摘要:
探讨了随机平衡傅里叶振幅敏感性分析方法(RBD-FAST)和扩展傅里叶振幅敏感性分析方法(EFAST)在陆面过程模式参数敏感性研究中的应用。试验中使用通用陆面过程模式(CoLM)和通榆退化草地2008年夏季观测资料,针对陆气相互作用中重要的要素：感热通量(SH)、潜热通量(LH)、地表温度(ST),2 m气温(T2m)和2 m湿度(Q2m),分析了11个参数(土深、1—5层黏土比率、孔隙度、最大露水厚度、50%植物根深、地表空气粗糙度和冠层下土壤拖曳系数)的敏感性大小。结果表明, RBD-FAST和EFAST对参数的一阶敏感性检验结果较为一致且与之前的研究结果类似, EFAST方法还可以得到考虑了参数间相互作用的整体敏感性。 RBD-FAST的优势主要表现为在极大地减少了计算消耗机的同时,一次取样即可计算所有参数的一阶敏感性,而EFAST的优势则在于通盘考虑了参数之间的相互影响,可以得到更为合理的整体敏感性序列。针对不同需求,选择使用这两种敏感性分析方法,有助于提高陆面过程模式参数化方案的改进效率。
Abstract:
In this paper, we discuss the applications of random balance design Fourier amplitude sensitivity test (RBD-FAST) and extended Fourier amplitude sensitivity test (EFAST) in the parameter sensitivity analysis of land surface process model. We use the common land model and data of Tongyu station, which is a reference site of CEOP in the semi-arid regions, use five model outputs (sensible heat flux, latent heat flux, surface temperature, temperature of air at 2 m over surface, moisture of air at 2 m over surface) as focus output, and use 11 model parameter (soil depth, the soil proportion of 1–5 layers of soil, the porosity of soil, the max dew depth, the roughness of the air between surface and the canopy, and the drag coe?cient under the canopy) as the parameters to be analyzed. After the 10 RBD-FAST experiments, we obtain the first-order sensitivity results, and we gain not only first-order sensitivity but also the total sensitivity after the EFAST experiment. The first-order results of two methods show their consistency. The RBD-FAST takes less computing time and is easy to implemente, while the EFAST also has a more comprehensive and reasonable total sensitivity result. All results above illustrate the applications of both RBD-FAST and EFAST in the parameter sensitivity analysis of land surface model. Researchers can choose the suitable one to solve the different problems.
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