1982～2006年祁连山北麓草原植被指数与气候及载畜量的关系

Variation of grassland NDVI,climate factors and standing carrying capacity and their correlation in northern Qilian Mountains from 1982 to 2006

利用祁连山北麓东段的天祝县、中段的肃南县和西段的肃北县1982～2006年的植被指数（NDVI）和气候因子（气温和降水量）及载畜量数据,对祁连山北麓25年间 NDVI 与气候和载畜量的变化趋势及相关性进行分析.结果表明：气温、降水量和载畜量变化的地域性差异明显,其中东段天祝县的变化最大.天祝县和肃南县的气温呈显著增加,3个县的年降水量和 NDVI变化均不明显,但1998～2006年草地 NDVI 空间变化特征表明,3个县9年间植被均呈现退化趋势；天祝县的载畜量呈明显增加而肃南县和肃北县的载畜量呈极显著降低变化.天祝县的年均气温和3个县降水量的稳定性较弱,而3个县的 NDVI和载畜量的稳定性较强.天祝、肃南和肃北县的年均气温、降水量、NDVI和载畜量的多年均值分别为0.3、5.0、7.1℃,339.2、263.7、152.0 mm,0.25、0.31和0.08,96.7、69.1、28.3万只羊单位.天祝县和肃北县的 NDVI 分别与气温（R=0.403）和年降水量（R=0.411）均呈显著正相关,肃南县的植被 NDVI与气候因素和载畜量均相关性不明显.分析认为,气候因素是影响祁连山草地 NDVI变化的主要因素.

The variation of grassland vegetation NDVI,climate factors and standing carrying capacity and their correlation in Tianzhu,Sunan and Subei counties located in eastern,middle and western Qilian Mountains from 1982 to 2006 were studied respectively.The results showed that the variation of tempera-ture,precipitation and standing carrying capacity had significant differences in different regions.The varia-tions of temperature,precipitation and standing carrying capacity in Tianzhu were the most compared to other two counties.The temperature in Tianzhu and Sunan significantly increased.However,the variations of precipitation and vegetation NDVI had no significant differences.The standing carrying capacity in Tianzhu significantly increased while which decreased in Sunan and Subei.The stability of annual average temperature in Tianzhu and annual average precipitations in three counties were weak.However,the stabil-ity of NDVI and standing carrying capacity in three counties were strong.The annual average temperature, precipitation,NDVI and standing carrying capacity in Tianzhu,Sunan and Subei were 0.3 ℃,5.0 ℃, 7.1 ℃;339.2 mm,263.7 mm,152.0 mm;0.25,0.31,0.08;96.7,69.1,28.3 ten thousands SU respective-ly.The correlation between NDVI and temperature in Tianzhu and Subei were significant and the R value were 0.403 and 0.411 respectively.The correlation between NDVI and climate factors and standing carry-ing capacity were not significant.Based on above analyses,the climate factors were the main factors that in-fluenced grassland vegetation NDVI in northern-Qilian Mountains.