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Abstract
Since August 2005, RAMSES, the Raman lidar for atmospheric moisture sensing, has been monitoring the water vapor field and clouds above the Richard Aßmann Observatory of the German Meteorological Service at Lindenberg. Although measurements of high quality were obtained on a routine basis, their range of application was limited because, (1) the lidar operated only at night, and (2) the set of measured parameters was restricted to water vapor mixing ratio, particle backscatter coefficient and extinction coefficient. To overcome these limitations, the RAMSES receiver has been upgraded this year to permit also observations of temperature and depolarization ratio, and to allow of daytime observations. Temperature profiles of the troposphere and the stratosphere are determined by combining the rotational Raman technique with the Rayleigh and Raman integration techniques. For the detection of the rotational Raman signals a new beamsplitter/interference filter receiver design has been implemented which is more compact and robust, and easier to align and optimize than previous experimental setups. Accurate measurements of depolarization ratio require a careful calibration of the lidar raw data. The new receiver is designed to allow of two independent methods for this purpose. In this conference contribution, an overview of the optical layout of the RAMSES receiver is given. Furthermore, the necessary modifications to the operational system control, and to the signal processing software are summarized. First measurements are presented to illustrate the data quality of RAMSES.