We have carried out a series of calculations with a one-dimensional, time-marching, radiative-convective model to assess the impact of the El Chichon volcanic cloud on the radiation budget of the northern tropics during the 6-month period following the injection of volcanic material into the stratosphere. Extensive measurements of the cloud obtained from airborne, spacecraft, and gorund platforms were used to define the model parameters and to test the predictions of the model. The El Chichon cloud is predicted to have caused an increase in planetary albedo of 10% a decrease in total solar radiation of 2-3% at the ground on cloudless days and an increase in temperature of 3.5 K at the 24 km (30 mb) level. These predictions are compatible with relevant observations, within their respective error bars. |