Abstract
Abstract. MARSCHALS (Millimetre-wave Airborne Receivers for Spectroscopic CHaracterisation in Atmospheric Limb Sounding) is a limb viewing instrument working in the millimetre and sub-millimetre spectral regions (from 294 to 349 GHz). The scientific rationale of MARSCHALS is the study of the Upper Troposphere and Lower Stratosphere region. In March 2010 MARSCHALS was deployed on-board the M-55 Geophysica stratospheric aircraft during the PREMIER(PRocess Exploration through Measurements of Infrared and millimetre-wave Emitted Radiation)-Ex field campaign. From the campaign base at Kiruna, Sweden, a research flight to investigate the Arctic atmosphere was conducted. For the first time the instrument fully exploited the three spectral bands. In this paper, we present results of the analysis of MARSCHALS measurements acquired during the PREMIER-Ex flight as processed by the Millimetre-wave Atmospheric Retrieval Code. For the second time after the SCOUT-O3 flight in 2005, MARSCHALS measured vertical distributions of temperature, water vapour, ozone and nitric acid over an altitude range of 4 to 24 km. In addition, vertical profiles of carbon monoxide and nitrous oxide were obtained for the first time. The measurements were performed in clear sky conditions and in presence of low and high altitude clouds (that were able to obscure measurements in the middle infrared spectroscopic region) and some information about thick clouds were extracted from the data. The capabilities to derive information on upper tropospheric and lower stratospheric vertical profiles of temperature and minor constituents from millimetre-wave limb sounding observations in the northern polar region are presented and discussed for each of the individual targets. The results of MARSCHALS data analysis contributed to demonstrate the scientific relevance and technical feasibility of millimetre-wave limb-sounding of the UTLS proposed for the ESA Earth Explorer 7 candidate Core Mission PREMIER. PREMIER was not selected at the end of the Earth Explorer 7 evaluation process, but it is still being considered for future launch opportunities.
Highlights
The Upper Troposphere and Lower Stratosphere (UTLS) is a pivotal region of the Earth’s atmosphere
We presented the results from the data analy- individual measurements in the millimetre-wave region, sis of limb sounding observations of the Arctic UTLS, the as well as for their potential synergy with the information
The availability of all the spectral bands allowed to and middle infrared limb measurements in the UTLS was retrieve the vertical profiles of temperature, water vapour, successfully tested using MARSCHALS measurements re
Summary
The Upper Troposphere and Lower Stratosphere (UTLS) is a pivotal region of the Earth’s atmosphere. Radiative and dynamical processes that take place at these altitudes have a substantial and mutual influence on surface climate (ESA, 2012 and references therein) This atmospheric region – due to the very low temperatures of the layers immediately above and below the tropopause height – is where Essential Climate Variables (Mason, 2010) such as surface air temperature and Earth radiation budget are most sensitive to changes in the distribution of radiatively active gases and clouds. The primary scientific objective of the PREMIER mission was to gain a better understanding of the interaction processes linking atmospheric chemistry and dynamics with climate This imply the investigation of distribution and transport of trace gases and of the radiative effects of water vapour and clouds in the mid- to upper troposphere and lower stratosphere.
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