Some practical notes on the land surface modeling in the Tibetan Plateau

Abstract. The Tibetan Plateau is a key region of land-atmosphere interactions, as it provides an elevated heat source to the middle-troposphere. The Plateau surfaces are typically characterized by alpine meadows and grasslands in the central and eastern part while by alpine deserts in the western part. This study evaluates performance of three state-of-the-art land surface models (LSMs) for the Plateau typical land surfaces. The LSMs of interest are SiB2 (the Simple Biosphere), CoLM (Common Land Model), and Noah. They are run with default parameters at typical alpine meadow sites in the central Plateau and typical alpine desert sites in the western Plateau. The recognized key processes and modeling issues are as follows. First, soil stratification is a typical phenomenon beneath the alpine meadows, with dense roots and soil organic matters within the topsoil, and it controls the profile of soil moisture in the central and eastern Plateau; all models significantly under-estimate the soil moisture within the topsoil. Second, a soil surface resistance controls the surface evaporation from the alpine deserts but it has not been reasonably modeled in LSMs; a new scheme is proposed to determine this resistance from soil water content. Third, an excess resistance controls sensible heat fluxes from dry bare-soil or sparsely vegetated surfaces, and all LSMs significantly under-predict the ground-air temperature difference in the daytime. A parameterization scheme for this resistance has been shown effective to remove this bias.

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Some practical notes on the land surface modeling in the Tibetan Plateau

Hydrology and Earth System Sciences ◽

10.5194/hess-13-687-2009 ◽

2009 ◽

Vol 13 (5) ◽

pp. 687-701 ◽

Cited By ~ 93

Author(s):

K. Yang ◽

Y.-Y. Chen ◽

J. Qin

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Soil Water ◽

Land Surface ◽

Heat Fluxes ◽

The Tibetan Plateau ◽

Sensible Heat ◽

Central Plateau ◽

Alpine Meadows ◽

Common Land Model

Abstract. The Tibetan Plateau is a key region of land-atmosphere interactions, as it provides an elevated heat source to the middle-troposphere. The Plateau surfaces are typically characterized by alpine meadows and grasslands in the central and eastern part while by alpine deserts in the western part. This study evaluates performance of three state-of-the-art land surface models (LSMs) for the Plateau typical land surfaces. The LSMs of interest are SiB2 (the Simple Biosphere), CoLM (Common Land Model), and Noah. They are run at typical alpine meadow sites in the central Plateau and typical alpine desert sites in the western Plateau. The identified key processes and modeling issues are as follows. First, soil stratification is a typical phenomenon beneath the alpine meadows, with dense roots and soil organic matters within the topsoil, and it controls the profile of soil moisture in the central and eastern Plateau; all models, when using default parameters, significantly under-estimate the soil moisture within the topsoil. Second, a soil surface resistance controls the surface evaporation from the alpine deserts but it has not been reasonably modeled in LSMs; an advanced scheme for soil water flow is implemented in a LSM, based on which the soil resistance is determined from soil water content and meteorological conditions. Third, an excess resistance controls sensible heat fluxes from dry bare-soil or sparsely vegetated surfaces, and all LSMs significantly under-predict the ground-air temperature gradient, which would result in higher net radiation, lower soil heat fluxes and thus higher sensible heat fluxes in the models. A parameterization scheme for this resistance has been shown to be effective to remove these biases.

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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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Trends of land surface heat fluxes on the Tibetan Plateau from 2001 to 2012

International Journal of Climatology ◽

10.1002/joc.5119 ◽

2017 ◽

Vol 37 (14) ◽

pp. 4757-4767 ◽

Cited By ~ 16

Author(s):

Cunbo Han ◽

Yaoming Ma ◽

Xuelong Chen ◽

Zhongbo Su

Keyword(s):

Tibetan Plateau ◽

Land Surface ◽

Surface Heat ◽

Heat Fluxes ◽

The Tibetan Plateau ◽

Surface Heat Fluxes ◽

Land Surface Heat Fluxes

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Land-surface processes and summer-cloud-precipitation characteristics in the Tibetan Plateau and their effects on downstream weather: a review and perspective

National Science Review ◽

10.1093/nsr/nwz226 ◽

2020 ◽

Vol 7 (3) ◽

pp. 500-515 ◽

Cited By ~ 8

Author(s):

Yunfei Fu ◽

Yaoming Ma ◽

Lei Zhong ◽

Yuanjian Yang ◽

Xueliang Guo ◽

...

Keyword(s):

Boundary Layer ◽

Tibetan Plateau ◽

Land Surface ◽

Sensible Heat Flux ◽

Vertical Direction ◽

Heat Fluxes ◽

Surface Processes ◽

Convective Precipitation ◽

The Tibetan Plateau ◽

Land Surface Processes

Abstract Correct understanding of the land-surface processes and cloud-precipitation processes in the Tibetan Plateau (TP) is an important prerequisite for the study and forecast of the downstream activities of weather systems and one of the key points for understanding the global atmospheric movement. In order to show the achievements that have been made, this paper reviews the progress on the observations for the atmospheric boundary layer, land-surface heat fluxes, cloud-precipitation distributions and vertical structures by using ground- and space-based multiplatform, multisensor instruments and the effect of the cloud system in the TP on the downstream weather. The results show that the form drag related to the topography, land–atmosphere momentum and scalar fluxes is an important part of the parameterization process. The sensible heat flux decreased especially in the central and northern TP caused by the decrease in wind speeds and the differences in the ground-air temperatures. Observations show that the cloud and precipitation over the TP have a strong diurnal variation. Studies also show the compressed-air column in the troposphere by the higher-altitude terrain of the TP makes particles inside clouds vary at a shorter distance in the vertical direction than those in the non-plateau area so that precipitation intensity over the TP is usually small with short duration, and the vertical structure of the convective precipitation over the TP is obviously different from that in other regions. In addition, the influence of the TP on severe weather downstream is preliminarily understood from the mechanism. It is necessary to use model simulations and observation techniques to reveal the difference between cloud precipitation in the TP and non-plateau areas in order to understand the cloud microphysical parameters over the TP and the processes of the land boundary layer affecting cloud, precipitation and weather in the downstream regions.

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A Spatial and Temporal Continuum Remotely Sensed Soil Moisture Dataset of the Tibet Plateau From 2002 to 2015

10.5194/egusphere-egu2020-20846 ◽

2020 ◽

Author(s):

Yaokui Cui ◽

Chao Zeng ◽

Jie Zhou ◽

Xi Chen

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Land Surface ◽

European Space Agency ◽

Remotely Sensed ◽

General Regression Neural Network ◽

Tibet Plateau ◽

The Tibetan Plateau ◽

Space Agency ◽

Spatio Temporal

Abstract:Surface soil moisture plays an important role in the exchange of water and energy between the land surface and the atmosphere, and critical to climate change study. The Tibetan Plateau (TP), known as &#8220;The third pole of the world&#8221; and &#8220;Asia&#8217;s water towers&#8221;, exerts huge influences on and sensitive to global climates. Long time series of and spatio-temporal continuum soil moisture is helpful to understand the role of TP in this situation. In this study, a dataset of 14-year (2002&#8211;2015) Spatio-temporal continuum remotely sensed soil moisture of the TP at 0.25&#176; resolution is obtained, combining MODIS optical products and ESA (European Space Agency) ECV (Essential Climate Variable) combined soil moisture products based on General Regression Neural Network (GRNN). The validation of the dataset shows that the soil moisture is well reconstructed with R2 larger than 0.65, and RMSE less than 0.08 cm3 cm-3 and Bias less than 0.07 cm3 cm-3 at 0.25&#176; and 1&#176; spatial scale, compared with the in-situ measurements in the central of TP. And then, spatial&#160;and&#160;temporal&#160;characteristics and trend of SM over TP were analyzed based on this dataset.Keywords: Soil moisture; Remote Sensing; Dataset; GRNN; ECV; Tibetan Plateau

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Developing the soil texture effects on the surface resistance to bare soil based on MOD16 algorithm to estimate evapotranspiration over the Tibetan Plateau

10.5194/egusphere-egu2020-3833 ◽

2020 ◽

Author(s):

Ling Yuan ◽

Yaoming Ma ◽

Xuelong Chen

Keyword(s):

Tibetan Plateau ◽

Soil Texture ◽

Land Surface ◽

Bare Soil ◽

The Other ◽

Accurate Estimation ◽

Surface Model ◽

The Tibetan Plateau ◽

The Mean ◽

Modified Algorithm

Evapotranspiration (ET), composed of evaporation (ETs) and transpiration (ETc) and intercept water (ETw), plays an indispensable role in the water cycle and energy balance of land surface processes. A more accurate estimation of ET variations is essential for natural hazard monitoring and water resource management. For the cold, arid, and semi-arid regions of the Tibetan Plateau (TP), previous studies often overlooked the decisive role of soil properties in ETs rates. In this paper, an improved algorithm for ETs in bare soil and an optimized parameter for ETc over meadow based on MOD16 model are proposed for the TP. The nonlinear relationship between surface evaporation resistance (rss) and soil surface hydration state in different soil texture is redefined by ground-based measurements over the TP. Wind speed and vegetation height were integrated to estimate aerodynamic resistance by Yang et al. (2008). The validated value of the mean potential stomatal conductance per unit leaf area (CL) is 0.0038m s-1. And the algorithm was then compared with the original MOD16 algorithm and a soil water index&#8211;based Priestley-Taylor algorithm (SWI&#8211;PT). After examining the performance of the three models at 5 grass flux tower sites in different soil texture over the TP, East Asia, and America, the validation results showed that the half-hour estimates from the improved-MOD16 were closer to observations than those of the other models under the all-weather in each site. The average correlation coefficient(R2) of the improved-MOD16 model was 0.83, compared with 0.75 in the original MOD16 model and 0.78 in SWI-PT model. The average values of the root mean square error (RMSE) are 35.77W m-2, 79.46 W m-2, and 73.88W m-2 respectively. The average values of the mean bias (MB) are -4.08W m-2, -52.36W m-2, and -11.74 W m-2 overall sites, respectively. The performance of these algorithms are better achieved on daily (R2=0.81, RMSE=17.22W m-2, MB=-4.12W m-2; R2=0.64, RMSE=56.55W m-2, MB=-48.74W m-2; R2=0.78, RMSE=22.3W m-2, MB=-9.82W m-2) and monthly (R2=0.93, RMSE=23.35W m-2, MB=-2.8W m-2; R2=0.86, RMSE=69.11W m-2, MB=-39.5W m-2; R2=0.79, RMSE=62.8W m-2, MB=-9.7W m-2) scales. Overall, the results showed that the newly developed MOD16 model captured ET more accurately than the other two models. The comparisons between the modified algorithm and two mainstream methods suggested that the modified algorithm could produce high accuracy ET over the meadow sites and has great potential for land surface model improvements and remote sensing ET promotion for the ET region.

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Determination of land surface heat fluxes over heterogeneous landscape of the Tibetan Plateau by using the MODIS and in-situ data

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-19617-2011 ◽

2011 ◽

Vol 11 (7) ◽

pp. 19617-19638 ◽

Cited By ~ 1

Author(s):

Y. Ma ◽

L. Zhong ◽

B. Wang ◽

W. Ma ◽

X. Chen ◽

...

Keyword(s):

Heat Flux ◽

Tibetan Plateau ◽

Land Surface ◽

Surface Heat ◽

Heat Fluxes ◽

The Tibetan Plateau ◽

Surface Heat Fluxes ◽

In Situ Data ◽

Plateau Area

Abstract. In this study, a parameterization methodology based on MODIS (Moderate Resolution Imaging Spectroradiometer) and in-situ data is proposed and tested for deriving the regional surface reflectance, surface temperature, net radiation flux, soil heat flux, sensible heat flux and latent heat flux over heterogeneous landscape. As a case study, the methodology was applied to the Tibetan Plateau area. Four images of MODIS data (30 January 2007, 15 April 2007, 1 August 2007 and 25 October 2007) were used in this study for the comparison among winter, spring, summer and autumn. The derived results were also validated by using the "ground truth" measured in the stations of the Tibetan Observation and Research Platform (TORP). The results show that the derived surface variables (surface reflectance and surface temperature) and surface heat fluxes (net radiation flux, soil heat flux, sensible heat flux and latent heat flux) in four different seasons over the Tibetan Plateau area are in good accordance with the land surface status. These parameters show a wide range due to the strong contrast of surface features over the Tibetan Plateau. Also, the estimated land surface variables and surface heat fluxes are in good agreement with the ground measurements, and all their absolute percent difference (APD) is less than 10 % in the validation sites. It is therefore concluded that the proposed methodology is successful for the retrieval of land surface variables and surface heat fluxes using the MODIS and in-situ data over the Tibetan Plateau area. The shortage and further improvement of the methodology were also discussed.

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Quantifying Long-Term Land Surface and Root Zone Soil Moisture over Tibetan Plateau

Remote Sensing ◽

10.3390/rs12030509 ◽

2020 ◽

Vol 12 (3) ◽

pp. 509 ◽

Cited By ~ 6

Author(s):

Ruodan Zhuang ◽

Yijian Zeng ◽

Salvatore Manfreda ◽

Zhongbo Su

Keyword(s):

Soil Moisture ◽

Tibetan Plateau ◽

Land Surface ◽

Root Zone ◽

Cumulative Distribution ◽

Analytical Relationship ◽

The Tibetan Plateau ◽

Climate Systems

It is crucial to monitor the dynamics of soil moisture over the Tibetan Plateau, while considering its important role in understanding the land-atmosphere interactions and their influences on climate systems (e.g., Eastern Asian Summer Monsoon). However, it is very challenging to have both the surface and root zone soil moisture (SSM and RZSM) over this area, especially the study of feedbacks between soil moisture and climate systems requires long-term (e.g., decadal) datasets. In this study, the SSM data from different sources (satellites, land data assimilation, and in-situ measurements) were blended while using triple collocation and least squares method with the constraint of in-situ data climatology. A depth scaling was performed based on the blended SSM product, using Cumulative Distribution Function (CDF) matching approach and simulation with Soil Moisture Analytical Relationship (SMAR) model, to estimate the RZSM. The final product is a set of long-term (~10 yr) consistent SSM and RZSM product. The inter-comparison with other existing SSM and RZSM products demonstrates the credibility of the data blending procedure used in this study and the reliability of the CDF matching method and SMAR model in deriving the RZSM.

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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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Estimation of land surface key parameters for the study of energy and water cycle over the Tibetan Plateau based on geostationary and polar orbiting satellites

10.5194/egusphere-egu21-2676 ◽

2021 ◽

Author(s):

Lei Zhong ◽

Yaoming Ma ◽

Zhongbo Su ◽

Weiqiang Ma ◽

Zeyong Hu ◽

...

Keyword(s):

Tibetan Plateau ◽

Land Surface ◽

Water Cycle ◽

Surface Characteristic ◽

Heat Fluxes ◽

Turbulent Heat ◽

The Tibetan Plateau ◽

Characteristic Parameters ◽

Turbulent Heat Fluxes ◽

Land Surface Parameters

Estimation of land surface characteristic parameters and turbulent heat fluxes is important for energy and water cycle studies, especially on the Tibetan Plateau (TP), where the topography is unique and the land-atmosphere interactions are strong. The land surface heating conditions also directly influence the movement of atmospheric circulation. However, high temporal resolution information on the plateau-scale land surface parameters has lacked for a long time, which significantly limits the understanding of diurnal variations in land-atmosphere interactions. On the other hand, how to remove cloud effects for optical satellite images is another important research issue. Based on Chinese FY geostationary satellite data and other polar orbiting satellite data, the hourly land surface characteristic parameters and turbulent heat fluxes were estimated. A new cloud&#8208;free time series of vegetation index data sets was reconstructed, and the vegetation density showed a general increasing trend along with a warming trend in the TP. The regions showing significant increases accounted for 7.63% of the total Tibetan territory. Downwelling shortwave and longwave radiation parameterization schemes were improved to derive all-sky radiation over the TP. The diurnal and seasonal cycles of the land surface parameters were clearly identified, and their spatial distribution was found to be consistent with the heterogeneous land surface conditions and the general hydrometeorological conditions of the TP.

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