SPACE-TIME STRUCTURE OF RAIN RATE FIELDS

In this study, rain gage and radar data were used to determine empirically the spatial and temporal structure of the rain process as observed using rain rate as a tracer of the atmospheric motions and to test the validity of Taylor's hypothesis for relating their spatial and temporal statistics. Weather radar derived rain rate maps were employed to obtain one- and two-dimensional spatial power spectra. Azimuthally averaged two-dimensional spectra displayed the shape predicted for a passive scalar advected by a steady state field of two-dimensional turbulence driven by the input of energy over a narrow band of wave numbers. One-dimensional spatial spectra for a short line of rain gages had the same spectral shape as the azimuthally averaged spectra obtained from the radar data. -from Author