A long-term Northern Hemisphere snow cover extent data record for climate studies and monitoring

Abstract

Abstract. This paper describes the long-term, satellite-based visible snow cover extent National Oceanic and Atmospheric Administration (NOAA) climate data record (CDR) currently available for climate studies, monitoring, and model validation. This environmental data product is developed from weekly Northern Hemisphere snow cover extent data that have been digitized from snow cover maps onto a Cartesian grid draped over a polar stereographic projection. The data have a spatial resolution of 190.6 km at 60 • latitude, are updated monthly, and span the period from 4 October 1966 to the present. The data comprise the longest satellite-based CDR of any environmental variable. Access to the data is provided in Network Common Data Form (netCDF) and archived by NOAA's National Climatic Data Center (NCDC) under the satellite Climate Data Record Program (doi:10.7289/V5N014G9). The basic characteristics, history, and evolution of the data set are presented herein. In general, the CDR provides similar spatial and temporal variability to its widely used predecessor product. Key refinements included in the CDR improve the product's grid accuracy and documentation and bring metadata into compliance with current standards for climate data records.

Snow cover response to temperature in observational and climate model ensembles

“…This daily field is averaged over each month to produce a monthly snow cover fraction. This method is similar to how the NCDR monthly snow cover fraction is produced: submonthly binary snow cover fields are used to estimate the monthly snow cover fraction [Estilow et al, 2015]. For the NCDR, visible satellite imagery was originally used to determine the binary SCE on a grid with approximately 190 km resolution.…”

“…After this point, the use of the Interactive Multisensor Snow and Ice Mapping System (IMS) produced daily estimates of binary snow cover at 24 km resolution. The spatial and temporal resolution is downgraded to match that of the historical weekly product in an effort to maintain continuity of the record [Estilow et al, 2015]; however, improvements in the coverage and spatial resolution of satellite imagery and changes to charting procedures (including the consideration of in situ data [Helfrich et al, 2007]) mean that the NCDR may not be homogeneous in all regions and seasons [Brown and Derksen, 2013]. We note that observation-based data sets 2-6 are all either reanalyses that assimilate various sources of meteorological observations (but not snow) or fully prognostic land surface simulations that are driven by various sources of observed or reanalyzed temperature and precipitation.…”

Atmospheric moisture transport: the bridge between ocean evaporation and Arctic ice melting

“…Most likely these different mechanisms coexist to a certain extent and are not necessarily mutually exclusive. For instance the autumn and early positive trend is SCE (Estilow et al, 2015), which can be closely related to positive trends in Eurasian rivers (Yang et al, 2007). In particular, two of these works (Zhang et al, 2012;Kapsch et al, 2013) provide novel insight on the role played by the transport of moisture and the melting of sea ice or snow cover.…”

Satellite Climate Data Records: Development, Applications, and Societal Benefits

“…High resolution land images have been adopted in network transportation analyses [91]. For marine transportation, Synthetic Aperture Radar (SAR) images have been used for ice navigation in the Northern Sea Route [92], while snow cover extent CDR [93] also contributes to the shipping route design in Arctic regions.…”