Focal point: Thomas Maurer
real-time river discharge data capturing freshwater flux
Global Terrestrial Network for River Discharge (GTN-R).
The 380 river discharge stations along continental coastlines
cover 355 of the 391 basins depicted here (status as of
24 March 2005). The colour code indicates the latest data
available in the GRDC database.
Global Terrestrial Network for River Discharge (GTN-R) is
a recently launched project of the Global Runoff Data Centre
(GRDC), aiming at improving access to near real-time river
discharge data for selected gauging stations around the
world, capturing the majority of the freshwater flux into
oceans (Figure 1). GTN-R will draw together the already
available heterogeneous information on near-real-time river
discharge data provided by individual national hydrological
services, and redistribute the data in a harmonized way.
GTN-R is supported by an action item in the GCOS Implementation
Plan, published in October 2004.
will serve an increasing user community by supporting several
activities, including the GCOS baseline river discharge
network; GTN-H; future versions of the GRDC Long Term Mean
Annual Freshwater Surface Water Fluxes into the World Oceans
product; biogeochemical flux computations of the GEMS/Water
Programme Office (UNEP/DEWA); the WHYMAP project; and an
increasing number of activities and projects in the fields
of climate and hydrological research and monitoring.
has identified a priority network of around 380 river discharge
reference stations and associated river basins. Feedback
from local institutions will allow further refinement of
this initial network. A metadata file of the network can
be downloaded from the GTN-R Web site, as well as tables
summarizing the acquisition progress. In addition, the Web
site offers four visualizations of the network: images;
interactive ESRI-ArcReader map application; dataset for
use with the 3D-visualization software WorldWind (NASA);
and a map server based on Google-Maps.
core of GTN-R is software (currently being developed at
GRDC) that collects near-real-time discharge data from distributed
servers via the internet, harmonizes and summarizes them,
and makes them available again in a single, standard format
through an FTP server. GRDC is also developing an application
that will graphically display the collected and harmonized
data in an interactively scaleable world map that can be
accessed through the Web (similar to http://grdc.bafg.de/?9931).
Absolute and relative current discharge values will be displayed
GRDC has recently been contracted by the Joint Research
Centre (JRC) of the European Commission to provide services
very similar to GTN-R at the European scale, in support
of the European Flood Alert System (EFAS), a JRC research
project. Analogous to GTN-R, the associated project is called
European Terrestrial Network for River Discharge (ETN-R).
It significantly strengthens GRDC’s capacity, as both
projects require the same software tools and all developments
will symbiotically be applicable for both European-scale
and global-scale purposes. Moreover, ETN-R will foster data
contribution to GTN-R from European countries.
success of GTN-R is critically dependent on the regular
provision of near-real-time river discharge data from the
reference stations. GRDC thus kindly requests the assistance
of all organizations able to assist in providing access
to available data. For further information, please see the
corresponding sections on the GTN-R Web site.