Convectively driven tropopause-level cooling and Its influences on stratospheric moisture

Extreme deep convection is sampled based on the cloud top height (>17km) from CloudSat, and colocated temperature profiles from COSMIC are composited around the deep convection. Response of moisture to the tropopause-level cooling is also examined in the upper troposphere and lower stratosphere using microwave limb sounder measurements.

The composite temperature shows an anomalous warming in the troposphere and a significant cooling near the tropopause (at 16-19km) when deep convection occurs over the western Pacific, particularly during periods with active Madden-Julian Oscillation (MJO). The composite of the tropopause cooling has a large horizontal scale (similar to 6,000km in longitude) with minimum temperature anomaly of similar to-2K, and it lasts more than 2weeks with support of mesoscale convective clusters embedded within the envelope of the MJO.