我国北方地区植被对水分亏缺的响应特征分析

The Characteristics of Correlation between Vegetation and Water Shortage in the Northern China

我国北方地区普遍缺水,水分亏缺势必会对植物生长带来极大的负面影响。分析我国北方地区植被对水分亏缺的响应关系可为深入研究区域水量时空变化对植被的影响提供参考。参考我国干旱、半干旱气候区的划分方法,将我国北方地区分为寒温带针叶林区(Ⅰ)、温带落叶阔叶林区(Ⅱ)、暖温带落叶阔叶林区(Ⅲ)、温带草原区(Ⅳ)和温带荒漠区(Ⅴ)5个分区,采用GIMMS NDVI描述植被动态变化,以降水量和潜在蒸散发量的差值描述区域尺度的水分亏缺程度,分析中国北方地区不同分区植被对水分亏缺的响应程度和响应时间,结果表明:植被对水分亏缺的响应系数表现为Ⅰ分区>Ⅳ分区>Ⅱ分区>Ⅲ分区>Ⅴ分区,除Ⅴ分区外,植被对水分亏缺的响应时间集中在5或6个月;Ⅱ、Ⅲ、Ⅳ分区农田对水分亏缺的响应程度低于同分区的其他植被类型,沙漠植物对水分亏缺的响应程度明显低于其他植被类型。

Water shortage is widespread in the northern China,which will have a significant negative impact on plant growth.Analyzing the corre-lation between vegetation and water shortage in the northern China can provide reference for study on the impact of spatio-temporal changes of regional water on vegetation.Based on the zoning method of arid and semi-arid climate zones in China,the paper divided the northern China into five sub regions:cold-temperate coniferous forest area(Ⅰzone),temperate deciduous and broad-leaved forest area(Ⅱzone),warm-temperate deciduous and broad-leaved forest area(Ⅲzone),temperate grassland area(Ⅳzone),and temperate desert area(Ⅴzone).And the paper used GIMMS NDVI to describe vegetation dynamic changes and the difference between precipitation and potential evapotranspiration to describe the degree of water shortage at the regional scale to analyze the correlation between vegetation and water shortage in different sub-regions in the northern China.The outcomes show that a)the correlation coefficients between vegetation and water shortage are as followsⅠzone>Ⅳzone>Ⅱzone>Ⅲzone>Ⅴzone;b)except forⅤzone,the response time of vegetation to water shortage is 5 or 6 months;c)the correlation coefficients between vegetation and water shortage of farmland is lower than that of other vegetation types in the same zone inⅡ,Ⅲ,andⅣzones and the correlation coefficients between vegetation and water shortage of desert plants is significantly lower than that of other vegetation types.