Research of the agriculture drought and association with meteorological drought-a case study of above the Bengbu sluice in the Huaihe River Basin, China

Based on the meteorological data of 60 stations above the Bengbu Sluice of Huaihe River from 1961 to 2015, Crop Water Deficit Index (CWDI) and Relative Moisture Index (M) were calculated. Taking winter wheat drought as the representative of agricultural drought, the temporal and spatial characteristics of winter wheat drought and meteorological drought during growth period were analyzed. The duration, severity and frequency of 30 major drought events were identified through the run theory, and the correlation between agricultural drought and meteorological drought was studied. The results showed that: (1) In terms of time, the proportion of agricultural drought in winter wheat growth period was higher than that of meteorological drought, and the years with the largest interannual difference occurred in the pre-winter growth period; (2) In terms of space, the winter wheat drought and meteorological drought in the whole growth period and each growth period were distributed by zonal mode structure, and the drought gradually increases from south to north. More than 75% of the drought of winter wheat occurs from over-wintering period to filling and mature period, while meteorological drought only occurred during over-wintering period; (3) Winter wheat drought was delayed compared with meteorological drought, and its intensity was greater than meteorological drought; (4) When the duration of meteorological drought reached 1.28 dekad or the drought severity reached 3.35, the drought of winter wheat will be triggered, and the frequency of the duration and severity return period of winter wheat drought was greater than that of meteorological drought.