In this paper we report radiometric measurements of tropospheric brightness temperatures obtained during the AASE II experiment. These measurements represent the first attempt to characterize effective radiative temperatures as seen from the troposphere during the Arctic winter. The reported measurements include brightness temperatures at 6.7 and 10.5 &mgr;m as seen from the NASA DC-8 aircraft flying at about 11 km altitude. We also present radiative transfer calculations to estimate the effect of tropospheric brightness temperature on the lower stratospheric heating rates. Because of the recent massive eruption of the Pinatubo volcano, we also discuss the effects of a volcanic aerosol layer. It is concluded that small particles like the volcanic aerosol or PSCs type 1 do not affect stratospheric heating rates by much; on the other hand, larger particles, PSCs types 2 and 3, may have significant effects on heating rates and consequently on dynamics of the lower stratosphere. The dynamical effects of local stratospheric temperature variations are briefly discussed. ¿ American Geophysical Union 1993