4.1.1 Dr. Roger Barry reported on behalf of Dr. Wilfried Haeberli regarding the status of the existing glacier monitoring network.
4.1.2 Two TOPC-relevant variables are observed: glacier length and mass balance. Changes in glacier length have been observed annually or every 5-10 years at about 800 sites worldwide, primarily by field surveys, in some cases for up to a century; the measurements are supplemented in remote areas by air photos and high resolution satellite imagery. These sites provide tier 4 information and their countries report those records to the World Glacier Monitoring Service (WGMS) in Zurich. Most climatic zones are represented but the sites are unevenly distributed, with considerable long term data in European countries and sparse data in the three primary regions (the coastal Alaska-northern British Columbia and the Yukon, the southern Andes, and the Karakorum-Himalayas) contributing melt water to the world ocean. To assess the range of variation in individual climatic zones will require the use of regionally differing statistical criteria for glacier selection. There is also considerable unassembled and unorganized air photo and satellite imagery which could provide a historical baseline for tier 5 data. Future plans by the US Geological Survey, Flagstaff, AZ are being developed for a Global Land Ice Monitoring from Space (GLIMS) program based on Earth Observing System Advanced Spaceborne Thermal Emission and reflection Radiometer (ASTER) sensor to be launched in early 1999. Glacier mass balance, which is a direct indicator of net water exchange is measured on about 60 small glaciers annually. The spatial coverage and representativeness is uneven: about 11 glaciological field stations, mostly in Europe and Asia, represent tier 2 while the remaining sites with annual mass balance measurements are tier 3. The data on Fluctuations of Glaciers (FoG) and Glacier Mass Balance, together with a partial World Glacier Inventory (WGI), are organized by the WGMS following recommendations prepared by UNESCO in 1969. WGMS belongs to the Federation of Astronomical and Geophysical data analysis Services (FAGS) of the International Council of Scientific Unions.
4.1.3 Recently, a data base system has been developed at the WGMS containing FoG data for 1970-1990 and part of WGI. It is accessible at: http://www.geo.unizh.ch/wgms
4.1.3 The meeting participants discussed the report and recommended that WGMD should:
identify gaps in the existing data bases and reporting network (tiers 3-5) and suggest a strategy to improve the situation to achieve TOPC/GCOS goals;
approach national contacts to obtain commitments to data reporting on a regular and timely basis;
finalize the draft strategy and guidelines documents to enable the preparation of invitation letters to WMO representatives of participating countries.
4.2.1 Dr. Barry reported on the draft proposal of the International Permafrost Association (IPA) for a Circumpolar Active Layer Monitoring (CALM) network. There are currently 69 CALM sites, mostly in the circum-Arctic. Observations are made annually of the maximum depth of the permafrost active layer; some sites also measure ground temperatures. Summary data for the last five years appear on the IPA web site: http://www.geodata.soton.ac.uk/ipa
4.2.2 Site metadata are published on the Circumpolar Active-Layer Permafrost System (CAPS) CD-ROM produced by the World Data Center-A for Glaciology, Boulder, CO. Annual transfer of the CALM data to WDC-A for Glaciology is planned, together with the establishment of a separate CALM web site. Version 2 of a measurement protocol is under development. Additional sites in the Southern Hemisphere, the subarctic and high mountain areas will be solicited. A working group of CALM regional partners and GCOS/GTOS will be organized and coordination with the EC program on Permafrost and Climate in Europe (PACE) is under development. The next steps will be to obtain the endorsement and approval of the IPA Council at its meeting in Yellowknife in June, 1998.
4.2.3 The meeting participants recommended that the IPA address the following issues:
assign CALM sites to GCOS/GTOS tiers;
assess the representation of various permafrost climatic regimes and identify any gaps in coverage;
evaluate options for filling any gaps in the CALM network;
formalise organisational arrangements within the IPA/CALM structure;
finalise the strategy and guidelines documents to enable preparation of invitation letters to the WMO representatives of participating countries.
4.2.4 The follow-up activities are captured in the 1998/99 work plan (Annex 8.).
4.3.1 Observations of the terrestrial hydrology are critical for G3OS. Potential stresses on water resource systems are of primary concern when considering the impacts of climate change because water availability is critical to human society, just as it is for terrestrial ecosystems. Hydrologic variables, such as river discharge or fluctuations in a closed basin lake, provide an integrated assessment of climatic conditions over a river basin, and so are stand-alone indicator variables of regional climate trends. Importantly, hydrologic information is also needed in conjunction with meteorological variables to validate climate models as well as to close regional and global water budgets. The quality and quantity of freshwater input into the ocean also needs to be assessed, both to understand the transport of terrestrial material (such as sediments and carbon) into coastal systems and to quantify salinity changes in climatically critical ocean regions.
4.3.2 Hydrologic observations are commonly made in all countries, but there are no established international hydrologic monitoring networks although several collections of historic international data do exist. This situation exists for many reasons: funding agencies that pay for these expensive in-situ observations have national or regional concerns rather than global; there are generally no compelling reasons for local agencies to share information; national sensitivities to various water resource issues encourage centrifugal tendencies; etc.
4.3.4 Dr. Kibby briefly reviewed the present situation in hydrological data networks and data collection, including previous contacts and discussions undertaken by TOPC. These followed a meeting of experts in Geneva (GCOS, 1996) at which a number of important conclusions regarding terrestrial hydrological observations for climate were reached.
4.3.4 The difficulties involved in advancing the state of co-ordinated global hydrological observations were analysed in a subsequent discussion group and reviewed in the plenary session. It was agreed that TOPC should aim to make progress in areas where incremental, near-term improvements are realistically achievable, while stimulating consideration and discussion of more complex, longer-term issues. The specific activities and recommendations are:
Recommendation 1: Assess the availability of historic international stream discharge records to the TOPC user community.
Action: Consult with the Global Runoff Data Centre (GRDC) on the present practices and data availability, including discussions with present data users.
Recommendation 2: In collaboration with GRDC investigate the feasibility of routinely providing, on behalf of GTOS, certain specific discharge observations at global or continental scales in the future.
Action: Consult with GRDC about the feasibility of such a plan. The first draft of the proposal is given below:
What/Where:
Provide data records for rivers discharging into the ocean, when any one of three conditions is met:
The river is among the top 300 major inputs of freshwater into the ocean. This should account for about 60% of the estimated continental runoff (= precipitation minus evaporation) which flows into the oceans.
The river is a major freshwater source for a climatically sensitive region of the oceans, e.g. the North Atlantic or the Arctic Ocean.
The river basin contributing the outflow has a population of above 1,000,000 inhabitants.
When:
The data provided should include monthly and daily averages, as well as the maximum instantaneous annual peak event.
How:
These data could possibly be made available by GRDC via web access, perhaps following the example of the USGS water information web page, or any other means of easy data entry.
Recommendation 3: Asses the availability of the Flow Regimes from International Experiments Data (FRIENDS) data sets to the G3OS community.
Action: TOPC should approach FRIEND to investigate the availability of research data sets developed by the program to the general hydrologic and meteorological community, in particular, for access through the Global Observing Systems Information Centre (GOSIC).
4.3.5 The World Hydrological Cycle Observing System (WHYCOS) is implementing a number of regional networks to improve hydrological monitoring. Many of the collected data sets have strong potential to contribute to the monitoring of climate changes and impacts on the terrestrial hydrological cycle. Since the WHYCOS data are obtained for a variety of reasons, there is a need to examine the availability of the acquired data sets for climate-related applications, and to assist in making adjustments where this is feasible or desirable.
Recommendation 4: Assess linkages of GCOS and GTOS to the WHYCOS Network and the availability of WHYCOS data for climate purposes.
Action: TOPC should inquire about WHYCOS willingness to share its observations with TOPC, and should maintain a continuing contact with WHYCOS.
Recommendation 5: Develop or encourage the development of a hydrologic network of pristine discharge stations for climate purposes.
Action: Publicize the need among international hydrologic programs/associations, such as the International Association for Hydrological Sciences (IAHS) and IGBP, for an international hydrologic network of pristine river observations, using the USGS Benchmark network as a paradigm. A straw-man plan for the such network would include:
What/Where:
The observation sites could possibly be located in national parks throughout the world. It may be possible to combine these with a BAHC (Biospheric Aspects of the Hydrological Cycle) proposal to develop a high mountain gauging network. The number of identified sites would probably not exceed 100 sites on a global basis.
Interest in developing this network could be promoted in the following ways:
Describe a straw-man sampling scheme as part of a TOPC presentation on international hydrologic observations during the IAHS workshops at the forthcoming IUGG meetings in 1999 (see Section 12.2);
Consult with various entities representing different aspects of international hydrologic activities, such as IAHS, GEWEX, IGBP, IHP, BAHC, perhaps also during the IUGG meeting in 1999;
Prepare an article about TOPC activities, including discussion of hydrologic proposals for hydrology, to a journal such as EOS, SCIENCE or NATURE that will reach the international scientific community.
4.3.6 Because of the complexities of the various issues, the above TOPC activities focus on surface water quantity observations, and sets aside questions pertaining to ground water and water quality.
4.4.1 Dr. Gosz reviewed the current situation in the establishment of the GT-Net (see also Section 2.2). Following the Guernica meeting, letters of invitation were sent to a number of the networks represented at the meeting. Numerous positive replies were received by the GTOS Secretariat. Under Dr. Gosz' direction, the LTER Secretariat proposed to act as the secretariat for the GT-Net. This proposal was endorsed, and funding support is expected from the U.S. National Science Foundation and from the GTOS Secretariat. This will be used to set up data management support for the NPP demonstration project (refer to Section 5.1). The draft terms of reference for the GT-Net proposed by the LTER Office are reproduced in Annex 7.
4.4.2 The status of the GT-Net, the terms of reference, and related activities will be considered by GTSC at its next meeting in June, 1998. The participation of networks and sites not represented at the Guernica meeting will also be addressed by GTSC.
