1982—2014年华北及周边地区生长季NDVI变化及其与气候的关系

利用690个气象观测站数据和1982―2014年GIMMS NDVI 3g数据, 运用趋势分析、小波偏互相关分析、偏相关分析和滞后分析方法, 探究华北及周边地区33年来生长季(5―10月) NDVI的变化规律及其与气候的关系, 得到如下结论。1) 33年来, 研究区植被生长季活动整体上显著增强, 生长季NDVI由20世纪80年代的平均0.44升至2010年以来的0.49; 生长季NDVI在研究区中部区域快速增长, 而在西北部荒漠地区下降。2) 研究区生长季NDVI的上升得益于温度升高和降水增加, 其中降水的影响更大; 研究区NDVI与气温在大部分地区正相关; 除研究区东南部地区外, NDVI与降水有很强的正相关关系。3) 在15天的时间分辨率尺度下, 研究区大部分地区生长季内 NDVI对温度的响应无明显滞后, 或存在1期(15 d)滞后, 对降水的响应存在1~2 期(15~30 d)滞后, 因此从总体上看, 华北及周边地区植被生长对温度的响应比对降水的影响更迅速。

Change of NDVI during Growing Season and Its Relationship with Climate in North China and the Adjacent Areas from 1982 to 2014

Using data from 690 meteorological observatories and GIMMS NDVI 3g data from 1982 to 2014, trend analysis, wavelet partial cross-correlation analysis, partial correlation analysis and lag analysis were used to explore the change rule of NDVI during the growing season (May to October) and its relationship with climate in North China and the adjacent areas in the past 33 years. The results showed that the average growing season NDVI increased from 0.44 in the 1980s to 0.49 in the 2010s. NDVI in the growing season increased rapidly in the central part of the research area, but decreased in the northwest desert area. The increase of NDVI in the growing season of the research area was benefited from the increase of temperature and precipitation, and the influence of precipitation was greater. NDVI of the research area was positively correlated with the temperature in most areas. Except for the southeastern part of the study area, NDVI and precipitation had strong positive correlation. At 15-day resolution, the response of NDVI to temperature in the growing season in most areas did not have obvious lag or was lagged in one period (15 days), and the response to precipitation was lagged about 1–2 periods (15–30 days). Therefore, in general, vegetation growth in North China and the adjacent areas responded more rapidly to temperature than precipitation.