PSMSL Annual Report for 1997

1. Introduction

This report reviews briefly the work of the Permanent Service for Mean Sea Level (PSMSL) during 1997. This year the PSMSL has organised a number of major workshops and training courses, has edited the new Implementation Plan for GLOSS, and has continued its data collection and analysis activities.

2. GLOSS Activities

2.1 GGE-5 Meeting

The Global Sea Level Observing System (GLOSS) is an Intergovernmental Oceanographic Commission (IOC) project, one of the aims of which is to improve the quality and quantity of data supplied to the PSMSL. GLOSS can be considered as one of the first components of the Global Ocean Observing System (GOOS).

The Fifth Meeting of the GLOSS Group of Experts (GGE) was held at the Jet Propulsion Laboratory (JPL), California, USA during 19-21 March, hosted by Dr.Ruth Neilan and colleagues from the International GPS Service for Geodynamics (IGS). This meeting was the first at which Dr.Woodworth acted as GLOSS Chairman, having been Acting Chairman for the past year since the resignation of Dr.David Pugh. The meeting thanked Dr.Pugh and Dr.Albert Tolkatchev, the retiring GLOSS/GOOS Technical Secretary at IOC, for their many years of work for GLOSS.

The GGE meeting resulted in many plans being laid for interesting future activities, which are summarised in a workshop report available from IOC.

2.2 GLOSS Implementation Plan 1997

A particularly important task for the GGE-5 meeting was the review of the draft new Implementation Plan for GLOSS prepared over the past half year with contributions from many sea level scientists. This was endorsed by the meeting, subject to some recommended modifications, and was subsequently presented for endorsement by the 19th Session of the IOC Assembly at UNESCO House in Paris in July. The Assembly also endorsed the Plan, with minor modifications, and the final version is now undergoing printing by IOC for publication in early 1998.

The Implementation Plan was also presented in June to international attendees at the First GOOS Forum meeting in Paris, and was discussed also during the I-GOOS-III meeting following the Forum.

2.3 GLOSS Training Course 1997

A training course for eight sea level scientists from Mediterranean and Black Sea countries was held at the Proudman Oceanographic Laboratory (Bidston Observatory) during 16-27 June. This course was organised by Mr.Graham Alcock, who was responsible for the many previous successful GLOSS courses at POL during the 1980s. The main themes of the course concerned the background science, the need for related geodetic measurements, and hands on training sessions (HOTS)'. Invited external speakers included Drs.David Pugh and M.Tsimplis (Southampton Oceanography Centre), Dr.Albert Tolkatchev (IOC), Dr.A.Plater (Liverpool University), Dr.R.Bingley (Nottingham University) and Dr.D.Rosen (Israel Oceanographic and Limnological Research). A number of POL scientists also provided lectures and organised trips to nearby tide gauges. A presentation was made to Dr.Tolkatchev to mark his retirement.

2.4 GLOSS Handbook Updating

In preparation for the International World Ocean Circulation Experiment (WOCE) conference in Halifax, Canada in May 1998, the PSMSL and British Oceanographic Data Centre (BODC) have begun work on a new CD-ROM which will contain WOCE Sea Level Centre data sets, together with an updated version of the GLOSS Handbook, and (probably) the PSMSL data set. In August, all GLOSS Contacts were circulated with a request to update and extend the information in the current version of the Handbook and most replies have now been received. It is anticipated that the new CD-ROM will be available for distribution in mid-1998. Meanwhile, the existing GLOSS Handbook entries can be inspected via the web at:

and any scientist with updated information to provide, or comments to make on particular sites, is invited to contact the PSMSL.

2.5 GLOSS Publications

Issue 5 of the GLOSS Bulletin is now available on the web at:

Meanwhile, issue 2 of volume 2 of the Afro-America GLOSS News has been published and circulated by the University of Sao Paulo (USP) in Brazil. The USP intend that the AAGN will also be available via the web in future.

2.6 Future GLOSS Meetings

It is intended that the approximately two-yearly meetings of the GGE will continue as previously, enhanced by regional meetings in intervening years whenever possible. In July 1998, it is intended to hold a GLOSS meeting for countries of the western Pacific region alongside the Western Pacific Geophysics Meeting (WPGM), together a scientific session on sea level studies at the WPGM itself. In addition, the PSMSL will be represented at the GOOS/GCOS 'Action Plan for Existing Bodies and Mechanisms' meeting at Sydney, Australia in March and at the International WOCE meeting in Halifax in May.

2.7 Temporary GLOSS Technical Secretary

Following the retirement of Dr.Tolkatchev from IOC, and the reorganisation of the GOOS Office in Paris following the appointment of new Director, Dr.Colin Summerhayes, the role of GLOSS Technical Secretary has been taken until the end of 1997 by Mme.Janice Trotte from the Directoria de Hidrografia e Navegacao (DHN) in Brazil. Janice's work for GLOSS, and indirectly for the PSMSL, is much appreciated. Thereafter, it is hoped that a permanent appointment can be made to this important position.

3. Other Meetings

3.1 PSMSL/IGS Workshop

Prior to the GGE-5 meeting, a workshop was held at JPL during 17-18 March organised by the PSMSL and IGS on the use of GPS at tide gauge benchmarks, for the measurement of rates of vertical land movement at those sites, and for the long term calibration of satellite radar altimeters. The two main products of the meeting will be a proceedings report, containing the many excellent papers contributed to it, and the work of a Technical Committee, set up by the workshop to investigate certain technical issues in greater detail. This work is an excellent example of two Services of the Federation of Astronomical and Geophysical Data Analysis Services (FAGS) working together to approach a geophysical problem of common interest.

3.2 Sea Level Workshop at Barcelona

A meeting was held in Barcelona, Spain during 9-12 April concerned with European approaches to sea level and coastal protection and was attended by Dr.Woodworth. Most of the scientists in Europe involved in sea level and climate studies were at the meeting, and a book entitled 'Sea-Level Change and Coastal Processes: Implications for Europe' will stem from it, edited by D.Smith, S.Raper, S.Zerbini, A.Sanchez-Arcilla and R.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.

3.3 UK Network Sea Level Workshop

On 20 May, a workshop was held by the UK Ministry of Agriculture, Fisheries and Food (MAFF) in London on the development of the 'A Class' national network of gauges. The meeting was attended by Dr.Woodworth who made a presentation of PSMSL/GLOSS research, putting the UK measurements into a global context. The main conclusion was that the present UK network of 45 gauges should be enhanced, with duplicate systems at some sites, and expanded in areas where there is a need for flood protection purposes. Dr.Woodworth also made the case for MAFF support for the 7 UK gauges in the South Atlantic and Antarctica, which form an important component of GLOSS. A workshop report, edited by G.Alcock and E.Spencer, is currently being printed.

3.4 International Sea Level Workshop at Hawaii

A excellent workshop on different aspects of sea level studies, concentrating especially on climate and oceanographic interests, took place at the University of Hawaii, Honolulu, USA during 10-11 June and was attended by Dr.Woodworth who made several presentations. This workshop considered the roles of remotely sensed and in situ systems for monitoring different aspects of the ocean/climate system which result in observable sea level signals. A workshop report, edited by Dr.N.Smith (Chairman of the Ocean Observing Panel on Climate, OOPC), and a study of the global network by Dr.V.Gornitz (Goddard Institute for Space Studies), will be published in 1998.

One recommendation of the meeting relates to the possibility of establishing a scientific sea level advisory group jointly between IOC and other bodies (such as CLIVAR and the OOPC) to provide ongoing scientific advice to the wider GLOSS group. At the time of writing, this proposal is being considered at IOC.

3.5 IAG Conference at Rio de Janeiro

In September, Mesquita from the University of Sao Paulo represented the PSMSL and GLOSS at the Rio de Janeiro conference of the International Association of Geodesy (IAG) and gave an oral and poster presentation on the status of GLOSS.

3.6 Ocean Data Symposium in Dublin

During 15-18 October, Dr.Rickards represented the PSMSL at the Ocean Data Symposium at Dublin, Ireland and presented a paper on the WOCE Sea Level Centres together with Dr.B.Kilonsky from the University of Hawaii. At this meeting, issues of GLOSS data flow, outlined in the GLOSS Implementation Plan, were discussed in detail between Drs.Rickards and Kilonsky who comprise the core of the GLOSS Data Coordination Panel.

3.7 EOSS Management Meeting

On 16-17 December, Dr.Woodworth and Mr.Axe from the PSMSL attended the management meeting of the European Union EOSS project (formerly called NOSS). EOSS aims to enhance sea level (tide gauges) and land level (GPS) monitoring, and associated data exchange, in Europe primarily by sets of bilateral (i.e. no new cost) agreements. First activities in this five year project are likely to centred around the North Sea, where most of the countries which have so far signed up the project commitments are located.

3.8 Tidal Science '96

As reported previously, a meeting entitled Tidal Science '96 was held at the Royal Society in October of that year. During 1997, papers stemming from the meeting were submitted to a special issue of Progress in Oceanography, with Dr.R.Ray (Goddard Space Flight Center) and Dr.Woodworth acting as editors. Publication of the special issue is expected in mid-1998.

4. Altimetry and Gravity Field Activities

Full participation has been maintained with the ERS and TOPEX/POSEIDON (T/P) altimeter working groups. In March, Dr.Hughes represented PSMSL/POL interests at the ERS conference at Florence, Italy. During October, Dr.Woodworth attended the T/P Science Working Team meeting (13-14 Oct.) and the following 'Monitoring the Oceans in the 2000s: an Integrated Approach' conference (15-17 Oct.) at Biarritz, France and presented a poster on GLOSS.

Dr.Woodworth has been invited to join the Mission Advisory Group (MAG) of the European Space Agency 'Gravity Field and Steady State Ocean Circulation Experiment (GOCE)' mission, which has now entered the Phase-A funding stage. The provision of a more precise model of the Earth's gravity field and geoid is of great importance to a range of oceanographic and geophysical studies.

5. PSMSL Data Receipts for 1997

In the period since the last Annual Report (i.e. since mid-December 1996), just over 800 station-years of data were entered into the PSMSL database. This is approximately the amount of data entered each year for the last few years, although much lower than the record 2500 in 1996. The new sets of data are summarised in Appendix 1 and Figure 1.

Anonymous FTP remains the main means by which data are distributed to scientists (via ftp node and directory /pub/psmsl), while CD-ROM and floppy disk products can be provided depending on requirements.

6. PSMSL/WOCE Centre Staffing

One excellent development in 1997 was that, at the start of the year, the PSMSL was joined by Mr.Philip Axe from the University of Plymouth. Philip has recently finished his Ph.D studies on coastal processes in the south of England and is currently completing his thesis. His main duties at the PSMSL and WOCE Centre include the bringing up to date of several WOCE-related sea level data sets, overlaps with the various European and global GPS/tide gauge activities, and of course scientific analysis of the data.

7. Visitors to the PSMSL in 1997

Visitors to the PSMSL during 1997 included Dr.K.Heywood (University of East Anglia, UK), Dr.D.Pugh (Southampton Oceanography Centre, UK), Drs.H.Fagard and A.Orsoni (Institut G‚ographique National, France), Mr.C.Magori (Kenya Marine and Fisheries Research Institute), Dr.H.Waldron (University of Cape Town, South Africa), Prof.G.Lennon (Flinders University, Australia), Dr.P.Moore (Aston University, UK), Prof.A.Wroblewski (Polish Academy of Sciences), Dr.B.Richter (Ifag, Frankfurt, Germany), Prof.J.Harari (University of Sao Paulo, Brazil), Mr.D.Pillich (SevenCs, Germany) and Mr.Robert Swan (Robert Swan Foundation, UK).

Mr.Swan was the first person to walk to both the North and South Poles and has established a Foundation for young people to learn about, and travel to, Antarctica which has attracted support from UNESCO and the business world. The PSMSL and POL intend to work closely with the Foundation with regard to issues of sea level and climate change.


It can be seen that 1997 has been a further active year with regard to important workshops and conferences, and a busy one with regard to data acquisition and analysis.

Particular thanks as usual go to Mrs.Elaine Spencer (PSMSL Secretary) and to members of staff of the Proudman Oceanographic Laboratory (Bidston Observatory) who contribute part of their time to PSMSL activities.

P.L.Woodworth (December 1997)

Appendix 1: Number of station-years entered into the databank for each country or coastline in the period mid-December 1996 to mid-December 1997 (807 total).

 SPITSBERGEN                   3
 NORWAY                        22
 SWEDEN                        9
 POLAND                        10
 NETHERLANDS                   11
 BELGIUM                       6
 UNITED KINGDOM                43
 IRELAND                       1
 CHANNEL ISLANDS               1
 FRANCE (ATLANTIC)             3
 SPAIN (ATLANTIC)              13
 PORTUGAL                      7
 GIBRALTAR                     2
 MALTA                         5
 ITALY (ADRIATIC)              1
 CROATIA                       13
 GREECE                        34
 BULGARIA                      145
 TURKEY                        4
 SPANISH N. AFRICA             6
 GUINEA                        1
 ASCENSION                     2
 NIGERIA                       2
 ST. HELENA                    2
 MOZAMBIQUE                    7
 SEYCHELLES                    1
 MAURITIUS                     3
 MALDIVES                      7
 TANZANIA                      1
 KENYA                         3
 GULF                          2
 MUSCAT & OMAN                 1
 INDIA                         21
 MALAYSIA                      14
 SINGAPORE                     10
 VIETNAM                       1
 HONG KONG, CHINA              7   
 JAPAN (HOKKAIDO)              16
 JAPAN (SHIKOKU)               8
 JAPAN (KYUSHU)                18
 JAPAN (AMAMI GUNTO)           5
 SARAWAK                       3
 SABAH                         6
 PAPUA NEW GUINEA              1
 OF MICRONESIA)                3
 PALAU ISLANDS                 1
 MARSHALL ISLANDS              1
 KIRIBATI                      1
 NEW CALEDONIA                 17
 WESTERN SAMOA                 18
 HAWAIIAN ISLANDS              1
 LINE ISLANDS                  1
 PENRHYN ISLAND                1
 ILES DE LA SOCIETE            1
 COOK ISLANDS                  1
 MARQUESAS                     2
 GAMBIER ISLAND                1
 EASTER ISLAND                 3
 MEXICO (PACIFIC)              10
 GUATEMALA (PACIFIC)           8
 PANAMA (PACIFIC)              1
 COLOMBIA (PACIFIC)            2
 ECUADOR                       6
 PERU                          16
 CHILE                         21
 ARGENTINA                     5
 FRENCH GUIANA                 4
 PANAMA (CARIBBEAN)            1
 BARBADOS                      1
 CAYMAN ISLANDS                3
 GREENLAND                     17
 ANTARCTICA                    20