Validation of version-4.61 methane and nitrous oxide observed by MIPAS
- ISSN: 1680-7324
- DOI: 10.5194/acp-9-413-2009
The ENVISAT validation programme for the atmospheric instruments MIPAS,\nSCIAMACHY and GOMOS is based on a number of balloon-borne, aircraft,\nsatellite and ground-based correlative measurements. In particular\nthe activities of validation scientists were coordinated by ESA within\nthe ENVISAT Stratospheric Aircraft and Balloon Campaign or ESABC.\nAs part of a series of similar papers on other species [this issue]\nand in parallel to the contribution of the individual validation\nteams, the present paper provides a synthesis of comparisons performed\nbetween MIPAS CH4 and N2O profiles produced by the current ESA operational\nsoftware (Instrument Processing Facility version 4.61 or IPF v4.61,\nfull resolution MIPAS data covering the period 9 July 2002 to 26\nMarch 2004) and correlative measurements obtained from balloon and\naircraft experiments as well as from satellite sensors or from ground-based\ninstruments. In the middle stratosphere, no significant bias is observed\nbetween MIPAS and correlative measurements, and MIPAS is providing\na very consistent and global picture of the distribution of CH4 and\nN2O in this region. In average, the MIPAS CH4 values show a small\npositive bias in the lower stratosphere of about 5%. A similar situation\nis observed for N2O with a positive bias of 4%. In the lower stratosphere/upper\ntroposphere (UT/LS) the individual used MIPAS data version 4.61 still\nexhibits some unphysical oscillations in individual CH4 and N2O profiles\ncaused by the processing algorithm (with almost no regularization).\nTaking these problems into account, the MIPAS CH4 and N2O profiles\nare behaving as expected from the internal error estimation of IPF\nv4.61 and the estimated errors of the correlative measurements.