CLM3.5模式对青藏高原玛曲站陆面过程的数值模拟研究

Simulation Analysis on Land Surface Process at Maqu Station in the Qinghai-Xizang Plateau Using Community Land Model

利用通用陆面过程模式(CLM3.5)和青藏高原玛曲站2010年6月-2011年2月的观测资料进行了9个月的单点数值模拟试验。通过比较辐射通量、能量通量、土壤温度及土壤含水量的模拟值和观测值,结果表明,CLM3.5模式能较成功地模拟玛曲地区的陆面能量与水分特征。该模式对夏季向上短波辐射的模拟较好,冬季整体偏小。向上长波辐射的模拟整体较好,但模拟值稍偏大。净辐射的模拟整体较好,模拟值与观测值的相关系数为0.99,偏差为-1.28 W.m-2。感热通量的模拟较差,整体显著偏高。潜热通量的模拟较好,随季节变化特征明显。土壤热通量的模拟夏季较好,冬季土壤冻结及消融期的偏差较大,主要原因与冬季模拟的积雪偏少有关。土壤温度的模拟夏季较好、冬季较差,6层土壤温度模拟值与观测值的相关系数均在0.98以上,平均偏差为-1.80℃。模式较好地模拟出了冬季土壤冻结后存留的未冻水,冻结后土壤含水量的模拟较该模式以前的版本有了很大的改善,6层土壤含水量模拟值与观测值的平均相关系数为0.94,平均偏差为-0.015m3.m-3。

Using the Community Land Model version 3.5of NCAR（CLM3.5）and the observed data at Maqu station in the Qinghai-Xizang Plateau during June 2010to February 2011,a single point simulation experiment has been done.The comparison of the simulated and observed physical variables such as radiation fluxes,energy flux,soil temperature and soil moisture proved that the model simulated the land surface process successfully.The simulation of the upward short wave radiation in summer is better,but bias occurs during winter.The simulation of the upward long wave radiation is good but the result is a little higher.The simulation of the net radiation is also good,the correlation coefficient of the observed value and the simulated value is 0.99and the bias is-1.28W.m-2.The simulated result of the sensible heat flux is higher than the observed value in total while the simulation of the latent heat flux is good enough.The simulation of the soil heat flux is better in summer but worse in winter.A shallower of the simulated snow depth may lead to the bias.The comparison of the simulated and observed soil temperature showed that the result in summer is better than that in winter.The correlation coefficients of the six soil layers are all above 0.98,and the mean bias is-1.80℃.The simulated the unfrozen water is successfully when the soil is frozen,which is a big improvement in soil moisture simulation comparing with the previous version of the CLM model.The mean correlation coefficient of the six soil layers is 0.94,and the mean bias is-0.015m3.m-3.