2.1 WMO/HWR
Dr Grabs provided an outline of the position of the Hydrology and Water Department of WMO. He informed the participants that to serve the needs of the United Nations Framework Convention on Climate Change, the fourth Conference of the Parties (COP-4) urged that Parties undertake programmes of systematic observations based on the requirements developed by GCOS. Hydrological data and information are included in the call to support national networks to collect, exchange and preserve terrestrial data. The WMO Commission for Hydrology (CHy) in which 125 countries and their hydrological services are represented, plays a vital role by supporting national and regional hydrological activities as well as global hydrological data collection initiatives.
For many reasons, it has traditionally been difficult to acquire hydrological data and information at regional and global scales on a routine basis for climate and water resources studies. In most countries, routine hydrological observations are made which could be used for climate research and monitoring purposes and for freshwater assessments. However, a comprehensive global hydrological network that serves observational requirements of several programmes and which operates on a set of agreed procedures for data collection, processing, dissemination, analysis and use does not yet exist.
The meeting objectives and agenda (see Annex II) are fully consistent with the expectations of the Hydrology and Water Resources Programme of WMO. The WMO World Climate Programme - Water (WCP-Water), which is jointly implemented with UNESCO, serves as a link between water and climate related issues in research and applications.
In the view of WMO, a global hydrological network is a milestone to advance our understanding of hydrological processes on regional and global scales, especially in the areas of coupled modelling and improved forecasting. The establishment of the network will also meet observational requirements of GCOS and GTOS.
WHYCOS, GRDC and GPCC are flagships of WMO in the collection of global hydrological data. These initiatives, in collaboration with other global projects such as the Continental Scale Experiments of GEWEX, are important pillars in the establishment of the global hydrological network that would produce near real-time data sets for climate users and for others in hydrology and water resources management. As the UN agency responsible for the collection of hydrological and related data, WMO is ready to oversee the establishment of a global hydrological network and to participate actively in the operation of the planned network.
2.2 GCOS
As background to discussing the goals of the meeting, Dr Thomas reviewed the results from COP-5, in particular decision 5/CP.5 on systematic observations. This decision has several important provisions relevant to a global hydrological network for climate:
Parties are to provide the COP with detailed national reports in accordance with the UNFCCC Reporting Guidelines on global climate observing systems, prepared by GCOS on behalf of its partner programs
The UNFCCC Secretariat, in conjunction with the GCOS Secretariat, is to develop a process for synthesising and analysing the information in the reports
COP, recognising the needs of developing countries for capacity building to participate in systematic observations, invited the GCOS Secretariat to organise regional workshops in consultation with international organisations, including the GEF.
Dr Thomas then addressed the implementation activities of GCOS related to these decisions of COP and the need for defining and implementing a global hydrological network for climate. Including a hydrology network in the revision of the UNFCCC Reporting Guidelines in the 2002 time frame should be a priority. The GCOS Steering Committee will be meeting in September 2000 and two issues for discussion should be of direct interest to this workshop: the GCOS Chair is interested in identifying the top priorities for terrestrial observing systems, and the GCOS Steering Committee will be discussing strategies for implementing networks, such as a global hydrological network for climate, based on national (or consortia of national) and agency contributions.
The GCOS view of the goals of the meeting is to:
Develop a vision and strategy for an initial end-to-end global hydrology observing system for climate
Define an action plan for an Initial Operational System that can be implemented in the next 2-3 years, including observing networks, production of near real-time data and products; centres/programs for monitoring data availability, quality control and assembly; and centres for data archiving and distribution
In particular, identify the requirements for satellite observations and for data assimilation techniques.
2.3 FAO
Dr Reichert discussed FAO interests in hydrology issues. Land and water are essential resources for agricultural production. Given that globally a large fraction (~75 percent) of fresh water is consumed by agriculture-related activities, its sustainable management is of vital interest to FAO and its member countries. Water is becoming increasingly scarce in many regions due to growing use for irrigation and the increasing consumption for domestic and industrial purposes, which can also affect the quality of water. Careful management of water resources is therefore imperative. This requires reliable and up-to-date information on its status and changes over time, in terms of quantity and quality.
The Land and Water Development Division of FAO has developed the AQUASTAT database as an information system on water in agriculture and development which produces regional analysis and country profiles on water resources (http://www.fao.org/waicent/faoinfo/agricult/agl/
AGLW/AQUASTAT/Aquastat.htm). FAO is also co-operating in the preparation of the World Water Report for the year 2002. Given the importance of water resources to FAO, the Organisation will contribute to the establishment of a global hydrological network for the collection, exchange and analysis of data on hydrology and the preparation of related products.
2.4 GTOS
Dr Reichert provided a brief perspective on GTOS. Availability of freshwater resources is one of the five key issues of GTOS, affecting also the other four (changes in land quality, biodiversity, impact of climate change, and effects of pollution and toxicity). GTOS, in co-operation with GCOS, has generated a list of critical variables to be observed in the assessment and monitoring of freshwater resources which forms part of the database on Terrestrial Ecosystem Monitoring Sites (TEMS). TEMS is presently being re-designed and upgraded with additional features, based on the recommendations of TOPC (see chapter 5.11 and GTOS (2000)).
Within GTOS, the Global Terrestrial Observing Network (GT-Net) has been established as a system of networks with similar thematic objectives (thematic networks) or covering a specific geographical region (regional networks). Thematic networks so far established include the ecology, glaciers and permafrost (see section 2.5). A thematic network for hydrology is envisaged as consisting of networks, institutions and sites that measure, monitor, archive, analyse and exchange hydrological data and products following commonly agreed standards. GTOS would be ready to host a hydrological network, assist in the establishment of a metadata base in the framework of TEMS and provide secretarial assistance including the reparation of meetings, establishment of HOPC and other support as might be required.
2.5 TOPC
Following a request by the GCOS Steering Committee for a meeting of experts, TOPC was one of the prime organisers for this meeting. In introducing TOPC goals relevant to the meeting, Dr Landwehr presented the following background information.
TOPC was established in 1995 as a scientific advisory panel to both GCOS and GTOS, to advise on issues which fall in both their spheres in the terrestrial domain. The terrestrial hydrologic systems, both continental and coastal, were included in this charge. A major initial concern of TOPC was to identify an over-arching set of terrestrial variables for which observations are needed globally to predict, detect and assess climate change. To this end, TOPC published the GCOS/GTOS Plan for Terrestrial Climate-Related Observations (GCOS, 1997). This report identified 65 variables in 9 terrestrial categories as necessary to establish the aforementioned task, and provided a justification for each variable with a suggestion of the spatial and temporal resolution with which observations are needed. The "Hydrology" category identified seven variables, namely, biogeochemical transport from land to ocean, evapotranspiration, ground water storage fluxes, precipitation accumulated as both solid and liquid, relative humidity, surface water flow as discharge, and surface water storage fluxes. Two additional variables in the list of 65 were also singled out as important for hydrologic purposes, namely snow water equivalent and soil moisture.
Subsequent to the identification of these variables, TOPC members have sought to ascertain the electronic availability of data for these variables. Their findings have been published in the Report of the GCOS/GTOS Terrestrial Observation Panel for Climate, Fourth Session, 1998, Corvallis, USA (TOPC, 1998). An additional variable of global hydrologic concern for terrestrial systems - water use - was identified in the TOPC report of its fifth session (TOPC, 1999). Water use is an untypical variable in the climate context, because it explicitly reflects anthropogenic forcing; however, water use information is critically important to detecting and understanding climate variability and change. These outcomes are also summarised on the Global Observing Systems Information Center (GOSIC) Internet site (http://www.gos.udel.edu/) which serves as an information dissemination point for the GxOS (GCOS, GTOS and GOOS) activities. In brief, some of the variable categories are data rich, but most are not and some are virtually non-existent.
To address the lack of available appropriate data, several global terrestrial networks have been established within GTOS with TOPC initiative. These include: GTN-G (for glaciers) supported by the University of Zurich, GTN-P (permafrost) with support of the International Permafrost Association, and GTN-E (ecology) in association with ILTER. In addition, GCOS had established an observation network for meteorological data based on operational systems and WMO protocols, the GCOS Surface Network (GSN). The major remaining gap is in hydrologic systems and hence, the need for a specialised network. However, hydrologic information poses unique challenges. Where it exists, most hydrologic data is collected for reasons of national and operational interest, rather than for research or scientific purposes, and frequently does not follow a tradition of global availability as with meteorological information as hydrologic observations are frequently limited by unique proprietary concerns. Ideally, the global hydrological network would provide hydrologic observations, either single time series or concurrent sets of information, with appropriate spatial and temporal resolution, and with appropriate quality assurance, in a timely manner that is easily accessible with minimal cost to all requesters.
Consequently, the TOPC objectives for this meeting were:
1. Develop a vision or framework for a global hydrological network
2. Develop a strategy for an end-to-end system, from observer to user
3. Identify existing resources, and
4. Develop an implementation plan.
