Tropical Rainfall Measuring Mission

TRMM PR Data Simulation

During the TOGA COARE campaign, ARMAR was mounted on the NASA DC-8 aircraft, and flew a total of 13 missions in January and February 1993, observing precipitation mostly in mesoscale convective systems (MCS).

To synthesize the measurements that the TRMM radar would have made had it flown over the MCS's observed by ARMAR, the ARMAR data was re-sampled to a uniform cartesian grid (necessary because of aircraft motion), by dividing the atmosphere into 60-meter-thick horizontal slices, and using a Delaunay triangulation with linear interpolation to create a set of uniformly sampled radar reflectivities over each slice. We thus end up with a volume of reflectivities spaced 60m apart vertically and 200m horizontally. This data is convolved with a Gaussian chosen to model the range-match-filtering and the 2-way antenna pattern of ARMAR. The result is illustrated by the following along-track reflectivity profiles:

The raw ARMAR reflectivities are shown in the top panel, the synthesized TRMM PR ones in the bottom panel. The vertical axis represents 8 km in altitude and mirror return (the surface is the bright horizontal slice towards the bottom of each panel), the horizontal axis represents 40 km of track.

The manuscript describing the simulation and its implications about beam-filling can be downloaded by clicking here for the ASCII LaTeX file, here for the figure-less postscript file.

To retrieve a copy of the 1995 Radio Science paper comparing ARMAR's radar-estimated attenuation with the radiometer-estimated attenuation:

For further info email s.durden@jpl.nasa.gov

Back to the JPL TRMM top page