Data gap reported in MetOffice contribution to C3S seasonal forecast for March 2021

A data gap in MetOffice's GloSea6 forecast data has been reported as "Data gap G5" in C3S Seasonal Forecast known issues

  • No data is available from MetOffice GloSea6 (system=600) for the following start dates: 22 and 23 February 2021
  • An issue with assimilation of sea-ice data was reported by the MetOffice affecting forecasts initialised on 22 and 23 February 2021. Due to the potential impact of that wrong sea-ice initialisation throughout the forecast, those start dates haven't been processed by C3S.


More details here

The GloSea6 forecasts initialised on 22 and 23 February were initialised with low Arctic sea ice extents. This resulted from corrupt data used in the derivation of ocean initial conditions. The sea ice largely recovers in these forecasts, but is biased low through the whole 6-month forecast compared to neighbouring days.

Initial sea-ice conditions for different GloSea6 February 2021 start dates:


Evolution of sea-ice fraction forecasts for different GloSea6 February 2021 start dates: