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 (http://www.iaea.org/programs/ri/gnip/gnipmain.htm) 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.
Mr. T.W.D. Edwards (PAGES)
Department of Earth Sciences
University
of Waterloo
e-mail: twdedwar@uwaterloo.ca
Mr. K. Froehlich
e-mail: K.Froehlich@aou.at
Ms. L. Gourcy
Isotope Hydrology Section, IAEA
e-mail: L.Gourcy@iaea.org
Mr. H. Grassl
World Climate Research Programme
WMO
Mr. M. Latif
Max Planck Institut für Meteorologie
e-mail: latif@dkrz.de
Mr. U. Schotterer
ISOHYC
Physikalisches Institut der
Universitat Bern
e-mail: schotterer@climate.unibe.ch
Mr. A. Soudine
Environment Division
WMO
e-mail: soudine_a@gateway.wmo.ch
Representatives of National Networks
Mr. D. Rank
Österreichisches Forschungs- und
Prüfzentrum Arsenal
Ges.m.b.H.
e-mail: rank.d@arsenal.ac.at
Mr. W. Stichler
Institut für Hydrologie der GSF
e-mail: stichler@gsf.de
Expert from the Permanent Mission of Chile
Mr. A. Pollastri
e-mail:
apollast@ping.at
Experts from the IAEA, Isotope Hydrology Section
Mr. Manfred Groening
e-mail: M.Groening@iaea.org
Ms. Johanna Lippmann
e-mail: J.Lippmann@iaea.org
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:
ii) National networks composed of stations operated by national authorities;
iii) Affiliated stations which are stations resulting from studies, often of a short term nature, that are set up for various scientific/research purposes by national institutions.
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
effective:
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.
Scope
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.
Membership
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.
Meetings
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.
2. Experts representing the scientific community
- Environmental
Physics: U.Schotterer, ISOHYC, Switzerland
- Meteorology: S.
Hastenrath, USA
- Climatology: M. Latif, Germany
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.
1. RECENT EVOLUTION OF THE NETWORK
1975-80 - Increase of national networks (from 200 to 900 analyses per year)
1987 - Proposal to incorporate 36 new stations - Only 17 have provided data
1990-94 - Decrease of national networks (from 1200 to 450 analyses per year)
1995 - GNIP Web site
1998 - Memorundum of Understanding
1999 - First Scientific Steering Committee meeting
Isotope data (figure
1): Tritium: ~ 44 000
Oxygen-18: ~ 32 200
Deuterium: ~ 27 200
Meteorological data: Precipitation: ~ 61 400
Temperature: ~ 52 100
Water vap.
press.: ~41 900
Total number of stations included: 595 stations
123 with only tritium
58 with only stable isotope
49 laboratories
measuring tritium (28 countries)
39 lab. measuring stable isotopes (27
countries)
700 tritium data 300 samples measured at IAEA
400 samples at cooperating labs
770 stable isotope data 320 samples measured at IAEA
450 samples at cooperating
labs
| COUNTRY | SITUATION | RECENT EVOLUTION |
| Canada | 17 re-established | increase |
| China | 12 stations (since 1998) | increase |
| Australia | to be extended in 1999 | increase |
| Argentina | 15 stations | increase |
| France | 10 stations (since 1996) | increase |
| Spain | 14 stations (09/1999) | increase |
| Chile | 6 stations | stable |
| Germany | 19 stations | stable |
| Switzerland | 5 stations | stable |
| Austria | 80 stations sampled | stable |
| Netherlands | 4 stations | stable |
| Portugal | 5 stations | stable |
| South Africa | 4 stations | stable |
| New Zealand | 5 stations | stable |
| Italy | 3 stations | stable |
| Brazil | inactive? | decrease |
| USA (tritium) | reduced? | decrease |
| Russian Federation | closed | decrease |
Countries contributing to GNIP with 1-2 stations:
United Kingdom, Poland, Hungary, Slovenia, Croatia, Israel, Jordan, El Salvador, Monaco, Indonesia
5. SITUATION OF THE DATABASE AT THE END OF 1998
>30 years 26
>20
years 29
>10 years 58
>5 years 106
>= 1 year 188
< 1 year 66
Number of stations with tritium data: 410
Number of stations with
a tritium record of (figure
4):
>30 years 26
>20
years 47
>10 years 65
>5 years 115
>= 1 year 151
< 1 year 6
short term network (Philippines, Portugal) for specific studies 22 - 12
daily measurement rain+vapour (Portugal) 2
2 Research Contracts to help in installation of national network in China and Argentina
2nd release of the GNIP online and new software for the GNIP database
2nd interlaboratory comparison test for analytical laboratories engaged in routine analyses of hydrogen and oxygen stable isotope - 26 GNIP laboratories participating.
68,000 records --> 100,000 isotope data
~
35 % GNIP
~ 65 % National networks
Sampling is done on purely voluntary basis
Inadequate sampling in some cases > anomalous results
Missing
samples > Incomplete record > sending problem
Tritium analyses are decreasing in some National Network, not actually in IAEA
Need to define baseline (long-term) stations
(Guarantee continuity of
operation)
Need to increase quality (sampling and analyses)
Stability of GNIP (at a low stage) since 1994:
Lack of homegeneity in the distribution of stations
Closure
of some key long-term stations
Increasing importance of national
networks
Dedicated sampling mode and network operation (daily measurement, air moisture sampling, other isotopes…)
Links with other database