Validation of MIPAS-ENVISAT NO2 operational data

• Main Authors: Wetzel, G., Bracher, A., Funke, B., Goutail, Florence, Hendrick, F., Lambert, J.-C., Mikuteit, S., Piccolo, C., Pirre, Michel, Bazureau, Ariane, Belotti, C., Blumenstock, T., de Mazière, M., Fischer, H., Huret, Nathalie, Ionov, D., López-Puertas, M., Maucher, G., Oelhaf, H., Pommereau, Jean-Pierre, Ruhnke, R., Sinnhuber, M., Stiller, G., van Roozendael, M., Zhang, G.
• Other Authors: Institute for Meteorology and Climate Research (IMK), Karlsruhe Institute of Technology = Karlsruher Institut für Technologie (KIT), Institute of Environmental Physics and Remote Sensing Bremen (IUP/IFE), University of Bremen, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Cientificas España = Spanish National Research Council Spain (CSIC), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), University of Oxford, Laboratoire de physique et chimie de l'environnement (LPCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Istituto di Fisica Applicata "Nello Carrara" (IFAC), National Research Council of Italy
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarc*; Antarctic; polar night
• Online Access: https://hal.science/hal-00328049; https://hal.science/hal-00328049/document; https://hal.science/hal-00328049/file/acpd-7-3333-2007.pdf; https://doi.org/10.5194/acpd-7-3333-2007

International audience The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument was launched aboard the environmental satellite ENVISAT into its sun-synchronous orbit on 1 March 2002. The short-lived species NO2 is one of the key target products of MIPAS that are operationally retrieved from limb emission spectra measured in the stratosphere and mesosphere. Within the MIPAS validation activities, a large number of independent observations from balloons, satellites and ground-based stations have been compared to European Space Agency (ESA) version 4.61 operational NO2 data comprising the time period from July 2002 until March 2004 where MIPAS measured with full spectral resolution. Comparisons between MIPAS and balloon-borne observations carried out in 2002 and 2003 in the Arctic, at mid-latitudes, and in the tropics show a very good agreement below 40 km altitude with a mean deviation of roughly 3%, virtually without any significant bias. The comparison to ACE satellite observations exhibits only a small negative bias of MIPAS which appears not to be significant. The independent satellite instruments HALOE, SAGE II, and POAM III confirm in common for the spring-summer time period a negative bias of MIPAS in the Arctic and a positive bias in the Antarctic middle and upper stratosphere exceeding frequently the combined systematic error limits. In contrast to the ESA operational processor, the IMK/IAA retrieval code allows accurate inference of NO2 volume mixing ratios under consideration of all important non-LTE processes. Large differences between both retrieval results appear especially at higher altitudes, above about 50 to 55 km. These differences might be explained at least partly by non-LTE under polar winter conditions but not at mid-latitudes. Below this altitude region mean differences between both processors remain within 5% (during night) and up to 10% (during day) under undisturbed (September 2002) conditions and up to 40% under perturbed polar night conditions (February and ...