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

MUSICA IASI water isotopologue pair product (optimal estimation pair processing version 2)

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 water isotopologue pair product standard output data format. It consists of netCDF data files compliant with version 1.7 of the CF (Climate and Forecast) metadata naming convention.  The data are provided in two global files per day, one for the morning and one for the evening overpasses. Both files include Metop-A and Metop-B observations. The file name is ‘IASI[multipleS]_MUSICA_[V]_L2pp[VPP]_H2Oiso_[DAY]_[OP] The symbols within the edged parenthesis indicate placeholders: [multipleS] informs about the considered sensors (here ‘AB’ for IASI on Metop-A and -B), [V] refers to the MUSICA IASI retrieval processor version (here ‘030201’ for version 03.02.01), [VPP] refers to the water isotopologue a posteriori processing version (here ‘02’), [DAY] displays the day of the observation (Universal Time, format YYYYMMDD), and [OP] indicates the overpass (which can be ‘morning’ or ‘evening’).


Data volume:

The typical size of a global daily map for an individual overpass type is about 2 GB.

By providing two files per day, this results in around 1.5 TB per year.

The full data set comprises all Metop-A and -B observations between October 2014 and June 2019 and its full data volume is around 7 TB.



This is a global and multi-annual space-borne data set of tropospheric {H2O,δD} pairs based on radiance measurements from the nadir thermal infrared sensor IASI (Infrared Atmospheric Sounding Interferometer) onboard the Metop satellites of EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites). The data set is an a posteriori processed extension of the MUSICA (MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water) IASI full product dataset distributed as MUSICA IASI full retrieval product. The a posteriori processing guarantees H2O and δD states having almost identical and good vertical sensitivities, i.e. can be used as a {H2O,δD} pair data product.

The data are available for all cloud-free MUSICA IASI retrievals for the continuous time period between October 2014 and June 2019 and with a global coverage twice per day (local morning and evening overpass times). In total, there are more than 1200 million individual observations. The retrievals show best sensitivities for the free troposphere. Up to 30 % of all retrievals contain vertical profile information. 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 the H2O and δD vertical profile together with estimations of the leading error components, and information on the vertical representativeness in form of the averaging kernels. Averaging kernel metrics and flags indicating sensitivity and reliability (data with acceptable errors) of the data are also provided and allow a user specific filtering with respect to the data characteristics and quality.


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.