snow cover - Global Cryosphere Watch

WMO GCW Advisory Group Meeting
“Snow Watch” group of Products task team
Update on activities
Kari Luojus (FMI, Finland)
Ross Brown (Ouranos, Canada)
Barry Goodison, Jeff Key, Chris Derksen (EC)
23-24 January 2014 – WMO GCW Advisory Group Meeting
IMO, Reykjavik, Iceland
1) A brief background of Snow Watch (Toronto GCW meeting)
2) Snow intercomparison project ESA SnowPEX
3) Development of Hemispheric snow ”anomaly”
trackers for SE & SWE
4) An inventory of snow datasets
5) Additional items
- Memberships for the different actions?
- Budget & upcoming meetings?
Brief background of GCW Snow Watch
The Snow Watch project was initiated as an invited expert workshop at EC premises,
Toronto, January 2013, with goals to:
determine the current state of snow data, products and information,
particularly concerning satellite products (and relevant ground data)
identify any critical issues that need to be addressed (in regard to item 1)
make recommendations on the initial content and structure of the “project”
(“Snow Watch group” within “Products task team”)
The team chose to focus on a single piece of the overall puzzle - a single
parameter <snow cover> to keep activities manageable (for a limited team
without much funding) and still get moving forward “quickly”
Tackling all the parameters & issues …? (more time & budget is needed)
1st Snow Watch meeting, Toronto, Jan. 2013
• First workshop on implementing a Snow Watch component of
GCW hosted by Environment Canada at Toronto, Canada from
January 28-30, 2013.
• Twenty-eight scientists from nine countries (Austria, Canada,
Finland, Italy, France, Norway, Switzerland, United Kingdom and
USA) participated
• Aim:
• to determine the current state of global snow monitoring
• to identify critical issues affecting the ability to provide authoritative
information on the current state of snow cover
• to initiate “GCW Snow Watch sub-projects” to address priority areas
• Approach: Questionnaire, discussions at the meeting & hooking up key actors
for the identified priority areas
1st Snow Watch meeting, Toronto, Jan. 2013
The initial actions of the Snow Watch group, defined at the 1 st
meeting were:
• initiate a satellite snow products evaluation/intercomparison activity
• initiate a principal investigator self-assessment for snow products
• initiate a global snow data rescue activity
• develop hemispheric “snow anomaly trackers" for SE and SWE
• develop inventory of existing snow datasets
• initiate activity to standardize snow-related nomenclature
• improve NRT snow depth obs on GTS (zero value reporting,
missing regions) …<Gianpaolo will present this activity>
Snow intercomparison project – ESA SnowPEX
• Toronto Snow Watch meeting agreed that comprehensive evaluation/
intercomparison of snow cover products was a high priority (one of the
highest identified tasks from questionnaire) for GCW given the increase
in the number of products in recent years and the need to provide
uncertainty estimates for assimilation of data into operational snow
analysis schemes
• ESA offered to initiate a “Satellite Snow Products intercomparison
and evaluation EXercise – SnowPEX” project to be carried out by a
team of international experts beginning in 2014 (2 year project)
• Relevant for CryoNet as independent and integrated CryoNet sites could
serve as important independent data sources for such intercomparisons
of not only snow but also other cryosphere components
Snow intercomparison project – ESA SnowPEX
• The project will intercompare and evaluate current global/
hemispheric satellite snow products for assessing their quality and
for better quantifying the uncertainty of long term trends of the
seasonal snow pack deduced from satellite data.
• Parameters: snow extent (SE) and snow water equivalent (SWE)
• Lead: ESA T.O: B. Bojkov (ESA/ESRIN), PI: T. Nagler (Enveo, Austria)
• Team: C. Derksen (EC), R. Brown (Ouranos), K. Luojus (FMI), S.
Metsämäki (SYKE), R. Fernandes (CCRS)
• 2 International workshops to be arranged (summer 2014
Canada/USA & summer 2015 Europe Innsbruck?)
Snow intercomparison project – ESA SnowPEX
• Compilation of generally available reference datasets suitable
for algorithm and product evaluation (for SE & SWE)
• Assess & gather the reference data
• High to very high resolution optical data (Landsat, SPOT, …)
• Distributed data: snow courses/snow transects
• Different spatial scales
• Different temporal scales (climate & trend analyses)
• Goal: provide the reference data (where possible) to the whole
snow community – for self-assessment & development
Snow intercomparison project – ESA SnowPEX
• Example: various SE datasets for 2011
PI-led self assessment for snow products
• An initiative for a PI self-assessment of snow cover products
was proposed (in parallel to ESA SnowPEX) to provide
quick feedback on the strengths and weakness of current
snow cover products to the user community. This may help
avoid situations where products with known weaknesses
contribute to misleading conclusions
• Lead: R. Fernandes (CCRS);
• Team: D. Hall (NASA) & K. Luojus (FMI)
Development of Hemispheric snow ”anomaly”
trackers for SE & SWE
• The Snow Watch Group stimulated the development of new daily
“trackers” for Northern Hemisphere snow extent (SE) and snow water
equivalent (SWE).
• Snow trackers have been developed for GCW by the Finnish
Meteorological Institute and Environment Canada. The FMI SWE tracker
used SWE algorithms developed by GlobSnow, was initially developed
shortly after the meeting. These products are available in near real-time
on the GCW and Globsnow websites. Satellite, in-situ and operational
NWP analyses contribute to the development of these snow products.
These products are relevant to CryoNet, since in-situ snow depth data
are used in the algorithm to generate SWE. Hence standards, guidelines
and exchange of data in real-time for snow depth measurements are
very important for development and validation of products.
• Team: K. Luojus, R. Brown, C. Derksen, D. Robinson, S. Wunderle
These 3 trackers
are currently
Daily graphs
distrivuted via
An inventory of snow datasets
• The development of a baseline inventory of snow-related
datasets was considered an important priority for GCW
• A draft inventory is being prepared for discussion at a GCWrelated meeting in conjunction with this year’s Eastern Snow
Conference (ESC), to be organized in Boone, North
Carolina, USA 3-5 June 2014
• Team: R. Brown (Ouranos) & Julie Friddell (U. Waterloo)
Initiate activity to standardize snow-related nomenclature, and
promote standards and best practices as a contribution to CryoNet
• Standardization of observing practices and snow-related nomenclature
was considered a high priority activity in the questionnaire particularly
for snowfall and solid precipitation where practices vary widely
between countries.
• Jeff Key has led the compilation of standards and best practices for
cryospheric measurements for GCW, including snow measurements.
GCW is drawing on existing measurement methods where possible
and where a scientific consensus has been or can be reached. An
initial inventory of existing documents describing measurement
practices is given on the GCW website, under CryoNet
• A glossary has also being initiated for GCW by Jeff Key and currently
has over 2000 entries from several sources
• Action is a contribution to CryoNet development and will also
contribute to the work of the Infrastructure and Practices Team.
Additional items
• Identify/confirm interested experts for the different actions?
• Upcoming meetings – 2 alternative approaches:
• Low budget: “smaller” side meetings combined with
conferences & workshops (ESC, IGARSS, SnowPEX, …)
• WMO funded: a dedicated snow watch meeting…
• 2-3 day meeting in 2014?
• Hosted by?
• …Budget?
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