Institute of Meteorology and Climate Research - Atmospheric Trace Gases and Remote Sensing (IMK-ASF)

MUSICA IASI full retrieval product standard output (processing version 3.2.1)

Example of daily MUSICA IASI data coverage: CH4 at 11km a.s.l. on 1. August 2018

Data download:


Terms of data use:

The data are provided with the license: CC BY 4.0 Attribution.


Data format:

The product is provided in form of the MUSICA IASI full retrieval product standard output data format. This are netcdf data files compliant with version 1.7 of the CF (Climate and Forecast) metadata convention. The data are provided orbit wise, i.e. for each orbit there is an individual data file. The file name is 'IASI[S]_MUSICA_[V]_L2_AllTargetProducts_[D]_[O].nc'. The symbols within the edged parenthesis indicate placeholders: '[S]' for the IASI sensor (A or B for IASI on the satellites Metop-A or –B, respectively), '[V]' for the used MUSICA IASI retrieval processor version (here '030201'), '[D]' for the starting date and time of the observation (Universal Time, format YYYYMMDDhhmmss), and '[O]' for the number of the orbit.

On our data base these files are provided in daily tar-files, with all orbits of all IASI instruments archived into a single tar-file, with the name IASI[multipleS]_MUSICA_[V]_L2_AllTargetProducts_[DAY].tar. The placeholders are: '[multipleS]' for the considered sensors, e.g. 'AB' if IASI sensors on Metop-A and –B are considered, '[V]' for the used MUSICA IASI retrieval processor version (here '030201'), and '[DAY]' is the date of the observations (Universal Time, format YYYYMMDD).


Data volume:

The typical size of a single orbit file is about 540 MB.

Per day a Metop satellite completes 14 orbits. For the period used for the version 3.2.1 processing Metop-A and -B have been in operation, i.e. two satellites and thus 28 orbits per day. The typical size of a tar-file with all individual orbit wise netcdf files of a single day (typically 28 orbits) is 15 GB.

The time period between October 2014 and June 2019 (time period with version 3.2.1 processing) consists of more than 1700 days and the total data volume of this data set is more than 25 TB.



IASI (Infrared Atmospheric Sounding Interferometer) is the core instrument of the currently three Metop satellites of EUMETSAT (European Organization for the Exploitation of Meteorological Satellites). The MUSICA IASI processing has been developed in the framework of the European Research Council project MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water). The processor performs an optimal estimation of the vertical distributions of H2O, the ratio HDO/H2O, N2O, CH4, and HNO3, and works with IASI radiances measured for cloud-free conditions in the spectral window between 1190 and 1400 cm-1. Currently, the MUSICA IASI processing with version 3.2.1 has been applied to all IASI measurements available between October 2014 and June 2019, which means that more than 1 billion individual retrievals have been performed. 

The data set is provided in form of netcdf data files that are compliant with version 1.7 of the CF (Climate and Forecast) metadata convention. It contains full information on retrieval settings (a priori usage and constraints) and retrieval inputs (including the measured IASI radiances and some results for the EUMETSAT level 2 processing). It provides the full MUSICA IASI retrieval output: the atmospheric trace gas and temperature profiles, profiles of the leading error components, information on vertical representativeness in form of the averaging kernels as well as averaging kernel metrics, which are more handy than the full kernels and can be used for filtering out data with irregular sensitivity and/or vertical representativeness.

The supply of the comprehensive information on the retrieval settings and retrieval products' characteristics results in a rather large data volume. This apparent drawback of large data files is counterbalanced by the very good possibilities for data interoperability and reusability offered by this comprehensive information.


Archiving information:

This data set is archived at bwDataArchive, a long-term data archive for scientific data. The German federal state service bwDataArchive offers a solution for long-term data archiving, which is especially available for employees of universities and public research institutions in Baden-Württemberg. Data archiving is carried out at the Karlsruhe Institute of Technology (KIT) and includes reliable storage of even large data sets for a period of ten or more years. The service enables a qualified implementation of the recommendations of the German Research Foundation (DFG) for the securing and storage of research data.