呼伦贝尔草甸草原地上净初级生产力对气候变化响应的模拟

利用内蒙古呼伦贝尔草原额尔古纳右旗牧业气象试验站1994-2009年牧草生长季逐月实测资料,对CENTURY模型进行检验,模拟了呼伦贝尔草甸草原1961-2010年间地上净初级生产力(ANPP)动态,并与26个气象因子进行相关性分析。模型检验结果显示,生长季内逐月地上生物量模拟值与观测值之间的相关系数为R²=0.53,斜率b=0.94,误差平方根值为72.07 g/m²,平均绝对百分比误差为38.02%。检验结果表明,CENTURY模型能够成功地模拟这类草原的季节动态和年际变化。在过去的50年中,呼伦贝尔草甸草原温度增加,降水略增,ANPP增加。相关分析表明,ANPP与生长季降水量(r=0.372)呈极显著正相关;与年平均最低气温、年平均地面气温、年平均气温、7月降水量呈显著正相关;与年平均风速(r=-0.382)呈极显著负相关;与其他气象因子无显著的相关关系。应用区域气候模式系统PRECIS输出的2021-2050年气候情景数据分析得出,在SRES B2、A2和A1B情景下,未来呼伦贝尔草甸草原平均最高气温和最低气温都将呈显著升高趋势,降水量略增,ANPP虽然在年际间存在波动,但总体呈明显增加态势,分别较基准时段增加了67.14%,69.65%和76.58%,增加速率分别为16.51,17.34和16.42 g/(m²·10 a)。在3种情景下,未来气候变化均会对呼伦贝尔草甸草原群落生产力产生显著的正面影响。

Response of meadow steppe ANPP to climate change in Hulunbeir, Inner Mongolia-a simulation study

Long-term ecological research has resulted in a large amount of data on aboveground biomass and productivity, and on climatic and soil regimes at the animal husbandry meteorological experiment station of Inner Mongolia Hulunbeir meadow steppe. Using monthly aboveground biomass data in the growing seasons of 1994-2009, dynamic changes of the simulated aboveground net primary production (ANPP) were studied with the CENTURY model in Inner Mongolia meadow steppe and the correlations of ANPP with 26 meteorological parameters from 1961-2010, were analysed. The r² for comparison of the observed and simulated aboveground biomass in the growing season was 0.53, the slope was 0.94, root mean square error was 72.07 g/m² and the ratio of the absolute mean error was 38.02%. These results suggested that the CENTURY model can successfully simulate the seasonal and inter-annual trend of ANPP in Hulunbeir meadow steppe. Over the last 50 years, the temperature has increased, the precipitation increased slightly and ANPP also increased. Along with temperature and precipitation changes, the change curve of simulated ANPP indicated significant seasonal changes. ANPP was significantly and positively correlated with the precipitation in the growing season, and was positively correlated with annual mean minimum temperature, mean surface temperature, annual mean temperature, precipitation of July, and was significantly negatively correlated with annual average wind speed but not with other meteorological parameters. Predicted cllimate data of RCM PRECIS output was analysed for 2021-2050. Under the SRES (special report on emission scenarios) B2, A2 and A1B scenarios, in Hulunbeir meadow steppe, mean maximum temperature and mean minimum temperature both showed significantl increasing trends in the future, with a slight increase in precipitation. ANPP significantly increased by 67.14%, 69.65% and 76.58% compared to that in 1961-1990, and the rising rates were 16.51, 17.34, and 16.42 g/m²·10 a, respectively. Under SRES B2, A2 and A1B scenarios, the climate change in the future would have significant positive impacts on the productivity of the Hulunbeir meadow steppe.