Obtaining High Frequency Data

Historically, obtaining higher frequency (HF) sea level data (typically hourly values) was more complicated than obtaining MSL data. No formalities existed for the international exchange of higher frequency data, and a number of countries were reluctant to exchange HF data because they were perceived to have either military or commercial value (unlike MSL).

This situation has changed dramatically. Many countries have taken part in international scientific programmes (e.g. the World Ocean Circulation Experiment (WOCE) of the 1990s) which required extensive data exchange. In addition, there has been a recognition that by not charging for HF data, one makes the information more accessible and therefore more 'useful' to the community, with benefits all round. This has been aided in a number of countries by changes to the laws with regard to access to data, so as to provide data free of charge (or with minimal charge) to the user. The availability of web services has aided these developments considerably.

Aside from GLOSS, a user wanting HF data from a particular region must consult one of a number of national and international (regional) data centres. The PSMSL maintains a list of such National and International Data Centres.

However, be aware each centre will provide data in different formats and possibly subject to a charge.