In this issue, we again have articles on software and hardware for tide gauge measurements. These articles are drawn from experience at the Proudman Oceanographic Laboratory (POL) in operating gauges around the UK and in the South Atlantic. The first one is a link to pages at the British Oceanographic Data Centre (BODC) on the EDTEVA data processing package written by Steve Loch. EDTEVA is used extensively at BODC/POL to process tide gauge data from all around the world, and Steve would be interested in developing links with other organisations who might be interested in using it. The second is a description of the "B gauge" datum control method for pressure tide gauges that POL now uses extensively in its networks.
Each October, the Permanent Service for Mean Sea Level (PSMSL) tries to present an overview of the status of GLOSS as it sees it, and a short article on this topic is included in this issue. The development of GLOSS in areas where there have not been many gauges so far is always of interest. In this issue, we have news from Satish Shetye on progress with the IOC-UNEP-WMO Indian Ocean sea level pilot project; from Rupert Summerson on Australian activities in the Antarctic and Southern Ocean; and from Bjorn Engen and David Pugh on the opening of an excellent, new geodetic observatory at Ny-Alesund, where one of the major geodetic instruments is the tide gauge.
We include two examples of scientific analyses of datasets relevant to sea level studies, but not necessarily based on conventional tide gauge data. The first, contributed by Richard Bingley, discusses the monitoring of European land levels within the large Eurogauge GPS programme. By this means, European land and sea level changes can eventually be decoupled in time series of relative sea level obtained from the gauge data. Incidentally, we (PSMSL) have had several discussions in 1995 with scientists from the International GPS Service for Geodynamics (IGS), including Ruth Neilan and colleagues, on how to make a worldwide survey of GPS activities relevant to the monitoring of vertical land movements at tide gauges. We need to know how well the recommendations of the "Carter Committees" are being implemented (see the report of the IAPSO Surrey meeting in issue 1 of the Bulletin). So, many tide gauge and GPS people (including Richard!) will be receiving joint PSMSL/IGS questionnaires from us in the near future.
The second scientific analysis, from Mike Meredith, concerns the use of bottom pressure measurements ("pelagic tide gauge measurements") in monitoring the variability of transport through the Drake Passage, of major importance to the World Ocean Circulation Experiment.
A third scientific analysis, using conventional tide gauges this time, concerns the use of the global tide gauge network for on-going calibration of satellite altimeter data. I think that this could be an extremely important function of GLOSS in the future and Gary Mitchum's article points the way for this application.
As in issue 1, we have included news of working groups on sea level and tides. Albert Tolkatchev has provided a summary of the very large changes in level of the Caspian Sea which have taken place recently, while Bill Carter has reported on a LOICZ meeting recently held in the Philippines. LOICZ has a strong sea level component which should be of interest to many coastal scientists around the world. In addition, my colleagues within the TOPEX/POSEIDON tides working group have updated their statement included in issue 1 of which global tide models are currently recommended for general use.
The summer of 1995 had two large international meetings with significant sea level content. These were the IUGG, Boulder and IAPSO, Hawaii conferences and we include short impressions of both from David Pugh and Afranio de Mesquita.
In commenting on issue 1, several readers pointed out that a lot of sea level information already exists on the WWW. For altimetry in particular, there are a number of organisations producing excellent material. For example, Goddard has pages at: http://santafe.gsfc.nasa.gov/topex/topex.html which describe their global sea level work with TOPEX/POSEIDON data. JPL's corresponding information can be found via: http://topex-www.jpl.nasa.gov/, NOAA's at: http://www.grdl.noaa.gov/ and AVISO's at: http://www-aviso.cls.cnes.fr/. Take a look at all of these. The information within these pages will be very informative to tide gauge people who are not very familiar with altimetric data products.
You should also take a look at the Afro-America GLOSS News . The GLOSS Bulletin is just one of two "newsletters" about GLOSS and related activities. While the Bulletin is in electronic form, the Afro-America GLOSS News is avaliable on paper with most articles in Spanish and Portuguese. Two issues are available so far. If you would like a copy of them, mail Professor Afranio Rubens de Mesquita at ardmesqu@fox.cce.usp.br.
Many thanks to the contributors to this second issue. Happy reading!
Philip Woodworth plw@pol.ac.uk