Best wishes
Philip Woodworth
Meetings
The first part of 1997 has included a large number of excellent meetings on different aspects of sea level measurements, a situation which has conspired against my producing this issue before now. I'll mention four of them.
On 17-18 March, the International GPS Service for Geodynamics (IGS) and the Permanent Service for Mean Sea Level (PSMSL) organised a joint Workshop on the use of GPS for monitoring the rates of change of the height of tide gauge benchmarks. Such measurements have application in removing the contributions of land movements in sea level records obtained from tide gauges, and, together with gauges, in providing a calibration system for ongoing altimetric measurements. The meeting was hosted by the IGS Central Bureau at the Jet Propulsion Laboratory (Ruth Neilan and colleagues).
Aside from a meeting proceedings report, which will contain papers based on presentations at the meeting and which will be edited by Ruth, one of the main recommendations (see the GE5 meeting report mentioned below for a full list of recommendations) concerns the setting up of a Technical Committee which will provide practical advice from experts on how to operate GPS at or near gauges. In turn, this should lead to an 'IOC Manual No.3' on this subject. (Manuals 1 and 2 were concerned with operating gauges themselves.)
The second meeting to mention was the 5th Meeting of the IOC Group of Experts on GLOSS. This was held during 19-21 March also at JPL, following on from the GPS Workshop. The main item to be discussed concerned the 1997 GLOSS Implementation Plan, although a wide range of national and regional matters were also discussed. A short meeting report is included as part of this issue of the Bulletin . I have also included on these web pages the Chairman's report to the meeting, together with any short working papers submitted to the GE5 meeting which I happened to have in computer form. (Working papers are not normally circulated in formal IOC reports but these may be of interest to some people.) The full meeting report has been printed and can be obtained on paper from IOC.
At that meeting, the major contributions of David Pugh (former GLOSS Chairman) and Albert Tolkatchev (retiring IOC GLOSS Technical Secretary) were recognised, and the individuals thanked heartily for their efforts for GLOSS through the years.
The third meeting was held in Barcelona, Spain during 9-12 April and was concerned with European approaches to sea level and coastal protection. It was attended by most of the scientists in Europe concerned with sea level and climate studies and a book entitled 'Sea-Level Change and Coastal Processes: Implications for Europe' will stem from it, edited by David Smith, Sarah Raper, Susanna Zerbini, Antonin Sanchez-Arcilla and Robert Nicholls. A section of the book will be concerned with the science of sea level changes, with an introduction by Hans-Peter Plag. GLOSS, altimetry and related matters were well represented at the meeting and will be covered fully in the individual chapters.
The fourth meeting was an International Workshop on Climate Aspects of Sea Level held at the University of Hawaii during 10-11 June. This meeting, chaired by Neville Smith from Australia and funded primarily by NOAA, included presentations by a large number of sea level scientists and will result in an important Workshop Report. That report will contain a review by Vivien Gornitz of the present network of gauges with respect to particular science interests in climate change, such as long term trends or ENSO. One of the most interesting recommendations from the meeting relates to the possibility of establishing a scientific sea level advisory group jointly between IOC and other bodies to provide ongoing scientific advice to the wider GLOSS group etc. At the time of writing, this proposal is being considered at IOC.
Sea level changes were also, of course, discussed in detail at the IAPSO/IAMAP and WOCE meetings in Australia during June-July. At the IAG conference in Rio de Janeiro in September, GLOSS and the PSMSL were represented by Prof.Afranio de Mesquita from the University of Sao Paulo who presented a GLOSS poster (see below). In October, sea level will be a central theme of the TOPEX/POSEIDON Science Working Team and the 'Monitoring the Ocean' conference in Biarritz, France.
Staff Movements at IOC
At the GE5 meeting at JPL, we were very pleased to welcome Colin Summerhayes, the new Director of the GOOS office at IOC. Colin kindly also kindly functioned as Secretary for the meeting as Albert Tolkatchev could not attend. Colin's arrival at IOC represents a new start for GOOS and, therefore, for GLOSS as well.
Also newly arrived at IOC is Janice Trotte from DHN in Brazil. Janice is well known in the IOC community and has agreed to fit in as much GLOSS-related work as possible after Albert's retirement, until a new full-time GLOSS Technical Secretary can be appointed.
GLOSS Implementation Plan
The version of the 1997 Implementation Plan which followed the 5th GLOSS Experts meeting was presented to the First GOOS Forum and then the 19th IOC Assembly during July. At the time of writing, the draft version of the Plan presented to the Assembly is still on the PSMSL ftp disk
ftp bisag.nbi.ac.uk
cd pub/general/plw/gip
with three text files (.html) and a number of figures.
However, the draft version will be replaced on the ftp disk by the final version when that is ready for printing some time in October.
GLOSS Poster and Brochure
In between all these meetings in exotic places, some people have been trying to do some work in spite of the summer! The first thing to mention is that Robert Smith from POL has produced a GLOSS poster in the form of 2 sheets each about 1.5 x 1 m which includes some of the figures from the Implementation Plan together with some of the photographs from the original GLOSS brochure of some years ago. This poster was shown at the IAG meeting in Rio in September.
Although we cannot offer to make multiple copies of this poster yet, partly because we would like to make it a bit more professional, we might be able to send copies to anyone attending a major conference who is prepared to publicise GLOSS, for example by submitting an abstract on a regional GLOSS activity. If this offer is at all attractive, then please let me know. We shall also investigate making it available via the web or ftp, although it is very large.
By the end of the year, I also hope that the poster can be turned into some kind of brochure which can be made available via the web, and which can be printed on peoples' colour copiers as and when required for publicity purposes. Of course, this will not replace having brochures printed professionally, but it will fill an important niche in GLOSS publicity.
Questionnaire 1: GLOSS Handbook Updating
The Implementation Plan describes how the GLOSS Core Network has been reduced to a set of 287 sites, defining 'GLOSS97'. We now need to bring up-to-date as soon as possible our knowledge of all of these sites so that appropriate action can be taken, wherever the opportunities arise. Therefore, during July and August all GLOSS Contacts were mailed either via email, fax or letter with a request to update the site entry information in the GLOSS Handbook.
So far, we have received replies from about 12 countries, but we would be very grateful for replies from everyone we have mailed, and YES THIS MEANS YOU! , so that we can include the information in a new CD-ROM to be mastered before the end of the year.
Meanwhile, if anyone else, whether a formal GLOSS Contact or not, has information about any GLOSS site which should be included in the Handbook, please email either me (plw@pol.ac.uk) or Lesley Rickards (ljr@pol.ac.uk) who will once again be producing the Handbook CD-ROM.
Questionnaire 2: Survey of North European Higher Frequency Data Availability
As part of the European EOSS/EuroGLOSS activities, which can be considered a regional component of GLOSS, a questionnaire was circulated during August to ascertain the extent to which northern Europe tide gauge authorities were prepared to share 'higher frequency' data (monthly means already of course being contributed to the PSMSL) and, moreover, to make the data available freely for research purposes either on their own ftp/web server or via a centre. (GLOSS experts will recognise this as reflecting regionally the requirements for GLOSS itself outlined in Chapter 7 of the Implementation Plan.)
At the time of writing, only about 6 replies have been received but the results of the survey will be circulated before the end of the year by my colleague Philip Axe via the GLOSS Bulletin .
Privately (or as private as the web can be!), I expect the survey to show Europe to rather backward in data-sharing and the use of the web and ftp. I have started compiling a list on the Sea Level Home Page at POL (DEAD LINK) of national agencies which freely make tide gauge data available over the web. (I do not include the PSMSL and WOCE international centres in this list.) The list is very short at the moment, containing only Australia, Japan, South Africa and the US, and no European countries, and must be expanded if the ideas for widely distributed data availability in GLOSS are going to work as outlined in the Implementation Plan.
If anyone knows of any other countries, in Europe or not, which make sea level data available freely via the web or ftp, please let me know.
Questionnaire 3: Survey of European GPS Activities
Also as part of European EOSS/EuroGLOSS activities, my colleagues Trevor Baker and Philip Axe circulated a questionnaire to European GPS agencies with the object of publicising the main findings of the IGS/PSMSL GPS Workshop at JPL, and of seeing how best to go forward. First results of the survey will be circulated at an EOSS meeting in September, then made available via the Bulletin.
Arctic Sea Level Study
A recommendation of the 4th meetings of the GLOSS GE in Bordeaux in 1995 was that it would be very useful if a small group of people could undertake a review of the status of, and oceanographic (climate, coastal etc.) needs for, sea level monitoring in the Arctic. For one reason or other, this study did not take place, but the need for it was confirmed at the 5th meeting of the GLOSS Group in March this year.
Since then, Dr.Oleg Zilberstein from the State Oceanographic Institute in Moscow has kindly agreed to take the editing lead. He will aided by experts from each of the countries with Arctic coastlines:
Dr Savi Narayanan (Director, MEDS, Canada)
Mr.Fred Stephenson (Canadian Hydrographic Office)
Mr. John Sundsby (Statens Kartverk,Norway)
Mr. Wolfgang Scherer (NOS/NOAA, USA)
Prof.Pentti Maelkki (for the historical Finland Arctic coast)
Ms.Lonny Hansen (DMI, Denmark for Greenland)
and a representative from Iceland.
Aside from this study resulting in a report to the GLOSS GE, IOC will publish the report in one of their series and, if suitable, it will also be published in a scientific journal.
POL 1997 GLOSS Training Course and Kos Summer School
A training course on sea level measurements and analysis was held at POL during 16-27 June funded by POL, IOC and the CIESM. Sea level specialists attended from eight Mediterranean and Black Sea countries and invited speakers came from Israel, IOC and from several UK universities. Graham Alcock, the UK GLOSS Contact, is to be thanked for organising such a successful course which has laid important foundations for regional GLOSS activities such as MedGLOSS and BlackGLOSS. A workshop report is currently being printed at IOC.
During the course, Albert Tolkatchev, formerly GLOSS Technical Secretary and subsequently an IOC Consultant, was presented with some 'souvenirs of the Proudman Oceanographic Laboratory' to mark his retirement and return to Russia.
A week later Susanna Zerbini and colleagues organised a European Commission funded summer school on sea level changes on the Greek Island of Kos which was attended by many sea level scientists and students across Europe. The school will also of course play a major role in furthering the development of MedGLOSS.
New Tide Gauge Types
Five years ago IOC and the IAPSO Commission on MSL and Tides held a joint meeting in Paris to discuss issues of sea level measurement and quality control. The proceedings of the meeting were written up in IOC Workshop Report No.81 (ed.N.E.Spencer). On re-reading that report several technical developments have clearly taken place. For example:
- acoustic gauges of the NOAA 'Next Generation' or Australian 'SEAFRAME' type, which were something of an unknown outside the US in 1992, have proved their accuracy and robustness in many locations
- the multiple pressure 'B gauge' systems of POL have proved to be highly accurate both around the UK and in the South Atlantic
On the other hand:
- several countries including Spain, France and South Africa (and I believe Italy? - to be confirmed by Susanna Zerbini) have invested heavily in acoustic systems which bounce sound pulses up and down in the free air, and not down a tube as with the SEAFRAMES. This type of gauge was described in the Workshop Report in a short article by P-Y. Dupuy. However, now that several years of experience have been acquired in several countries, just how good are they? It is an important question as (a) there are now a lot of them and some are at GLOSS sites, and (b) they are relatively cheap so they could clearly be favoured for installation in many cases if funds became available.
Howard Waldron from Cape Town has assured me that they will attempt there to keep the older float systems running in parallel with the new sensors for as long as possible. However, perhaps this is clear example of the need for a technical report to the GLOSS GE? Over the next few weeks I'll ask some of the main people involved in Spain and France if they would work with Howard to provide such a report.
The GLOSS Implementation Plans and training materials have never recommended a particular type of tide gauge. Rather, the Plan specifies (I paraphrase) that a gauge should be capable of measuring to 1 cm in all conditions. Also, if a country has successfully operated stilling wells, for example, for a century, it would have to think very carefully before changing to a 'better' technology. However, should there be a GLOSS policy of stating a small number of gauge types and manufacturers which should be considered for new GLOSS sites? And should we try to positively discourage GLOSS Contacts from purchasing certain types? I would welcome your views.
WOCE Sea Level Data Management
As most people will know, there are two centres charged with providing global sea level data sets for the World Ocean Circulation Experiment. They are the 'fast centre' at the University of Hawaii (UH) and the 'delayed mode centre' at the British Oceanographic Data Centre (BODC).
Lesley Rickards of BODC and Bernie Kilonsky of UH have produced a report on 'Developments in Sea Level Data Management and Exchange' which will be presented at the Ocean Data Symposium at Dublin Castle, 15-18 October. Copies can be obtained from Lesley (ljr@pol.ac.uk) and we intend to make it available over the web shortly.
Lesley and Bernie also form the nucleus of a GLOSS Data Coordination Panel which will provide guidelines for data formats etc. to the large number of national and international data centres now storing sea level data. The establishment of the Panel follows the recommendations of the Implementation Plan Chapter 7.
News from the Baltic
It is always very nice to hear from people interested in sea level changes with whom one has not communicated before. The other day I had a mail from Alvina Reihan who points to the existence of very long records from Estonia in which the coastal observation network was established in 1885, and regular sea level measurements started in 1842 in Tallinn. At present, the network contains 10 stations with staffs, 3 with gauges and one automatic hydrometric station 'HMS 1820'.
The historical data have been collected and quality controlled, but most of them have not been computerised until now and are still kept on paper. Alvina points out that they have already created the sea level databank, but have not been able to computerise the long term sea level data because of lack of time and money. If anyone can suggest a means of collaborating with Estonia to computerise the historical information, please mail Svetlana Jevrejeva (sveta@np.emhi.ee).
During 1996-97, I at POL and David Pugh at SOC have had two very useful visits from Professor Andrzej Wroblewski from the Polish Academy of Sciences who is working on statistical analysis of Baltic sea level variations. For a short abstract of Andrzej's present work, Click Here.
News from the Indian Ocean
The Department of Ocean Development in India has produced a proposal for a 40 gauge network called IOSLON in the IOCINDIO region, following on from the Second Session of IOCINDIO held in Goa last November. Copies may be obtained from Dr.B.N.Krishnamurty, Director of the DOD. Each country with interests in the region is being asked to sign up to a programme of modernisation and enhancement of the regional network.
The UNESCO Participation Programme
Natalie Philippon-Tulloch from IOC has brought to our attention the existence of the UNESCO Participation Programme (PP). This is described in an extract from the Draft 29C/5 (UNESCO Draft Programme and Budget for 1998-99) which sets forth how this programme of assistance is designed. The extract shows that requests are normally forwarded to the Director General of UNESCO via the UNESCO National Committee in a member state, although there is also a possibility for requests from Non-Governmental Organisations etc. Natalie has suggested that it might be possible for concerned parties at the national level to encourage their National Committee for UNESCO to include in their Participation Programme (PP) requests at least one on ocean and coastal areas. This, obviously, could apply to GLOSS - for example, a training activity at POL/PSMSL (now that the UK has rejoined UNESCO!) or elsewhere.
The PP has been in operation for a number of year, but UNESCO has received relatively few requests under the PP for marine science related activities. This may be a reflection of the difficulties in convincing national authorities (the UNESCO National Committees are often based in the educational sector, rather than that of science) that priority should be accorded to ocean and coastal concerns.
Therefore, anyone within the GLOSS community who feels able to investigate this possibility should be strongly encouraged to try. We shall try from here from a UK point of view. One would hope that the 1998 International Year of the Ocean will provide an impetus for favourable consideration of PP proposals at the national level.
More Meetings
To return to the theme of meetings with which I started this letter, a major issue concerned with IOC's ability to manage GLOSS effectively stems from its lack of resources to have as many meetings as one would like in as many regions as possible. Therefore, we have to take advantage as far as possible of email and of conferences and other meetings which as many of us as possible are likely to attend.
One upcoming important meeting is the Western Pacific Geodesy Meeting in Taiwan in July 1998. My colleague C.K.Shum from Ohio State University has suggested the holding of a regional GLOSS meeting there, alongside a scientific session devoted to sea level matters. More details will be available at a later date. In addition, I shall try to organise at least one other GLOSS related meeting in either Europe or the US during 1998, again taking advantage of a major conference venue if possible.
Tidal Science 1996
An important meeting last year which I would like to mention was the 'Tidal Science 1996' conference at the Royal Society of London in October. Since that meeting, Richard Ray from the Goddard Space Flight Center, USA and I have been assembling papers based on presentations at the conference. Twenty two papers on many different aspects of tidal science have been accepted and will be published in a special issue of Progress in Oceanography at the end of this year.
GLOSS Bulletin Changes
Finally, this is the last edition of the Bulletin I shall be editing, having accepted the generous offer of Bill Mitchell and colleagues at the National Tidal Facility in Australia to have a shot at producing a few issues! Many thanks to everyone for the input to the first five issues.
Meanwhile, a new version is nearly due of the Afro-America GLOSS News (a newsletter on paper with articles mainly in Spanish and Portuguese, edited by the University of Sao Paulo) and investigations are underway on the production of a web version of the AAGN.
I hope to be able to keep in touch on GLOSS matters through the NTF's GLOSS Bulletin , the AAGN and through the GLOSS circular emails.
Philip Woodworth plw@pol.ac.uk
