GCOS Implementation Plan - WMO

Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC
(2010 Update)
Discharge (GTN-R). Data from these stations will capture about 70% of the global freshwater flux to
the oceans (see Figure 12). All these stations have reported at some time in the past, and most are
operating today. This network is now being adjusted in consultation with national hydrological
services, and a total of 185 stations have been confirmed. The status of another 265 stations has not
yet been clarified.
Figure 12: Baseline River Discharge Network (GTN-R) based on the GRDC priority stations
(Source: GRDC).
The WMO, through CHy, will request that the National Hydrological Services responsible for the
stations marked in Figure 12 (a) evaluate the identified gauging stations, determine their operational
status and provide the GRDC with this information, i.e., all existing data and metadata, including the
measurement and data transmission technology used; and (b) ensure that daily discharge data be
submitted to the GRDC within one year of its observation (definition of “near-real time”).
Whilst the emphasis will be initially on the priority stations and a reporting delay of no more than one
year, it is a limited but important step towards the ultimate goal of near real-time receipt from as many
stations as possible on all significant rivers. Some stations are currently able to transmit near realtime
data; others need to be upgraded. The GTN-R, in cooperation with WMO CHy, will develop
standards for the near real-time transmission to the GRDC of river discharge observations taken by
the National Hydrological Services. When these standards have been developed, they will be
presented to CHy for its approval, and then promulgated by WMO. Implementation will be assessed
by the number of priority stations reporting annually with a maximum one-year delay, by the number
of near real-time stations established, by the amount of data transferred or made accessible, and by
the number of countries submitting timely data to the GRDC.
Long-term, regular measurements of upstream river discharge on a more detailed spatial scale than
GTN-R within countries and catchment areas are necessary to assess potential impacts of climate
change on river discharge in terms of river management, water supply, transport and ecosystems.
Parties should take steps to assess their individual needs for such measurements, and propose steps
to fill gaps in their river gauge network, as identified.
Action T6 [IP-04 T4]
Action: Confirm locations of GTN-R sites, determine operational status of gauges at all GTN-R sites,
and ensure that the GRDC receive daily river discharge data from all priority reference sites within
one year of their observation (including measurement and data transmission technology used).
Who: National Hydrological Services, through WMO CHy in cooperation with TOPC, GTOS, GRDC.
Time-Frame: 2011.
Performance Indicator: Reports to WMO CHy on the completeness of the GTN-R record held in the
GRDC including the number of stations and nations submitting data to the GRDC, National
Communication to UNFCCC.
Annual Cost Implications: 1-10M US$ (60% in non-Annex-I Parties).
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