黑河上游山区植被的空间分布特征及其影响因素

以祁连山区的生态植被为研究对象,应用MOD IS NDVI遥感数据及DEM地形高程数据,定量分析了海拔高度、坡向对植被发育的影响,并对降雨、地温等气候因素对植被生长的影响进行了讨论。结果表明:1)植被指数随高程的增加逐渐增大,在高程3400m处达到峰值,植被发育最好,而后又随着高程的增加逐渐减小;2)在海拔3400m以下,植被指数随着降雨量的增大而增大,随着地表温度的增加而减小;在海拔3400m以上,植被指数则随着降雨量的增加而减小,随着地表温度的增大而增大;3)受太阳辐射的影响,在高程3200m~3600m范围内,坡向为NE0~70o,NW 330~360o之间的区域植被长势最好,这一变化则主要受地温的影响。其它高程范围内,植被长势与坡向关系不明显。

Distribution Characteristics of Mountain Vegetation and the Influence Factors in Upstream of Heihe River Basin

Take the ecological vegetation as research object,the MODIS NDVI and DEM data were used to quantitatively analyze the effect of elevationand hill'side direction on vegetation growth in Qilian Mountain.Furthermore,the influence factors of precipitation and groundtemperature were discussed in this paper.The results suggested that: 1) The NDVI increases with elevation,it reaches peak value on 3400m height and then it becomes decrease with the elevation.2) The NDVI increases with the precipitation and decreases with the ground temperature if the elevation is lower than 3400m.The NDVI decreases with the precipitation and increaseswith the ground temperature if the elevation is higher than 3400m.3) Affected by solar radiation,the vegetation growth is best when the hillside direction is from NE0o to 70o,NW330o to 360oif the elevation is between 3200m and 3600m.This result is mainly affected by the ground temperature.The relationship between vegetation growth and hillside direction is not clear in the rest elevation.