Estimating surface soil moisture from satellite microwave measurements and a satellite derived vegetation index

Abstract Normalized 18 GHz microwave brightness temperatures ( T B ) and a vegetation index were calculated from satellite radiometer data, and subsequently used in conjunction with climatically modeled surface moisture estimates to calibrate a simple physically based soil moisture model. Test sites within the U.S. Southern Great Plains were chosen for their range of climatic conditions from east to west. Normalized T B values correlated well with soil moisture when the data were segregated by vegetation index range, but less so when all data were combined. With the introduction of a vegetation index parameter, the model accounted for approximately 70% of the variability in modeled surface soil moisture. The model was validated with data from three separate test sites, with predicted moisture again accounting for 70% of the variability in the modeled surface moisture. The approach appears to be valid, at least for areas of arid or semiarid climatic conditions. These results are more encouraging than previous truck- or aircraft-mounted radiometers of similar frequency have indicated.

[1]  Thomas J. Schmugge,et al.  Soil moisture variation patterns observed in Hand County, South Dakota , 1982 .

[2]  T. Schmugge,et al.  Passive microwave remote sensing of soil moisture from an aircraft platform , 1984 .

[3]  Richard W. Newton,et al.  Utilization of vegetation indices to improve microwave soil moisture estimates over agricultural lands , 1984, IEEE Transactions on Geoscience and Remote Sensing.

[4]  C. W. Richardson,et al.  Calculating Evaporation from Native Grassland Watersheds , 1976 .

[5]  James R. Wang.  Passive microwave sensing of soil moisture content: The effects of soil bulk density and surface roughness , 1983 .

[6]  T. Schmugge,et al.  A hydrological analysis of east Australian floods using Nimbus-5 electrically scanning radiometer data , 1979 .

[7]  P. Sellers.  Canopy reflectance, photosynthesis and transpiration , 1985 .

[8]  H. R. Haise,et al.  Estimating evapotranspiration from solar radiation , 1963 .

[9]  Bhaskar J. Choudhury,et al.  Simulating Soil Water Recession Coefficients for Agricultural Watersheds , 1983 .

[10]  G. Wilke.  Multispectral Passive Microwave Correlations with an Antecedent Precipitation Index Using the Nimbus 7 SMMR. , 1984 .

[11]  M. Owe.  Long-term streamflow observations in relation to basin development , 1985 .

[12]  Peggy E. O'Neill.  Microwave remote sensing of soil moisture: a comparison of results from different truck and aircraft platforms , 1985 .

[13]  Alfred T. C. Chang,et al.  Quantifying spatial and temporal variabilities of microwave brightness temperature over the U.S. Southern Great Plains , 1987 .

[14]  James R. Wang.  Effect of vegetation on soil moisture sensing observed from orbiting microwave radiometers , 1985 .

[15]  T. Schmugge.  Remote sensing of soil moisture , 1976 .

[16]  T. J. Schmugge.  Effect of soil texture on the microwave emission from soils , 1980 .

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

[18]  Effects of Varying Soil Moisture Contents And Vegetation Canopies on Microwave Emissions , 1982, IEEE Transactions on Geoscience and Remote Sensing.

[19]  Thomas J. Schmugge.  Effect of Texture on Microwave Emission from Soils , 1980, IEEE Transactions on Geoscience and Remote Sensing.

[20]  T. J. Schmugge,et al.  Satellite microwave observations of soil moisture variations , 1977 .

[21]  T. Schmugge,et al.  An Empirical Model for the Complex Dielectric Permittivity of Soils as a Function of Water Content , 1980, IEEE Transactions on Geoscience and Remote Sensing.

[22]  B. Choudhury,et al.  Effect of surface roughness on the microwave emission from soils , 1979 .

[23]  J. A. Gatlin,et al.  Monitoring vegetation in the Nile Delta with NOAA-6 and NOAA-7 AVHRR imagery , 1982 .

[24]  T. Mo,et al.  A model for microwave emission from vegetation‐covered fields , 1982 .

[25]  Bruce J. Blanchard,et al.  Correlation of spacecraft passive microwave system data with soil moisture indices (API). [Southern Great Plains States: Oklahoma and Kansas] , 1979 .

[26]  A. D. Nicks,et al.  Stochastic generation of temperature and solar radiation data , 1980 .

[27]  C. Federer,et al.  Simulated streamflow response to possible differences in transpiration among species of hardwood trees , 1978 .

[28]  T. Schmugge,et al.  Passive microwave sensing of soil moisture under vegetation canopies , 1982 .

[29]  Thomas J. Schmugge,et al.  Estimation of Soil Moisture with Api Algorithms and Microwave Emission , 1981 .

[30]  C. J. Tucker,et al.  Relationship between atmospheric CO2 variations and a satellite-derived vegetation index , 1986, Nature.