A new satellite deep convective ice index for tropical climate monitoring: Possible implications for existing oceanic precipitation data sets

摘要

The tropical atmosphere is continually overturning, with deep moist convective cloud systems exporting energy from the subcloud layer and depositing it in the upper troposphere. A new satellite index of this deep convective activity is based upon measurements of large ice particles in the upper portions of tropical convective complexes. This 20-year record reveals a strong signal of the El Nino Southern Oscillation (ENSO), with 10 to 15 % upward (downward) swings in the deep convective index during El Nino (La Nina). Warming of tropical sea surface temperatures (SST), whether from anthropogenically-produced greenhouse gases or natural climate variability, is expected to be associated with more convective overturning of the atmosphere. While other tropical precipitation climatologies vary dramatically in their support of this relationship, the present deep convective ice (DCI) index shows a strong correlation between interannual variations of tropical convection and SST. [References: 19]