Articles | Volume 9, issue 4
Atmos. Meas. Tech., 9, 1533–1544, 2016

Special issue: GOME-2: calibration, algorithms, data products and...

Atmos. Meas. Tech., 9, 1533–1544, 2016

Research article 07 Apr 2016

Research article | 07 Apr 2016

Validation of GOME-2/Metop total column water vapour with ground-based and in situ measurements

Niilo Kalakoski1, Jukka Kujanpää1, Viktoria Sofieva1, Johanna Tamminen1, Margherita Grossi2, and Pieter Valks2 Niilo Kalakoski et al.
  • 1Finnish Meteorological Institute, Helsinki, Finland
  • 2Institut für Methodik der Fernerkundung (IMF), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Oberpfaffenhofen, Germany

Abstract. The total column water vapour product from the Global Ozone Monitoring Experiment-2 on board Metop-A and Metop-B satellites (GOME-2/Metop-A and GOME-2/Metop-B) produced by the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) is compared with co-located radiosonde observations and global positioning system (GPS) retrievals. The validation is performed using recently reprocessed data by the GOME Data Processor (GDP) version 4.7.

The time periods for the validation are January 2007–July 2013 (GOME-2A) and December 2012–July 2013 (GOME-2B). The radiosonde data are from the Integrated Global Radiosonde Archive (IGRA) maintained by the National Climatic Data Center (NCDC). The ground-based GPS observations from the COSMIC/SuomiNet network are used as the second independent data source.

We find a good general agreement between the GOME-2 and the radiosonde/GPS data. The median relative difference of GOME-2 to the radiosonde observations is −2.7 % for GOME-2A and −0.3 % for GOME-2B. Against the GPS, the median relative differences are 4.9 % and 3.2 % for GOME-2A and B, respectively. For water vapour total columns below 10 kg m−2, large wet biases are observed, especially against the GPS retrievals. Conversely, at values above 50 kg m−2, GOME-2 generally underestimates both ground-based observations.