## A simple model for surface stress and low-level flow in the tropical
atmosphere driven by prescribed heating

**J. David Neelin **

Quart. J. Roy. Meteor. Soc., 1988.

**Abstract.**
A simple model is developed for time-mean, large-scale flow in the tropical
boundary layer forced by vertical velocity at the top of the boundary layer.
The model is formulated as an integral over the boundary layer and is
closed by assuming the stress to be proportional to the boundary layer mass
transport. Since vertical velocity is closely related to diabatic heating in
the tropics, the model can also be forced by latent heating as measured by
precipitation. In this case, the model can be made equivalent to the widely
used Matsuno-Gill model by adding a Newtonian cooling term. This term can be
shown to have little effect on the zonally asymmetric component of the flow
and, in its absence, the boundary layer flow is decoupled from the flow at
upper levels. It is suggested that the success of the Gill model for low-level
flow is due to this effective decoupling. The model is quite successful at
simulating GCM results for both the total climatology and El Niño anomalies.
A second model, which takes into account some effects of vertical structure
in the boundary layer, is also presented. The zonally symmetric component of
the flow is shown to be poorly reproduced in these models.

**Citation. **
Neelin, J. D., 1988: A simple model for surface stress and low-level flow
in the tropical atmosphere driven by prescribed heating.
Quart. J. Roy. Meteor. Soc., **114**, 747-770.