中国东北样带植被净初级生产力时空动态及其对气候变化的响应

摘要

An improved Carnegie Ames Stanford Approach model (CASA model) was used to estimate the net primary productivity (NPP) of the Northeast China Transect (NECT) every month from 1982 to 2000. The spatial-temporal distribution of NPP along NECT and its response to climatic change were also analyzed. Results showed that the change tendency of NPP spatial distribution in NECT is quite similar to that of precipitation and their spatial correlation coefficient is up to 0.84 (P < 0.01). The inter-annual variation of NPP in NECT is mainly affected by the change of the aestival NPP every year, which accounts for 67.6% of the inter-annual increase in NPP and their spatial correlation coefficient is 0.95 (P < 0.01). The NPP in NECT is mainly cumulated between May and September, which accounts for 89.8% of the annual NPP. The NPP in summer (June to August) accounts for 65.9% of the annual NPP and is the lowest in winter. Recent climate changes have enhanced plant growth in NECT. The mean NPP increased 14.3% from 1980s to 1990s. The inter-annual linear trend of NPP is 4.6 gC·m-2·a-1, and the relative trend is 1.17%, which owns mainly to the increasing temperature.%根据净初级生产力(NPP)遥感估算模型,重建了中国东北样带(NECT)1982-2000年间每月的NPP时空序列,分析了研究时段内NPP的时空格局特征及其与气候因子的关系.结果表明:(1)NECT样带植被NPP的空间变化趋势同降水量的空间变化十分相似,由东到西逐渐降低,二者在空间上的相关性达到了0.84(P《0.01),说明NECT样带的植被NPP在空间分布上主要受水分趋动;(2)NECT样带植被NPP的年际变化主要是由各年份夏季NPP的变化造成的,夏季对NECT样带植被NPP的年际增长贡献率最大(67.6%),二者之间的相关性达到了0.95(P《0.01);(3)NECT样带的植被NPP积累期主要发生在5-9月份,这5个月的NPP占了全年NPP总量的89.8%,整个夏季(6-8月份)的NPP占了全年的65.9%,冬季(12-2月份)的NPP最低,基本为0;(4)近19年来的气候变化促进了NECT样带的植被生长,从1980年代到1990年代,NPP显著增加,年代际相对增长率为14.3%,平均年际绝对增长趋势为4.6 gC(m-2(a-1,相对增长趋势为1.17%,这主要是由温度升高引起的.