Showing papers by "Robert Meneghini published in 1991"

Dual-parameter radar rainfall measurement from space: a test result from an aircraft experiment

Abstract: An aircraft experiment has been conducted with a dual-frequency (X/Ka-bands) radar to test various rainfall retrieval methods from space. The authors test a method to derive raindrop size distribution (DSD) parameters from the combination of a radar reflectivity profile and a path-integrated attenuation derived from the surface return, which may be available from most spaceborne radars. The test results indicate the feasibility of the dual-parameter radar measurement from space in achieving a better accuracy in quantitative rainfall remote measurements. >

Space: A Test Result From an Aircraft Experiment

Abstract: An aircraft experiment has been conducted with a dual-frequency (X/Ka-bands) radar to test various rainfall re- trieval methods from space. In this paper, we test a method to derive raindrop size distribution (DSD) parameters from the combination of a radar reflectivity profile (in our test, X-band) and a path-integrated attenuation derived from surface return, which may be available from most spaceborne radars. The es- timated DSD parameters are reasonable in that the values gen- erally fall within the range of commonly measured ones and that shifts in DSD parameters appear to be correlated with changes in storm type. The validity of the estimation result is also demonstrated by a consistency check using the Ka-band reflectivity profile which is independent of the DSD estimation process. Although errors may occur in the cases of nonuniform beam filling, these test results indicate the feasibility of the dual- parameter radar measurement from space to achieve a better accuracy in quantitative rainfall remote measurements.

Estimation of raindrop size distribution parameters from a dual-parameter spaceborne radar measurement

Abstract: A method to estimate raindrop size distribution (DSD) parameters from a combined Zm profile and path-integrated attenuation is shown, and a test result of the method using the data from an aircraft experiment is presented. The 'semi' dual-parameter (SDP) measurement is employed to estimate DSD parameters using the data obtained from an aircraft experiment conducted by Communications Research Laboratory, Tokyo, in conjunction with NASA. The validity of estimated DSD parameters is examined using measured Ka-band radar reflectivities. The estimated path-averaged N(0) is consistent with the Ka/X Ze ratio, and the use of estimated DSD shows excellent agreement between the rain rates estimated from the X-band and K-band Zes. The feasibility of estimating DSD parameters from space is confirmed.

Multi-parameter airborne rain radar experiment in the western Pacific

Abstract: The study presents preliminary results from an airborne radar/radiometer experiment (Typhoon Experiment) which was conducted in the western Pacific Ocean during September 1990, with emphasis on the multiparameter radar results. One of the objectives of this experiment is to make radar/radiometer measurements over rain to support the algorithm development and science studies for the Tropical Rainfall Measuring Mission (TRMM) and the spaceborne weather sensors. The extremely high linear depolarization ratio value observed at the melting height is considered to be procured by the melting particle with large eccentricity. It is shown that the multiparameter airborne radar provides valuable information by distinguishing the hydrometeor particles of the rainfall.