中国半湿润/半干旱类型及区域划分指标的研究

半湿润与半干旱地区之间的差异是客观存在的,但长期以来由于各种区划所采用的原则、方法和指标不同, 对它们之间的划分存在着较多的分歧和争议。本文对我国从综合自然地理学角度进行半湿润与半干旱区划分的指标进行了对比分析, 指出了其中存在的不足,并提出了在指标的选取上应着重考虑的几个方面。试图为中国生态地理区域系统的建立提供有益的参考。

A Study on Demacation Indexes between Subhumid and Semiarid Sectors in China

The climate, vegetation, soils, and farming are obviously different between subhumid and semiarid areas. For a long time, because of the difference of principles, methods, and indexes, there is divergence about the boundary line. The indexes, which have been used in physico-geographical regionalization in China, have been compared. We can see that the aridity or humidity indexes, aerial relative humidity, vegetation, soil and its sectional texture, and crops had been used as the major indexes. The formula, calculating the aridity or the humidity indexes, is based on experience. The formulas computing the potential evaporation are different. At the same time, the data comes from a year, so they can not comprehensively mirror the seasonal change of aridity and humidity. The real moisture condition can not be reflected either. The aridity and humidity of a region should be measured on the basis of moisture balance. But its function in regionalization was limited owing to some components and parameters. In views of the above-mentioned facts, the author put forward the indexes, which should be considered emphatically when a boundary line between subhumid and semiarid sectors is delimited. According to some principles and methods, it will be the prerequisite for the demarcation between subhumid and semiarid sectors to integrate the comprehensive and the dominant factors, and select the indexes well.