GNIP - Global Network of Isotopes in Precipitation

1 - 2 July 1999
IAEA Headquarters
Vienna, Austria

1. Opening
The first meeting of the GNIP scientific Steering Committee was held at IAEA headquarters in Vienna from 1 to 2 July, 1999.  The meeting was opened by Mr. D.D. Sood, Director of the Division of Physical and Chemical Sciences, Department of Nuclear Sciences and Applications who welcomed the members of the GNIP-SSC and other participants (Annex 1).  He underlined the role of GNIP and the SSC for the isotope community and the importance of improving the GNIP database for its utilisation in climate, hydrology and hydrogeology.
The SSC gave recognition to the persons and Institutes that have been contributing to the Global Network of Isotopes in Precipitation (GNIP) since its inception in 1961. This long-standing collaboration between WMO and IAEA has progressively strengthened year after year, leading to the recent ratification of the Memorandum of Understanding between WMO and IAEA relating to the Global Network of Isotopes in Precipitation (Annex 3). The joint WMO-PAGES/IGBP-IAEA-IAHS International Workshop on Tracing Isotopic Composition of Past and Present Precipitation-Opportunities for Climate and Water Studies, held in Rüttihubelbad near Bern, Switzerland in January 1995 was a major milestone. During this meeting, under the chairmanship of Mr. H. Oeschger (who died in December 1998), the importance of GNIP for global change science achieve broad recognition. Until then, GNIP has been nearly exclusively used for hydrogeological and hydrological studies. ISOHYC, funded by a private Swiss organisation, aimed also at developing a better understanding on the ongoing internally and externally forced variability of ocean-atmosphere interactions and their implication on the water cycle by using isotopes.

Documentation of recent and ongoing global climate change and fuller understanding of climate dynamics is a critical international priority, with a key challenge being the need to separate human influence due to enhanced greenhouse gas forcing and others factors from natural climate variability and evolution. Unfortunately, available instrumental records are too short to separate natural variability in ENSO (El Niño/Southern Oscillation) from human influence on it and scientists need older "archives" that have to be calibrated carefully.  Isotopes have been proven to be useful for this purpose.  Other databases and networks like GNIP for rivers, air moisture, tree-ring, glacier-ice, corals, etc., are necessary to increase the knowledge of isotopes in global biogeochemical cycles.

The GNIP is now a formal task within the regular programme and budget of the Isotope Hydrology Section of the IAEA and, with the assistance of the scientific steering committee, should acquire in future, more international and multi-disciplinary recognition and support.  Advice given by the SSC should enhance the role of GNIP as a fundamental international resource in the hydrosciences, including climatology, hydrogeology and hydrology.

2. Composition of the Scientific Steering Committee
The present SSC is composed of scientists from two United Nations agencies (WMO and IAEA), one international scientific research project (Past Global Changes Project of the International Geosphere-Biosphere Programme) and several research institutes, and this balance should be preserved (Annex 4).  Representation from active researchers will ensure that new ideas are brought forward and the GNIP continues to meet the requirements of the international scientific community, while the UN structure should guarantee the long-term stability of the network.

The IAEA is sustaining the main part of GNIP activities, including the management of the GNIP Database and analysis of samples from a subset of stations, while the WMO mainly assists in provision of samples and meteorological data.

The present composition of the committee has been approved by the Deputy Director General of the  IAEA and the Deputy Secretary General of the WMO.
The quota for the scientific community members (up to 6) has not been filled and additional scientists should be recruited before the next meeting of the SSC.  Mr. Hastenrath, representative of the scientific community, could not attend the meeting but he did contribute some input and suggestions for further development of GNIP (Annex 5).
Mr. Grassl will leave the WCRP in September and the SSC invited him to continue as a member of the scientific community to give support to the GNIP.
The SSC expressed interest in having additional members of the hydrological/hydrogeological communities in the GNIP committee.  National Networks should also be represented and a good geographical representation of the members should always be sought.
The SSC has proposed that the chairmanship of the committee remain for the time being with the IAEA in view of the stronger involvement in both isotope applications and the development of the GNIP database. The responsibilities for the organisation of the meetings of the GNIP-SSC should rotate between the two sister organisations.

3. Operational aspects
The Isotope Hydrology Section, presenting the annual review of the status of the GNIP and the GNIP Database, emphasized the significant challenge of maintaining long-term stations, while also striving to increase co-operation with external institutions.  For the SSC members, the major concern is the stability and integrity of the network over the long term to ensure its continuing value to the international scientific community.  GNIP has historically been sustained mainly on a voluntary and individual basis by enthusiastic scientists, and sampling and analysis of precipitation are rarely included in the formal plans and budgets of the institutes involved.  This partly explains the large number of incomplete and short chronicles within the GNIP database.

The SSC suggested that greater formal involvement of national authorities in the management and operation of national networks for isotopes in precipitation would be highly desirable, to share some of the burden of the GNIP program and to enhance its overall effectiveness. The IAEA and WMO should, through official channels, request that national governments support the management and operation of national networks for isotopes in precipitation.

From the point of view of the collaboration between the two UN organisations, it is appropriate that the IAEA continue to undertake the bulk of the database and network management, while the WMO also fulfils its obligations to the GNIP as stipulated in the Memorandum of Understanding, giving full support to the GNIP for all the climatological aspects, including meteorological data and liaison with national meteorological services.  The SSC recognised the significant difficulties encountered by the WMO and, more precisely the Hydrology and Water Resources Programme (HWR), as a result of the growing number of projects in the face of decreasing budgets and personnel, and dwindling national contributions, in spite of increasing interest in "collaborative" programmes using the UN as a focal point.

4. Terms of reference
* Examples of Interaction with major ongoing scientific programmes
Mr. Latif presented some preliminary results which pointed to the importance of the GNIP data set for ENSO (El Niño/Southern Oscillation) studies (relationship between an ENSO index (the Niño-3 index which is an area average of SST anomalies over the eastern equatorial Pacific) and the time series of delta O-18 measured in Manaus,Brazil).
A more detailed analysis of global circulation model results revealed that isotopes in Antarctic snow may provide a powerful archive of the past ENSO activity. The Antarctic and Greenland as well as carefully selected low latitude glacier sites may also provide powerful archives of the past ENSO activity.  The models are probably able to help reconstruct climate anomalies if more archives like tree-rings or ice-cores become available.  The models also help to decide where to look for more information in further studies.

The ISOMAP project within IGBP/PAGES is designed to develop and advance isotopic methodologies in the study of changes in the hydrologic cycle and climate and to map the distribution of isotopes in paleo-precipitation for GCM data-model comparison.  The GNIP network and database are absolutely essential for calibration of isotopic indicators preserved in various natural archives, in order to reconstruct or constrain the isotopic indicators composition of past precipitation and ancillary hydrologic and climatic parameters.

GNIP is used in hydrology to study seasonal variations and the effects of amount of precipitation, evaporation, altitude, continentality and latitude.  These effects have been identified based on the statistics resulting from the GNIP data.
Complementary to the information derived from tritium and stable isotopes (O-18 and H-2), the deuterium excess (D-excess) is gaining more and more importance.  Since the deuterium equilibrium fractionation factor as a function of the temperature is not linear (like for O-18), the D-excess is not easy to correlate with the temperature.  It is clear, however, that the sea surface temperature (SST) dominates the D-excess value.
The source of humidity is also very important for the fingerprint.  If the position of the source changes (Azores anticyclone more in the South or North), then the isotopic composition of water vapour will change in consequence.  The understanding of isotopic composition is sufficient for basic studies but  insufficient when carrying out climate or irrigation return studies, where not only high accuracy but also a better knowledge of the physics of isotopes is necessary.

* Definition of the reference stations and the necessary revisions/extensions
There was considerable discussion of what constituted the Reference Stations.
The geographic distribution of the stations is presently inadequate, and WMO/IAEA recommendations should be made in order to encourage some countries (like USA) to build and manage a National Network.  A letter to this effect will be sent to permanent missions to the IAEA,  WMO and the countries concerned.
It is important not to stop the long term stations and to reactivate those currently closed, since, in geoscience, the use of data can change and it is necessary to continue with or without any specific need.  GNIP started in the early sixties to study the tritium coming from the nuclear tests.  Most of these stations are no longer active. The climate research community only recently started the intense use of the GNIP data for GCM calibration.  One conclusion of an intense discussion was that the unspecific term "reference station" should not be used.  The actual criteria for selecting reference stations are various, depending on the use of the data (climate, hydrogeology, hydrology) and on-going research.  It is also difficult, at a global scale, to define the most representative stations.  Local conditions are unknown and can heavily affect the isotope content in precipitation. The stations where temperature and amount effects are increased by local effects should be selected instead of stations where these effects reduce the signals.  It was decided that the criteria for "reference" stations will be: the stations to be maintained under all circumstances and the stations necessary to fill large gaps.
At this stage, the SSC was not able to give a more precise list of sites where stations can be installed.  The SSC recommended further to increase the network in combining the GNIP network with the GAW (chemistry in precipitation) stations.  The WMO will send this list to the IAEA to identify some additional stations that can participate in the GNIP network.
The scientific community should also try to better understand the physics of isotopes in order to better select stations. Isotopic composition of water vapour, together with an event based rain sampling, are necessary additional data for a better understanding of the physical behaviour of the isotopes in precipitation and to prove the suitability of monthly composites. Although, these data cannot be incorporated in the GNIP Database at the present stage, they will be included in ISOHIS (Isotope Hydrology Information System, IAEA).

* Strengthening the involvement of national networks and laboratories in the GNIP
In 1995, 54% of the GNIP data was provided by national networks.  Since this date, we notice a stability and even a small increase in their participation.
Some of the national networks are managed by the hydrological research community without direct help or support of their national authorities. This leads to difficulties in obtaining the climatological data necessary for the interpretation of the isotope data and also adds to the instability of the networks which are usually created only for specific and short-term research/projects.
The SSC felt that the national networks should have official support, meaning collaboration between the meteorological institutes, the isotope analysis laboratories and the political organisations.

Some of the existing national networks have, perhaps, not yet been identified.  It is necessary to try to approach the authorities working with precipitation and/or isotopes in order to complete the actual global network.  Meteorological services are actually the services more engaged in the management of the networks (for chemistry and others parameters).  Upon recommendation of the SSC, the WMO should approach Meteorological Services in countries where additional measurement of isotopes in precipitation are needed and invite them to contribute to the GNIP programme.

The SSC recognised a general need to strengthen the involvement of national networks in the interpretation of the data and not only in the sampling and subsequent analyses.  An annual publication presenting GNIP results should be sent to the participating national authorities.

The main problems encountered by some National Networks and the individual GNIP stations are the sampling and the shipment of the samples.  There was considerable debate about the possible payment of the sampling and/or shipment. The SSC felt that the sampling cannot and should not be paid in the case of official meteorological stations but it seems indispensable to find funds to help the shipment of the samples coming from the least developed countries.

* Data quality assurance
For the stable isotopes, it is difficult to verify the quality of the data because the natural variability of the isotope content is not predictable.  Most of the studies use stable isotope data coming from more than one station.  Often, these stable isotopes have been analysed by various laboratories and therefore, the use of different sources of data is a sensitive point. A report was provided to the SSC on the action taken by the IAEA to improve the quality of isotopic data entered into the GNIP database.
The Isotope Hydrology Laboratory (IHL) organised the 2nd interlaboratory comparison test for analytical laboratories engaged in routine analyses of hydrogen and oxygen stable isotopes.  Only one of the 26 laboratories actually sending data to the GNIP, did not participate in this exercise.  The apparent interlaboratory precision derived from the whole pool of the analysed results (from 85 laboratories) is in the order of 0,11 ‰ for d18O and 1,3 ‰ for d2H, which is similar to typical standard uncertainties reported by the majority of laboratories.  The results obtained from the "GNIP laboratories" are similar to those obtained from the whole group.  It seems that there is a shift towards more negative values which could be due to a slight evaporative enrichment of the internal standards with time after the calibration against VSMOW.  This systematic error can cause problems when data coming from different laboratories are mixed.  Individually, the laboratories have correct relative value but present a certain offset.  It is remarkable that the error in isotope measurement is much lower than the error given for some meteorological data (humidity).

The SSC expressed great satisfaction concerning this exercise and encouraged the IAEA to give continued support to analyses.  An interlaboratory comparison test should be organised regularly.

The second source of errors is the sampling procedure. The IAEA sends a form on the "technical procedure for sampling" to the participating institutes. It might be necessary to revise the sampling procedure and to edit a guideline.  A new device has been designed by the IHL and is being tested. The most important advantage of this new device will be the absence of paraffin oil to avoid the evaporation on the surface of the rain gauge/collecting container.  Snow sampling remains a problem for high elevation stations and high latitudes.  The SSC identified the need for the publication of a technical document on sampling procedures for isotope measurements.

Because of the importance of errors in using the GNIP data, the IHS envisaged adding to the database the uncertainties of the data and/or an indicator of the quality of the data entered (qualitative accuracy of the lab. performing the analyses based on the interlaboratory comparison test). The SSC agreed that the idea is good and more efforts should be made to maintain the data quality.

* Attracting funding from donors to support the activities of the GNIP
The possibility for private sponsoring is demonstrated by ISOHYC which received private support for a limited period of time.  At the moment, there are no private funds available for the management of GNIP but there are some for the scientific activities related to the application of isotope techniques. The donors can be considered as the scientists (and their Institutes) actually involved in isotope research and the national authorities providing support to their respective scientific institutions. Investigation, meetings, conferences organised by the scientific institutes are providing an impetus to the GNIP.

* Promotion of the utilisation of the GNIP Database
The SSC considered once again the desirability of a more attractive Web site.  The GNIP/Web site ( should place more emphasis on non-UN participation (laboratories and national networks). Citation of the National Authorities supporting the national networks should be added to the database. For some countries, a previous publication of the data is requested before their free distribution through Internet.
The World Data Centre-A for Paleoclimatology has a mirror site of GNIP, and the SSC urged the IAEA to ensure that this site is regularly updated.  The GPCC (Global Precipitation Climatology Centre) in Offenbach, Germany, which operates the World Data Centre is improving presentation of the data and the GNIP should benefit from the investment made for this database by various organisations.  The IAEA was requested to approach the institute in charge of the WDC.

The GNIP homepage should also have some direct links with scientific research on isotope and climate (like "recording ENSO with Isotopes" from the Max Planck Institute for Meteorology). The GNIP booklet should also be incorporated in the GNIP homepage.

The SSC expressed interest in having also a list of published articles using the GNIP data attached to the GNIP Home page and in keeping the national networks informed about the on-going research based on the GNIP data.

5. Status of GNIP and the GNIP database
Both the status of GNIP and the GNIP Database are appended as Annex 6 to this report.

6. Work plan and recommendation
- The Isotope Hydrology Section should continue efforts to enhance international recognition of GNIP.  An IAEA-SSC member is invited to present GNIP to the Working group on Coupled Modelling (WGCM) of WCRP at its meeting in September 1999.

 - WMO/IAEA should consider approaching the meteorological/hydrological services to help in the management of national networks.

- Contact should be established with the National Climatic Data Centre (NCDC) of the USA in order to have a direct link with the GNIP.

- The IAEA should contact the Institutes that can include in their Web site, a portion related on isotopes in precipitation in order to establish direct links with GNIP (Max Planck Institute, Laboratoire des Sciences du Climat et de l'Environnement (LSCE), ISOMAP,…).

- The list of national networks on isotopes in precipitation should be completed.

- WMO should approach the national meteorological services and provide them the report of the meeting.

- All the important publications of GNIP should be sent to the national networks and GNIP stations.

- IAEA should compile all the publications using the GNIP data, and this list should complete the information given to the national networks and GNIP stations.

- IAEA and WMO should send an annual report including main conclusions and recommendations of the SSC meeting report to the GNIP network stations and to the meteorological services participating in the programme.

- A short report of the SSC meeting should be sent to the newsletters of some Institutes and included in the CLIVAR newsletter Exchanges.
- The SSC recommended to include scientists from other continents (Asia, Australia, South America) in the SSC.

- The SSC asked that a task group be formed to consider the gaps and needs for more stations.

- Some regions have already been identified and should be contacted in order to start/continue sampling ( Brazil, tropical Andes, West Africa, India, Central Asia).

- The SSC recommended that the networks of Global Atmosphere Watch (GAW) of WMO be used as much as possible and as needed for the GNIP networks.

- The ISOHYC conference on Climate and Isotopes, earlier planned for May 1999, will take place in September 2000 in Hamburg, Germany.  The conference "In memoriam Hans Oeschger: Isotope Climatology" will be prepared by a working group composed of an IAEA staff member, a national network member, an ISOHYC member, H. Grassl and M. Latif.

Next meeting:

The SSC shall meet just after the planned Conference In Memoriam Hans Oeschger: Isotope Climatology in September 2000 in Hamburg.



This Memorandum of Understanding is made between the International Atomic Energy Agency (hereinafter referred to as the "IAEA") whose address is Wagramerstrasse 5, P.O. Box 100, A-1400 Vienna, Austria, and the World Meteorological Organization (hereinafter referred to as "WMO") whose address is 41, Avenue Giuseppe Motta, Geneva, Switzerland.

WHEREAS the relationship between the IAEA and the WMO is conducted within the framework of the Agreement between the International Atomic Energy Agency and the World Meteorological Organization;

WHEREAS anticipated changes in the water cycle and in climate call for collaboration among the institutions and organizations responsible for monitoring parameters indicative of those changes;

WHEREAS institutions in Member States have made available to the IAEA and WMO precipitation samples for isotope analysis and/or results of the observation of isotopic composition of atmospheric precipitation;

WHEREAS the IAEA and WMO desire to create a framework for co-operation to
sustain observation on the isotopic composition of atmospheric precipitation;

NOW, THEREFORE, the IAEA and WMO hereby agree on the following:

1 . The IAEA and WMO hereby establish a framework for co-operation to sustain observation on isotope composition of atmosphere precipitation as follows:

a) A Global Network of Isotopes in Precipitation (GNIP) which shall consist of the following components:


The lists of the stations/networks shall be agreed upon from time to time by the IAEA and WMO.

b) A data base which shall include all data provided by the GNIP and which shall be operated by the IAEA under the name of GNIP Data Base;

c) A Scientific Steering Committee which shall review operational and scientific aspects of the GNIP and the GNIP Data Base and advise the IAEA and WMO in matters related to the GNIP and the GNIP Data Base during periodic meetings. The terms of reference and composition of the Scientific Steering Committee are set out in Annex 1.

2. The basic mode of operation of GNIP stations referred to in Clause I (a), (b) and (c) above shall be:

a) the sampling of precipitation (monthly totals) at selected locations at which other relevant meteorological parameters will also be routinely observed, and

b) collection of meteorological data accompanying the samples, such as monthly mean surface air temperature, monthly mean water vapor pressure in surface air and monthly amount of precipitation.

3. Sampling, sample curation and subsequent shipment of samples to the analytical laboratories in Annex 2 shall be the responsibility of the operators of each station/network.  The protocols to be followed shall be as defined by the IAEA.  The effectiveness and quality of the sampling, sample curation and sample shipment procedures shall be established by the IAEA and the WMO.

4. The isotope and relevant meteorological data from the reference stations, the national networks and affiliated stations shall be collected by the IAEA and placed in the GNIP data base.

5. The IAEA shall, through interaction with the stations network, provision of standards, organization of inter-laboratory comparisons and provision of specialized training, ensure that the quality of the isotope data being collected is maintained at an appropriate level.

6. WMO shall recommend to its Members that all relevant meteorological data are collected at the reference stations (or the nearest available synoptic stations) and that their quality is maintained at an appropriate level.

7. The IAEA shall be responsible for:

a) liaison with analytical laboratories with a view to providing advise on effective isotope analyses of water samples and analytical quality;

b) isotope analysis of the water samples of at least 40 reference stations; and

c)      data archiving, management and dissemination.

8. The WMO shall be responsible for liaison with the national Meteorological and Hydrometeorological Services of its Members with a view to providing advise on

a) sampling of precipitation at the network stations;

b) shipment of the samples to analytical laboratories;

c) provision of relevant meteorological data to the stations network.

9. The IAEA and WMO shall, subject to the budgetary appropriations approved by their competent bodies, make the necessary financial arrangements for their activities to be carried out under the Memorandum of Understanding.

10. The IAEA and WMO may agree from time to time to explore the feasibility of liaison with other institutions, working in the area covered by this Memorandum of Understanding.

11. The IAEA and WMO agree that, to the extent practicable without cost to either organization and with prior consultation, they will allow other scientific institutions, governments and governmental bodies and other interested parties to have access to the data contained in the GNIP data base.

12. Neither Party may assign, transfer, pledge or make any other disposition of this Memorandum of Understanding without the prior written consent of the other Party.

13. Each Party shall be responsible for the acts or omissions of its employees, agents, and contractors in the execution of this Memorandum of Understanding.

14. All disputes arising out of or relating to the interpretation or implementation of this MOU, which cannot otherwise be settled by the Parties, shall be referred by either Party to arbitration for settlement in accordance with the UNCITRAL Arbitration Rules in force at the date the dispute is referred to arbitration.  The number of arbitrators shall be one.  The place of arbitration shall be Vienna, Austria.  The language of the arbitration shall be English.  The decision of the arbitrator shall be final and binding on the Parties.

15.  This Memorandum of Understanding may be terminated by either Party in whole or in part, upon sixty (60) days written notice to the other.

16. This Memorandum of Understanding may be amended or modified by written agreement signed by the authorized representative of the Parties.

17. This Memorandum of Understanding shall enter into force on the date of the last signature by the representatives of the Parties.

ANNEX 1 of the MoU
The GNIP - Scientific Steering Committee


The GNIP Scientific Steering Committee (GNIP-SSC) shall provide advice to the IAEA and
WMO on matters related to the GNIP and to the GNIP Data Base.

Terms of reference

The mandate of the GNIP SSC includes:

(a) annual review of the status of the GNIP and the GNIP Data Base;

(b) report to IAEA and WMO on the status of the GNIP and the GNIP Data Base;

(c) recommendations to IAEA and WMO on actions needed with respect to:
- interaction with major ongoing scientific programmes;
- definition of the reference stations and the necessary revisions/extensions;
- strengthening the involvement of national networks and laboratories in the GNIP and the GNIP Data Base;
- attracting funding from donors to support the activities of the GNIP;
- promotion of the utilisation of the GNIP Data Base.


1. The IAEA and WMO shall be represented on the GNIP SSC by two representatives of WMO (including a representative of WCRP), two representatives of IAEA, one representative of the Past Global Changes project (PAGES), a core project of the International Geosphere Biosphere Programme (IGBP).

2. The scientific community shall be represented by up to six members selected for a period of three years and with the possibility of one renewal selected by the IAEA and WMO.

3. The IAEA and WMO may invite representatives of other international organizations, programmes and National Networks to attend meetings of the SSC as observers.

4. The Chairmanship of the GNIP-SSC shall rotate every two years between the IAEA and WMO.


The regular meetings of the GNIP-SSC shall take place once a year.  Other meetings of the GNIP-SSC may be held as agreed between the IAEA and WMO.  The Parties shall determine the venue of each meeting.

ANNEX 2 of the MoU
Participating  Laboratories
Australian Atomic Energy Commission, Lucas Heights, NSW, Australia
Bergakademie Freiberg, Freiberg (Sachs), Germany
Boris Kidric Institute of Nuclear Sciences, Beograd, Yugoslavia
British Geological Survey, Maclean Builing, Crowmarsh Gifford, Wallingford, Oxfordshire, UK
Bundesanstalt für Gewässerkunde, Koblenz, Germany
Bureau de Recherches Geologiques et Minieres, Paris, France
Centre de Recherches Géodynamiques, Universite Pierre et Marie Curie, Thonon-les-Bains, France
Centre for Isotope Research, Groningen, The Netherlands
Centro de Energia Nuclear na Agricultura, Piracicaba, Brazil
Chalk River Nuclear Laboratories, Chalk River, Ontario, Canada
Columbia University, New York, NY, USA
Commonwealth Scientific and Industrial Research Organizations, Glen Osmond, South
Faculty of Physics and Nuclear Techniques, University of Mining and Metallurgy, Kracow, Poland
Hydrometeorological Service, Moscow, Russia
IAEA Isotope Hydrology Laboratory, Vienna, Austria
Institut für Hydrologie, GSF Forschungszentrum für Umwelt und Gesundheit, Neuherberg, Germany
Institut für Umweltphysik, Universität Heidelberg, Heidelberg, Germany
Institut Jozef Stefan, Ljubljana, Slovenia
Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand
Institute of Hydrogeology & Engineering Geology, Shiajiazhuang, Hebei, China
Institute of Isotopes of the Hungarian Academy of Sciences, Budapest, Hungary
Instituto de Geocronología y Geología Isotópica, Buenos Aires, Argentina
Instituto Tecnológico Nuclear, Sacavem, Portugal
Istituto di Mineralogia, Petrografia e Geochimica dell' Universita Palermo, Italy
Istituto Internazionale per le Ricerche Geotermiche, Pisa, Italy
Laboratoire de Biogeochimie isotopique. Universite Pierre et Marie Curie, Paris, France
Laboratorio de Aplicaciones Nucleares, CEDEX, Madrid, Spain
Laboratorio de Isótopos Ambientales, CCHEN, Santiago, Chile
Mass Spectrometry Laboratory, Division of Hydrology, University of Uppsala, Uppsala,
Österreichisches Forschungs- und Prüfzentrum Arsenal, Vienna, Austria
Physikalisches Institut, Universität Bern, Bern Switzerland
Radiocarbon Dating Laboratory, Stockholm, Sweden
Rudjer Boskovic Institute, Zagreb, Croatia
Tata Institute of Fundamental Research, Colaba, Bombay, India
Technische Hochschule, Darmstadt, Germany
Tritium Laboratory, University of Miami / RSMAS, Miami, Florida, USA
Umweltforschungzentrum Leipzig-Halle GmbH, Leipzig, Germany
United States Geological Survey, Reston, VA, USA
Universität Köln, Köln, Germany
University of California, La Jolla, California, USA
University of Chicago, Chicago, Illinois, USA
University of Iceland Reykjavik, Iceland
University of Waterloo, Ontario, Canada
University of Witwatersrand, Johannesburg, South Africa
Water Authority Laboratory, Ministry of Water and Irrigation, Amman, Jordan
Water Problems Institute, Academy of Sciences, Moscow, Russia
Weizmann Institute of Science, Rehovoth, Israel
Westwood Laboratories (Isotopes Inc.), Westwood, New Jersey, USA


 1. It seems essential that stations  are  at locations strategic within the general circulation and that they will function without interruption for a long time and at the same site. The network mapped does mostly not meet these criteria , but seems to be strongly compromised by the
constraints of finding willing collaborators.

2.Northeast Brazil is a  region with marked annual cycle of rainfall, associated with the Intertropical Convergence Zone,  it is drought-prone and subject to long-term variations. It has thus long been recognised as a prominent "problem climate".  Of the numerous long-term raingauge stations note in particular Fortaleza and Quixeramobim. FUNCEME is a functioning
regional institution, with which co-operation should be sought.

3.Amazon basin is of much interest in relation  to the issues of deforestation and long-term environmental change. It is the swath of land over which water vapor is transported from the tropical Atlantic to the Andes. Recycling is an issue for the water budget of the rainforest.  Of
the formerly dense network of rainfall isotope measurements little seems to be left. As a minimum Manaus and Belem should be envisaged, where long-term gauge records exist.

4.Tropical Andes, glaciers, Lake Titicaca:: link up with ORSTOM and national meteorological services to explore options for a few  sites that may offer the prospect of long-term functioning.

5. Chile: cultivate what has been started.

6. West African Monsoon system has marked seasonality of rainfall, again associated with the Intertropical Convergence Zone.  One should attempt to capture somewhat of a trajectory of the moisture transport from the Gulf of Guinea to the Sahel and beyond . A number of options  offer themselves at locations well taken care of by national meteorological services :Lagos, Abidjan, Niamey,  Bamako, Tombouctou. Then one should continue the transect northward. Take advantage of the Observatory at Tamanrasset in the Hoggar, and carry on to the Mediterranean, to end at Algiers Dar-el-Beida

7. The Indian monsoon system also merits more attention than what appears from the present map, and the India Meteorological Department seems an obvious partner. .

8.The glaciers of Central Asia have been monitored extensively in Soviet times, but what is left of that effort beyond the Abramov in the Pamir and the Tuyuksu in Tienshan? In the entire Chinese empire there is only one being monitored, Urumqui No. l.  Abramov is being taken care of by an institute in Tashkent, Tuyuksu by  colleagues in Almaty, and  that Chinese glacier is also under the wings of a large organization.  There are prospects for cooperation, and the glaciers merit sttention also in relation to isotope measurements.

Vienna, June 1999
Laurence GOURCY