Objective The scientific objectives of CHELOSBA to investigate are: - the seasonal and diurnal cycle of the NOy partitioning at various height in the mid-latitudes. In this respect, two major questions remain to answer: (a) How well is the NOy budget described by considering the species NO, NO2, NO3, N2O5, HNO2, HNO3, HO2NO2, ClONO2 and BrONO2? (b) Is the heterogeneous conversion of HO2NO2 into HNO2 at night and the subsequent photolysis of HNO2 in the early morning hours an important stratospheric OH-source? - the seasonal cycle of the Cly partitioning at various heights and latitudes in particular the annual cycle of the stratospheric HCl/ClONO2 ratio - the CH4 oxidation by measurement of the CH4/CH2O ratio. Derivation of the stratospheric OH concentration. - the potential impacts of iodine-containing species on the stratospheric ozoneThe work programme proposed comprises totally eleven balloon flights with two different kinds of payloads, intended to become flown at Leon/Spain, Gap/France and Kiruna/Sweden during spring, summer and late winter, respectively. Two different balloon payloads will be used for the measurements: 1. The LPMA gondola, which will accommodate the LPMA absorption FTIR together with the IUP UVvisible spectrometer. 2. The MIPAS gondola, which will accommodate the MIPAS emission FTIR. The photochemical information obtained will be interpreted with 3-D model calculation (SLIMCAT and TOMCAT) of the University of Cambridge. The meteorological support for the flight planning and the post flight data interpretation will be given by NILU and the Free University of Berlin meteorological groups. The data obtained within the project will be delivered to the ZARDOZ computer, and access will be given to any colleagues who have signed the data protocol. Fields of science natural sciencesearth and related environmental sciencesatmospheric sciencesnatural scienceschemical scienceselectrochemistryelectrolysis Programme(s) FP4-ENV 2C - Specific programme of research and technological development in the field of environment and climate, 1994-1998 Topic(s) 01020101 - Stratospheric chemistry and depletion of the ozone layer Call for proposal Data not available Funding Scheme CSC - Cost-sharing contracts Coordinator RUPRECHT-KARLS-UNIVERSITAET HEIDELBERG EU contribution No data Address Im Neuenheimer Feld 229 69117 HEIDELBERG Germany See on map Total cost No data Participants (4) Sort alphabetically Sort by EU Contribution Expand all Collapse all Centre National de la Recherche Scientifique (CNRS) France EU contribution No data Address 4 place Jussieu 75252 Paris See on map Total cost No data FORSCHUNGSZENTRUM KARLSRUHE GMBH - TECHNIK UND UMWELT Germany EU contribution No data Address 5,Hermann von Helmholtz Platz 1 76344 EGGENSTEIN-LEOPOLDSHAFEN See on map Total cost No data NORWEGIAN INSTITUTE FOR AIR RESEARCH Norway EU contribution No data Address Instituttveien 18 2027 KJELLER See on map Total cost No data THE CHANCELLOR, MASTERS AND SCHOLARS OF THE UNIVERSITY OF CAMBRIDGE United Kingdom EU contribution No data Address Trinity Lane, The Old Schools, CB2 1TN CAMBRIDGE See on map Total cost No data