Abstract:  Based on disasteraffected areas of drought, flood, windhail, low temperature, combining with grain yield data in Northeast China from 1971 to 2009, agrometeorological disasters tendency variation and their impacting on grain yield in Northeast China had been studied in this paper. The tendency variation results showed that, in recent 39 years, only disasteraffected area ratio of windhail presented decreasing tendency obviously, while flood, drought and low temperature existed phase characteristics. In 1970s, disasteraffected area ratio of drought was higher than flood, which was on the contrary in 1980-1990s, and recent period was in relatively dry phase again, in terms of low temperature, it began to rebound in early 1990s and early 21st century. R/S analysis showed that Hurst index results of 4 agrometeorological disasters were more than 0.5, indicating future tendency variation would be consistent with the past, namely, disasteraffected area ratio of windhail would continue to decrease, and drought would maintain the increment, while flood and low temperature would present fluctuant trend. Gray correlation analysis indicated that the impaction of agrometeorological disasters on average grain yield performed differently in different provinces, in Liaoning as, drought＞windhail＞flood＞low temperature, in Jilin as, flood＞drought＞low temperature＞windhail, in Heilongjiang as, drought＞flood＞low temperature＞windhail, which revealed drought and flood were major agrometeorological disasters during grain production, and the impacts of low temperature was much greater towards the high latitude in Northeast China.

Key words: Northeast China, Agro meteorological disasters, Disaster affected area ratio, Grain yield, R/S analysis, Gray correlation analysis