Engineering topics
Publications and source records attributed to Im, E..
A millimeter wave Cassegrain dual-reflector rada antenna (~94GHz) with super-quadric projected aperture boundaries concept, that includes sub-reflector blockage effect, is evaluated for the spaceborne radar measurement of the vertical cloud profile structure.
Current passive-microwave rain-retrieval methods are largely based on databases built off-line using cloud models.
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Current passive-microwave rain-retrieval methods are largely based on databases built off-line using cloud models.
Atmospheric latent heating field is fundamental to all modes of atmospheric circulation and upper mixed layer circulations of the ocean.
The need for enhanced observational capabilities in a spaceborne microwave radar instrument to measure rainfall rates, vertical velocities with precipitation, and latent-heating profiles accurately and at sufficiently good resolution and spatial coverage throughout the tropics and mid-latitudes requires a large antenna with high-performance beam-scanning capabilities to avoid contamination by the surface clutter known as range ambiguity.
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Explore the source record for details and available documents.
The spaeccraft of the Cassini Mission is planned to be launched towards Saturn in October 1997. The mission is designed to study the physical structure and chemical composition of Titan. The results of the tests performed on the Cassini radar engineering qualification model (EQM) are summarized. The approach followed in the verification and evaluation of the performance of the radio frequency subsystem EQM is presented. The results show that the instrument satisfies the relevant mission requirements.
The NASA/JPL Airborne Rain Mapping Radar (ARMAR) on board the NASA DC-8 aircraft, several airborne multi-channel radiometers on board the NASA ER-2 aircraft, and the doppler radars on board the NOAA P-3 aircraft were deployed for rainfall observations collected over the Western Pacific Ocean during the TOGA/COARE experiment in January and February of 1993. Results of rain system observations are given.
The spacecraft of the Cassini mission is planned to be launched towards Saturn in October 1997. The mission is designed to study the physical structure and chemical composition of Titan. The results of the tests performed on the Cassini radar engineering qualification model (EQM) are summarized. The approach followed in the verification and evaluation of the performance of the radio frequency subsystem EQM is presented. The results show that the instrument satisfies the most relevant mission requirements.
Several algorithms to calculate a rain-rate profile from a single-frequency air-or spaceborne radar backscatter profile and a given path-integrated attenuation have been proposed. The accuracy of any such algorithm is limited by the ambiguities between the (multiple) exact solutions, which depend on the variability of the parameters in the Z-R and k-R relations used. In this study, coupled Z-R and k-R relations are derived based on the drop size distribution. It is then shown that, because of the coupling, the relative difference between the multiple mutually ambiguous rain-rate profiles solving the problem must remain acceptably low, provided the available path-integrated attenuation value is known to within 0.5 dB.
This paper addresses the problem of finding a parametric for for the rain drop size distribution which 1) is an appropriate model for tropical rainfall, and 2) involves statistically independent parameters.
It is easy to understand heuristically why single-frequency spaceborne radar measurements, by themselves, are not sufficient to solve the inverse problem of retrieving an exact underlying rain-rate profile.