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- Title
Validation of MIPAS-ENVISAT H<sub>2</sub>O operational data collected between July 2002 and March 2004.
- Authors
Wetzel, G.; Oelhaf, H.; Berthet, G.; Bracher, A.; Cornacchia, C.; Feist, D. G.; Fischer, H.; Fix, A.; Iarlori, M.; Kleinert, A.; Lengel, A.; Milz, M.; Mona, L.; Müller, S. C.; Ovarlez, J.; Pappalardo, G.; Piccolo, C.; Raspollini, P.; Renard, J.-B.; Rizi, V.
- Abstract
Water vapour (H2O) is one of the operationally retrieved key species of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument aboard the environmental satellite ENVISAT which was launched into its sun-synchronous orbit on March 2002 and operated until April 2012. Within the MIPAS validation activities, independent observations from balloons, aircraft, satellites, and ground-based stations have been compared to European Space Agency (ESA) version 4.61 operational H2O data comprising the time period from July 2002 until March 2004 where MIPAS measured with full spectral resolution. No significant bias in the MIPAS H2O data is obvious in the lower stratosphere (above the hygropause) between about 15 and 30 km. Differences of H2O quantities observed by MIPAS and the validation instruments are mostly well within the combined total errors in this altitude region. In the upper stratosphere (above about 30 km), a tendency towards a small positive bias (up to 10 %) is present in the MIPAS data when compared to its balloon-borne counterpart MIPASB, to the satellite instruments HALOE (Halogen Occultation Experiment) and ACE-FTS Atmospheric Chemistry Experiment, Fourier Transform Spectrometer), and to the MMwave airborne sensor AMSOS (Airborne Microwave Stratospheric Observing System). In the mesosphere the situation is unclear due to the occurrence of different biases when comparing HALOE and ACE-FTS data. Pronounced deviations between MIPAS and the correlative instruments occur in the lowermost stratosphere and upper troposphere, a region where retrievals of H2O are most challenging. Altogether it can be concluded that MIPAS H2O profiles yield valuable information on the vertical distribution of H2O in the stratosphere with an overall accuracy of about 10 to 30% and a precision of typically 5 to 15% - well within the predicted error budget, proving that these global and continuous data are very valuable for scientific studies. However, in the region around the tropopause retrieved MIPAS H2O profiles are less reliable, suffering from a number of obstacles such as retrieval boundary and cloud effects, sharp vertical discontinuities, and frequent horizontal gradients in both temperature and H2O volume mixing ratio (VMR). Some profiles are characterized by retrieval instabilities.
- Subjects
WATER; ACQUISITION of data; NATURAL satellite atmospheres; STRATOSPHERE; ATMOSPHERIC chemistry; ATMOSPHERIC models; COMPARATIVE studies
- Publication
Atmospheric Chemistry & Physics Discussions, 2013, Vol 13, Issue 2, p4433
- ISSN
1680-7367
- Publication type
Article
- DOI
10.5194/acpd-13-4433-2013