Sensitivity of Stratospheric Forecasts to Tropospheric Forecast

Abstract

 The sensitivity of stratospheric forecasts to tropospheric forecasts is investigated using the UCLA GCM. For this purpose, forecasts for the major stratospheric sudden warming of February 1979 are compared to “forecasts” from identical initial conditions but with selected components of the tropospheric fields periodically replaced by the observed. The comparison shows that the accuracy of stratospheric forecasts can be drastically improved when errors in the tropospheric forecast, particularly in the zonal mean flow, are reduced.