The development of organized convection associated with the MJO during TOGA COARE IOP: Trimodal characteristics

Abstract

We constructed a composite lifecycle of the Madden‐Julian oscillation (MJO) with cloud‐top information and atmospheric temperature and moisture profiles. Japanese Geostationary Meteorological Satellite (GMS/IR T BB) histograms and upper‐soundings from the Tropical Ocean‐Global Atmosphere Coupled Ocean‐Atmosphere Response Experiment (TOGA COARE) intensive observation period (IOP) were analyzed around Ujung Pandang (119°E, 5°S) and Kupang (123°E, 10°S), which encountered the mature phase of MJO from January to February, 1993. Under a large‐scale boundary layer (BL) convergence, convection developed in stages:1) ‘suppressed stage’ with suppressed clouds, 2) ‘shallow convection stage’ (2–3 days) with clouds confined under the trade inversion level, 3) ‘developing stage’ (3–4 days) with most clouds stopped at the mid‐troposphere but some tall convective clouds developing 4) ‘mature stage’ (4–5 days) with large anvil cloud shields, and 5) ‘decaying stage’ with decaying anvils. These stages of MJO were related to three stable layers; trade inversion, 0°C level, and tropopause. It is suggested that staged convective development associated with the MJO was strongly affected by the interaction among convection, stable layers, and atmospheric moistening.