Modelling surface energy fluxes and temperatures in dry and wet bare soils

Abstract

A physically‐based numerical model was developed to estimate the temporal course of the surface energy flux densities and the soil temperatures in dry and wet bare soils. Aerodynamic heat, vapour and momentum transfer theory was used to calculate the sensible and latent heat flux densities at the surface under diabatic and adiabatic conditions. A finite‐difference solution of the differential equation describing one‐dimensional heat transfer was used to calculate the surface soil heat flux density and soil profile temperatures. The surface temperature was determined iteratively by the simultaneous solution of equations describing radiative, heat and momentum transfer at the surface. The model was tested with measurements from energy balance studies conducted on a dry, sandy soil and a wet, silt loam soil, and was found to predict accurately the surface energy fluxes and soil temperatures over three‐day periods under conditions of potential and negligible evaporation. The sensitivity of the model to uncertainties in the aerodynamic roughness lengths for momentum (z₀) and heat (z_T) is reported. Values for z₀ and Z₀/Z_T of 0.5 mm and 3.0, respectively, resulted in the best agreement between modelled and measured values of the fluxes and temperatures for both soils.     

Local climates simulated by two generations of Canadian GCM land surface schemes

Abstract

The performance of two Canadian land surface schemes of widely differing complexity is compared and contrasted in a pair of year‐long simulations using the GCM developed at Atmospheric Environment Service, Canada. The old land surface model incorporates the force‐restore method for soil temperatures and the bucket approximation for soil moisture; the new model, CLASS (Canadian Land Surface Scheme) features three soil layers, an explicitly modelled snow layer, a thermally separate vegetation canopy, and physically‐based calculations of heat and moisture transfers between all of the land surface components and the atmosphere.

It was reported in previous papers that compared with observations, the old scheme tends to generate a climate which is characterized by anomalously high precipitation rates and cold temperatures over land. In this paper, by reference to field measurements and to the energy fluxes and temperatures generated by the two models at local scales, the hypotheses earlier postulated as to the underlying reasons for this are validated. The main factor contributing to the climate anomalies observed with the old scheme is found to be its generation of excessive evaporation rates; this is caused by the fact that the evaporation rate is never directly energy‐limited, the fact that the scaling of the evaporation rale with decreasing soil moisture content underestimates the effect of vegetation stomatal resistance, and the fact that the evaporation rate over bare soil depends not on the surface soil moisture, but on the moisture content of whole modelled soil column. The cold surface temperatures are additionally attributed to systematic errors incurred by the forward‐stepping temperature scheme, and to the fact that soils subjected to subzero temperature forcing in the winter are modelling as freezing completely. Finally, the inability of the old scheme to simulate partially frozen soils means that it proves unable to handle either shallow frost penetration at temperature latitudes, or the development of an active layer in permafrost.     

Towards closing the vertical water balance in Canadian atmospheric models: Coupling of the land surface scheme class with the distributed hydrological model watflood

Abstract

Second generation land surface schemes are the subject of much development activity among atmospheric modellers. This work is aimed at, among other things, improving the representation of the soil water balance in order to simulate, more properly, exchanges with the atmosphere and to permit the use of model output to generate streamflow for model validation. The Canadian development program is centred on CLASS, the Canadian Land Surface Scheme, developed at Environment Canada. This paper focuses on the improvement of hydrology in CLASS. This was accomplished by designing a two‐way interface to WATFLOOD, a distributed hydrologic model developed at the University of Waterloo. The two models share many features, which facilitated the coupling procedure.

The interface retains the three‐layer vertical moisture budget representation in CLASS but adds three horizontal runoff possibilities. Runoff from the surface water follows Manning's equation for overland flow. Interflow is generated from the near‐surface soil layer using a parametrization of Richard's equation and base flow is produced by Darcian flow from the bottom of layer 3. An approximation of the internal topography of grid elements is used to supply horizontal gradients for the runoff components.

Tests are in progress in four Canadian study areas. Initial results are presented for the summer of 1993 for the Saugeen River in southwestern Ontario. The new scheme produces realistic hydrographs, whereas the old scheme did not. Bare ground evaporation is reduced by about 17% as a consequence of reduced water availability in layer 1. Evapotranspiration is not affected because the rooting depth extends into layer 3, in which soil moisture does not change appreciably with the new scheme. These results suggest that the new scheme improves the representation of streamflow in WATFLOOD/CLASS and of the soil moisture budget in CLASS. Work is in progress to validate this result over basins, such as the BOREAS study watersheds, where both runoff and evapotranspiration measurements are available.     

The subsurface transport of heat and moisture and its effect on the environment: A numerical model

A numerical model was developed to study the transport of heat and vapor under the surface of bare soil and soil covered by some materials such as asphalt and concrete under no rainfall conditions. The computational results provide a good match with the experimental data. The results show that the transport of water vapor inside the soil has an important effect on the subsurface distribution of temperature, especially for bare soil. Because of evaporation, the temperature of bare soil is much lower than that under covered surfaces throughout the day and the temperature of the surface covered by asphalt is extremely high-higher than the atmospheric temperature even at night. An increase of thickness of the covering material further increases the temperature and heat stored under surfaces. The stored heat is released to the atmosphere at night, contributing to environmental effects such as the urban heat island.     

基于变分客观分析方法的青藏高原试验区夏季对流降水过程热动力特征分析

本文利用基于变分客观分析方法的物理协调大气分析模型,构建了青藏高原试验区大气热力—动力相互协调的数据集,并通过该数据集对青藏高原试验区夏季深厚及浅薄对流降水过程的热动力特征进行分析,结果表明:变分客观分析后的垂直速度场能更好地与实际观测的对流降水过程相吻合;深厚对流降水期高云含量多,整层大气为较强的上升运动,上升运动可达100 hPa左右,浅薄期高云含量少,上升运动仅能延伸到300 hPa左右;两种对流降水过程中视热源Q₁在低层为冷却作用,高层为加热作用,在深厚期中高层Q₁存在两个加热中心,中层受较强的水汽凝结释放潜热加热所影响,高层主要受过冷云水凝结成冰晶形成高云时释放的热量所影响;在浅薄期中高层Q₁只存在一个加热中心,大气的加热主要来源于水汽的凝结潜热释放;深厚对流降水期视水汽汇Q₂的加热作用可以延伸到200 hPa,而浅薄期仅到340 hPa左右。     

Effects of crop residue on soil and plant water evaporation in a dryland cotton system

Summary Dryland agricultural cropping systems emphasize sustaining crop yields with limited use of fertilizer while conserving both rain water and the soil. Conservation of these resources may be achieved with management systems that retain residues at the soil surface simultaneously modifying both its energy and water balance. A conservation practice used with cotton grown on erodible soils of the Texas High Plains is to plant cotton into chemically terminated wheat residues. In this study, the partitioning of daily and seasonal evapotranspiration (E _t) into soil and plant water evaporation was compared for a conventional and a terminated-wheat cotton crop using the numerical model ENWATBAL. The model was configured to account for the effects of residue on the radiative fluxes and by introducing an additional resistance to latent and sensible heat fluxes derived from measurements of wind speed and vapor conductance from a soil covered with wheat-stubble. Our results showed that seasonalE _t was similar in both systems and that cumulative soil water evaporation was 50% ofE _t in conventional cotton and 31% ofE _t in the wheat-stubble cotton. Calculated values ofE _t were in agreement with measured values. The main benefit of the wheat residues was to suppress soil water evaporation by intercepting irradiance early in the growing season when the crop leaf area index (LAI) was low. In semiarid regions LAI of dryland cotton seldom exceeds 2 and residues can improve water conservation. Measured soil temperatures showed that early in the season residues reduced temperature at 0.1 m depth by as much as 5°C and that differences between systems diminished with depth and over time. Residues increased lint yield per unit ofE _t while not modifying seasonalE _t and reducing cumulative soil water evaporation.With 8 Figures     

Theoretical determination of the surface energy balance and thermal regimes of bare soils

An analytical theory that determines the thermal regimes in the soil and the thermal and moisture regimes in the atmosphere for bare surfaces is derived. Both soil and atmospheric thermal properties are assumed to be power functions of depth and height, respectively. Evaporation is determined using a surface resistance to vapour flow. Fourier superposition is used to represent nonsinusoidal variations in time due to effects such as variable cloud cover. The theory is in acceptable agreement with micrometeorological measurements made at two bare soil sites of contrasting surface bulk density. It is concluded that the surface resistance model for evaporation is applicable to bare soils which remain wet at depth, particularly if their surface is loosened. The theory is used to predict the diurnal thermal regimes of saturated and dry sand, loam, and peat soils.     

The surface heat flux density of a bare soil

Abstract

Half‐hourly measurements of soil surface heat flux density (G₀ ), solar irradiance (S), and the surface energy balance components were made at Agassiz, b.c., in the spring and early summer of 1978 at two adjacent bare‐soil sites, one of which was culti‐packed while the other was disc‐harrowed. G₀ was calculated using the null‐alignment procedure from half‐hourly measurements of soil temperature at 30 depths down to 1 m, and volumetric soil heat capacity calculated from measurements of bulk density, organic matter fraction, and moisture content. The latent and sensible heat flux densities were measured using the energy balance/Bowen ratio technique.

It was found that both the daily averages and diurnal variations of Go at each site were not affected as the soil surface dried, despite reductions in evaporation rate of as much as 50% at the culti‐packed site and 75% at the disc‐harrowed site on the clear dry‐soil days. Diurnal variations of G₀ at the disc‐harrowed site were about 25% less than at the culti‐packed site, although daily averages were similar at both sites. Daily and daytime averages of G₀ at each site were linear functions of S alone, or functions of net radiation and some measure of near‐surface soil water content. Night‐time averages of G₀ at each site were linear functions of a cloudiness ratio equal to the fraction received of the clear‐day S.     

Application of a mixed-layer model to bare soil surfaces

A model that couples the surface energy balance equation, a surface hydraulic resistance equation, and the force-restore soil temperature model to a mixed-layer model of the planetary boundary layer is described. The mixed layer is separated from the soil by a relatively thin surface layer and is overlain by a stable free atmosphere with prescribed profiles of potential temperature and water vapour density. The model is in reasonably good agreement with daytime micrometeorological measurements made at a wet bare site at Agassiz, British Columbia, and a desert site at Pampa de La Joya, Peru. The sensitivity of the mixed-layer model to conditions in the free atmosphere, to the parameters describing the growth of the mixed layer, and to surface roughness lengths, surface hydraulic resistance, and windspeed is examined.     

Bare-ground surface heat and water exchanges under dry conditions: Observations and parameterization

A simplified land-surface parameterization is tested against bare-soil data collected during the EFEDA experiment conducted in Spain in June 1991. A complete data set, made up of soil properties as well as hydrological and atmospheric measurements, is described and discussed. The 11-day data set is characterized by very dry conditions and high surface temperatures during the day. Large values of sensible and soil heat fluxes and small values of surface evaporation (≈1 mm/day) were observed. This data set was modelled, leading to the following conclusions:

1. In the model, the parameterization provides values of the soil thermal properties and subsequently of the predicted soil heat fluxes which are overestimated when compared with the observations.
2. Following the literature, a value of the ratio between the roughness lengths for momentumZ _oand heatZ _ohof close to 10 for fairly homogeneous areas of bare soil and vegetation is used. This value leads to a fair prediction of the surface temperature. If the roughness lengths were taken to be equal, as is often assumed in atmospheric modelling, a poorer prediction results.
3. Finally, the vapor phase transfer mode is found dominant close to the surface and a modified parameterization including this effect is proposed. It allows a fair prediction of both surface evaporation and near-surface water content.

     

Design of land-air parameterization scheme (LAPS) for modelling boundary layer surface processes

Summary A land-air parametrization scheme (LAPS) describes mass, energy and momentum transfer between the land surface and the atmosphere. The scheme is designed as a software package which can be run as part of an atmospheric model or a stand-alone scheme. A single layer approach is chosen for the physical and biophysical scheme background. The scheme has six prognostic variables: two temperatures (one for the canopy vegetation and one for soil surface), one interception storage, and three soil moisture storage variables. The scheme's upper boundary conditions are: air temperature, water vapour pressure, wind speed, radiation and precipitation at some reference level within the atmospheric boundary layer. The sensible and latent heat are calculated using resistance representation. The evaporation from the bare soil is parametrized using the scheme. The soil part is designed as a three-layer model which is used to describe the vertical transfer of water in the soil.The performances of the LAPS scheme were tested using the results of meteorological measurements over a maize field at the experimental site De Sinderhoeve (The Netherlands). The predicted partitioning of the absorbed radiation into sensible and latent heat fluxes is in good agreement with observations. Also, the predicted leaf temperature agrees quite well with the observed values.With 9 Figures     

Modelling evaporation from wetland tundra

Evapotranspiration is a major component of both the energy and water balances of wetland tundra environments during the thaw season. Reliable estimates of evapotranspiration are required in the analysis of climatological and hydrological processes occurring within a wetland and in interfacing the surface climate with atmospheric processes. Where direct measurements are unavailable, models designed to accurately predict evapotranspiration for a particular wetland are used.This paper evaluates the performance, sensitivity and limitations of three physically-based, one-dimensional models in the simulation of evaporation from a wetland sedge tundra in the Hudson Bay Lowland near Churchill, Manitoba. The surface of the study site consists of near-saturated peat soil with a sparse sedge canopy and a constantly varying coverage of standing water. Measured evaporation used the Bowen ratio energy balance approach, to which the model results were compared. The comparisons were conducted with hourly and daily simulations.The three models are the Penman-Monteith model, the Shuttleworth-Wallace sparse canopy model and a modified Penman-Monteith model which is weighted for surface area of the evaporation sources.Results from the study suggest that the weighted Penman-Monteith model has the highest potential for use as a predictive tool. In all three cases, the importance of accurately measuring the surface area of each evaporation source is recognized. The difficulty in determining a representative surface resistance for each source and the associated problems in modelling without it are discussed.

List of Symbols

Models BREB Bowen ratio energy balance - P-M Penman-Monteith combination - S-W Shuttleworth-Wallace combination - W-P-M Weighted Penman-Monteith combination Other AE Available energy-all surfaces - AE _c Available energy-canopy (S-W, W-P-M) - AE _s Available energy-bare soil (S-W, W-P-M) - AE _w Available energy-open water (W-P-M) - C _p Specific heat of air - D Vapor pressure deficit - DAI Dead area index - FAI Foliage area index - LAI Leaf area index - Q ^* Net radiation - Q _e Latent heat flux-total - Q _ec Latent heat flux-canopy (S-W, W-P-M) - Q _es Latent heat flux-bare soil (S-W, W-P-M) - Q _ew Latent heat flux-open water (W-P-M) - Q _g ground heat flux - Q _h Sensible heat flux - S Proportion of area in bare soil - W Proportion of surface in open water - r _a Aerodynamic resistance (P-M, W-P-M) - r _c Canopy resistance - r _s Generalized optimized surface resistance - r _st Stomatal resistance - r _c ^a Bulk boundary layer resistance (S-W) - r _s ^a Aerodynamic resistance below mean canopy level (S-W) - r _s ^s Soil surface resistance (S-W, W-P-M) Greek Bowen ratio - Psychrometer constant - Air density - Slope of saturation vapour pressure vs temperature curve     

用全球大气混合层海洋环流模式模拟二氧化碳增加对土壤湿度季节变化的影响

本文利用全球三维大气耦合混合层海洋环流模式模拟大气中二氧化碳浓度增加对土壤湿度的影响。敏感试验(2×CO_2)与控制试验(1×CO_2)对照表明,当大气中二氧化碳浓度增加时,全球土壤湿度在各季发生明显变化。其中两半球低纬度地区在冬季土壤温度变温,两半球中纬度地区则在各季土壤湿度变干,北半球高纬度地区土壤湿度在夏季变干,其余各季变温。分析大气中二氧化碳浓度增加造成土壤温度全球变化的可能物理机制表明,地面水循环和热量循环是重要的因素。     

2008年7—9月中国北方不同下垫面晴空陆面过程特征差异

采用2008年7—9月观测的中国干旱/半干旱区实验观测协同与集成研究资料,选取了9个下垫面(包括裸地、草地、森林和农田),分析了中国北方不同下垫面以及不同地区同类下垫面的晴空陆面辐射平衡和热量平衡日变化特征差异。结果表明,不同下垫面以及不同地区同类下垫面的地表辐射和能量过程特征差异明显,而这种差异主要源于下垫面的光学特性、水热特性以及局地陆-气系统中可利用水分的不同。在辐射平衡的比较方面,荒漠沙地发射的长波辐射最大,高寒森林的长波辐射最低,农田下垫面发射的长波辐射总体低于草地;荒漠沙地、草地、农田和高寒森林的反射率依次减弱;荒漠沙地、草地、农田、森林下垫面的净辐射依次增大。在能量平衡方面,荒漠区沙地可利用能量大部分(约80%)用于加热大气,约20%消耗于蒸发和加热土壤;草地下垫面可利用能量中用于加热大气的能量比蒸发水分消耗的能量高,但高寒草甸例外;农田下垫面可利用能量的大部分消耗于蒸发,消耗于加热大气的能量不到20%。水含量越高,潜热通量越大,能量闭合率越低,能量过程也更复杂。     

Spatially explicit surface energy budget and partitioning with remote sensing and flux measurements in a boreal region of Interior Alaska

Extrapolating energy fluxes between the ground surface and the atmospheric boundary layer from point-based measurements to spatially explicit landscape estimation is critical to understand and quantify the energy balance components and exchanges in the hydrosphere, atmosphere, and biosphere. This information is difficult to quantify and are often lacking. Using a Landsat image (acquired on 5 August 2004), the flux measurements from three eddy covariance flux towers (a 1987 burn, a 1999 burn, and an unburned control site) and a customized satellite-based surface energy balance model of Mapping Evapotranspiration at High Resolution with Internalized Calibration (METRIC), we estimated net radiation, sensible heat flux (H), latent heat flux (LE), and soil heat flux (G) for the boreal Yukon River Basin of Interior Alaska. The model requires user selection of two extreme conditions present within the image area to calibrate and anchor the sensible flux output. One is the “hot” condition which refers to a bare soil condition with specified residual evaporation rates. Another one is the “cold” condition which refers to a fully transpiring vegetation such as full-cover agricultural crops. We selected one bare field as the “hot” condition while we explored three different scenarios for the “cold” pixel because of the absence of larger expanses of agricultural fields within the image area. For this application over boreal forest, selecting agricultural fields whose evapotranspiration was assumed to be 1.05 times the alfalfa-based reference evapotranspiration as the “cold” pixel could result in large errors. Selecting an unburned flux tower site as the “cold” pixel could achieve acceptable results, but uncertainties remain about the energy balance closure of the flux towers. We found that METRIC performs reasonably well in partitioning energy fluxes in a boreal landscape.     

Improvement of a soil-atmosphere-transfer model for the simulation of bare soil surface energy balances in semiarid areas

A soil-atmosphere-transfer model (SATM) was evaluated using observational data from the Tongyu Cropland Station and Audubon Research Ranch in semiarid areas, where the land cover was nearly bare soil during the simulation period. Simulations by the SATM at both sites were conducted using the new and original surface thermal roughness length parameterization schemes, respectively. Comparisons of simulations and observations have demonstrated that using the new surface thermal roughness length scheme in this model made sound improvements in the simulation of soil surface temperatures, sensible heat fluxes and net radiation fluxes in the daytime at both sites, compared to the original scheme, because the new scheme produced a larger aerodynamic resistance for turbulent heat transfer in the daytime. With respect to latent heat fluxes, the improvement was not as obvious as that attained for soil surface temperature since the soil water content in the surface layer in a semiarid area is a more important factor than surface soil temperature in controlling evaporation rate. Accordingly, it can be concluded that the new surface thermal roughness length parameterization scheme could improve the ability of the SATM to simulate bare soil surface energy budget with latent heat flux component being innegligible in semiarid areas.     

SEASONAL CHANGES OF SOIL MOISTURE INDUCED BY INCREASED CO2 AS SIMULATED BY THE ATMOSPHERIC GENERAL CIRCULATION AND MIXED LAYER OCEAN MODEL

The atmospheric general circulation model coupled to the mixed layer ocean model has been used to simulate thechanges of the global soil moisture.Comparing the simulated results with observations,it is shown that the model is ca-pable of doing sensitive experiments about the carbon dioxide change.The 2×CO_2/1×CO_2 comparison shows that there are the obvious changes of the soil moisture in the global forfour seasons.There are the wet soil moisture in the lower latitudes of both hemispheres and dry soil moisture in the mid-dle latitudes of both hemispheres for four seasons.The dry soil moisture in summer and wet in other seasons are foundin the northern higher latitudes.The analyses of the physical feedbacks responsible for the CO_2-induced changes of soil moisture show that the bud-gets of the surface water and heat are the important factors.     

The influence of surface cover and climate on energy partitioning and evaporation in a subarctic wetland

Energy partitioning and evaporation were measured over three wetland surfaces in a subarctic coastal marsh during pre-growing and growing periods. These surfaces included an alder/willow woodland, a sedge marsh and a raised backshore sedge meadow. A combination model analysis was used to assess the relative importance of surface resistance and meteorological conditions on the magnitude of the Bowen ratio, , during the growing period.Overall, the three surfaces experienced important site-to-site and seasonal differences in and evaporation, Q _E. During the non-foliated period, Q _E was largest and was smallest for the open water marsh, while the dry backshore site experienced the smallest Q _E and largest . The non-foliated woodland assumed intermediate values of and Q _E. After the vegetation covers were established, the woodland assumed the smallest and largest Q _E flux. It was also found that at the marsh site increased with the presence of a vegetation cover.Wind direction was always an important factor in determining Q _E and at all sites. was substantially larger and Q _E was smaller for onshore winds (i.e., originating from James Bay) than for offshore winds. The combination model analysis showed that canopy resistance at all sites was largest during warm offshore winds, which were associated with large saturation deficits. However, the effect of increased canopy resistance on during offshore winds was offset by a large climatological resistance, resulting in small values and large Q _E. When winds originated from James Bay, canopy resistance was smaller than for offshore winds, but the climatological resistance also was much smaller, resulting in larger and small Q _E. The results have important implications for changes in land cover and climate on the regional water balance.     

SENSITIVITY TESTS OF INTERACTION BETWEEN LAND SURFACE PHYSICAL PROCESS AND ATMOSPHERIC BOUNDARY LAYER

In this paper,an interactive model between land surface physical process and atmosphereboundary layer is established,and is used to simulate the features of soil environmental physics,surface heat fluxes,evaporation from soil and evapotranspiration from vegetation and structures ofatmosphere boundary layer over grassland underlying.The sensitivity experiments are engaged inprimary physics parameters.The results show that this model can obtain reasonable simulation fordiurnal variations of heat balance,soil volumetric water content,resistance of vegetationevaporation,flux of surface moisture,and profiles of turbulent exchange coefficient,turbulentmomentum,potential temperature,and specific humidity.The model developed can be used tostudy the interaction between land surface processes and atmospheric boundary layer in cityregions,and can also be used in the simulation of regional climate incorporating a mesoscalemodel.     

Surface energy, water and carbon cycle in China simulated by the Australian community land surface model (CABLE)

Through an Australia-China climate change bilateral project, we analyzed results of 51-year global offline simulations over China using the Australian community atmosphere biosphere land exchange (CABLE) model, focusing on integrated studies of its surface energy, water and carbon cycle at seasonal, interannual and longer time-scales. In addition to the similar features in surface climatology between the CABLE simulation and those derived from the global land-surface data assimilation system, comparison of surface fluxes at a CEOP reference site in northeast China also suggested that the seasonal cycles of surface evaporation and CO₂ flux are reasonably simulated by the model. We further assessed temporal variations of model soil moisture with the observed variations at a number of locations in China. Observations show a soil moisture recharge–discharge mechanism on a seasonal time scale in central-east China, with soil moisture being recharged during its summer wet season, retained in its winter due to low evaporation demand, and depleted during early spring when the land warms up. Such a seasonal cycle is shown at both 50- and 100-cm soil depths in observations while the model only shows a similar feature in its lower soil layers with its upper layer soil moisture varying tightly with rainfall seasonal cycle. In the analysis of the model carbon cycle, the net primary productivity (NPP) has similar spatial patterns as the ones derived from an ecosystem model with remote sensing. The simulated interannual variations of NPP by CABLE are consistent with the results derived from remote sensing-based and process-based studies over the period of 1981–2000. Nevertheless an upward trend from observations is not presented in the model results. The model shows a downward trend primarily due to the constant CO₂ concentration used in the experiment and a large increase of autotrophic respiration caused by an upward trend in surface temperature forcing data. Furthermore, we have compared river discharge data from the model experiments with observations in the Yangtze and Yellow River basins in China. In the Yangtze River basin, while the observed interannual variability is reasonably captured, the model significantly underestimates its river discharge, which is consist with its overestimation of evaporation in the region. In the Yellow River basin, the magnitudes of the river discharge is similar between modeled and observed but its variations are less skillfully captured as seen in the Yangtze River region.