中国陆地净初级生产力时空特征模拟

应用生态系统机理性模型估算1981～1998年中国陆地生态系统净初级生产力 (NPP) 的时空变化，并分析了NPP对年际间气候变化的响应。结果表明，中国陆地生态系统1981～1998年NPP总量波动于2.86～3.37 Gt C/yr之间，平均约为3.09 Gt C /yr ，单位NPP平均约为342 g C m²/yr。在研究时段内，NPP有缓慢增长趋势，年增长率约为0.32%，NPP总量平均值从 1980年代 (1981～1989年) 的3.03 Gt C/yr上升到1990年代 (1990～1998年) 的3.14 Gt C/yr。在一些厄尔尼诺 (El Nino) 发生年，NPP有明显的下降，但由于地域差异和季风环流的影响，NPP同ENSO的关系还十分复杂。从全国来看，在厄尔尼诺现象发生的1982年、1986年、1991年和1997年，NPP都有一定程度的减少。但在1993年和1994年两个厄尔尼诺发生年，NPP并没有表现为明显的下降趋势，1994年NPP总量甚至比上一年增加了0.12Gt，这主要是由于温度和降水量在不同地区的分布差异以及不同地区对厄尔尼诺现象的响应差异造成的。

Temporal and Spatial Pattern of Net Primary Production of Terrestrial Ecosystems in China

In this study, we used a biogeochemical model that has been validated at regional and global scales to estimate the temporal and spatial variations of China's terrestrial NPP (Net Primary Productivity) and its responses to interannual climate variability in the period of 1981-1998. The results show that the average annual total NPP is about 3.09 Gt C/yr and average NPP is about 342 g C/m 2 . NPP exhibited an increasing trend during the study period by 0.32%/yr. In some ENSO years (e.g. 1982, 1986, and 1997) NPP decreased significantly, but the relationship between the ENSO cycle and NPP is complex due to the complex effects of monsoons and regional climatic variability. For example, in the ENSO years of 1993 and 1994, NPP did not show a clear decreasing trend, even increased with 0.12 Gt in 1994. At the national level, the precipitation is the key factor controlling the NPP variations and a weak correlation exists between NPP and temperature, but regional responses are different. Northeast China (R 2 = 0.85,P< 0.01), Northwest China (R 2 = 0.97, P< 0.01), Inner Mongolia (R 2 = 0.97, P< 0.01), and North China (R 2 = 0.96, P< 0.01) have significant correlation with precipitation. In South China, the middle and lower reaches of the Yangtze River, and Central China, the correlation is weak.