Ocean Observing and Climate Research Group

Satellite wave climatologies
The prime objective of our work is to build long-term climatologies of ocean significant wave height (SWH) and wave period based on satellite altimeter datasets. The development of such global climatologies is driven by the need to validate present day operational wave forecasting systems, as well as to improve our understanding of the role of waves in atmosphere-ocean dynamics, ocean surface transport and mixing, and to facilitate the detection and measurement of global climate change as revealed in ocean wave parameters. Typical applications also include better estimation of ocean-based renewable energy resources and improved estimation of extreme sea states.

The basic methodology is first to calibrate altimeter-derived SWH and wave period estimates against a network of in situ buoy measurements. The wave period parameter we present here is the zero-crossing period, Tz which is calculated from Hs and radar backscatter coefficient, sigma-0, using the algorithm of Mackay et al. (JGR, 113, C03029, 2008). In this study, we use buoy data extracted from the National Data Buoy Center (NDBC) database, made available freely online by the US National Oceanic and Atmospheric Administration.

The development of these satellite-derived wave climatologies is part of Theme 10 of Oceans 2025.


Sample along-track dataset now available
You can download a sample NetCDF file of global along-track TOPEX altimeter data:


Movies of gridded wave period and SWH data also now available
The provisional gridding scheme used here is Gaussian smooothing (see sample figure below). We are currently working on applying optimal interpolation and will then make gridded data products available. In the meantime, you can download provisional sample movies of global Gaussian-gridded data for TOPEX wave period and SWH data:


Further information

A paper describing the preparation of the climatologies and some initial analysis is currently in preparation: David Cromwell and Christine Gommenginger, 'Developing global long-term altimeter datasets and climatologies of ocean wave measurements.' For further info, email: ddc@noc.soton.ac.uk

Figure: Gridded calibrated TOPEX-derived significant wave height for December 2004. We used a Gaussian gridding scheme with the full-width at half-maximum and the search radius both set to 300 km.