A possible influence of the recent cooling trends in the polar stratosphere on the tropospheric circulation in the Northern Hemisphere winter is studied over the period from 1979 to 1992. Changes in circulation associated with cooling trends in the stratosphere are compared with those triggered by heating due to volcanic aerosols in the stratosphere, which are considered asa prototype of the atmospheric responses to an external forcing. In both cases, strengthening of t he stratospheric polar night jets are observed in early winter and perturbations in zonal-mean zonal winds propagate down into the troposphere by forming dipole type anomalies which are associated with changes in planetary waves. ¿ American Geophysical Union 1994