edf8abd23f4a40aabd4d52e48dec06ea English 8-bit variable size UCS Transfer Format, based on ISO/IEC 10646 dataset NERC EDS Centre for Environmental Data Analysis 01235446432 RAL Space STFC Rutherford Appleton Laboratory, Harwell Campus Didcot OX11 0QX United Kingdom support@ceda.ac.uk pointOfContact 2026-05-13T03:35:38 UK GEMINI 2.3 WGS 84 ESA Snow Climate Change Initiative (Snow_cci): Snow Water Equivalent (SWE) level 3C daily global climate research data package (CRDP) (1979 - 2023), version 4.0 2025-09-04T16:10:21 publication 2025-09-04T16:10:21 creation https://catalogue.ceda.ac.uk/uuid/edf8abd23f4a40aabd4d52e48dec06ea edf8abd23f4a40aabd4d52e48dec06ea NERC EDS Centre for Environmental Data Analysis 10.5285/edf8abd23f4a40aabd4d52e48dec06ea doi This dataset contains v4.0 of the Daily Snow Water Equivalent (SWE) product from the ESA Climate Change Initiative (CCI) Snow project, at 0.1 degree resolution. Snow water equivalent (SWE) is the depth of liquid water that would result if the of snow cover melted completely, which equates to the snow cover mass per unit area. The SWE product covers the Northern Hemisphere from 1979/01 to 2023/12 with complex terrain, land ice, and large lakes masked. The dataset covers the Northern Hemisphere winter season (October – May; occasional data produced during June and September) at a daily frequency starting in October 1987 and every second day from 1979 to May 1987. Retrievals are not produced for coastal regions of Greenland. The product combines passive microwave data with ground-based snow depth measurements, via Bayesian non-linear iterative assimilation, to estimate SWE. It is based on data from the recalibrated enhanced resolution CETB ESDR dataset (MEaSUREs Calibrated Enhanced-Resolution Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature (CETB) Earth System Data Record (ESDR) https://nsidc.org/pmesdr/data/), resampled to the 12.5km EASE-Grid 2.0. A background snow-depth field, derived from re-gridded snow-depth observations made at synoptic weather stations, and a passive microwave emission model are the key components of the retrieval scheme. Snow density, which varies in both time and space, is parameterized from interpolated in situ observations from snow courses and snow pillows equipped with co-located snow depth sensors. The dataset is aimed to serve the needs of users working on climate research and monitoring activities, including the detection of variability and trends, climate modelling, and aspects of hydrology and meteorology. The Finnish Meteorological Institute (FMI) is responsible for the SWE product generation. The SWE development is carried out in collaboration by FMI and Environment and Climate Change Canada (ECCC). Changes from v3.1 The time series has been extended from version 3.1 by one year, to 2023. The retrieval algorithm has been modified to prioritize morning overpass (descending) data over evening (ascending) data. This change affects the SWE retrieval for all years except 1988–1991. Data from those years is from the F08 satellite, which has a reversed orbit, and evening (descending) data is prioritized, as in earlier versions of the SWE retrieval. Snow masking in post-production now uses CryoClim SCE data for 35–40° latitude and −30–3° longitude. Elsewhere, the baseline snow mask and CryoClim are combined so that any pixel flagged by either is marked snow-covered, as in v3.1. The pixel-wise uncertainty model has been updated for North America using extensive snow course data. Luojus, Kari Unavailable author Unavailable author Venäläinen, Pinja Unavailable author Unavailable author Moisander, Mikko Unavailable author Unavailable author Pulliainen, Jouni Unavailable author Unavailable author Takala, Matias Unavailable author Unavailable author Lemmetyinen, Juha Unavailable author Unavailable author Mortimer, Colleen Unavailable author Unavailable author Mudryk, Lawrence Unavailable author Unavailable author Schwaizer, Gabriele Unavailable author Unavailable author Nagler, Thomas Unavailable author Unavailable author NERC EDS Centre for Environmental Data Analysis custodian 01235446432 RAL Space STFC Rutherford Appleton Laboratory, Harwell Campus Didcot OX11 0QX United Kingdom support@ceda.ac.uk custodian NERC EDS Centre for Environmental Data Analysis distributor 01235446432 RAL Space STFC Rutherford Appleton Laboratory, Harwell Campus Didcot OX11 0QX United Kingdom support@ceda.ac.uk distributor NERC EDS Centre for Environmental Data Analysis point_of_contact 01235446432 RAL Space STFC Rutherford Appleton Laboratory, Harwell Campus Didcot OX11 0QX United Kingdom support@ceda.ac.uk pointofContact NERC EDS Centre for Environmental Data Analysis publisher 01235446432 RAL Space STFC Rutherford Appleton Laboratory, Harwell Campus Didcot OX11 0QX United Kingdom support@ceda.ac.uk publisher notPlanned dataset DMSP-F08 DMSP-F11 DMSP-F13 DMSP-F17 DMSP-F18 Nimbus-7 Level 3C MERGED snow SMMR SSM/I SSMI/S ESA CCI Snow SWE orthoimagery theme GEMET - INSPIRE themes, version 1.0 2008-06-01 publication otherRestrictions Public data: access to these data is available to both registered and non-registered users. otherRestrictions Under the following licence https://artefacts.ceda.ac.uk/licences/specific_licences/esacci_snow_terms_and_conditions.pdf, appropriate use of these data may fall under any use. This message is intended as guidance, always read the full licence. When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record. grid English imageryBaseMapsEarthCover -180.0 180.0 -90.0 90.0 1979-01-02T00:00:00 2023-12-31T23:59:59 NetCDF NERC EDS Centre for Environmental Data Analysis Data Center Contact 01235446432 RAL Space STFC Rutherford Appleton Laboratory, Harwell Campus Didcot OX11 0QX United Kingdom support@ceda.ac.uk distributor https://catalogue.ceda.ac.uk/uuid/edf8abd23f4a40aabd4d52e48dec06ea CEDA Data Catalogue Page Detail and access information for the resource information http://data.ceda.ac.uk/neodc/esacci/snow/data/swe/MERGED/v4.0/ DOWNLOAD Download Data download https://doi.org/10.1016/j.rse.2011.08.014 Takala et al, 2011, Estimating northern hemisphere snow water equivalent for climate research through assimilation of space-borne radiometer data and ground-based measurements, Remote Sensing of Environment. DOI:10.1016/j.rse.2011.08.014 No further details. information https://doi.org/10.5194/tc-15-2969-2021 Impact of dynamic snow density on Globsnow snow water equivalent retrieval accuracy. DOI: 10.5194/tc-15-2969-2021 No further details. information https://climate.esa.int/en/projects/snow/snow-key-documents/ Technical Documentation for Snow CCI No further details. information https://climate.esa.int/projects/snow Snow CCI webpages No further details. information https://climate.esa.int/ ESA Climate Change Initiative website No further details. information https://ieeexplore.ieee.org/document/763302 HUT Snow Emission Model and its Applicability to Snow Water Equivalent Retrieval. DOI: 10.1109/36.763302 No further details. information https://www.sciencedirect.com/science/article/abs/pii/S0034425706000241 Mapping of snow water equivalent and snow depth in boreal and sub-arctic zones by assimilating space-borne microwave radiometer data and ground-based observations. DOI: 10.1016/j.rse.2006.01.002 No further details. information https://climate.esa.int/media/documents/Snow_cci_D4.3_PUG_v5.1.pdf Product User Guide No further details. information https://climate.esa.int/media/documents/Snow_cci_D4.2_CRDP_v4.1.pdf Climate Research Data Package (CRDP) v4.1 No further details. information dataset Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services 2010-12-08 Data were produced by the project team and supplied for archiving at the Centre for Environmental Data Analysis (CEDA) as part of the CCI Knowledge Exchange project.