ESA’s ice mission, CryoSat, has been monitoring Earth’s ice and water for over 14 years. In that time, throughout nearly 77,000 orbits around our planet as of the time of writing, it has generated around 350 terabytes of radar altimetry data.

Those data have been critical in our ongoing efforts to understand the rapid changes occurring because of climate change. Glacier mass balance, ice sheet elevation, summer and winter sea ice, snow depth over ice, polar oceans, coastal oceans, and even river and lake levels: CryoSat covers the lot.

Making CryoSat data accessible, usable and shareable takes a great deal of skill and expertise - from the daily quality reports informing users of periods of data unavailability, to the detailed data products that allow new users to apply CryoSat data to their research across multiple disciplines.

Here is a short introduction to those products and services, and the research they have supported, which have helped make this a “golden age” for satellite altimetry.

1. Ice and Ocean products

The first tenets of CryoSat data are the Ice and Ocean products.

The ice products, provided for glaciologists working on sea ice and ice sheets in the Arctic and Antarctica, have underpinned our long-term climate records of polar ice for over 14 years.

It is thanks to these records we’ve been able to track record ice loss in Greenland and Antarctica, with the highest rates of melt occurring in the past decade.

CryoSat’s Ocean products are dedicated to the study of ocean surfaces and provided specifically for the needs of the oceanographic community.

As the only satellite-borne radar altimeter measuring up to 88 degrees North and South, CryoSat’s records of polar sea levels are unique.

A recent update from the National Oceanography Centre (NOC) used CryoSat Ocean data to develop a new CryoSat sea level anomaly product to enable ocean science and the development of operational marine applications.

The NOC team provides daily and monthly scientific quality control reports for the ocean products by comparing variables like sea level anomaly, significant wave height, and more, with as validation data from tidal gauges, buoys, and other satellites.

Near-real time ocean data from CryoSat are used operationally by NOAA, in their high seas forecasting and hurricane prediction centres. The near-real time ocean products are also available to weather forecasters around the world through the World Meteorological Organization’s Global Telecommunications System network.

More information on CryoSat Ice and Ocean products, including how to access data, can be found via the CryoSat data page.

2. CryoTEMPO

CryoTEMPO provides access to CryoSat’s long term records of global ice and water levels thanks to six dedicated thematic products: Land Ice, Summer Sea Ice, Winter Sea Ice, Polar Oceans, Coastal Oceans and Inland Waters.

As of summer 2024, the Summer Sea Ice product was the latest to be added to the Cryo-TEMPO portfolio, which allows year-round monitoring of Arctic sea ice.

The aim of Cryo-TEMPO is to make it quicker and easier to work with CryoSat data, particularly for new users, and to provide fully characterised measurement uncertainties.

They are developed by a consortium led by the UK Centre for Polar Observation & Modelling (CPOM), and the Lancaster University-UKCEH Centre of Excellence in Environmental Data Science (CEEDS).

The products have been used for a variety of projects, including the planning of field campaigns in Antarctica, as well as intercomparisons with NASA’s ICESat-2 satellite as part of the Cryo2ice project.

Recent published research using Cryo-TEMPO includes a multi-satellite study published in Nature Communications, which investigates the rapid retreat of the Cadman glacier in West Antarctica.

In the first quarter of 2025, we will release an operational snow depth on sea ice product generated from CryoSat and ICESat-2, which will further improve sea ice thickness estimates from satellite altimetry.

3. CryoTEMPO-EOLIS

A technique called swath processing, applied to CryoSat’s SARIn data, allows scientists to better measure ice in complex terrain such as mountains. With swath processing we can map land ice, including mountain glaciers, in much finer spatial and temporal resolution.

CryoSat’s swath data are made available thanks to CryoTEMPO-EOLIS, a product developed for ESA by Earthwave, the University of Edinburgh and isardSAT. It initially provided highly detailed elevation changes over the Greenland and Antarctic ice sheets, and has since been extended to cover glaciers worldwide.

Glaciers covered include those of Antarctica, Greenland, Iceland, Svalbard, Alaska, the Southern Andes, High Mountain Asia and the Russian Arctic. More regions are being added all the time, with the latest additions including New Zealand coming in February 2024.

Research published in 2023 used CryoSat swath data, via CryoTEMPO-EOLIS, to show glaciers worldwide shrank by 2% between 2010 and 2020.
 

4. cs2eo

CryoSat data products, including CryoTEMPO and CryoTEMPO-EOLIS, are now available to CryoSat users via the “one stop shop” satellite altimetry platform cs2eo.

The cs2eo platform was developed to make it quicker and easier to access, compare and download altimetry data from ESA, NASA and other sources. It also includes datasets such as ICESat-2, CryoVEx and Operation IceBridge, and as of August 2024, added Sea Ice and Snow Depth datasets from the AWI IceBird campaign.

The website boasts many useful features, including options to view the geospatial coverage of selected datasets. Along with a new interface, the website is constantly being updated with improved features and datasets.

For the most up to date information, you can visit the releases page on the cs2eo website.

5. SIN’XS

Another new data comparison tool that draws heavily on CryoSat data is the sea ice thickness product intercomparison exercise (SIN’XS), a NOVELTIS-led project funded by ESA.

Whilst remote sensing has come a long way in monitoring and modelling sea ice, different approaches including processing algorithms and assumptions mean there is little consensus about sea ice volume variability and change, in both the Arctic and Antarctic.

SIN’XS aims to address this by providing a tool to compare datasets and support the science community. After a period of data submission, the task of comparing the data is well underway, and the SIN’XS team is welcoming collaborations and contributions to the analysis.

It will all help to provide a reconciled estimate of sea ice thickness. If you would like to know more, please get in touch with the team.
 

6. Quality is key

A dedicated team from Telespazio UK monitors CryoSat data quality, and much more.

The Quality Assurance for Earth Observation (IDEAS-QA4EO) service monitors all CryoSat operational data to detect anomalies, support investigations, and inform users about data quality.

Occasionally, gaps in the datasets can arise. These are often due to planned orbital manoeuvres (where the SIRAL instrument is switched off), or unexpected processing failures.

For users of all the data products described above, if you have noticed a gap in CryoSat data and want to check it, you can visit the CryoSat data unavailability periods page. There you can find all periods of planned and unplanned unavailability of the SIRAL instrument.

The team also provides an overview of overall mission performance, the status of the SIRAL instrument, and the data quality of the CryoSat products each month. This is complemented by a daily performance quality report, which is generated only when an issue is identified.

For information you can visit the CryoSat Data Quality Reports page.

To achieve the highest quality data products, the CryoSat processors are periodically updated. Processing algorithms are improved based on recommendations from the scientific community and validation campaigns.

If you notice a problem with data, we encourage you to submit requests through the EO Help Desk and to provide feedback through the user survey.