2001-2013年宝鸡地区植被NDVI对气温和降水量的季节响应特征

目的]研究2001-2013年陕西省宝鸡地区植被变化与气温和降水量的时空变化特征及其相关性,为区域农业发展和区域生态文明建设提供有力支撑.方法]基于2001-2013年宝鸡地区气温和降水量数据,利用MODIS NDVI数据和11个气象站点实测数据,结合实际调查,采用一元线性回归、标准化处理、相关分析等方法,基于季尺度、参照年尺度分析宝鸡地区植被覆盖季节时空变化及其与气温和降水量的相关性.结果]夏季植被NDVI增加趋势最为明显,其次为秋季,冬季植被覆盖最差;宝鸡地区四季标准化值NDVI与气温、降水量的变化趋势相接近,其最大值点的出现时间与气温和降水量基本对应.同一季节NDVI与气温的相关系数均高于NDVI与相应季节降水量的相关系数(除夏季);春季NDVI与冬季气温(-0.592)、夏季NDVI与春季降水量(0.640)之间显著相关,表明近13 a来春季植被覆盖变化与冬季气温、夏季植被覆盖与春季降水量的变化较为一致,NDVI与降水之间的滞后关系为0～3个月.结论]2001-2013年宝鸡地区年均、季NDVI整体均呈增加趋势,8月植被覆盖变化与降水量的变化较为一致,降水量较气温对8月植被生长影响强烈.

Seasonal Response Characteristics of Temperature and Precipitation Based on Vegetation NDVI in Baoji Area During 2001-2013

Objective] Temporal and spatial variations of vegetation and its links with temperature and precipitation in Baoji area of Shaanxi Province in the past 13 years during 2001-2013 were studied, in order to provide a strong support for regional agricultural development and ecological civilization construction work.Methods] Based on the temperature and precipitation in Baoji area from 2001 to 2013, using MODIS NDVI data and 11 meteorological site data, combined with field investigation, univariate linear regression, standardized processing, correlation analysis and other methods were used to analyze the temporal and spatial variation of vegetation cover and its correlations with temperature and precipitation in Baoji area at seasonal scale and reference yearly scale.Results] Summer vegetation NDVI had an obvious increasing trend, followed by the autumn one, winter vegetation coverage was the worst. The trend of seasonally normalized NDVI in Baoji area was similar to that of temperature and precipitation, the occurrence time of the maximum point was corresponding to that of temperature and precipitation. The correlation coefficients between NDVI and temperature of the four seasons were all higher than that between NDVI and precipitation of the same season (except summer). Correlation coefficient between spring NDVI and winter temperature (-0.592), summer NDVI and spring precipitation (0.640) were all significantly correlated, which implied that spring vegetation cover and previous winter temperature changed consistently in the past 13 years. Summer vegetation cover was coincided with spring precipitation, and NDVI had a lag of 0~3 months behind precipitation.Conclusion] The average annual and seasonal NDVI in Baoji area showed an increasing trend over all from 2001 to 2013. The vegetation cover change of Baoji area in August was consistent with the change of precipitation, meanwhile precipitation affected vegetation cover stronger than air temperature did in August.