Spectral representation of rain profiles and diurnal variations observed with TRMM PR over the equatorial area

[1] A summary of rainfall statistics over the equatorial area (10degreesN-10degreesS), observed by a space-borne precipitation radar of the Tropical Rainfall Measuring Mission (TRMM), is presented utilizing all nadir data of PR2a25 version 5 for the period of 1998-1999. Spectral representation of rain profiles is introduced, and convective and stratiform rain characteristics over land and over ocean are examined. With 0.3 mm hr(-1) rain-top threshold, convective: stratiform rain ratios at 2-4 km over land and over ocean are, 61:39 and 50:50 in amount, 20:80 and 17:83 in area, respectively. For diurnal variations over ocean, two types of rain vary almost synchronously, with an early-morning maximum in 03-06 LT, indicating that direct radiative effect is the dominant diurnal control. Over land, convective rain has a distinct maximum of afternoon showers in 15-18 LT, while stratiform rain has a midnight (24-03LT) maximum. Also shown is that afternoon showers are more frequent but nighttime rain is stronger, suggesting contributions from large-scale disturbances.