Update to ASCAT Level 1 processing

NOTE: Update of the ASCAT regional wind products will take place on 16 January 2023.

The new version of the ASCAT operational processor will introduce the following changes:

• Addition of the Land Contribution Ratio (LCR). This parameter uses the shape and orientation of the Spatial Response Function (SRF) to estimate the impact of backscatter from land surfaces on the ocean signal in coastal regions.
• Improvements to the Level-1 product flagging. The product flags have been consolidated into a single flag field for all Level-1 products.

This update will affect ASCAT Level 1 global data and ASCAT regional wind products, as listed below:

Global data:

• ASCAT Level 1 Sigma0 Full Resolution
• ASCAT Level 1 Sigma0 resampled at 12.5km Swath Grid
• ASCAT Level 1 Sigma0 resampled at 25km Swath Grid

Regional data:

• ASCAT Coastal Winds at 12.5km - Metop - Regional Data Service
• ASCAT Ocean Surface Winds at 25km Node Grid — Metop - Regional Data Service

It will also affect the ASCAT Coastal Winds at 12.5km generated by the OSI SAF.

The new input data containing the Land Contribution Ratio (LCR) will allow to retrieve winds closer to the coast. The minimum distance of winds to the coast will be reduced from approximately 20km in the current products to 10–15km in the updated products. More information can be found in this technical report.

Test data for the updated ASCAT L1 global data and ASCAT regional wind products are available on our SFTP server: https://sftp.eumetsat.int/public/folder/UsCVknVOOkSyCdgpMimJNQ/User-Materials/Test-Data/ASCAT_PPFv11.3/

The ASCAT Level 1 Product Format Specification has further details.

A Product Validation Report will be made available in the future.

For more information, contact our User Service Helpdesk.