黄土高原地区主要植被类型的气候梯度分布

应用Thronthwaite的方法,对黄土高原286个气象站(台)的某些气候指标进行了计算,其中包括校正的潜在蒸散(APE)、水分指数(IM)、热量系数(TE)、干旱指数(IA)和湿润指数(IH)。同时,得到了每项气候指标的地理回归模型,并利用各项地理回归模型分别做出了各项气候指标的地区分布图。APE和IM与黄土高原地区植被的主要类型及其分布格局有密切的关系。本区大多数的植被类型的IM均为负值,照例划入干旱亚湿润-半干旱-干旱(dry subhumid-semiarid-arid)地区内,而大部分植被的TE在57.1—85.5之间,应属中温范畴。植被与气候指标的相关性表明:黄土高原南端的地带性植被,实际上为干旱森林、疏林和灌丛,它们在性质上与分布于山地上的辽东栋(Quercus liaotungensis Koiz.)林有所区别。

CLIMATIC GRADIANT OF MAIN VEGETATION TYPES IN THE LOESS PLATEAU REGION

Based on the climatic data from 286 meteorological stations on the eoess plateau China, Thornthwaite's method (1948) was used to calculate the annual adjusted potential evapotrans- piration (APE), moisture index (IM), thermal efficiency index (TE), aridity index (IA) and humidity index (IH). Geographical regression models for each index were developed and ap- plied to generate regional distribution maps for each index. For instance, APE=1812-8.79 Lat-5.91 Long-0.17Alt. APE and IM were closely related to main vegetation types and their distribution on the Loess Plateau. Most vegetation types had negative IM and were usually classified into the dry subhumid-semiarid-arid region. TE of most vegetation types was wi- thin the range of 57.1-85.5, belonging to mesothermal category. Zonal vegetation on the southern Loess Plateau was xeric forest, woodland and shrubland, which are different from Quercus liaotungensis kolz. forest on mountains in terms of community characters and distribu- tion.