Multifrequency measurements of the effects of soil moisture, soil texture, and surface roughness

Journal Article · Fri Dec 31 23:00:00 EST 1982 · IEEE Trans. Geosci. Remote Sens.; (United States)

DOI:https://doi.org/10.1109/TGRS.1983.350529· OSTI ID:6055484

Wang, J R; Engman, E T; Jackson, T J; O'Neill, P E

An experiment on remote sensing of soil moisture content was conducted over bare fields with microwave radiometers at the frequencies of 1.4, 5, and 10.7 GHz, during July-September of 1981. Three bare fields with different surface roughnesses and soil textures were prepared for the experiment. Ground-truth acquisition of soil temperatures and moisture contents for 5 layers down to the depths of 15 cm was made concurrently with radiometric measurements. The experimental results show that the effect of surface roughness is to increase the soil's brightness temperature and to reduce the slope of regression between brightness temperature and moisture content. The slopes of regression for soils with different textures are found to be comparable and the effect of soil texture is reflected in the difference of regression line intercepts at brightness-temperature axis. The result is consistent with laboratory measurement of soil's dielectric permittivity. Measurements on wet smooth bare fields give lower brightness temperatures at 5 than at 1.4 GHz. This phenomenon is not expected from current radiative transfer theory, using laboratory measurements of the relationship between dielectric permittivity and moisture content for different soil-water mixtures at frequencies of less than or equal to5 GHz.

• Research Organization: NASA, Goddard Space Flight Center, Greenbelt, MD 20771
• OSTI ID: 6055484
• Journal Information: IEEE Trans. Geosci. Remote Sens.; (United States), Journal Name: IEEE Trans. Geosci. Remote Sens.; (United States) Vol. 21:1; ISSN IGRSD
• Country of Publication: United States
• Language: English

Related Subjects

440105 -- Radiation Instrumentation-- Radiometric Instruments-- (-1987)
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
510101* -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (-1989)
54 ENVIRONMENTAL SCIENCES
CHEMISTRY
DIELECTRIC PROPERTIES
ELECTRICAL PROPERTIES
ELECTRONIC EQUIPMENT
EQUIPMENT
FREQUENCY RANGE
GEOPHYSICAL SURVEYS
GHZ RANGE
GHZ RANGE 01-100
MATHEMATICS
MEASURING INSTRUMENTS
MEASURING METHODS
MICROWAVE EQUIPMENT
MOISTURE
PHYSICAL PROPERTIES
RADIATION DETECTORS
RADIOMETERS
RADIOMETRIC SURVEYS
REGRESSION ANALYSIS
REMOTE SENSING
ROUGHNESS
SOIL CHEMISTRY
SOILS
STATISTICS
SURFACE PROPERTIES
SURVEYS
TEMPERATURE EFFECTS
TEXTURE