Global Cryosphere Watch - Satellites and Variables

Snow Dataset Inventory

Here is an inventory of satellite-derived, in situ, and analysis/reanalysis snow datasets, compiled by the Snow Watch Team as of 23 February 2015. This inventory of snow cover datasets was compiled following a recommendation of the GCW Snow-Watch meeting in Toronto, January 2013. The workshop highlighted the need for an up-to-date and comprehensive inventory of snow cover datasets in light of the significant increases in sources of snow cover information over the past decade. The inventory is provided in three categories: (1) Satellite-derived snow products and datasets, (2) Analyses, reanalyses and reanalysis-driven snow products and datasets, and (3) In-situ snow products and datasets. A dataset must be freely available online, represent an important source of information, and have supporting English documentation to be included in the inventory. The inventory is meant as a living document with updates and additions incorporated on an ongoing basis. To change, update or add datasets to the inventory please e-mail the required information to Ross Brown (ross.brown at canada.ca).

Scroll table up-down, left-right (after 1st column)

Product(s)	Type	Organization	Description	Period	Areal Coverage	Resolution	Variables	Frequency	Data Sources	Comments	References	Dataset Location	Contact
CryoClim Multi-Sensor Snow Cover Product	Satellite	ESA, Norwegian Computing Centre, Norwegian Met. Inst.	Combined optical and microwave fusion with SCE estimation based on Hidden Markov Model approach	1982-	Northern Hemisphere	5 km	snow / no snow	Daily, monthly, annual	SMMR, SSM/I, AVHRR GAC	An update of the dataset will take place in 2015/16 together with a more comprehensive validation	http://www.cryoclim.net	http://www.cryoclim.net/cryoclim/subsites/data_portal/	Rune Solberg (rune.solberg@nr.no)
Cryoland PanEuropean Fractional Snow Extent Product	Satellite	ESA, ENVEO	Snow cover fraction estimated from NDSI thresholding	Nov 2000-	Pan-European Domain; 35-72 deg. N 11-50 deg. E	~500 m	Fractional Snow Cover and uncertainty	Daily (latency < 1 day)	MODIS (VIIRS; Sentinel-3)	Some misclassification of patchy snow in spring/summer related to MODIS Cloud Product; larger uncertainties in rugged terrain as only one band is used in the snow cover calculations	not specified	http://cryoland.eu	Thomas Nagler (Thomas.nagler@enveo.at)
EURACSnowAlps	Satellite	Institute for Applied Remote Sensing, EURAC, Bolzano, Italy	Higher resolution snow cover estimates from MODIS using topographic correction for MODIS bands	2002-	European Alpine Arch (43-48 deg. N, 5-15 deg. E)	250 m	Fractional snow cover	Daily	MODIS, band 1 (RED) and band 2 (NIR) (for snow)	Improved mapping of snow in mountain regions compared to standard MODIS products especially patchy snow; Topographic correction cannot eliminate completely shadow effect in very steep slope especially during the morning acquisition (TERRA);Some limitations in detecting snow in forested areas; Some misclassification of snow-cloud	Notarnicola et al. (2013)	webgis.eurac.edu/snowalps/	Claudia Notarnicola (claudia.notarnicola@eurac.edu)
European Alps AVHRR SE dataset	Satellite	Remote Sensing Research Group, University of Bern, Switzerland	1 km snow extent climatology for the Alpine region derived from AVHRR data over the period 1985-2011	1985-2014	European Alps + Europe	1 km	snow / no snow		AVHRR		Hüsler et al (2014), Hüsler, et al (2012)	http://www.geography.unibe.ch/content/forschungsgruppen/fernerkundung/forschung/globsnow/index_eng.html	Stefan Wunderle (Stefan.wunderle@giub.unibe.ch)
Global 4KM Multisensor Automated Snow/Ice Map Product (GMASI)	Satellite	NOAA NESDIS	Combined optical and microwave retrievals with recurrent gap filling to maintain data continuity	2006-	Global	4 km	snow / no snow	Daily	MetOp AVHRR, MSG SEVIRI, GOES Imager and DMSP SSMIS		http://www.star.nesdis.noaa.gov/smcd/emb/snow/documents/Global_Auto_Snow-Ice_4km_ATBD_February_2014.pdf	Maps: http://satepsanone.nesdis.noaa.gov/; Data: contact PI	Peter Romanov (peter.romanov@noaa.gov)
GlobSnow Snow Extent	Satellite	ESA, Finnish Meteorological Institute (FMI)	Estimation of fractional snow covered area from SCAmod algorithm	1995-	Northern Hemisphere	0.01 deg	Fractional Snow Cover	Daily; weekly; monthly	ERS-2/ATSR-2 and EnviSat/AATSR	Global daily coverage not possible due to narrow swath width of AATSR; snow cover fraction may be overestimated over very dense forest due to low reflectance dynamics	Metsämäki et al. 2015	http://www.globsnow.info	Sari Metsämäki (sari.metsamaki@ymparisto.fi)
GlobSnow SWE	Satellite	ESA, Finnish Meteorological Institute (FMI)	Combination of climate station snow depth observations and forward microwave emission model simulations with SMMR and SSM/I satellite passive microwave data. Version 3.0 includes several enhancements: (1) inclusion of lake ice; (2) revised modelling of forest canopy Tb; (3) enhanced surface obs and QC. A V3 bias-corrected version includes corrections based on snow s	1979-	Northern Hemisphere	25 km	SWE	Daily; weekly; monthly	SMMR; SSM/I; AMSR-E; SSM/I-S	Evaluation with surface obs over Eurasia gave an RMSE of 30 to 40mm for SWE values below 150 mm; systematically underestimates SWE for snowpacks > 150 mm; SWE masked out over areas with complex topography, glaciers and ice sheets. The above issues are corrected in the V3 bias-corrected version of the dataset.	Takala et al., 2011; Pulliainen et al. 2020	http://www.globsnow.info	Kari Luojus (kari.luojus@fmi.fi)
GRACE	Satellite	NASA JPL, German Space Agency, ESA, University of Texas at Austin	Area-averaged estimates of terrestrial water storage anomalies (snow + ice + soil + ground water)	March 2002-	Global	1x1 deg. and 4X4 deg. grids	Water storage anomalies (depth)	monthly		Requires expert knowledge to use these data correctly. See Frappart et al (2011) and Forman et al (2012) for examples of GRACE applications related to snow water storage.	Landerer and Swenson, (2012)	Grace Products: http://podaac.jpl.nasa.gov/grace	Felix.W.Landerer@jpl.nasa.gov
Japanese Global Snow Cover Extent for Climate Dataset (GHRM5C)	Satellite	JAXA (Japan Aerospace Exploration Agency)	Estimate of global SCE from 5 channels of AVHRR and MODIS to create climate record from 1979	1979-2013	Global	0.05 deg	snow / no snow / wet snow	Daily, weekly, monthly	AVHRR (1979-2000), MODIS (2000-2013)	Higher resolution coverage than NOAA CDR product; Discriminates between dry and wet snow; Some missing months in 1980, 1981, 1994, 1995, 2001; Values over Antarctic are not valid; degraded performance in dense forest, cold desert and high mountains	not specified	http://kuroshio.eorc.jaxa.jp/JASMES/index.html	Masahiro Hori (EORC/JAXA) (hori.masahiro@jaxa.jp)
JAXA AMSR2 Snow Products	Satellite	JAXA	Rosenkrantz (1998) (11 yr RAOB + RT)	2012-	Near-global (daily)	10 & 25 km, swath	Snow Cover, SWE, SD	Daily	AMSR2 (18, 36, 10 23 GHz)			http://gcom-w1.jaxa.jp (V1 product)	Richard Kelly (rejkelly@uwaterloo.ca)
MEaSUREs Northern Hemisphere Terrestrial Snow Cover Extent Daily 25km EASE-Grid 2.0	Satellite	NSIDC	Snow cover presence/absence from three satellite sources plus a merged source estimate	1999-2012; MODIS in 2000-2012 period	Northern Hemisphere	25 km	snow cover presence/absence	daily	IMS, MODIS Collection 5 Cloud Gap Filled Snow Cover, PMW brightness temperature, merged estimate		Robinson et al (2014). NSIDC. DOI: 10.5067/MEASURES/CRYOSPHERE/nsidc-0530.001 ; http://nsidc.org/data/docs/measures/nsidc-0530/index.html#data_description	ftp://sidads.colorado.edu/pub/DATASETS/nsidc0530_MEASURES_nhsnow_daily25/	Hall, Robinson and Mote nsidc@nsidc.org
MEaSUREs Northern Hemisphere Terrestrial Snow Cover Extent Weekly 100km EASE-Grid 2.0	Satellite	NSIDC	Snow cover presence/absence from two satellite sources plus a merged source estimate	1966-2012; PMW in 1979-2012 period	Northern Hemisphere	100 km	Snow cover presence/absence	weekly	NOAA-CDR, PMW brightness temperature, merged estimate		Robinson et al (2014). NSIDC. DOI: 10.5067/MEASURES/CRYOSPHERE/nsidc-0531.001; http://nsidc.org/data/docs/measures/nsidc-0531/index.html#data_description	ftp://sidads.colorado.edu/pub/DATASETS/nsidc0531_MEASURES_nhsnow_weekly100/	Robinson and Mote; nsidc@nsidc.org
MODIS MODSCAG Products	Satellite	NASA JPL	Snow cover fraction estimated from spectral mixture analysis MODSCAG method	March 2000-	Global		Snow cover fraction (%)	Research Dataset	TERRA, AQUA		Painter et al. (2009)	http://snow.jpl.nasa.gov/portal/browse/dataset/urn:snow:MODSCAG	Tom Painter (Tom.Painter@jpl.nasa.gov)
MODIS Snow Products Collection 6	Satellite	NASA Goddard	Snow cover fraction estimated from the spectral characteristics of reflected solar energy. Daily data are cloud gap filled.	Terra: 24 Feb 2000; Aqua: 4 July 2007-	Global	500 m swath; 0.05 by 0.05 deg.	Snow cover fraction (%), cloud persistence count, QA assessment	day, 8-day, month	MODIS bands 1,2,4,6	More accurate mapping of spring and summer snow cover in mountainous areas achieved by removing the surface temperature screen	Hall, D. K., V. V. Salomonson, and G. A. Riggs, 2006.	NSIDC	Dorothy Hall (Dorothy.K.Hall@nasa.gov)
NASA Airborne Snow Observatory (ASO)	Satellite	NASA	Gridded snow depth data at 3-meter and 50-meter resolutions derived from airborne light detection and ranging (lidar) measurements of surface elevations; derived gridded SWE from 50-meter resolution snow depths	Various flight times from 3 April 2013 to 16 July 2019	River basins in the western United States	3-meter and 50-meter	Snow depth, estimated SWE, snow albedo	Various times	NSIDC		Painter et al. (2016)	https://nsidc.org/data/aso/data-summaries	NSIDC user services
NASA Prototype AMSR-E	Satellite	NASA	Combination of numerical techniques, snow emission modeling and climatology	2002-2011	Northern Hemisphere	25 km	SWE	Daily; monthly	AMSR-E				Marco Tedesco (cryocity@gmail.com)
NASA Standard AMSR-E	Satellite	NASA	19 and 37 GHz Tb difference; enhancements for vegetation and grain size evolution; distinction between shallow and deep snow	2002-2011	Northern Hemisphere	25 km	SWE	Daily; pentad; monthly	AMSR-E, AMSR2		Kelly, 2009	http://nsidc.org/data/docs/daac/ae_swe_ease-grids.gd.html	Marco Tedesco (cryocity@gmail.com)
NOAA AMSR2 Snow Products	Satellite	NOAA	Variation of NASA AMSR-E methodology	2014-	Global	25 km	Snow Cover, Depth, SWE	Daily	AMSR2	This is a new set of products that is generated routinely at CIMSS/University of Wisconsin, but will not be operational in NOAA until later in 2015			Yong-Keun Lee (yklee@ssec.wisc.edu) or Jeff Key (jeff.key@noaa.gov)
NOAA-CDR	Satellite	Rutgers University, NOAA, NCDC	89 x 89 Polar Stereographic grid (190.5 km spacing)	1966; Some missing months in 1966-1971 period	Northern Hemisphere	190.5 km	snow presence/absence based on 50% snow cover threshold (weekly); snow cover duration fraction % (monthly)	weekly, monthly	Mainly visible imagery (VHRR, AVHRR, VISSR, VAS); Based on IMS 24 km from June 1999-	Data extensively used for climate monitoring (e.g. IPCC, BAMS State of Climate), model evaluation and snow cover-climate studies. Mainly recommended for continental-hemispheric scale studies. Changes in charting procedures and satellite resolution and frequency have occurred over time that impact data homogeneity e.g. anomalous trends in autumn and summer SCE (Brown and Derksen 2013; Mudryk et al. 2014). Note that the monthly snow cover fraction is a duration fraction not an areal fraction.	Robinson et al. (2012) NOAA National Climatic Data Center. doi: 10.7289/V5N014G9; Robinson et al. (1993); Estilow et al. (2013)	http://climate.rutgers.edu/snowcover/	David Robinson (david.robinsonrobins@rci.rutgers.edu); Thomas Estilow (thomas.estilowesti@rci.rutgers.edu)
Theia Snow Product	Satellite	CNES, CESBIO	Snow cover presence or absence	Nov-15	Western Alps, Pyrenees, Atlas (to be extended to European mountains)	20 m	snow and cloud presence or absence	5 to 10 days	Sentinel-2	Real-time data production scheduled to start in December 2017	Gascoin, Simon, & Grizonnet, Manuel. (2017). Algorithm theoretical basis documentation for an operational snow cover extent product from Sentinel-2 and Landsat-8 data. Retrieved from http://tully.ups-tlse.fr/grizonne	theia.cnes.fr	Simon Gascoin (simon.gascoin@cesbio.cnes.fr)
US National Ice Center Operational Global Snow Products (IMS)	Satellite	NIC	Trained analyst interpretation of satellite imagery and derived mapped products	IMS 24 km 1997-, IMS 4 km 2004-, IMS 1 km 2015-	Northern Hemisphere, Global	1 km, 4 km, 24 km	snow /no snow	Daily	AVHRR, MODIS, GOES, SSMI, as well as derived mapped products (USAF Snow/Ice Analysis, AMSU, AMSR-E, NCEP models, etc.) and surface observations		Ramsay 1998; Helfrich et al. 2007	http://www.natice.noaa.gov/ims/	Sean Helfrich (sean.helfrich@noaa.gov)
20CR (V2)	Reanalysis	NCEP	Derived snow cover information from 4-layer Noah LSP model based on assimilating only surface pressure reports with observed; monthly sea-surface temperature and sea-ice distributions as boundary conditions.	1871-2012	Gobal	2 deg.	SD, snow cover fraction	3-hourly, daily, monthly; Note: 20CR includes the mean and spread from 56 ensemble members	Updated annually	Peings et al. (2013) found 20CR provided realistic simulations of snow cover onset variability over Eurasia.	Compo et al (2011)	http://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.html	Gil Compo, Research Scientist, CIRES University of Colorado compo@colorado.edu
Canadian Meteorological Centre (CMC) Daily Snow Depth Analysis	Reanalysis	Env. and Climate Change Canada	Optimal interpolation of real-time snow depth obs with first guess field generated by a snow model forced with analyzed air temp and forecast precip (Brasnett, 1999). Mean monthly SWE estimated from mean mly snow depth using mly mean snow density look-up table by snow-climate region (Brown and Mote, 2009)	Aug 01 1998 - July 31 2014	NH land area subset of global output corresponding to the 1024x1024 grid used by the IMS-24km product	The native resolution of the global analysis is ~35 km. The NH subset archived at NSIDC is interpolated to a 24 km Polar Stereographic grid	Daily SD, monthly average estimated SWE	daily, monthly average	Research subset over NH updated annually. Will be replaced in 2015 with a high resolution land data assimilation scheme using in situ and satellite obs.	Contains discontinuity in 2007 due to change in precip forecast. Quality assessment and error notes included in the online documentation at NSIDC.	Brown, Ross D. and Bruce Brasnett. 2010, updated annually. Canadian Meteorological Centre (CMC) Daily Snow Depth Analysis Data. Environment Canada, 2010. Boulder, Colorado USA: National Snow and Ice Data Center.	http://nsidc.org/data/nsidc-0447	Ross Brown (rdbrown@videotron.ca)
CanSISE	Reanalysis	Env. and Climate Change Canada	Gridded terrestrial SWE (average and spread) from 5 SWE products: GlobSnow V2, ERA-Interim/Land, MERRA, Crocus snowpack model driven by ERA-Interim, and GLDAS SWE product. See Mudryk et al. (2015) for a description of datasets and intercomparison results.	1981-2010	NH	1 deg.	SWE (avg, spread)	daily	Static	Provides an indication of the uncertainty in SWE from the spread in the 5 datasets. The multi-dataset average is typically more strongly correlated with surface observations than any single dataset. The gridding process created an artificial gradient around coastlines that can be removed by setting a minimum SWE threshold ~5-10 mm.	Mudryk, L. R. and C. Derksen. 2017. CanSISE Observation-Based Ensemble of Northern Hemisphere Terrestrial Snow Water Equivalent, Version 2. [Indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice	http://nsidc.org/data/NSIDC-0668	Lawrence Mudryk, Env. and Climate Change Canada, lawrence.mudryk@canada.ca
CFSR - Climate Forecast System Reanalysis	Reanalysis	NCEP	3DVAR assimilation using snow simulated by Noah 4-layer land surface process model, SWE obs from US Air Force daily snow depth analysis and snow cover analysis from IMS.	1979-2010; Version 2 updates from 2011	Global	0.5 deg.	Snow cover, SD, SWE	Hourly, 6-hourly, monthly	Ongoing. 1-2 month delay.	Klehmet et al. (2013) found CFSR to underestimate SWE over most of Siberia compared to GlobSnow and surface observations.	Saha et al. (2010)	http://rda.ucar.edu/pub/cfsr.html; http://rda.ucar.edu/datasets/ds093.1/	http://cfs.ncep.noaa.gov/cfsr/
ERA-40	Reanalysis	ECMWF	Assimilation of surface snow depth observations where available. Background field generated by LSP model driven by forecast fields (Douville et al. 1995).	1957-2002	Global	2.5 deg.	SWE, snow melt, snow sublimation, snowfall	6-hourly, daily, monthly	Replaced by ERA-interim	Snow depth observations between 1992 and 1994 inadvertently omitted from analysis. Khan et al. (2008) found reasonable agreement with surface obs over Russia.	Uppala et al. (2005)	http://apps.ecmwf.int/datasets/data/era40_daily/	http://www.ecmwf.int/
ERA5	Reanalysis	ECMWF	Assimilation of surface snow depth observations. NOAA IMS-4km SCE assimilated from 2004. Background field generated by H-TESSEL land surface scheme (de Rosnay et al. 2014).	1981-	Global	30 km	SCF, SWE, depth, density, evaporation, snowmelt, albedo, snowfall, snow layer temperature	hourly, monthly	Ongoing with back extension to 1950	Discontinuity in 2004 with assimilation of IMS-4km snow cover extent (Orsolini et al. 2019; Mortimer et al. 2020)	Hersbach et al. (2020)	Copernicus Climate Data Store, https://cds.climate.copernicus.eu	http://www.ecmwf.int
ERA5-Land	Reanalysis	ECMWF	Statistical downscaling of ERA5 fields to H-TESSEL land surface scheme (Dutra et al. 2020).	1981-	Global	9 km	SCF, SWE, depth, density, evaporation, snowmelt, albedo, snowfall, snow layer temperature	hourly, monthly	Ongoing with back extension to 1950	No known issues. Corrects the discontinuity in ERA5 snow.	Muñoz Sabater (2019)	Copernicus Climate Data Store, https://cds.climate.copernicus.eu	http://www.ecmwf.int
ERA-Interim	Reanalysis	ECMWF	Assimilation of surface snow depth observations where available. NOAA IMS-24km SCE assimilated from 2003. Background field generated by LSP model driven by forecast fields (Douville et al. 1995).	1979-2019	Global	0.75 deg.	SWE, snow density, snow melt, snow sublimation, snow albedo, snow temperature, snowfall	6-hourly, daily, monthly	Ended August 2019	Documented problems with the in situ snow depth assimilation from 2003-2010. The Cressman analysis method creates unrealistic spatial patterns in mountainous and data sparse regions.	Dee et al. (2011)	http://apps.ecmwf.int/datasets/data/interim_full_daily/	http://www.ecmwf.int/
ERA-interim/Land	Reanalysis	ECMWF	HTESSEL land surface model driven by ERA-Interim + GPCP v2.1 adjustments	1979-2010	Global	80 km	Snow water equivalent, albedo, density	6-hourly	Superseded by ERA5/Land		Balsamo et al., 2013	http://apps.ecmwf.int/datasets/data/interim_land/	Gianpaolo Balsamo gianpaolo.balsamo@ecmwf.int
GLDAS-1 (Noah, Vic, Mosaic and CLM LSMs)	Reanalysis		Suite of land surface models driven offline by GLDAS-1 output	1979-2020	Global	1 x 1 deg.	SWE, snow melt, snowfall rate (additional snow variables for the Vic simulation)	3-hourly, monthly	Decommissioned June 2020	"GLDAS-1 forcing data sources were switched several times, over the record from 1979 to present, which introduced unnatural trends and resulted in highly uncertain forcing fields in 1995-1997". (Rui and Beaudoing 2014)	NASA, Rodell et al., 2004; Online Documentation (Rui 2011): ftp://hydro1.sci.gsfc.nasa.gov/data/s4pa/GLDAS_V1/README.GLDAS.pdf	http://disc.sci.gsfc.nasa.gov/hydrology/data-holdings	http://ldas.gsfc.nasa.gov/gldas/
GLDAS-2.0 Reanalysis (Noah LSM)	Reanalysis		Noah land surface model driven offline by GLDAS-2 forced with the global meteorological data set from Princeton University (Sheffield et al., 2006).	1948-2014	Global	0.25 x 0.25 deg.	SWE, SD, snow melt, snowfall rate, snow sfc temp	3-hourly, monthly	Infrequent updates	Abnormally high SWE values over Greenland and other points with conditions conducive to land ice formation. These need to be masked out.	NASA, Rodell et al., 2004 ; Online documentation (Rui and Beaudoing 2014): http://hydro1.sci.gsfc.nasa.gov/data/s4pa/GLDAS/README.GLDAS2.pdf	http://disc.sci.gsfc.nasa.gov/hydrology/data-holdings	http://ldas.gsfc.nasa.gov/gldas/
JRA-25	Reanalysis	JMA	3D-Var data assimilation. Incorporates snow depth from SYNOP reports plus additional historical data from China. Snow cover extent from NOAA weekly product used prior to 1987; SSM/I-derived snow depth and snow cover used from 1987.	1979-2004	Global	~120 km	SWE, SD, snowfall	6-hourly, monthly	Replaced by JRA-55	Snow mass is not represented explicitly in the analysis. A constant snow density of 200 kg/m3 is assumed. Analyzed snow depths over Siberia prior to winter 1982/83 are too low due to omission of snow depth obs. See Onogi et al (2007) Section 4.1.2 for documentation of other snow-related issues in the analysis. Khan et al. (2008) found JRA-25 underestimated SD over most of the main Russian river basins.	Onogi et al. (2007)	Data support no longer provide by JMA; Data archived at UCAR; http://rda.ucar.edu/datasets/ds625.0/	Dave Stepaniak (303-497-1343). davestep@ucar.edu
JRA-55	Reanalysis	JMA	4D-Var data assimilation. Includes the same snow data sources as JRA-25 plus additional snow depth data over USA, Russia and Mongolia	1958-2012	Global	~60 km	SWE, SD	3-hr, 6-hr, daily, monthly	Static		Ebita et al (2011) http://jra.kishou.go.jp/JRA-55/index_en.html	3-hr, 6-hr and daily: http://rda.ucar.edu/datasets/ds628.1/; Monthly means and variances: http://rda.ucar.edu/datasets/ds628.1/	Dave Stepaniak (303-497-1343). davestep@ucar.edu
Liston and Hiemstra (2011)	Reanalysis	UCAR/NCAR	SnowModel driven by 10 km downscaled MERRA output. Incorporates SnowTran blowing snow model.	1979-2009	NH land area north of ~55N	10 km	SWE	Daily	One-off research dataset	No land/sea mask provided. SWE set to zero over water points.	Liston and Hiemstra, 2011	http://data.eol.ucar.edu/codiac/dss/id=106.309	Glen Liston, (Glen.Liston@colostate.edu)
MERRA Reanalysis (Catchment LSM)	Reanalysis	NASA	Catchment land surface model driven by MERRA's AGCM (3DVAR assimilation of mainly satellite-derived atmospheric variables and surface pressure obs)	1979-2016	Global	0.5 x 0.67 deg.	Snowfall, SWE, SD, Snow sfce and layer temps, Snowmelt, Fractional snow covered area	Variables available at hourly, synoptic, daily, and monthly averaging periods	Replaced by MERRA-2	No evidence of major discontinuities in SWE over the period	NASA, Rienecker et al., 2011	http://disc.sci.gsfc.nasa.gov/daac-bin/DataHoldings.pl	merra-questions@lists.nasa.gov
MERRA-Land Reanalysis (Catchment LSM with enhanced precip forcing)	Reanalysis	NASA	Catchment land surface model driven by MERRA's AGCM (3DVAR assimilation of mainly satellite-derived atmospheric variables, surface pressure obs and precipitation)	1979-2016	Global	0.5 x 0.67 deg.	Snowfall, SWE, SD, Snow sfce and layer temps, Snowmelt, Fractional snow covered area	Variables available at hourly, synoptic, daily, and monthly averaging periods	Replaced by MERRA-2	This version of MERRA-land contains a discontinuity in SWE related to changes to precip forcing (RDB). Does not perform as well as MERRA or MERRA-2 (Reichle et al. 2017).	NASA, Reichle et al. 2011	Data: http://disc.sci.gsfc.nasa.gov/daac-bin/DataHoldings.pl Variable definitions: http://gmao.gsfc.nasa.gov/products/documents/MERRA_File_Specification.pdf	Rolf Reichle, (rolf.h.reichle@nasa.gov; merra-questions@lists.nasa.gov)
MERRA-2 Reanalysis	Reanalysis	NASA	SWE diagnosed from MERRA, 2 fields with multilayer, physical snow pack model	1980-	Global	0.5 x 0.625 deg.	Snowfall, SWE, SD, Snow sfce and layer temps, Snowmelt, Fractional snow covered area	Variables available at hourly, synoptic, daily, and monthly averaging periods	Typically updated 2-3 weeks after the end of the month	Performance comparable to MERRA and ERA-Interim Land. Brown et al. (2018) found MERRA-2 ability to capture interannual variability in maximum annual SWE over southern Quebec was degraded compared to MERRA.	NASA, Gelaro et al. 2017; Reichle et al. (2017)	https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/data_access/	https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/diag_feedback.php
NARR	Reanalysis	NCEP	Based on the Noah land surface process model and assimilated snow depths from US Air Force daily snow depth analysis	1979-2014	North America	32 km	SD, SWE, snow cover fraction, snow melt, albedo	3hr, daily, monthly	Static	Found to greatly underestimate maximum SWE compared to Brown et al. (2003) historical analysis.	Mesinger et al. (2006)	3-hourly data: ftp://ftp.cdc.noaa.gov/Datasets/NARR/	http://www.emc.ncep.noaa.gov/mmb/rreanl/
NCEP/DOE (NCEP Reanalysis 2	Reanalysis	NCEP	Similar to Reanalysis-1 but allows snow accumulation from dynamic snow model.	1979-	Global	1.875 deg.	SWE	6 hours	Updated annually	Found to overestimate winter SWE cf GlobSnow over Siberia in period prior to 2001 and to underestimate from 2001 (Klehmet et al. 2013). Khan et al. (2008) report poor results over Russia for 1979-2004 period.	Kanamitsu et al (2002)	http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis2.gaussian.html	http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis2.html
NCEP/NCAR (NCEP Reanalysis 1)	Reanalysis	NCEP	3D-Var assimilation using snow cover from NESDIS weekly charts. Snow cover capped at 100 mm.	1948-	Global	1.875 deg.	SWE	6 hours	Updated daily	Snow fields not recommended for various reasons. See Khan et al. (2008) and Klehmet et al. (2013).	Kalnay et al. (1996)	http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surfaceflux.html	http://www.esrl.noaa.gov/psd/data/reanalysis/reanalysis.shtml
NLDAS LSM	Reanalysis	NASA	Mosaic, Vic, Noah and SAC LSMs forced with output from NLDAS-2	1979-	North America	0.125 deg.	SD, SWE, snow cover fraction, snow melt, sublimation	Hourly, monthly			Sheffield et al. (2003), Pan et al. (2003), Livneh et al. (2010), Rui and Mocko (2014)	http://ldas.gsfc.nasa.gov/nldas/NLDAS2model_download.php	David Mocko David.Mocko@nasa.gov
SNODAS (SNOw Data Assimilation System); NSIDC G02158	Reanalysis	NWS/NOHRSC	Output from snow modelling and data assimilation system run at NOHRSC. Incorporates satellite data, surface observations, and output from physical snowpack model.	30 Sept 2003-	Contiguous US and southern Canada up to 58.23 deg N	30 arc seconds	SWE, SD, Snowmelt Runoff, Snowpack temperature, Sublimation, Solid/Liquid Precipitation	NSIDC archives fields representing the model state for 06:00 Universal Time (UTC).	Operational product	SNODAS has varying spatial coverage over southern Canada. For eastern Canada, coverage is non-existent up to 2010, extends up to 50 deg N in 2011 and 2012, then extends to 58.23 deg N from 2013.	National Operational Hydrologic Remote Sensing Center. 2004. Snow Data Assimilation System (SNODAS) Data Products at NSIDC, Boulder, Colorado USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5TB14TC	http://nsidc.org/data/docs/noaa/g02158_snodas_snow_cover_model/	Andy Rost (andy.rost@noaa.gov)
Canadian Historical Snow Depth Data	In situ	Env. and Climate Change Canada	Mainly manual ruler observations (average of several measurements in open area free of drifting snow), but with more frequent SR50-equipped autostation observations in the period since ~2000.	1883-2017; Pan-Canadian coverage after ~1955	Canada	Variable spatial coverage; peak of ~2000 stations in 1980s; most data located south of ~55N	SD from manual ruler or SR50 sensor-equipped autostations	daily	Variable number of stations over time; peak of ~2000 stations in 1980s; rapid decline in station numbers after 1995. Dataset not updated regularly	Observations are made at open, grassed sites, often at airports, that may not be representative of snow conditions in the prevailing land cover. Manual ruler observations report systematically more snow than SR50 sensors.	Brown and Braaten (1998), Brown et al. (2021).	Dataset will be published on the Government of Canada Open Data site. Daily snow depth observations can also be downloaded from https://climate-change.canada.ca/climate-data/#/daily-cl	Ross Brown (rdbrown@videotron.ca)
Canadian Historical Snow Survey Data	In situ	Env. and Climate Change Canada	Mainly manual snow measurements of SWE from gravimetric method (MSC snow sampler) with snow pillow observations from mountainous region of western Canada	1928-2017	Canada	Variable density; network peaks at ~2000 surveys in period 1965-1985; most data located south of ~55N	Average SD and SWE from 5-10 point snow course	bi-weekly; observations tend to be concentrated in the 2nd half of the snow season to capture annual maximum SWE	Relatively few snow courses with 30+ years of continuous measurements. Dataset not regularly updated.	Due to proprietary data restrictions post-1985 observations from Quebec are not included in the dataset. These data were included in a 0.1 degree lat/long box average version of the data for the period 1950-2016.	Braaten (1998), Brown et al. (2019)	https://open.canada.ca/data/en/dataset/f57afb37-90c7-4ff0-a757-ba792a4f40a1	Ross Brown (rdbrown@videotron.ca)
Chinese historical daily snow depth data	In situ	China Meteorological Administration, National Meteorological Information	Manual observations of daily snow depth from ruler	1951-2014 updated annually	China	212 stations (GTS stations)	SD	daily	The length of station record varies across the 212 stations but the majority of stations have more than 50 years of data in the period since 1950.	SD is reported to nearest cm. SD is set to 32700 for trace values (SD < 0.5 cm) and 32766 for missing values. Data format is described in a Readme file included in the dataset. Some stations from the tropical regions of China have entirely zero snow depths.		ftp://ccrp.tor.ec.gc.ca/pub/RBrown/China_Snow_Data	Zhifu Zhang (zzfrain@126.com); Yu Yu (yuyu@cma.gov.cn)
French Alpine snow data,	In situ	Meteo-France	Snow depth, snow properties and climate observations from mountain stations run by Meteo-France partners for avalanche risk monitoring	1971-	French Alps	156 stations	snowfall, SD, liquid water content of snowpack, snowpack density, information on snow grain size	12 hours	Operational program			https://donneespubliques.meteofrance.fr/?fond=produit&id_produit=94&id_rubrique=32	http://www.meteofrance.com/contact
Global Historical Climate Network - Daily (GHCN-D)	In situ	NOAA NCDC	Daily snow depth observation from various sources subject to a common set of QC protocols.	1763-	Mainly countries reporting real-time snow depth observations to the WMO GTS/WIS	Spatial coverage highly variable in space and time; most dense coverage over NH mid-latitudes	SD, snowfall, SWE; other climate variables such as temperature, precipitation and pressure are also included in the dataset	daily	Station numbers vary in time. Data updated in near real-time		Menne et al (2012)	ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/ http://www1.ncdc.noaa.gov/pub/data/ghcn/daily/	http://www.ncdc.noaa.gov/oa/climate/ghcn-daily/
Integrated Surface Database (ISD)	In situ	NCDC	The Integrated Surface Database (ISD) consists of global hourly and synoptic observations compiled from numerous sources into a single common ASCII format and common data model. ISD integrates data from over 100 original data sources, including numerous data formats that were key-entered from paper forms during the 1950s–1970s time frame. http://www.ncdc.noaa.gov/isd	1902-	Global	~20,000 station; NH coverage most dense over mid-latitudes	SD, snowfall	sub-daily, daily			Smith et al (2011)	http://www.ncdc.noaa.gov/isd/data-access	http://www.ncdc.noaa.gov/contact
Morphometric Characteristics of Ice and Snow in the Arctic Basin: Aircraft Landing Observations from the Former Soviet Union, 1928-1989, NSIDC G02140	In situ	NSIDC		1928-1989	200 stations max.		SD, snow cover, density					http://nsidc.org/data/g02140
Russian Historical Snow Depth Data	In situ	RIHMI-WDC	Manual obs of daily snow depth (avg of readings from 3 fixed stakes)	1881-	Russia and Former Soviet Union	600 stations - higher density of coverage over European sector	SD; snow cover fraction	daily	Continuous measurements at most stations. Updated annually.		Bulygina et al (2011)	http://meteo.ru/english/climate/snow.php	Natalia Korshunova (nnk@meteo.ru)
Russian Historical Snow Survey Data	In situ	RIHMI-WDC	Manual snow surveys	1966-	Russia and Former Soviet Union	517 stations - higher density of coverage over European Sector	snow cover fraction, SD, SWE, ice crust presence and thickness; observations at both open and vegetated survey lines at some sites	1-3 times per month (typically every 10 days)	Continuous measurements at most stations. Updated annually.		Bulygina et al (2011)	http://meteo.ru/english/climate/snow1.php	Natalia Korshunova (nnk@meteo.ru)
SCAN Network	In situ	Natural Resources Conservation Service (NRCS) of US Dept. of Agriculture	Automated soil moisture/temperature stations with other climatic parameters including precipitation and air temperature. Snow depth and SWE at some sites	1991-	Across the USA and Puerto Rico and US Virgin Islands	221	SWE, SD at some sites. Mostly soil moisture/temperature and climatic parameters	Hourly, daily, 7-day, Monthly	Online data updated in near real-time	National soil moisture and soil temperature network	http://www.wcc.nrcs.usda.gov/scan/	http://www.wcc.nrcs.usda.gov/webmap/index.html	Mike Strobel (michael.strobel@por.usda.gov)
SNOlite	In situ	Natural Resources Conservation Service (NRCS) of US Dept. of Agriculture	Automated snow depth and snow water equivalent network across the western USA and Alaska in support of water resource and flood management. Basic sites have a snow depth and temperature sensor.	2012-	Concentrated in mountains of western USA and Alaska	22 sites	Snow depth and other climatic observations	Hourly,daily, 7-day, Monthly	Online data updated in near real-time	These data compliment SNOTEL observations and replace manual/aerial observation points	http://www.wcc.nrcs.usda.gov/snow/	http://www.wcc.nrcs.usda.gov/webmap/index.html	Mike Strobel (michael.strobel@por.usda.gov)
SNOTEL (Snow Telemetry)	In situ	Natural Resources Conservation Service (NRCS) of US Dept. of Agriculture	Automated snow depth and snow water equivalent network across the western USA and Alaska in support of water resource and flood management. Basic sites have a snow pillow, precipitation gauge and temperature sensor.	1979-	Concentrated in mountains of western USA and Alaska	853	Snow depth, SWE; additional climate observations, soil moisture and temperate at most sites	Hourly,daily, 7-day, Monthly	Online data updated in near real-time	NRCS data interface provides mainly single site access. Serreze et al (1999) developed a QCd compilation of SNOTEL data covering 1980-1998 period but it is not known if this dataset has been updated.	http://www.wcc.nrcs.usda.gov/snow/	http://www.wcc.nrcs.usda.gov/snow/snotel-wedata.html	Mike Strobel (michael.strobel@por.usda.gov)
Snow Survey of Great Britain	In situ	British Glaciological Society (1945-1953), Met Office (1953-2007)	Manual observation of the elevation of the local snowline (> 50% snow cover)	1945-2007	The data for Scotland are digitised; Great Britain data still paper records	145 stations in digitized dataset for Scotland	Snowline elevation	Daily (Oct-May)	Not all stations reported each year or for whole record	Example of data use: https://scottishsnow.wordpress.com/2014/11/09/derrylodge/	Spencer et al (2014)	http://badc.nerc.ac.uk/	Mike Spencer (m.spencer@ed.ac.uk)
USDA snow courses	In situ	Natural Resources Conservation Service (NRCS) of US Dept. of Agriculture	Manually measured snow courses in the Western US, Canada, and Alaska	1935--	Concentrated in mountains of western USA, Canada and Alaska	1,111 courses	SWE, SD	Monthly from January to June	Online data updated monthly	Data used for monthly water supply forecasts	http://www.wcc.nrcs.usda.gov/snow/	http://www.wcc.nrcs.usda.gov/webmap/index.html	Mike Strobel (michael.strobel@por.usda.gov)
Western Italian Alps Monthly Snowfall and Snow Cover Duration, NSIDC G01186	In situ	NSIDC	Monthly snowfall amounts and monthly snow cover duration in days	1877-1996	18 stations. Available stations range from 565 meters to 2720 meters in elevation.		Snow cover duration	monthly	The period of record varies with each station, with the longest station record including data from 1877 to 1996. The average station record duration is approximately 61 years.		Mercalli and Castellano ( 1999)	http://nsidc.org/data/g01186

Last updated 11 December 2020

Acronyms

AATSR	Advanced Along Track Scanning Radiometer (ESA)
AMSR-2	Advanced Microwave Scanning Radiometer on JAXA GCOM-W1 spacecraft, launched May 18, 2012. This instrument is currently operating.
AMSR-E	Advanced Microwave Scanning Radiometer on NASA's EOS Aqua spacecraft, launched May 4, 2002. The instrument stopped rotating Oct 4, 2011.
AMSU	Advanced Microwave Sounding Unit
ATSR-1/2	Along-Track Scanning Radiometer on ERS-1/2 (ESA)
Aqua	One of the two NASA MODIS satellites. The local equatorial crossing time is approximately 1:30 p.m. in an ascending node.
AVHRR	Advanced Very High Resolution Radiometer (NOAA, NESDIS)
AVHRR GAC	Global Area Coverage (reduced resolution image data processed onboard the satellite)
CDR	Climate Data Record
CMC	Canadian Meteorological Centre (Environment Canada)
ECMWF	European Centre for Medium-Range Weather Forecasts
EnviSat	Environmental Satellite (ESA)
EOS	Earth Observing System (NASA)
ERS-1/2	European Remote Sensing satellite (ESA)
ESA	European Space Agency
FMI	Finnish Meteorological Institute
GCOM-W1	Global Change Observation Mission – Water (JAXA)
GOES	Geostationary Operational Environmental Satellite system (NOAA, NESDIS)
GRACE	Gravity Recovery and Climate Experiment (NASA, German Aerospace Center)
IMS	Interactive Multisensor Snow and Ice Mapping System (NOAA, NESDIS)
INTAS-SCCONE	International Association for the promotion of co-operation with scientists from the New Independent States of the former Soviet Union — Snow Cover Changes Over Northern Eurasia
JAXA	Japan Aerospace Exploration Agency
JMA	Japan Meteorological Agency
MetOp	Series of three polar orbiting meteorological satellites operated by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT).
MODIS	Moderate Resolution Imaging Spectroradiometer (NASA)
MODSCAG	MODIS Snow Covered Area and Grain Size method for snow cover fraction retrieval
MSG SEVIRI	Spinning Enhanced Visible and Infrared Imager on the Meteosat Second Generation satellite (ESA)
NASA	National Aeronautics and Space Administration (US)
NASA Goddard	NASA Goddard Space Flight Center, Greenbelt, MD (US)
NASA JPL	NASA Jet Propulsion Laboratory, Pasadena, CA (US)
NCAR	National Center for Atmospheric Research (US)
NCDC	National Climatic Data Center (NOAA, US)
NCEP	National Centers for Environmental Prediction (NOAA, US)
NESDIS	National Environmental Satellite, Data, and Information Service (NOAA, US)
NIC	National Ice Center (US)
NIR	Near infrared
NMIC	National Meteorological Information Center (China)
NOAA	National Oceanic and Atmospheric Administration (US)
NOHRSC	National Operational Hydrologic Remote Sensing Center (NWS, US)
NSIDC	National Snow and Ice Data Center (US)
NWS	National Weather Service (
RIHMI-WDC	All-Russia Research Institute of Hydrometeorological Information - World Data Centre
Sentinel-3	Satellite in the ESA Copernicus mission
SMMR	Scanning Multichannel Microwave Radiometer (NASA)
SSM/I	Special Sensor Microwave/Imager (NASA)
SSMIS	Special Sensor Microwave Imager Sounder (NASA)
SWE	Snow Water Equivalent
Terra	One of the two NASA MODIS satellites. The local equatorial crossing time is approximately 10:30 a.m. in a descending node.
UCAR	University Corporation for Atmospheric Research (US)
USDA	United States Department of Agriculture
VIIRS	Visible Infrared Imaging Radiometer Suite (NASA)

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