The ESA Sea State Climate Change Initiative (CCI) project has produced global merged multi-sensor time-series of monthly gridded satellite altimeter significant wave height (referred to as Level 4 (L4) data) with a particular focus for use in climate studies.

This dataset contains the Version 1.1 Remote Sensing Sea Surface Height product, gridded over a global regular cylindrical projection (1°x1° resolution), averaging valid and good measurements from all available altimeters on a monthly basis (using the L2P products also available). These L4 products are meant for statistics and visualization.

This first version of the Sea State CCI products is inherited from the GlobWave project, building on experience and existing outputs. It extends and improves the GlobWave products ,which were a post-processing over existing L2 altimeter agency products with additional filtering, corrections and variables. A major improvement consists in a new denoised sea surface height variable using Empirical Mode Decomposition, which was used as input to these monthly statistical fields.

The altimeter data used in the Sea State CCI dataset v1.1 come from multiple satellite missions spanning from 1991 to 2018 (ERS-1, ERS-2, Topex, Envisat, GFO, CryoSat-2, Jason-1, Jason-2, Jason-3, SARAL). Many altimeters are bi-frequency (Ku-C or Ku-S) and only measurements in Ku band were used, for consistency reasons, being available on each altimeter but SARAL (Ka band).