Abstract:Based on MODIS-NDVI data, taking Shaanxi and Gansu provinces as examples, the correlation between different grades of winter wheat growth and main meteorological factors at 7 different phenophases were explored. Firstly, the development stage of winter wheat was divided into 7 different stages. Then the growth condition of winter wheat from sowing to maturity stages from 2011—2012 were assessed based on MODIS-NDVI data. Furthermore, the lag correlation between different grades of winter wheat growth in each phenophase and the meteorological factors with corresponding phenophases (temperature, precipitation and sunshine), which taken from 32 meteorological stations distributed within Shaanxi and Gansu provinces, were analyzed by using correlation analysis and GIS spatial analysis methods. The results showed that the winter wheat growth varied across time and space in the study area. And no matter what grades of winter wheat growth, the correlation coefficients between winter wheat growth condition and accumulated precipitation were higher than synchronous precipitation and pre-phenophase precipitation in terms of the average value in 7 phenophases, which showed the accumulated precipitation during the whole growing season had greater influence on winter wheat growth than synchronous precipitation and pre-phenophase precipitation. The influences of temperature on winter wheat were different according to different grades of winter wheat growth. In terms of sunshine, no matter what grades of winter wheat growth, the correlation coefficients between winter wheat growth condition and accumulated sunshine were highest in terms of the average value in 7 phenophases. The study also showed that winter wheat with better and worse growth condition were more sensitive to precipitation, whereas winter wheat with normal growth condition were largely influenced by temperature in the whole.