ESA Climate Change Initiative

The ESA Climate Change Initiative is a framework program that aims to maximize the use of earth observation data by providing stable, long-term and error-characterized data set of Essential Climate Variables (ECVs) for climate change analysis. The program started in 2009 and included requirement assessment and the identification and developments of algorithms that yield consistent results across different satellite missions. The second phase of the CCI started in 2015 and will extent the production of data set time series of variables that describe the state of the atmosphere, land, ocean and the cryosphere.

Sea ice is listed as one of the 13 Essential Climate Variables and the aim of the sea ice CCI project group is to produce datasets of

  1. sea ice concentration
  2. sea ice thickness
  3. sea ice drift

that include Arctic and Antarctic sea ice and the respective uncertainties. The data sets both parameters will consist of a merged multi-mission data product with different temporal resolution and coverage period. Sea ice concentration, as measured by passive microwave sensors, is usually available on a daily basis and a consistent time series is available back until 1992. Radar altimetry data that can be used to calculate sea ice thickness is available back to 1993, but will be made available only in winter time and monthly averages.

The contribution of AWI to the project

In the second phase of the sea ice CCI, the Sea Ice Physics section of AWI is responsible for the production of a merged multi-mission sea-ice thickness time series from data of the ERS-1, ERS-2, EnviSat and CryoSat-2 radar altimeter missions of Arctic and Antarctic sea ice. The production of a time-series of Antarctic sea-ice thickness is based on a comparative study between radar altimeter data of EnviSat and CryoSat-2 that was done in the phase 1 of the sea ice CCI project. The sea-ice thickness production system will be maintained beyond the lifetime of the project and shall provide publically available sea-ice thickness datasets also for future radar altimeter missions.

The Sea Ice Physics group also provides observational data of sea ice properties (thickness, snow depth, drift) from airborne surveys and autonomous drifting stations for the validation for sea ice ECVs in both hemispheres.