November 26, 2019 | Published by | ,

It is well known that the average precipitation rate over a city-sized region in the tropics is a strong function of the humidity of that region. While a variety of mechanisms have been proposed to account for this relationship, their relative importance remains unknown.

In addition, little is understood about the relationship between precipitation and the thermal structure of the tropical atmosphere.

In this paper, CLEX researchers considered the steady-state response of the atmosphere to an imposed large-scale flow. They found that under these steady-state conditions, humidity increases with the precipitation rate, while the lapse rate (rate of decrease of temperature with height) increases.

These results are understood through a simple model of convection based on an entraining plume. The findings shed new light on the interaction of clouds with the larger-scale circulation of the atmosphere, an interaction that is particularly difficult to simulate in climate models.

  • Paper: Singh, M. S., Warren, R. A., & Jakob, C. ( 2019). A steady‐state model for the relationship between humidity, instability, and precipitation in the tropics. Journal of Advances in Modeling Earth Systems, 11.