster. In order to deal with drought events reasonably, a SPI index reflecting climate factors and several agricultural indexes reflecting nature and human activities together have been selected based on statistical data of nearly 60 years from 1950-2010 to analyze drought evolution characteristics. Meanwhile, a few of the natural and economic factors including rainfall, effective irrigation area and sown area, have been selected to reveal the possible reasons leading to the agricultural drought, and the relationship between these factors and drought area are analyzed by the SPSS software. The results were shown that: the climate in the Northeast of China appeared a drying temporal evolution trend in the recent 50 years. And there were different climate characteristic in season. Namely, drought dominant in spring, the alternately drought and wetting change in autumn and winter. In the spatial, drought events happened is more in the northwest and northeast of the whole region. At the same time, the frequency and intensity of agricultural drought had increased in the temporal scale, and the increasing feature from the North to the South in the region scale under the influence of nature and human activities. The drought events are 4 times in the period from 1980 to 2010 than that in the period from 1950 to 1979. In which, there was more increasing for above of the severe drought events than that of the other drought events. Associating with natural and social factors, by analyzing the correlation between drought area and precipitation, effective irrigation area and the sown area, the main reasons causing the above-stated drought condition in the whole northeast region were that the decreasing of rainfall and the increasing of effective irrigation area and sown area. In which, the decreasing rainfall amount is the direct factors leading to the drought. The large expansion of the sown area and the lack of the irrigation water in the effective irrigation area together aggravated the development of drought. (C) 2016 The Authors. Published by Elsevier Ltd.