Systematic swath elevation and monthly DEMs over the Greenland Ice Sheet margin from CryoSat

news

07 May 2020

Land-ice is declining globally, raising sea levels worldwide and impacting glacial risks and access to fresh-water in high-mountain glaciers regions. Land-ice monitoring via Earth Observation methods in general, and altimetry in particular, are essential for tracking the current status of ice volume change and its evolution as climate continues to evolve and mitigating actions are being pursued.

In this context, ESA launched the CryoSat ThEMatic PrOducts (Cryo-TEMPO) activity that aims to support a wide variety of end-users working in the areas of sea ice, polar oceans, land ice, coastal areas and hydrology. The CryoTEMPO-EOLIS (Elevation Over Land Ice from Swath), the first of the CryoTEMPO products developed by Earthwave, The University of Edinburgh and isardSat, are now live.

The EOLIS products exploit CryoSat's SARIn mode and the novel Swath processing technique to deliver increased spatial and temporal coverage of time-dependent elevation over land ice, a critical metric for tracking ice mass trends.

The CryoTEMPO EOLIS products are the operational result of heritage research and development projects CryoTop, and CryoTop-Evolution.

The dataset consists of systematic reprocessing of the entire CryoSat archive to generate new L2-Swath products, increasing data sampling by 1 to 2 orders of magnitude compared with the operational L2 ESA product. In addition, the EOLIS dataset is joined with the ESA L2 Point-Of-Closest-Approach to generate monthly DEM (Digital Elevation Model) products. This dataset will further the ability of the community to analyse and understand trends across the Greenland Ice Sheet margin.

EOLIS DEMs
Example of DEM time-series in the Jakobshavn Isbrae region of west-Greenland showing general thinning of the ice sheet margin and revealing seasonal and long-term trends in ice thickness change.

As with all CryoTEMPO products, the EOLIS products have been created with ease of use in mind, with a concise set of fields available, including an uncertainty measure and a gridded file structure. It allows for the quick download of areas of interest, keeping downloads small and fast.

EOLIS DEMs
Extent of the EOLIS DEMs over the SARIn zone of the Greenland Ice Sheet. For this illustration, the EOLIS DEM is merged with the ESA CryoTOP Evolution DEM product over the LRM zone in the interior of the Greenland Ice Sheet.

The EOLIS Point and DEM products are now available on the CryoSat Science Server from the month of June 2019 to January 2020, with further data becoming available on a monthly basis. In addition, by the end of June 2020, the products will be made available for all months since the start of the CryoSat mission in 2010. The products for Antarctica will be going live this summer and the remainder of the world's land-ice regions later in 2021.