Upcoming change in land mask for OSI SAF ASCAT 12.5 km winds - postponed to 5 December

The land mask update has been postponed by two days, to Thursday 5 December.

--- original message ---

On Tuesday, 3 December, the level 1b processing for ASCAT will be updated; these level 1b data are input to the OSI SAF 12.5 km coastal wind products (OSI-104-b, OSI-104-c). A new land mask will be used to compute the Land Contamination Ratio (LCR). The main impact of this update is an improvement of the land sea mask which will correct the location of some smaller islands and other coastlines. More information can be found on https://user.eumetsat.int/news-events/news/update-of-the-ascat-level-1-processing.

We have assessed the impact of the change on the wind products, and compared winds retrieved using the old and new land masks. We found that the new land mask is slightly more conservative, in some regions there are less winds very close to the coast. For the cases where both the old and new land mask yield a wind retrieval, the wind characteristics are very similar.

For the 25 km OSI SAF ASCAT wind products a different land masking is used, hence this change will have no impact on the 25 km winds.