The ER-2 Meteorological Measurement System provides accurate in-situ measurements of atmospheric state variables. During the Airborne Arctic Stratospheric Expedition (AASE) the ER-2 flew over the polar region on 14 occasions in January and February, 1989. Vertical temperature profiles, during aircraft takeoff at ≈60¿N and during mid-flight descent and ascent at high latitudes, are presented. Latitudinal variations of the horizontal wind measurement are illustrated and discussed. Based on observational data, model atmospheres at 60¿ and 75¿N, representative of the environment of the AASE campaign, are developed. ¿ American Geophysical Union 1990