ABSTRACT
ABSTRACT: The evolution characteristics of drought during winter wheat growing season based on multiscalar Standardized Precipitation Evapotranspiration Index (SPEI) and the relationship between SPEI and crop yield fluctuation were analyzed, using the monthly data of precipitation and temperature during 1951-2013 and historical wheat yield of prefecture level cities. The results showed that the climate in Shandong province tended to be drier in monthly, quarterly and annually time scalars since 1960. The drought conditions during what growth tended to aggravate and the drought frequency increased significantly with the advance of time. In 2000-2013 the frequency was 64.29% in the stage before wintering, 41.67% in wintering stage, 75.79% in the late growing stage and 73.81% in the whole growing stage. Against as in 1960-1979 and 1980-1999, the frequency of severe and extreme drought increased significantly. The drought severity identified by SPEI indices was well consistent with the historical document reported, and the yield fluctuation was positively related to SPEI of wintering stage, late growing stage and the whole growing stage. It was concluded that SPEI could be used for drought monitoring and risk assessment during winter wheat growth season in Shandong province.
