Clouds and Climate

Animations of deep convection with and without precipitation from work in progress.
GIF animations are available here and here.

In the paper published in JAS, "A transilient matrix for moist convection", it is found that boundary-layer parcels detrained by clouds in the free troposphere come primarily from within 100 meters of the surface. This has important implications for how convective instability is calculated in the atmosphere.

The first investigation of stratospheric HDO using a steady-state cloud-resolving simulation with isotope microphysics, "Isotopic composition of water in the tropical tropopause layer," is published in JGR. Simulating a Walker cell over an 8000-km-wide domain, the convective injection of ice and the generation of cirrus by gravity waves are found to be dominant controls on HDO in the stratosphere.

The first study of precipitation extremes in a high-resolution cloud-resolving model, "Response of tropical precipitation to global warming," is in press at JAS. Contrary to results from GCMs, convective updrafts become more vigorous when CO2 is doubled, contributing to higher rain rates.

The first direct measurement of convective entrainment. From the paper published in JAS, "A direct measure of entrainment," this figure shows the azimuthally averaged entrainment rate at three intervals in the life cycle of a deep cumulonimbus.

An animation of 2005 brightness temperatures and best-track data from the GRL paper "Overshooting convection in tropical cyclones."

An animation from a paper in the May 2010 issue of JAS, "Nature versus nurture in shallow convection."

Animations with and without precipitation of deep convection from work in progress.