The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface...The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface thermal-hydrologic processes among the three regions were studied based on the normalization of major variables of land surface thermal-hydrologic processes,using data collected during prevailing summer monsoon period(July and August,2008).It is shown that differences of surface thermal-hydrologic processes are remarkable among the three regions because of different impacts of summer monsoon.Especially their soil wet layers occur at different depths,and the average albedo and its diurnal variations are distinctly different.Surface net short-wave radiation in the Loess Plateau is close to that in the cool Northeast China,but its surface net long-wave radiation is close to that in the arid Northwest China.And the ratio of net radiation to global solar radiation in the cool Northeast China is higher than the other two regions,though its temperature is lower.There are obvious regional differences in the ratios of surface sensible and latent heat fluxes to net radiation for the three regions because of distinct contribution of sensible and latent heat fluxesto land surface energy balance.The three regions are markedly different in the ratio of water vapor flux to pan evaporation,but they are consistent in the ratio of water vapor flux to precipitation.These results not only indicate different influences of climate and environmental factors on land surface thermal-hydrologic processes in the three regions,but also show that summer monsoon is important in the formation and variation of the pattern of land surface thermal-hydrologic processes.展开更多
Soil is heterogeneous and has different thermal and hydraulic properties, causing varied behavior in heat and mois- ture transport. Therefore, soil has an important effect on lanatmosphere interactions. In this study,...Soil is heterogeneous and has different thermal and hydraulic properties, causing varied behavior in heat and mois- ture transport. Therefore, soil has an important effect on lanatmosphere interactions. In this study, an improved soil parameterization scheme that considers gravel and organic matter in the soil was introduced into CLM4.5 （Com- munity Land Model）. By using data from the Zoige and Madoi sites on the Tibetan Plateau, the ability of the model to simultaneously simulate the duration of freeze-thaw periods, soil temperature, soil moisture, and surface energy during freeze-thaw processes, was validated. The results indicated that： （1） the new parameterization performed bet- ter in simulating the duration of the frozen, thawing, unfrozen, and freezing periods; （2） with the new scheme, the soil thermal conductivity values were decreased; （3） the new parameterization improved soil temperature simulation and effectively decreased cold biases; （4） the new parameterization scheme effectively decreased the dry biases of soil li- quid water content during the freezing, completely frozen, and thawing periods, but increased the wet biases during the completely thawed period; and （5） the net radiation, latent heat flux, and soil surface heat flux of the Zoige and Madoi sites were much improved by the new organic matter and thermal conductivity parameterization.展开更多
利用分布式时变增益水文模型（DTVGM）的产流机制改进CLM3.5（Community Land Model version 3.5）的水文过程参数化,同时嵌入地下水开采对流域水循环影响的模块,并考虑经济社会用水,建立能够描述流域自然-人文过程的大尺度陆地水循环...利用分布式时变增益水文模型（DTVGM）的产流机制改进CLM3.5（Community Land Model version 3.5）的水文过程参数化,同时嵌入地下水开采对流域水循环影响的模块,并考虑经济社会用水,建立能够描述流域自然-人文过程的大尺度陆地水循环模型（CLM-DTVGM）。以地下水开采严重的海河流域为研究区,以中科院青藏高原研究所建立的中国区域高时空分辨率地面气象要素数据集作为大气强迫驱动,针对海河流域1980年-2010年的水循环过程进行模拟,分析地下水开采活动对流域水循环过程的影响。结果表明：地下水开采活动引起海河流域地表径流和土壤湿度整体有所减少,蒸散发则呈增加趋势,且各水循环要素空间分异较大。展开更多
基金supported by State Key Program of National Natural Science Foundation of China (Grant No. 40830957)Public Welfare Research Project of China (Grant No. GYHY200806021)
文摘The observation stations of Northern China are divided into three regions:the arid Northwest China,the Loess Plateau,and the cool Northeast China.The consistencies,differences,and associated mechanisms of land surface thermal-hydrologic processes among the three regions were studied based on the normalization of major variables of land surface thermal-hydrologic processes,using data collected during prevailing summer monsoon period(July and August,2008).It is shown that differences of surface thermal-hydrologic processes are remarkable among the three regions because of different impacts of summer monsoon.Especially their soil wet layers occur at different depths,and the average albedo and its diurnal variations are distinctly different.Surface net short-wave radiation in the Loess Plateau is close to that in the cool Northeast China,but its surface net long-wave radiation is close to that in the arid Northwest China.And the ratio of net radiation to global solar radiation in the cool Northeast China is higher than the other two regions,though its temperature is lower.There are obvious regional differences in the ratios of surface sensible and latent heat fluxes to net radiation for the three regions because of distinct contribution of sensible and latent heat fluxesto land surface energy balance.The three regions are markedly different in the ratio of water vapor flux to pan evaporation,but they are consistent in the ratio of water vapor flux to precipitation.These results not only indicate different influences of climate and environmental factors on land surface thermal-hydrologic processes in the three regions,but also show that summer monsoon is important in the formation and variation of the pattern of land surface thermal-hydrologic processes.
基金Supported by the National Natural Science Foundation of China(91537104,41375077,91537106,and 91537214)
文摘Soil is heterogeneous and has different thermal and hydraulic properties, causing varied behavior in heat and mois- ture transport. Therefore, soil has an important effect on lanatmosphere interactions. In this study, an improved soil parameterization scheme that considers gravel and organic matter in the soil was introduced into CLM4.5 （Com- munity Land Model）. By using data from the Zoige and Madoi sites on the Tibetan Plateau, the ability of the model to simultaneously simulate the duration of freeze-thaw periods, soil temperature, soil moisture, and surface energy during freeze-thaw processes, was validated. The results indicated that： （1） the new parameterization performed bet- ter in simulating the duration of the frozen, thawing, unfrozen, and freezing periods; （2） with the new scheme, the soil thermal conductivity values were decreased; （3） the new parameterization improved soil temperature simulation and effectively decreased cold biases; （4） the new parameterization scheme effectively decreased the dry biases of soil li- quid water content during the freezing, completely frozen, and thawing periods, but increased the wet biases during the completely thawed period; and （5） the net radiation, latent heat flux, and soil surface heat flux of the Zoige and Madoi sites were much improved by the new organic matter and thermal conductivity parameterization.
文摘利用分布式时变增益水文模型（DTVGM）的产流机制改进CLM3.5（Community Land Model version 3.5）的水文过程参数化,同时嵌入地下水开采对流域水循环影响的模块,并考虑经济社会用水,建立能够描述流域自然-人文过程的大尺度陆地水循环模型（CLM-DTVGM）。以地下水开采严重的海河流域为研究区,以中科院青藏高原研究所建立的中国区域高时空分辨率地面气象要素数据集作为大气强迫驱动,针对海河流域1980年-2010年的水循环过程进行模拟,分析地下水开采活动对流域水循环过程的影响。结果表明：地下水开采活动引起海河流域地表径流和土壤湿度整体有所减少,蒸散发则呈增加趋势,且各水循环要素空间分异较大。
