1. ABSTRACT Experiments undertaken in the 1970s demonstrated the sensitivity of radar backscatter to soil moisture conditions [1]. More recent advances in active microwave remote sensing have confirmed the potential for using current satellite data for the generation of soil moisture maps at different scales [2,3]. However, in addition to its strong sensitivity to the soil water content, radar ...

In this paper, we study an interference avoidance scenario in the presence of a smart interferer which can rapidly observe the transmit power of a backscatter wireless sensor network (WSN) and effectively interrupt backscatter signals. We consider a power control with a sub-channel allocation to avoid interference attacks and a time-switching ratio for backscattering and RF energy harvesting in...

We compared the output of the Santa Barbara microwave canopy backscatter model to polarimetric synthetic aperture radar ( S A R ) data for three ponderosa pine stands (ST2, ST-11, and SP-2) with discontinuous tree canopies near Mt. Shasta, California, at P-band (0.68-m wavelength), L-band (0.235m wavelength), and C-band (0.056-m wavelength). Given the SAR data calibration uncertainty, the model...

The performance of the European Centre for Medium-Range Weather Forecasts (ECMWF) model in simulating clouds is evaluated using observations by the Geoscience Laser Altimeter System lidar on the Ice, Cloud, and Land Elevation Satellite (ICESat). To account for lidar attenuation in the comparison, model variables are used to simulate the attenuated backscatter using a lidar forward model. This g...

Ultrasound backscatter and attenuation in the liver were measured in patients with diffuse liver disease and in 35 volunteers who had no history of liver ailments. Measurements were done using radiofrequency (RF) echo signals derived from a clinical scanner; a reference phantom was scanned to account for effects of gain, transmit-receive frequency response and transducer beam patterns on echo d...

PURPOSE Portal dose images acquired with an amorphous silicon electronic portal imaging device (EPID) suffer from artifacts related to backscattered radiation. The backscatter signal varies as a function of field size (FS) and location on the EPID. Most current portal dosimetry algorithms fail to account for the FS dependence. The ramifications of this omission are investigated and solutions fo...

gridded maps of biomass to be produced over time6. Radar backscatter is sensitive to vegetation fresh biomass7. At long wavelengths (0.7 m or longer), radar penetrates deep into the canopy and the backscatter energy depends on a combination of variables including the size, number density, and the water content and wood specific gravity of branches and stems. However, radar backscatter suffers f...

A method for estimating structural properties of random media is described. The size, number density, and scattering strength of particles are estimated from an analysis of the radio frequency (rf) echo signal power spectrum. Simple correlation functions and the accurate scattering theory of Faran [J.J. Faran, J. Acoust. Soc. Am. 23, 405-418 (1951)], which includes the effects of shear waves, w...

In this paper, we explore the potential for improving CALIPSO backscatter profiles through constraints imposed by MODIS derived path reflectances. This is done by processing the 2 channel lidar signals using a wide range of aeronet derived atmosphere models to determine both backscatter and mixing ratio and determining the set of models that satisfy all the MODIS path reflectance constraints.

We are developing methods to estimate and image structural properties of soft tissues. The basis for our methods are measurements of acoustic backscatter coefficients. From the backscatter coefficients four parameters are estimated and displayed in images. The ability to image independent physical properties of the tissue provides more descriptive information than a B-mode image which combines ...