中国区域1960~2000年活动积温年代变化和地表植被的适应性调整

一年多季农业耕作区域的布局和植被物候变化是长期气候适应的结果.随着20世纪80年代中期之后全球气候的持续变暖,以活动积温和天数为综合指标的各种级别的气候区域边界发生变化,中国北方地区一年两季农业耕作区域和植被物候也发生了适应性调整.其中20世纪60～80年代,活动积温和天数空间分布相对比较平稳,边界没有发生明显的拓展和收缩,但随着气温升高,20世纪90年代活动积温边界发生改变,各量级的活动积温和天数综合指标边界明显向北推进.对应于气候的持续变暖,来自遥感数据的谐波分析和物候监测结果显示,90年代北方地区一年两季耕作面积增加,范围向北扩展;同时植被物候也发生明显改变,80年代和90年代的物候变化比较显示,1995年之后植被生长期比1985年之前普遍提前约10d左右,在一年两季耕作区域,植被生长期提前将近20d左右.

Vegetation response to active accumulated temperature patterns from 1960-2000 in China

The land surface\|atmosphere interaction accounts for regional distribution of multi\|rotational cropping and phenological patterns of vegetations. In response to the global warming, boundaries categorized with active accumulated temperature and degree days have been changing since 1980s. Correspondently, the area with two crops per annum and phenological patterns of vegetations in northern China has changed, and the boundaries for most categories of active accumulated temperature and degree days therein have expanded to the north. Meanwhile, the magnitudes of the categorized active accumulated temperature has increased significantly in 1990s relative to the period from 1960s-1980s, during which the contours of active accumulated temperature were overall constant without noticeable expand or shrinkage. Consistent with these changes, the area with two crops per annum, which is estimated from Discrete Fourier transform investigation by applying the LAI data set on a per pixel basis, has expanded northward. The increase in accumulative active temperature and degree days generally set the vegetations growth during 1990-1995 ahead by ten days compared with during 1980-1985 in the northern region of China, and those with two crops per annum by about 20 days.