A concept is described for passive microwave sensing of soil moisture and ocean salinity from space. The Inflatable Radiometric Imaging System (IRIS) makes use of a large-diameter, offset-fed, parabolic-torus antenna with multiple feeds, in a conical pushbroom configuration.

soil moisture ocean salinity parabolic-torus anten↗

NASA NTRS1996

Soil Moisture Pathfinder: A Low-Cost Passive Spaceborne System Using Inflatable Structures

Explore the source record for details and available documents.

inflatable antennas↗

NASA NTRS1995

A Modeling Study on the Use of Passive Microwave Data for the

This paper presents some aspects of a scheme using remote.

remote sensing passive microwave land use monitori↗

NASA NTRS1994

An Approach to Estimating Surface Parameters and Fluxes Using Modeling and Multispectral Remote Sensing

Water and energy exchanges at the land-atmosphere interface play a key role in determining patterns of regional and global climate. However, accurate estimation of surface fluxes of sensible and latent over arid and semiarid regions is a challenging task. In this study, a scenario for assimilating satellite data in the visible-infrared (AVHRR) and in the microwave (SSM/I) spectral ranges in a hydrological flux model will be presented. The aim of our investigation over the HAPEX-Sahel area in West Africa is to show that the use of multispectral remotely sensed data, in conjunction with radiative transfer models and hydrological flux model, can provide reasonable estimates of the surface fluxes. A discussion of the potentials and limitations of the approach is presented.

surface fluxes climate satellite data↗

NASA NTRS1993

The Red Edge in Arid Region Vegetation: 340-1060 nm Spectra

This paper describes the detection of narrow spectral features in vegetation and the reports of the detection of the

remote↗

NASA NTRS1977

Theory for microwave thermal emission from a layer of cloud or rain

Microwave thermal emission from a layer of cloud or rain consisting of spherical particles has been investigated. Scattering effects are studied in great detail with both numerical and analytical approaches. In the absence of ground emission, it is found that scattering induces brightening for optically thin layers and vice versa for optically thick layers. As a function of observation angle, brightening occurs near nadir, while darkening occurs at large angles in the case of small optical thickness. For large optical thickness, darkening occurs at all angles because of backscattering effects. When the layer of cloud or rain is above an air layer and an ocean surface at a higher temperature, it is found that the darkening effect at large optical thickness is much more pronounced. The darkening effect is also larger for vertical polarizations because the ocean emits more vertically polarized components. The effect of thermal emission and molecular absorption by atmospheric gases is also taken into account. Results obtained from analytical formulas under single-scattering assumptions are compared and illustrated.

Tsang, L.↗

NASA NTRS1975

Microwave thermal emission from a stratified medium with nonuniform temperature distribution

Using the dissipation-fluctuation approach, the brightness temperature of a stratified medium with inhomogeneous permittivities and nonuniform temperature profiles is solved. The solution is expressed in closed form ready for machine computation. Numerical results are illustrated and compared with closed-form analytical solutions and results obtained from the WKB method for simple profiles.

Tsang, L.↗