陕西省不同地区NDVI变化与气候因子的关系及响应研究

Changes of NDVI in Different Areas of Shaanxi Province and Its Responses to Climate Factor

利用SPOT VEGETATION数据分别研究了陕西省近10a植被空间分布和动态变化,比较了陕南、关中和陕北地区植被NDVI的年际变化和月变化。结果表明,陕西省植被覆盖总体较好,各地区植被总体轻微改善。这3个地区的植被NDVI年均值均逐年增加,并且增长速度表现为:陕南>关中>陕北,不同地区植被夏季生长最好。通过对不同地区植被NDVI与气温、降水、日照时数的年际和年内相关关系及其响应的研究得出,不同地区植被NDVI与气温、降水、日照时数的年际相关性不大,而年内相关性显著。研究了不同地区植被NDVI对气温、降水、日照时数的滞后效应得出,陕南地区植被NDVI对气温降水的响应不具有滞后性,对日照时数的响应具有滞后性。关中和陕北地区植被NDVI对气温、日照时数的响应具有滞后性,对降水的响应具有即时性。

The spatial distribution and dynamic changes of vegetation in Shaanxi Province were analyzed using SPOT VEGETATION data for recent ten years. The NDVI values of different regions including the southern, Guanzhong and the northern areas were compared in regard to annual and monthly variations. It was showed that Shaanxi Province had good vegetation coverage that improved slightly as a whole during the past years. Annual aver- age NDVI of the three regions were increasing each year, with increasing rates of the southern area Guanzhong area^the northern area. By comparison, we found the vegetation NDVI had significant monthly and less significant annual correlations with temperature and precipitation in different areas. The responses vegetation NDVI showed no significant time lag to temperature and precipitation and exhibited noticeable lag to sunshine variations in Southern Shaanxi area. In Guanzhong and Northern Shaanxi area, in the response of NDVI was found one month of time lag to temperature and sunshine lagged while no lag to precipitation.