The vertical distribution of agrotopoclimatic resources in the warm sectors of the three gorges area of the Changjiang River

Abstract

The paper expounds the characteristics of the verticaldistribution of agrotopoclimatic resources in the warm sectors of the Three Gorges area of the Changjiang (Yangtze) River, sets up models of vertical distribution of resources, and make a vertical division of the agrotopoclimate. Mean temperature presents a linear decrease with increasing altitude. In general, the mean annual maximum temperature and the mean annual munimum temperature decrease with the altitude increase especially, the absolute minimum temperature presents an indicial decline. Days of high temperature decrease with the altitude increase and days of low temperature in reverse. Accumulated temperature and days of agricultural threshold temperature have negative relation with the height. Both annual sunshine hours and the sunshine hours between April and October present a linear decrease with increasing altitude. The precipitation in sectors above 300m increases with increasing altitude, but the precipitation in sectors below 300m goes in reverse. Annual change of precipitation has typical characteristics of East Asia monsoon climate with two peaks. In lower warm sectors the aridity index decreases with increasing altitude while in upper sectors it increases with the altitude increase. Nine indices of vertical division are selected to make a quantitative division of agrotopoclimate.