Mechanisms of droughts and their patterns during winter wheat growing season in Henan Province of China

Drought is the serious agrometeorological disaster influences the growth of winter wheat in Henan Province, China. The main causes of drought formation in the province was preliminarily described based on factors such as geographical, monsoon circulation and the global climate background and then drought patterns that happened during last more than 40 years were analyzed in terms of negative departure percentage from averaged precipitation as indicators. Results show that heavy droughts are centralized in northeast part of the province and light droughts centralized in southwest part. The light ones took place every 3 years, medium ones did every 7 years and heavy ones every 10 years. This study is beneficial to winter wheat cropping planning and drought-prevention in Henan Province.