The Assimilation of Envisat data (ASSET) project

Abstract. MIPAS, the Michelson Interferometer for Passive Atmospheric Sounding, is a mid-infrared emission spectrometer which is part of the core payload of ENVISAT. It is a limb sounder, i.e. it scans across the horizon detecting atmospheric spectral radiances which are inverted to vertical temperature, trace species and cloud distributions. These data can be used for scientific investigations in various research fields including dynamics and chemistry in the altitude region between upper troposphere and lower thermosphere.The instrument is a well calibrated and characterized Fourier transform spectrometer which is able to detect many trace constituents simultaneously. The different concepts of retrieval methods are described including multi-target and two-dimensional retrievals. Operationally generated data sets consist of temperature, H 2 O, O 3 , CH 4 , N 2 O, HNO 3 , and NO 2 profiles. Measurement errors are investigated in detail and random and systematic errors are specified. The results are validated by independent instrumentation which has been operated at ground stations or aboard balloon gondolas and aircraft. Intercomparisons of MIPAS measurements with other satellite data have been carried out, too. As a result, itCorrespondence to: H. Fischer (herbert.fischer@imk.fzk.de) has been proven that the MIPAS data are of good quality.MIPAS can be operated in different measurement modes in order to optimize the scientific output. Due to the wealth of information in the MIPAS spectra, many scientific results have already been published. They include intercomparisons of temperature distributions with ECMWF data, the derivation of the whole NO y family, the study of atmospheric processes during the Antarctic vortex split in September 2002, the determination of properties of Polar Stratospheric Clouds, the downward transport of NO x in the middle atmosphere, the stratosphere-troposphere exchange, the influence of solar variability on the middle atmosphere, and the observation of Non-LTE effects in the mesosphere.

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“…The MIPAS data are also self-consistent as shown by the data assimilation project AS-SET (Lahoz et al, 2007).…”

Section: The Esa Workhops On Validation In May 2004 and December 200mentioning

confidence: 95%

MIPAS: an instrument for atmospheric and climate research

Fischer¹,

Birk

Blom³

et al. 2008

Atmos. Chem. Phys.

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692

625

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“…In the troposphere, RH provides a better representation of clouds and precipitation; in the stratosphere, RH has very low values, which makes specific humidity better suited. The choice of water vapour control variable is being discussed in the literature (Hólm et al 2002;Dee and da Silva 2003;Lahoz et al 2007b). Lahoz et al (2007b) also discusses the quality of humidity analyses.…”

Section: Results From Wg2: Ozone and Humidity Analysesmentioning

confidence: 99%

“…Nieradzik and Elbern, 2006;Lahoz et al, 2007b). Recent reviews of constituent data assimilation have been provided by Lary (1999), Khattatov (2003) and Rood (2005).…”

Section: Wg2: An Assimilated Ozone and Humidity Datasetmentioning

confidence: 99%

“…ECMWF: Dethof, 2003) has become routine. A notable feature of the application of the data assimilation methodology to stratospheric constituents has been the strong interaction between the NWP and research communities, for example, in the EU-funded ASSET project (http://darc.nerc.ac.uk/asset; Lahoz et al, 2007b), in which the WG2 participants were strongly involved.…”

Section: Wg2: An Assimilated Ozone and Humidity Datasetmentioning

confidence: 99%

“…Recent reviews of constituent data assimilation have been provided by Lary (1999), Khattatov (2003) and Rood (2005). Lahoz et al (2007b) provide an overview of data assimilation work performed as part of the ASSET project; Lahoz et al (2007a) provide a review of stratospheric constituent data assimilation which builds on the Rood review and describes recent results, including those achieved within the ASSET project.…”

Section: Wg2: An Assimilated Ozone and Humidity Datasetmentioning

confidence: 99%

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The COST 723 Action

Lahoz

Buehler

Legras

2007

Q.J.R. Meteorol. Soc.

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An overview is provided of the COST 723 Action, 'Data Exploitation and Modelling of the Upper Troposphere and Lower Stratosphere'. The three working groups are introduced and a summary of Action activities within them is provided. The achievements of the Action are: three international workshops; the LAUTLOS humidity measurement campaign; dedicated meetings to discuss the quality of upper troposphere/lower stratosphere ozone and humidity measurements; two journal special issues; more than 90 papers in the peer-reviewed literature; one international summer school; and a successor COST Action which builds on COST 723. The recommendations made are: for COST to continue to support the short-term scientific missions instrument, as they are perceived to be value for money; to encourage the use of COST money to increase links between COST Actions and other scientific communities; and for the COST secretariat to recommend that Actions consider a summer school instead of a final workshop or meeting.

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Ten years of ENVISAT observations at ECMWF: A review of activities and lessons learnt

Dragani

Abdalla

Engelen

et al. 2014

Quart J Royal Meteoro Soc

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In 2002, the European Space Agency (ESA) launched the ENVIromental SATellite (ENVISAT), which carried ten instruments to provide continuous observation of Earth's land, atmosphere, oceans and ice caps. During the satellite's lifetime, the European Centre for Medium Range Weather Forecasts (ECMWF) has routinely monitored a variety of products from many of its instruments. A subset of these data has also been assimilated in the ECMWF operational system, along with two of its applications: the reanalysis and the Monitoring Atmospheric Composition and Climate (MACC) systems. This article reviews those activities and summarizes the lessons learnt in monitoring and assimilating data from a research satellite within a numerical weather prediction system. The value of continuous data monitoring and the benefits that a close collaboration between data provider and data user can bring to both parties are highlighted. For observations that were assimilated, impact assessments on the ECMWF products have been performed periodically. Two cases are presented in this article. The first one shows that the assimilation of ocean wave information can reduce the wave-height model random error by up to 8% at the analysis time, with benefits at later forecast times extending to up to 5 days in the Tropics. The second example shows that the assimilation of two ENVISAT ozone products improves the agreement of the ozone analyses with independent ozone observations obtained from sondes and the Microwave Limb Sounder. Finally, the use of ENVISAT reprocessed data is presented, with an emphasis on the importance of data reprocessing and long-term data preservation as key activities to ensure the future usage of these datasets.

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The Assimilation of Envisat data (ASSET) project

Cited by 34 publications

References 66 publications

MIPAS: an instrument for atmospheric and climate research

MIPAS: an instrument for atmospheric and climate research

The COST 723 Action

Ten years of ENVISAT observations at ECMWF: A review of activities and lessons learnt

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