SENSITIVITY OF THE RESIDUAL CIRCULATION DIAGNOSED FROM THE UARS DATA TO THE UNCERTAINTIES IN THE INPUT FIELDS AND TO THE INCLUSION OF AEROSOLS

The simultaneous measurements of temperature, aerosol extinction, and concentrations of radiatively active gases by several instruments aboa rd the Upper Atmosphere Research Satellite permit an assessment of the uncertainties in the diagnosed stratospheric heating rates and in the resulting residual circulation. In this paper, measurements taken by the Cryogenic Limb Array Etalon Spectrometer (CLAES) are used to compu te the circulation and to compare it against values obtained previousl y from the measurements obtained by the Microwave Limb Sounder (MLS). There is a broad agreement between the two sets of calculations and kn own biases in either CLAES or MLS ozone and temperature measurements a re found to be responsible for the areas of disagreement. The inclusio n of aerosols has improved the estimates of the residual circulation i n the lower stratosphere during the 1992-93 period covered by CLAES. P resent estimates of the aerosol heating are significantly different fr om those found in other studies, probably as a result of differences i n the treatment of tropospheric clouds and in the adopted vertical pro files of aerosol extinction. Moreover, a large uncertainty in these es timates is caused by the uncertainties in the assumed refractive indic es for sulfuric acid solutions.