Data products
ASCAT calibration monitoring
This page provides monitoring information on a monthly basis concerning the product calibration for the near-real time 25 km ASCAT winds on Metop-A, Metop-B and Metop-C. Mean monthly values of selected parameters are plotted as a function of time. The wind speed bias is computed against the wind forcasts of the operational ECMWF Numerical Weather Prediction model. For the NWP Ocean Calibration residuals, a separate plot is shown for each antenna. The user may choose to view the plots of the last year (here below) or the long term plots since 2013 (further below, click here).

For the Cone Metrics residuals, a plot of the residuals of last month is shown below (click here). Residuals are calculated against a reference, for which ASCAT-B data of 2013 is chosen. Other than NWP Ocean Calibration, Cone Metrics relies only on backscatter data, and does not depend on ECMWF winds and GMF. The advantage is that any anomaly seen by Cone Metrics can be attributed to an instrumental cause.

The monitoring of relevant quality parameters as a function of time yields a sensitive method of detecting deviations of normal operation. Deviations in product quality usually appear as a step in one or more of the plots. It can be checked if they are connected to an update of the wind product in the 'Modifications/anomalies' section on the main page of the specific product viewer (see links on the right hand side).

The NWP Ocean Calibration method is described in:
Verspeek, J., A. Stoffelen, A. Verhoef and M. Portabella, Improved ASCAT Wind Retrieval Using NWP Ocean Calibration
IEEE Transactions on Geoscience and Remote Sensing, 2012, 50, 7, 2488-2494, doi:10.1109/TGRS.2011.2180730.

The Cone Metrics method is described in:
Belmonte Rivas, M., A. Stoffelen, J. Verspeek, A. Verhoef, X. Neyt and C. Anderson, Cone Metrics: A New Tool for the Intercomparison of Scatterometer Records
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2017, 10, 5, 2195-2204, doi:10.1109/JSTARS.2017.2647842.
Plots of the last year
Plots since 2013
Cone Metrics residuals of the last month
Further information
Please contact the KNMI OSI SAF team.


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Discontinued Wind Products
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