Climatic regionalization of wine grapes in the Hengduan Mountain region of China

The Hengduan Mountain region of China is one of the world's highest altitude and lowest latitude wine grape cultivation areas. This study screened the existing regional indexes; the active accumulated temperature (AAT) for grapes in the growing season was chosen as the heat index, and the dryness index (DI) in the growing season was chosen as the water index for climatic regionalization. An analysis of 90-meter resolution digital elevation model (DEM) data and the corresponding slope degree and direction for the Hengduan Mountain region in the range of 97°E-103°E, 27°N-33°N, as well as daily meteorological data over 30 years (1981-2010) from 53 stations in the study region, were used to establish the AAT and DI models for the northern area of the Hengduan Mountains. According to the multiple stepwise regression method, the interaction terms among different geographical and topographic factors were considered. In addition, the residual errors were interpolated and corrected based on the modeling, and this approach further improved the simulation accuracy of meteorological factors. A regional climatic map of wine grapes was produced according to these results. The model was used to calculate the suitable altitude range for wine grape cultivation in different regions of the Hengduan Mountains. The study shows that the distribution of suitable wine grape cultivation areas in the northern part of the mountain range generally mimics distribution of dry warm and dry hot valleys. The accuracy of the results was confirmed based on the existing locations of vineyards in the Hengduan Mountain region