NASA Logo, National Aeronautics and Space Administration
LPVS website 
                banner

Web Standards to the rescue. One NASA Look and Feel CSS TEMPLATES

 

Focus Area on Snow Product Validation


Thomas Nagler, ENVEO, Austria

 

Snow Product Definitions

WMO definitions of snow cover

NSIDC (1) in general, the accumulation of snow on the ground surface
(2) the areal extent of snow-covered ground, usually expressed as percent of total area in a given region.
UNESCO In general, the accumulation of snow on the ground surface, and in particular, the areal extent of snow-covered ground (NSIDC, 2008); term to be preferably used in conjunction with the climatologic relevance of snow on the ground. See also snowpack.
METEOTERM Covering of the ground, either completely or partially, by snow.

These definitions are relevant to a specific user community but are ambiguous for the purpose of validation exercises. In this respect we refine these definitions of snow extent as:

Snow extent (SE) is defined as the unique area of snow covered surfaces projected on the local horizontal datum within a spatial mapping unit at a specified time. Here unique implies that the projected area from two vertically superimposed snow covered surfaces is only counted once. Also expressed as snow cover or snow fraction.

Units:
Snow extent, corresponds to SI units for area (m2).
Binary snow cover, snow/non-snow.
Snow cover fraction is expressed as a percentage or m2.


WMO definitions of Snow Water Equivalent

NOAA Hydrologic Terms The amount of water, in inches, obtained by melting a snow sample.
UNESCO In general, the accumulation of snow on the ground surface, and in particular, the areal extent of snow-covered ground (NSIDC, 2008); term to be preferably used in conjunction with the climatologic relevance of snow on the ground. See also snowpack.
NOAA Hydrologic Terms The water content obtained from melting accumulated snow.
NSIDC The water content obtained from melting.
NOAA Snow/Ice The water content obtained from melting accumulated snow.

Units:
Snow Water Equivalent: mm w.e.


Highest Validation Stage Currently Reached for Satellite-Derived Snow Cover Products

Validation stage 1-2 (LPV validation stage hierarchy) - The highest LPV validation stage reached for satellite-derived snow cover products. Limitations to reach higher validation stage include limited number of validation sites, spatial and temporal gaps of in situ reference data coverage.


Validation Good Practices Document

Snow extent and SWE validation good practices will be compiled by the ESA Satellite Snow product Intercomparison and Evaluation Experiment (SNOWPEX).


Snow Cover Validation Reference Data Sets

Open reference data sets are planned to be compiled from the ESA Satellite Snow product Intercomparison and Evaluation Experiment (SNOWPEX).

 

LPV Focus Areas

 

Meetings

North American CryoSat Science Meeting 20-24 March 2017, Banff, Alberta, Canada.

Polar and Snow Cover Applications User Requirements Workshop, June 23rd, 2016 in Brussels.

2nd International Workshop on Satellite Snow Product Intercomparison, Boulder, CO, September 2015.

1st Int'l Satellite Snow Product Intercomparison Workshop (ISSPI), College Park, MD, 21-23 July, 2013.

NASA Logo - nasa.gov