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Abstract
Abstract. Rayleigh lidar temperature profiles have been derived in the polar middle atmosphere from 834 measurements with the ALOMAR Rayleigh/Mie/Raman lidar (69.3° N, 16.0° E) in the years 1997–2005. Since our instrument is able to operate under full daylight conditions, the unique data set presented here extends over the entire year and covers the altitude region 30 km–85 km in winter and 30 km–65 km in summer. Comparisons of our lidar data set to reference atmospheres and ECMWF analyses show agreement within a few Kelvin in summer but in winter higher temperatures below 55 km and lower temperatures above by as much as 25 K, due likely to superior resolution of stratospheric warming and associated mesospheric cooling events. We also present a temperature climatology for the entire lower and middle atmosphere at 69° N obtained from a combination of lidar measurements, falling sphere measurements and ECMWF analyses. Day to day temperature variability in the lidar data is found to be largest in winter and smallest in summer.
Highlights
The polar middle atmosphere has received much attention because it harbours many different phenomena like polar stratospheric clouds, noctilucent clouds, stratospheric warmings, mesospheric inversion layers and gravity waves
We present a temperature climatology for the entire lower and middle atmosphere at 69◦ N obtained from a combination of lidar measurements, falling sphere measurements and European Centre for Medium-Range Weather Forecasts (ECMWF) analyses
During polar summer the mesopause region features the lowest temperatures occurring in the atmosphere falling to below 130 K
Summary
The ALOMAR Rayleigh/Mie/Raman (RMR) lidar was installed on the island of Andøya (69.28◦ N, 16.01◦ E) in Northern Norway in summer 1994. B18 m at 100 km altitude) at all times is needed for accurate determination of atmospheric temperatures with the RMR lidar, an automatic beam stabilisation system has been developed which uses a camera to observe the position of the laser beam in the FOV at 1 km distance and moves the last laser beam guiding mirror to keep the laser beam centred inside the FOV (Schöch and Baumgarten, 2003) This allows for very stable measurements even in marginal weather conditions when the telescope structure deforms due to heating by sunlight which can vary quickly due to tropospheric clouds. Since the major commitment of the RMR lidar team has been to noctilucent cloud measurements in summer and polar stratospheric cloud measurements in winter, the measurement efforts were concentrated on these seasons which is visible in the measurement distribution Another reason for the gaps in spring and autumn is the weather which is dominated by overcast weather at ALOMAR during these times of the year.
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