GCOS Implementation Plan - WMO

Implementation Plan for the Global Observing System for Climate in Support of the UNFCCC
(2010 Update)
health. Monitoring soil moisture is critical for managing these resources. This variable must be
developed within the GCOS framework to ensure proper coordination with other land surface
variables. In situ soil moisture activities can build on the soil-moisture data archive at Vienna
University. A satellite-based soil moisture product from the Advanced Scatterometer (ASCAT) has
recently been made available and could potentially contribute to a longer-term record by building on
data from earlier scatterometers. The various ways of representing soil moisture from both satellite
and in situ measurements, in combination with climate models, need harmonization and ultimately
standardisation. This could be achieved by an expanded network of reference stations to support the
validation of satellite measurements with in situ data. With this objective, a Global Terrestrial Network
for Soil Moisture (GTN-SM) will be initiated with the aid of TOPC.
Action T13
Action: Develop a record of validated globally-gridded near-surface soil moisture from satellites.
Who: Parties’ national services and research programmes, through GEWEX and TOPC in
collaboration with space agencies.
Time frame: 2014.
Performance indicator Availability of globally validated soil moisture products from the early
satellites until now.
Annual Cost Implications: 1-10M US$ (10% in non-Annex-I Parties).
Action T14
Action: Develop Global Terrestrial Network for Soil Moisture (GTN-SM).
Who: Parties’ national services and research programmes, through IGWCO, GEWEX and TOPC in
collaboration with space agencies.
Time frame: 2014.
Performance indicator: Fully functional GTN-SM with a set of in situ observations (possibly
collocated with reference network, cf. T3), with standard measurement protocol and data quality and
archiving procedures.
Annual Cost Implications: 1-10M US$ (40% in non-Annex-I Parties).
ECV – Snow Cover
Snowfall and snow cover play key roles with respect to feedback mechanisms within the climate
system (albedo, runoff, soil moisture, and vegetation) and are important variables in monitoring
climate change. About one third of the Earth's land surface is seasonally snow-covered and seasonal
snow melt is a key factor in runoff regimes in middle and high latitudes as well as in many other high
altitude locations. Snow depth and snow-cover duration affect the permafrost thermal state, the depth
and timing of seasonal soil freeze/thaw /break-up, and the melting of land ice and sea ice.
Many problems arise because: (a) snow-cover data are collected, even within one country, by several
agencies with differing goals; (b) funding support for snow research is fragmentary and not wellcoordinated;
(c) budget restrictions and attempts to reduce the cost of surface networks often result in
reduced coverage or automated measurement using different instrumentation whose compatibility is
not yet determined and (d) many existing datasets are not readily accessible.
The submission of in situ snow observations from the WWW/GOS surface synoptic network has
continued to show some decline due to financial pressures in many countries that have led to
closures of remote northern observation stations. In addition, there are major observational gaps in
mountainous areas and in Antarctica. Data receipt from the remaining stations has also been an
issue, with few stations including snow data in their submissions to the WMO Global
Telecommunication System (GTS) and not all providing the WMO SYNOP reports that normally
include snow parameters. Furthermore, there is no systematic global monitoring of the amount and
quality of in situ snow-related reports exchanged over the GTS. As a result, the creation of wellcalibrated
satellite products has been made more difficult.
Maintenance of adequate, representative surface networks of snow observations must begin with
documentation and analysis of the network densities required in different environments. Resolution of
the problem of data inaccessibility requires: promoting political commitment to data sharing, removing
practical barriers by enhancing electronic inter-connectivity and metadata, and data rescue and
digitization. The provision of necessary resources to improve, and to make available, existing archives
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