The spatial heterogeneity of land surface conditions and its influence on surface fluxes over a typical underlying surface in the Tibetan Plateau

Abstract. In this paper, we investigate the ability of the Noah Land Surface model (LSm) to simulate temperature states in the soil profile and surface fluxes measured during a 7-day dry period at a micrometeorological station on the Tibetan Plateau. Adjustments in soil and vegetation parameterizations required to ameliorate the Noah simulation on these two aspects are presented, which include: (1) Differentiating the soil thermal properties of top- and subsoils, (2) Investigation of the different numerical soil discretizations and (3) Calibration of the parameters utilized to describe the transpiration dynamics of the Plateau vegetation. Through the adjustments in the parameterization of the soil thermal properties (STP) simulation of the soil heat transfer is improved, which results in a reduction of Root Mean Squared Differences (RMSD's) by 14%, 18% and 49% between measured and simulated skin, 5-cm and 25-cm soil temperatures, respectively. Further, decreasing the minimum stomatal resistance (Rc, min) and the optimum temperature for transpiration (Topt) of the vegetation parameterization reduces RMSD's between measured and simulated energy balance components by 30%, 20% and 5% for the sensible, latent and soil heat flux, respectively.

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Simulation Analysis of Local Land Atmosphere Coupling in Rainy Season over a Typical Underlying Surface in the Tibetan Plateau

10.5194/hess-2020-199 ◽

2020 ◽

Author(s):

Genhou Sun ◽

Zeyong Hu ◽

Yaoming Ma ◽

Zhipeng Xie ◽

Jiemin Wang ◽

...

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Rainy Season ◽

Surface Fluxes ◽

Underlying Surface ◽

The Tibetan Plateau ◽

Spatial Distributions ◽

Initial Soil Moisture ◽

Initial Soil ◽

The Relationship

Abstract. The Local land atmosphere coupling (LoCo) focuses on the interactions between soil conditions, surface fluxes, planetary boundary layer (PBL) growth, and the formations of convective clouds and precipitations. Study of LoCo over the Tibetan Plateau (TP) is of great significance for understanding TP's role in the Asian Water Tower. A series of real-case simulations using the Weather Research and Forecasting Model (WRF) with different combinations of land surface models (LSM) schemes and PBL schemes has been carried out to investigate the LoCo characteristics over a typical underlying surface in the central TP in rainy season. The LoCo characteristics in the study area are analyzed by applying a mixing diagram to the simulation results. The analysis indicates that the WRF simulations using the Noah with BouLac, MYNN, and YSU produce closer results to the observation in terms of curves of Cp*θ and Lv*q, surface fluxes (Hsfc and LEsfc), entrainment fluxes (Hent and LEent) at site BJ/Nagqu than those using the CLM with BouLac, MYNN, and YSU. The frequency distributions of Hsfc, LEsfc, Hent, and LEent in the study area confirm this result. The spatial distributions of simulated Hsfc, LEsfc, Hent, and LEent using WRF with Noah and BouLac suggest that the spatial distributions of Hsfc and LEsfc in the study area are consistent with that of soil moisture, but the spatial distributions of Hent and LEent are quite different from that of soil moisture. A close examination of the relationship between entrainment fluxes and cloud water content (QCloud) reveals that the grids with small Hent and large LEent tend to have high QCloud and Hsfc, suggesting that high Hsfc is conductive to convective cloud formation, which leads to small Hent and large LEent. Sensitivity analysis of LoCo to the soil moisture at site BJ/Nagqu indicates that on a sunny day, an increase in soil moisture leads to an increase in LEsfc but decreases in Hsfc, Hent, and LEent. The sensitivity of the relationship between simulated maximum daytime PBL height (PBLH) and mean daytime evapotranspiration (EF) in the study area to soil moisture indicates that the rate at which the maximum daytime PBLH decreases with the mean EF increase as the initial soil moisture goes up. The analysis of simulated Hsfc, LEsfc, Hent, and LEent under different soil moisture conditions reveals that the frequency of Hent ranging from 80 to 240 W/m2 and the frequency of LEent ranging from −240 to −90 W/m2 both increase as the initial soil moisture increases. Coupled with the changes in QCloud, the changes in Hent and LEent as the initial soil moisture increases indicate that the rise in soil moisture leads to an increase in the cloud amount but a decrease in QCloud.

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The evaluation of land surface parameters for model to derive land surface fluxes in the Tibetan Plateau

10.5194/egusphere-egu21-1568 ◽

2021 ◽

Author(s):

Weiqiang Ma ◽

Yaoming Ma ◽

Yizhe Han ◽

Wei Hu ◽

Lei Zhong ◽

...

Keyword(s):

Tibetan Plateau ◽

Land Surface ◽

Atmospheric Model ◽

Surface Fluxes ◽

Heat Fluxes ◽

The Tibetan Plateau ◽

Default Model ◽

Model Configuration

Firstly, based on the difference of model and in-situ observations, a serious of sensitive experiments were done by using WRF. In order to use remote sensing products, a land-atmosphere model was initialized by ingesting land surface parameters, such as AMSR-E RS products, and the results were compared with the default model configuration and with in-situ long-term CAMP/Tibet observations.Secondly, a land-atmosphere model was initialized by ingesting AMSR-E products, and the results were compared with the default model configuration and with in-situ long-term CAMP/Tibet observations. The differences between the AMSR-E initialized model runs with the default model configuration and in situ data showed an apparent inconsistency in the model-simulated land surface heat fluxes. The results showed that the soil moisture was sensitive to the specific model configuration. To evaluate and verify the model stability, a long-term modeling study with AMSR-E soil moisture data ingestion was performed. Based on test simulations, AMSR-E data were assimilated into an atmospheric model for July and August 2007. The results showed that the land surface fluxes agreed well with both the in-situ data and the results of the default model configuration. Therefore, the simulation can be used to retrieve land surface heat fluxes from an atmospheric model over the Tibetan Plateau.All of the different methods will clarify the land surface heating field in complex plateau, it also can affect atmospheric cycle over the Tibetan Plateau even all of the global atmospheric cycle pattern.

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Dynamics in land-surface conditions on the Tibetan Plateau observed by Advanced Synthetic Aperture Radar (ASAR)

Hydrological Sciences Journal ◽

10.1623/hysj.54.6.1079 ◽

2009 ◽

Vol 54 (6) ◽

pp. 1079-1093 ◽

Cited By ~ 26

Author(s):

ROGIER VAN DER VELDE ◽

ZHONGBO SU

Keyword(s):

Tibetan Plateau ◽

Synthetic Aperture Radar ◽

Land Surface ◽

Synthetic Aperture ◽

The Tibetan Plateau ◽

Surface Conditions ◽

Aperture Radar

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Simulation Analysis of Local Land Atmosphere Coupling in Rainy Season over a Typical Underlying Surface in the Tibetan Plateau

10.5194/egusphere-egu2020-6648 ◽

2020 ◽

Author(s):

Genhou Sun ◽

Zeyong Hu ◽

Yaoming Ma ◽

Song Yang

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Rainy Season ◽

Surface Fluxes ◽

Underlying Surface ◽

The Tibetan Plateau ◽

Spatial Distributions ◽

Initial Soil Moisture ◽

Initial Soil ◽

The Relationship

The Local land atmosphere coupling (LoCo) focuses on the interactions between soil conditions, surface fluxes, PBL growth, and the formations of convective clouds and precipitations, and a study of LoCo over the Tibetan Plateau (TP) is of great significance to understand its role of &#8220;Asian Water Tower&#8221;. This study investigates the LoCo characteristics over a typical underlying surface in central TP in the rainy season based on a series of real case simulations using Weather Research and Forecasting Model (WRF) with different combinations of land surface model (LSM) schemes and planetary boundary layer (PBL) schemes based on in-situ measurements. Then the LoCo characteristics over a typical underlying surface in central TP are analyzed using a mixing diagram. The simulations results indicates that WRF simulations using Noah with BouLac, MYNN, and YSU produce much better results in terms of curves of Cp*theta and Lv*q, surface fluxes (Hsfc and LEsfc), entrainment fluxes (Hent and LEent) at site BJ/Nagqu that those using CLM with BouLac, MYNN, and YSU do. The frequency distributions of Hsfc, LEsfc, Hent, and LEent in the study area confirmed this result. The spatial distributions of simulated Hsfc, LEsfc, Hent, and LEent using WRF with Noah and BouLac suggest that the spatial distributions of Hsfc and LEsfc in the study area show a good consistent with that of soil moisture, but the spatial distributions of Hent and LEent are quite different from that of soil moisture. A close examination of the relationship between entrainment fluxes and cloud water contents (QCloud) reveals that the grids with small Hent and large LEent are likely to have high QCloud and Hsfc. This means that high Hsfc is conductive to convective cloud formations, which lead to small Hent and large LEent. Sensitivity analysis of LoCo to the soil moisture at site BJ/Nagqu indicates that in a sunny day, an increase in soil moisture leads to an increase in LEsfc but a decrease in Hsfc, Hent, and LEent. The sensitivity of the relationship between simulated max daytime PBLH and mean daytime EF in the study area to soil moistures indicates that the rate at which the max daytime PBLH decrease with the mean EF increases as the initial soil moisture goes up. The analysis of simulated Hsfc, LEsfc, Hent, and LEent under different soil moisture conditions reveals that the frequencies of Hent ranging from 80 W/m2 and over 240 W/m2 and frequency of LEent ranging from -240 W/m2 to -90 W/m2 increase as the initial soil moisture increases. Coupled with the changes in QCloud, the changes in Hent and LEent as the initial soil moisture increases indicate that the increase in soil moisture lead to an increase in cloud amounts but a decrease in QCloud.

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Simulation analysis of local land atmosphere coupling in rainy season over a typical underlying surface in the Tibetan Plateau

Hydrology and Earth System Sciences ◽

10.5194/hess-24-5937-2020 ◽

2020 ◽

Vol 24 (12) ◽

pp. 5937-5951

Author(s):

Genhou Sun ◽

Zeyong Hu ◽

Yaoming Ma ◽

Zhipeng Xie ◽

Jiemin Wang ◽

...

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Rainy Season ◽

Surface Fluxes ◽

Underlying Surface ◽

The Tibetan Plateau ◽

Spatial Distributions ◽

Initial Soil Moisture ◽

Initial Soil ◽

The Relationship

Abstract. The local land–atmosphere coupling (LoCo) investigates the interactions between soil conditions, surface fluxes, planetary boundary layer (PBL) growth, and the formations of convective clouds and precipitation. Studying LoCo over the Tibetan Plateau (TP) is of great significance for understanding the TP's role in the Asian water tower. A series of real-case simulations, using the Weather Research and Forecasting (WRF) model with different combinations of land surface model (LSM) schemes and PBL schemes, has been carried out to investigate the LoCo characteristics over a typical underlying surface in the central TP in the rainy season. The LoCo characteristics in the study area are analyzed by applying a mixing diagram to the simulation results. The analysis indicates that the WRF simulations, using the Noah with BouLac, Mellor-Yamada Nakanishi and Niino Level-2.5 PBL (MYNN), and Yonsei University (YSU) produce closer results to the observation in terms of curves of Cp⋅θ and Lv⋅q, surface fluxes (Hsfc and LEsfc), entrainment fluxes (Hent, and LEent) at site BJ of Nagqu Station (BJ/Nagqu) than those using the Community Land Model (CLM) with BouLac, MYNN, and YSU. The frequency distributions of Hsfc, LEsfc, Hent, and LEent in the study area confirm this result. The spatial distributions of simulated Hsfc, LEsfc, Hent, and LEent, using WRF with Noah and BouLac, suggest that the spatial distributions of Hsfc and LEsfc in the study area are consistent with that of soil moisture, but the spatial distributions of Hent and LEent are quite different from that of soil moisture. A close examination of the relationship between entrainment fluxes and cloud water content (QCloud) reveals that the grids with small Hent and large LEent tend to have high QCloud and Hsfc, suggesting that high Hsfc is conducive to convective cloud formation, which leads to small Hent and large LEent. A sensitivity analysis of LoCo to the soil moisture at site BJ/Nagqu indicates that, on a sunny day, an increase in soil moisture leads to an increase in LEsfc but decreases in Hsfc, Hent, and LEent. The sensitivity of the relationship between simulated maximum daytime PBL height (PBLH) and mean daytime evapotranspiration (ET) in the study area to soil moisture indicates the rate at which the maximum daytime PBLH decreases with the mean ET increase as the initial soil moisture goes up. The analysis of simulated Hsfc, LEsfc, Hent, and LEent under different soil moisture conditions reveals that the frequency of Hent ranging from 80 to 240 W m−2 and the frequency of LEent ranging from −240 to −90 W m−2 both increase as the initial soil moisture increases. Coupled with the changes in QCloud, the changes in Hent and LEent as the initial soil moisture increases indicate that the rise in soil moisture leads to an increase in the cloud amount but a decrease in QCloud.

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The evaluation of AMSR-E soil moisture data in atmospheric modeling using a suitable time series iteration to derive land surface fluxes over the Tibetan Plateau

10.5194/egusphere-egu2020-2546 ◽

2020 ◽

Author(s):

Weiqiang Ma ◽

Yaoming Ma ◽

Yizhe Han ◽

Wei Hu ◽

Lei Zhong

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Land Surface ◽

Surface Fluxes ◽

Heat Fluxes ◽

The Tibetan Plateau ◽

Default Model ◽

Model Configuration

Firstly, based on the difference of model and in-situ observations, a serious of sensitive experiments were done by using WRF. In order to use remote sensing products, a land-atmosphere model was initialized by ingesting AMSR-E RS products, and the results were compared with the default model configuration and with in-situ long-term CAMP/Tibet observations.Secondly, a land-atmosphere model was initialized by ingesting AMSR-E products, and the results were compared with the default model configuration and with in-situ long-term CAMP/Tibet observations. The differences between the AMSR-E initialized model runs with the default model configuration and in situ data showed an apparent inconsistency in the model-simulated land surface heat fluxes. The results showed that the soil moisture was sensitive to the specific model configuration. To evaluate and verify the model stability, a long-term modeling study with AMSR-E soil moisture data ingestion was performed. Based on test simulations, AMSR-E data were assimilated into an atmospheric model for July and August 2007. The results showed that the land surface fluxes agreed well with both the in-situ data and the results of the default model configuration. Therefore, the simulation can be used to retrieve land surface heat fluxes from an atmospheric model over the Tibetan Plateau.All of the different methods will clarify the land surface heating field in complex plateau, it also can affect atmospheric cycle over the Tibetan Plateau even all of the global atmospheric cycle pattern.

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Influence of thermodynamic soil and vegetation parameterizations on the simulation of soil temperature states and surface fluxes by the Noah LSM over a Tibetan plateau site

Hydrology and Earth System Sciences ◽

10.5194/hess-13-759-2009 ◽

2009 ◽

Vol 13 (6) ◽

pp. 759-777 ◽

Cited By ~ 47

Author(s):

R. van der Velde ◽

Z. Su ◽

M. Ek ◽

M. Rodell ◽

Y. Ma

Keyword(s):

Thermal Properties ◽

Tibetan Plateau ◽

Land Surface ◽

Land Surface Model ◽

Soil Heat Flux ◽

Stomatal Resistance ◽

Surface Fluxes ◽

Surface Model ◽

The Tibetan Plateau ◽

Soil Thermal Properties

Abstract. In this paper, we investigate the ability of the Noah Land Surface Model (LSM) to simulate temperature states in the soil profile and surface fluxes measured during a 7-day dry period at a micrometeorological station on the Tibetan Plateau. Adjustments in soil and vegetation parameterizations required to ameliorate the Noah simulation on these two aspects are presented, which include: (1) differentiating the soil thermal properties of top- and subsoils, (2) investigation of the different numerical soil discretizations and (3) calibration of the parameters utilized to describe the transpiration dynamics of the Plateau vegetation. Through the adjustments in the parameterization of the soil thermal properties (STP) simulation of the soil heat transfer is improved, which results in a reduction of Root Mean Squared Differences (RMSD's) by 14%, 18% and 49% between measured and simulated skin, 5-cm and 25-cm soil temperatures, respectively. Further, decreasing the minimum stomatal resistance (Rc,min) and the optimum temperature for transpiration (Topt) of the vegetation parameterization reduces RMSD's between measured and simulated energy balance components by 30%, 20% and 5% for the sensible, latent and soil heat flux, respectively.

Download Full-text