Effects of the Near-Surface Soil Moisture Profile on the Assimilation of L-band Microwave Brightness Temperature

Abstract The impact of model and observation errors in the European Land Data Assimilation System (ELDAS) data assimilation system on the analyzed surface variables has been studied using the Southern Great Plains Hydrology Experiment (SGP) 1997 and 1999 datasets. The model error for soil moisture was derived from an error propagation experiment based on perturbed rainfall forcing data. It was found that the errors for the top three model layers are 0.010, 0.010, and 0.0015 m3 m−3, respectively. Data assimilation experiments based on screen-level variables (2-m temperature and humidity) and L-band brightness temperature observations from SGP97 with this error distribution result in improved soil moisture forecasts when compared to model runs with a vertically constant model error of 0.005 m3 m−3. In the second part of this study, the effect of the vertical soil moisture distribution—which can hardly be resolved by large-scale hydrological models—in the assimilation system has been quantified using SGP99 d...

[1]  Thomas Wilheit,et al.  Radiative Transfer in a Plane Stratified Dielectric , 1975, IEEE Transactions on Geoscience Electronics.

[2]  Richard K. Moore,et al.  Microwave Remote Sensing - Active and Passive - Volume I - Microwave Remote Sensing Fundamentals and Radiometry , 1981 .

[3]  J. Shukla,et al.  Influence of Land-Surface Evapotranspiration on the Earth's Climate , 1982, Science.

[4]  F. Ulaby,et al.  Microwave Dielectric Behavior of Wet Soil-Part II: Dielectric Mixing Models , 1985, IEEE Transactions on Geoscience and Remote Sensing.

[5]  Richard K. Moore,et al.  Radar remote sensing and surface scattering and emission theory , 1986 .

[6]  A. Fung,et al.  Microwave Remote Sensing Active and Passive-Volume III: From Theory to Applications , 1986 .

[7]  Y. Kerr,et al.  A semiempirical model for interpreting microwave emission from semiarid land surfaces as seen from space , 1990 .

[8]  T. Jackson,et al.  ESTAR: a synthetic aperture microwave radiometer for remote sensing applications , 1994, Proc. IEEE.

[9]  Wim G.M. Bastiaanssen,et al.  A New Methodology for Assimilation of Initial Soil Moisture Fields in Weather Prediction Models Using Meteosat and NOAA Data. , 1997 .

[10]  Matthias Drusch,et al.  The impact of the SSM/I antenna gain function on land surface parameter retrieval , 1999 .

[11]  Thomas J. Jackson,et al.  Soil moisture mapping at regional scales using microwave radiometry: the Southern Great Plains Hydrology Experiment , 1999, IEEE Trans. Geosci. Remote. Sens..

[12]  Urs Wegmüller,et al.  Rough bare soil reflectivity model , 1999, IEEE Trans. Geosci. Remote. Sens..

[13]  D. Lüthi,et al.  The Soil-Precipitation Feedback: A Process Study with a Regional Climate Model , 1999 .

[14]  Jean-François Mahfouf,et al.  Evaluation of the Optimum Interpolation and Nudging Techniques for Soil Moisture Analysis Using FIFE Data , 2000 .

[15]  R. Hess,et al.  Assimilation of screen-level observations by variational soil moisture analysis , 2001 .

[16]  T. Jackson,et al.  Vegetative and Atmospheric Corrections for the Soil Moisture Retrieval from Passive Microwave Remote Sensing Data: Results from the Southern Great Plains Hydrology Experiment 1997 , 2001 .

[17]  D. McLaughlin,et al.  Downscaling of radio brightness measurements for soil moisture estimation: A four‐dimensional variational data assimilation approach , 2001 .

[18]  Yann Kerr,et al.  Soil moisture retrieval from space: the Soil Moisture and Ocean Salinity (SMOS) mission , 2001, IEEE Trans. Geosci. Remote. Sens..

[19]  Clemens Simmer,et al.  The Influence of Hydrologic Modeling on the Predicted Local Weather: Two-Way Coupling of a Mesoscale Weather Prediction Model and a Land Surface Hydrologic Model , 2002 .

[20]  J. D. Tarpley,et al.  The multi‐institution North American Land Data Assimilation System (NLDAS): Utilizing multiple GCIP products and partners in a continental distributed hydrological modeling system , 2004 .

[21]  Wade T. Crow,et al.  Using a Microwave Emission Model to Estimate Soil Moisture from ESTAR Observations during SGP99 , 2004 .

[22]  Yann Kerr,et al.  The hydrosphere State (hydros) Satellite mission: an Earth system pathfinder for global mapping of soil moisture and land freeze/thaw , 2004, IEEE Transactions on Geoscience and Remote Sensing.

[23]  Matthias Drusch,et al.  The Usage of Screen-Level Parameters and Microwave Brightness Temperature for Soil Moisture Analysis , 2004 .

[24]  Randal D. Koster,et al.  Global assimilation of satellite surface soil moisture retrievals into the NASA Catchment land surface model , 2005 .

[25]  T. Jackson,et al.  Using TRMM/TMI to Retrieve Surface Soil Moisture over the Southern United States from 1998 to 2002 , 2006 .