Data error reported in CMCC SPSv3.5 contribution to C3S seasonal forecasts from March 2022

An error has been identified in "sea surface temperature" and "land surface temperature" (called 'soil temperature level 1' in the CDS) data from CMCC SPSv3.5 forecasting system. The details can be found in the section "Not fixed errors" under the code E9 of our "Known issues" page

It affects the following data for those two variables:

  • forecast data (daily data, monthly data and anomalies) for nominal start dates March, April, May, June and July 2022

According to CMCC report about the issue:

The problem only affects the points at the borders between the three realms (sea ice, ocean and land), and is due to a change in the land-sea or sea ice-sea mask interpolation algorithm, which was implemented in the forecasts (starting from March).
Therefore, the anomalies of the above mentioned variables show unrealistic patterns near the sea-land or sea-sea ice boundaries, because, in these grid points, the new interpolation algorithm has made the forecasts, from March onwards, inconsistent with the hindcasts.
Starting from the August 2022 real-time forecast, it will be restored the procedure used in the hindcasts.