Measurement of the tropical UTLS composition in presence of clouds using millimetre-wave heterodyne spectroscopy
1Istituto di Scienze dell'Atmosfera e del Clima – CNR, Bologna, Italy
2Istituto di Fisica Applicata "N. Carrara" – CNR, Florence, Italy
3"Millimetre-wave Technology Group" RAL, Oxfordshire, UK
4"Remote Sensing Group" RAL, Oxfordshire, UK
5Institut für Meteorologie und Klimaforschung, Forschungszentrum Karlsruhe, Germany
*now at: Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA) CNRS/Université de Paris 12 et 7, France
Abstract. The MARSCHALS (Millimetre-wave Airborne Receiver for Spectroscopic CHaracterisation of Atmospheric Limb-Sounding) project has the general objectives of demonstrating the measurement capabilities of a limb viewing instrument working in the millimetre and sub-millimetre spectral regions for the study of the Upper Troposphere – Lower Stratosphere (UTLS). MARSCHALS has flown on board the M-55 stratospheric aircraft (Geophysica) in two measurements campaigns. Here we report the results of the analysis of MARSCHALS measurements during the SCOUT-O3 campaign held in Darwin (Australia) in December 2005 obtained with MARC (Millimetre-wave Atmospheric-Retrieval Code). MARSCHALS measured vertical distributions of Temperature, water vapour, ozone and nitric acid. The retrieval has been performed in the altitude range from 10 to 20 km in presence of clouds that obscure measurements in the middle infrared spectroscopic region. The minimum altitude range is determined by the high water concentration typical of the tropical region rather than the extensive cloud coverage experienced during the flight. The results have been validated using a few measurement made in less cloudy conditions by MIPAS-STR, an infrared limb-viewing instrument on board the M-55 during the same flight.