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

A summary of rainfall statistics over the equatorial area (10°N–10°S), 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.