A semiempirical model for interpreting microwave emission from semiarid land surfaces as seen from space

A radiative transfer model for simulating microwave brightness temperatures over land surfaces is described. The model takes into account sensor viewing conditions (spacecraft altitude, viewing angle, frequency, polarization) and atmospheric parameters over a soil surface characterized by its moisture, roughness, and temperature and covered with a layer of vegetation characterized by its temperature, water content, single scattering albedo, structure and percent coverage. In order to reduce the influence of atmospheric and surface temperature effects, the brightness temperatures are expressed as polarization ratios that depend primarily on the soil moisture and roughness, canopy water content, and percentage of cover. The approach used is described, and the sensitivity of the polarization ratio to these parameters is investigated. Simulation of the temporal evolution of the microwave signal over semiarid areas in the African Sahel is presented and compared to actual satellite data from the SMMR instrument on Nimbus-7. >

[1]  J. Kong,et al.  Microwave thermal emission from a stratified medium with nonuniform temperature distribution , 1975 .

[2]  J. Joseph,et al.  The delta-Eddington approximation for radiative flux transfer , 1976 .

[3]  C. Swift,et al.  An improved model for the dielectric constant of sea water at microwave frequencies , 1977 .

[4]  P. Gloersen,et al.  A scanning multichannel microwave radiometer for Nimbus-G and SeaSat-A , 1977, IEEE Journal of Oceanic Engineering.

[5]  J. Kong,et al.  Theory for passive microwave remote sensing of near‐surface soil moisture , 1977 .

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

[7]  Eni G. Njoku,et al.  Antenna pattern correction procedures for the Scanning Multichannel Microwave Radiometer (SMMR) , 1980 .

[8]  Leung Tsang,et al.  Radiative transfer theory for passive microwave remote sensing of a two‐layer random medium with cylindrical structures , 1980 .

[9]  E. Njoku,et al.  The Seasat scanning multichannel microwave radiometer (SMMR): Instrument description and performance , 1980, IEEE Journal of Oceanic Engineering.

[10]  B. Choudhury,et al.  Remote sensing of soil moisture content over bare field at 1.4 GHz frequency , 1981 .

[11]  Eni G. Njoku,et al.  Regression Techniques for Oceanographic Parameter Retrieval Using Space-Borne Microwave Radiometry , 1981, IEEE Transactions on Geoscience and Remote Sensing.

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

[13]  L. Tsang,et al.  Microwave emissions from soils with rough surfaces , 1982 .

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

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

[16]  F. Ulaby,et al.  Effects of Vegetation Cover on the Microwave Radiometric Sensitivity to Soil Moisture , 1983, IEEE Transactions on Geoscience and Remote Sensing.

[17]  James R. Wang,et al.  Multifrequency Measurements of the Effects of Soil Moisture, Soil Texture, And Surface Roughness , 1983, IEEE Transactions on Geoscience and Remote Sensing.

[18]  Fawwaz T. Ulaby,et al.  Measured microwave emission and scattering in vegetation canopies , 1984, IEEE Transactions on Geoscience and Remote Sensing.

[19]  F. Ulaby,et al.  Microwave Dielectric Behavior of Wet Soil-Part 1: Empirical Models and Experimental Observations , 1985, IEEE Transactions on Geoscience and Remote Sensing.

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

[21]  S. Paloscia,et al.  Microwave Emission and Plant Water Content: A Comparison between Field Measurements and Theory , 1986, IEEE Transactions on Geoscience and Remote Sensing.

[22]  Christopher O. Justice,et al.  Monitoring East African vegetation using AVHRR data , 1986 .

[23]  Eni G. Njoku,et al.  Observations of the seasonal variability of soil moisture and vegetation cover over Africa using satellite microwave radiometry , 1986 .

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

[25]  Compton J. Tucker,et al.  Monitoring vegetation using Nimbus-7 scanning multichannel microwave radiometer's data , 1987 .

[26]  T. Mo,et al.  Calculations of the Microwave Brightness Temperature of Rough Soil Surfaces: Bare Field , 1987, IEEE Transactions on Geoscience and Remote Sensing.

[27]  Bhaskar J. Choudhury,et al.  Relative sensitivity of normalized difference vegetation Index (NDVI) and microwave polarization difference Index (MPDI) for vegetation and desertification monitoring , 1988 .