汉江流域植被覆盖时空变化及其对气候因子的响应研究

Research on spatial and temporal changes of vegetation cover and response to climate factors in Hanjiang Basin

在1999—2010年SPOT VGT_INDV数据基础上,分析汉江流域不同类型植被覆盖年内、年际变化及空间分布差异情况,并结合研究区及周边38个气象站点数据分析植被与气温和降水的相关关系.结果表明,汉江流域农作物植被覆盖年内出现两次高值和两次低值,林地仅出现一次高值和一次低值.通过对比分析发现,对植被类型丰富的区域,采用均值法不能客观准确地反映客观实际.汉江流域研究时段内INDV总体呈波动上升趋势,且不同区域存在明显差异,主要表现为河流沿岸及周边的植被覆盖改善明显.植被覆盖与气温和降水的偏相关系数存在明显差异,汉江流域植被覆盖对气温的依赖性大于降水.人类活动降低了气温和降水对植被生长的制约程度.

Based on the SPOT VGT_INDv ten-day date during 1999--2010, this paper analyzed the intra- annual and inter-annual variation and different spatial distribution of types of vegetation coverage in Hanjiang Basin, and then analyzed correlation and retardation time between vegetation and temperature and precipitation combined the data from 38 meteorological stations in this district and surrounding area. The results showed： There are twice high values and twice low values of vegetation coverage in crops in Hanjiang Basin, and only once high value and once low value in forest land. Compared analysis discovers averaging method could not reflect objective reality exactly in the district rich in types of vegetation. INDV fluctuates but increases as a whole during study period, and has a significant difference in districts which mainly displayed vegetation coverage had a significantly improving in the river banks and surrounding area in Hanjiang Basin. The coefficient of partial correlation between vegetation cover and temperature was different obviously from it between vegetation cover and precipitation, and the dependency of vegetation cover to the temperature was bigger than that of the precipitation. Human activities reduced the restriction of the temperature and precipitation to vegetation growth.