Effects of Tunable Data Compression on Geophysical Products Retrieved from Surface Radar Observations with Applications to Spaceborne Meteorological Radars

Abstract

his paper presents results and analyses of applying an international space data compression standard to weather radar measurements that can easily span eight orders of magnitude and typically require a large storage capacity as well as significant bandwidth for transmission. By varying the degree of the data compression, the nonlinear response of models that relates measured radar reflectivity and/or Doppler spectra to the moments and properties of the particle size distribution characterizing clouds and precipitation was analyzed. Preliminary results for the meteorologically important phenomena of clouds and light rain indicate that for a ±0.5-dB calibration uncertainty, typical for the ground-based pulsed-Doppler 94-GHz (or 3.2 mm, W band) weather radar used as a proxy for spaceborne radar in this study, a lossless compression ratio of only 1.2 is achievable. However, further analyses of the nonlinear response of various models of rainfall rate, liquid water content, and median volume diameter show that a lossy data compression ratio exceeding 15 is realizable. The exploratory analyses presented are relevant to future satellite missions, where the transmission bandwidth is premium and storage requirements of vast volumes of data are potentially problematic.