基于CENTURY模型的乌审召滩地草场ANPP及对气候变化的响应

Observations and Modeling of ANPP Dynamics for Wushengzhao Town In Inner Mongolia Grassland and Its Responses to Global Climate Change Based on CENTURY Model

利用CENTURY模型对乌审召滩地草场1963─2010年地上净初级生产力(ANPP)动态进行了模拟研究,并将ANPP的模拟值与26个气象因子进行了相关性分析,以探讨气象因子对草地生产力的影响,为草地合理管理和持续利用提供理论支持。结果表明,CENRUTY模型能够比较准确地模拟这类草原的季节动态和年际变化。在过去的48年间,乌审召滩地草场生长季温度呈升高趋势,降水呈减少趋势,ANPP呈下降趋势,且ANPP下降幅度较降水量明显,其中每10年ANPP下降8.10 g·m^(-2)、降水量下降4.60 mm。利用气象观测资料模拟获得的年ANPP随气温和降水的变化而呈现出明显的变化规律,生长季内地上生物量对降水和温度的季节性分布也非常敏感。模型订正与验证结果显示,观测值与模拟值的相关系数变化范围为0.41~0.62,误差平方根值(RMSE)变化范围为57.29~87.17 g·m^(-2),平均绝对百分比误差(MAPD)变化范围为33.76%~63.39%。相关分析表明,不同时段降水量对ANPP均有明显影响,其中生长季、冬季和春季降水量对ANPP影响非常显著。极端高温对ANPP的负面影响非常显著,低温、蒸发、日照时数、风速以及年最大积雪深度等其他气象因子对ANPP的影响不显著。研究区ANPP呈下降趋势是降水量减少和极端高温事件频发共同作用的必然结果。

In order to explore the effect of climatic factors on the annual aboveground net primary production(ANPP) and provide theoretical support for rational management and sustainable utilization of grassland,Dynamic changes of ANPP were simulated by CENTURY model for Wushengzhao Town in Inner Mongolia grassland from 1963 to 2010, and correlations of simulated values of ANPP and 26 meteorological factors were analyzed. The results suggested that CENRUTY model can successfully simulate the seasonal and interannual dynamics of aboveground net primary productivity in Wushengzhao Town of Inner Mongolia grassland. In growing season, temperature increased, precipitation decreased and ANPP were on the downward trend in the past 48 years, and ANPP decline rate was more significant than the precipitation. With changes of temperature and precipitation, simulated ANPP using meteorological data showed significant changing patterns, and above ground biomass of growing season is very sensitive to temperature and precipitation seasonal distribution. Model correction and validation results showed that the r^2 for the comparison of observed and simulated values varied from 0.41 to 0.62 and root mean square error of ANPP varied from 57.29 to 87.17 g·m^(-2) and the ratio of the absolute mean error of ANPP varied from 33.76% to 63.39%. Correlation analysis showed that precipitation in different time interval obviously effected on ANPP, focus growing season, winter and spring rainfall. Extreme high temperature had very significant negative impact on ANPP, effects of other meteorological factors on ANPP was not significant, just as low temperature, evaporation, sunshine duration, wind speed, and annual max snow cover depth. It was precipitation decreasing and extreme high temperature events increasing that leaded to ANPP declining in the study area.