The evolution of total cloud cover and cloud types is composited across the Madden–Julian oscillation (MJO) using CloudSat data for June 2006–May 2010. Two approaches are used to define MJO phases: 1) the local phase is determined at each longitude and time from filtered outgoing longwave radiation, and 2) the global phase is defined using a popular real-time multivariate MJO (RMM) index, which assigns the tropics to an MJO phase each day. In terms of local phase, CloudSat results show a familiar evolution of cloud type predominance: in the growing stages shallow clouds coexist with deep, intense, but narrow convective systems. Widespread cloud coverage and rainfall appear during the active phases, becoming more anvil dominated with time, and finally suppressed conditions return. Results are compared to the convectively coupled Kelvin wave, which has a similar life cycle to the MJO. Convection in the MJO tends to be modulated more by moisture variations compared to the Kelvin wave. In terms of global phases, wide deep precipitating, anvil, cumulus congestus, and altocumulus types exhibit similar eastward propagation from the Indian Ocean to the central Pacific, while the narrow deep precipitating type only propagates to the Maritime Continent. These propagating types also show coherent Western Hemisphere signals. Generally, negative Western Hemisphere anomalies occur when anomalies are positive over the Indian Ocean. In both approaches, sampling leads to pictorial renderings of actual clouds across MJO phases. These mosaics provide an objective representation of the cloud field that was unavailable before CloudSat and serve as a reminder to the complex nature of the MJO’s multiscale features.

[1] We examine a radar-derived climatology of Earth's cloudiness, focusing on the vertical distribution echo tops. Between the two main peaks at $2 km and $14 km associated with low and high clouds, respectively, lie two distinct midlevel peaks in the tropics. One is in the 5 -6 km layer, the other between 7 and 8 km. Both are seen day and night, over land and sea, over each tropical ocean basin, and in published ground radar climatology. In the extratropics, the vertical echo top distribution by temperature reveals a strikingly sharp peak in the À15 to À20°C layer (corresponding to the 7 -8 km peak in the tropics). Again the signal is robust (night-day, land-sea, summer-winter). We consider interpretations of the À15°C peak ranging from data artifacts (unlikely), to mere radar brightening, to possible true microphysical or dynamical cloudiness enhancement mechanisms.

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