Millimeterwellenradiometrische Messung stratosphärischer Spurengase auf Grönland : Aufbau und Inbetriebnahme des neuen RAMAS-Radiometers

Abstract

This work discusses the development and deployment of the new ground-based millimeter wave radiometer RAMAS at Summit, Central Greenland. It detects rotational molecule spectra within the frequency range of 265 - 281 GHz, which can be used to retrieve atmospheric trace gas profiles. Summit Camp at the top of the greenlandic ice cap has been chosen due to its excellent measurement conditions. The very cold and very dry atmosphere and a state-of-the-art receiver allows to measure high quality spectra within short measurement times. It is planned to detect diurnal changes of the volume mixing ratios of several trace gases like HCN, HNO:sub:3:/sub:, O:sub:3:/sub:, N:sub:2:/sub:O and ClO. The RAMAS instrument has been developed at the University of Bremen within an EU projectin cooperation with the University of Bordeaux, the University of Leeds, the Danish Meteorological Institute and the Naval Research Laboratories. :p:The radiometer system is described in detail. The main parts like frontend and backend and their integration are shown. The frontend covers the quasi-optical parts, the backend comprises the signal amplification and the real time spectrometer. The measurementcomputer controls the complete operation of the instrument and records the measurements. In addition, it offers remote radiometer operation.:p:This thesis also covers the developement of the RAMAS container, which is designed for the extreme environmental conditions found at Summit. :p:The deployment of the radiometer is described in the final part of this work. The Instrument has been calibrated and first measurements of the 273 GHz ozone line have been done. Very good spectra have been measured using short integration times. A volume mixing ratio profile retrieval has been sucessfully performed using the atmosphericradiative transfer model ARTS and the retrieval software QPack.