07574d88-221a-447a-98b2-57e8ff3da51e Scenarios Network for Alaska and Arctic Planning uaf-snap-data-tools@alaska.edu 2024-11-21T14:47:43 ISO 19115:2003/19139 1.0 2 2557 771 3232 771 EPSG:3338 Projected Decadal Averages of Monthly Snow-Day Fraction 771m CMIP5/AR5 2018-05-04 1.0.0 These files include downscaled projections of decadal average monthly snow-day fraction ("fs", units = percent probability from 1 – 100) for each month of the decades from 2010-2019 to 2090-2099 at 771 x 771 m spatial resolution. Each file represents a decadal average monthly mean. Output is available for the CCSM4, GFDL-CM3, GISS-E2-R, IPSL-CM5A-LR, and MRI-CGCM3 models and three emissions scenarios (RCP 4.5, RCP 6.0 and RCP 8.5). These snow-day fraction estimates were produced by applying equations relating decadal average monthly temperature to snow-day fraction to downscaled decadal average monthly temperature. Separate equations were used to model the relationship between decadal monthly average temperature and the fraction of wet days with snow for seven geographic regions in the state: Arctic, Western Alaska, Interior, Cook Inlet, SW Islands, SW Interior, and the Gulf of Alaska coast, using regionally specific logistic models of the probability that precipitation falls as snow given temperature based on station data fits as in McAfee et al. 2014. These projections differ from McAfee et al. 2014 in that updated CMIP5 projected temperatures rather than CMIP3 temperatures were used for the future projections. Although the equations developed here provide a reasonable fit to the data, model evaluation demonstrated that some stations are consistently less well described by regional models than others. It is unclear why this occurs, but it is likely related to localized climate conditions. Very few weather stations with long records are located above 500m elevation in Alaska, so the equations used here were developed primarily from low-elevation weather stations. It is not clear whether the equations will be completely appropriate in the mountains. Finally, these equations summarize a long-term monthly relationship between temperature and precipitation type that is the result of short-term weather variability. In using these equations to make projections of future snow, as assume that these relationships remain stable over time, and we do not know how accurate that assumption is. These snow-day fraction estimates were produced by applying equations relating decadal average monthly temperature to snow-day fraction to downscaled projected decadal average monthly temperature. The equations were developed from daily observed climate data in the Global Historical Climatology Network. These data were acquired from the National Climatic Data Center in early 2012. Equations were developed for the seven climate regions described in Perica et al. (2012). Geospatial data describing those regions was provided by Sveta Stuefer. Perica, S., D. Kane, S. Dietz, K. Maitaria, D. Martin, S. Pavlovic, I. Roy, S. Stuefer, A. Tidwell, C. Trypaluk, D. Unruh, M. Yekta, E. Betts, G. Bonnin, S. Heim, L. Hiner, E. Lilly, J. Narayanan, F.Yan, T. Zhao. 2012. NOAA Atlas 14. Precipitation-Frequency Atlas of the United States. Matthew Leonawicz Michael Lindgren Tom Kurkowski John Walsh Scott Rupp Stephanie McAfee Jeremy Littell Scenarios Network for Alaska and Arctic Planning uaf-snap-data-tools@alaska.edu https://catalog.snap.uaf.edu/geonetwork/srv/api/records/07574d88-221a-447a-98b2-57e8ff3da51e/attachments/snow_day_preview.png https://creativecommons.org/licenses/by/4.0/ 771 eng climatologyMeteorologyAtmosphere 2010-01-15 2099-12-15 -178.20 -130.00 51.20 71.40 GeoTIFF 1.0 http://data.snap.uaf.edu/data/Base/AK_771m/projected/AR5_CMIP5_models/snow_day_fraction/ WWW:LINK-1.0-http--link Projected Decadal Averages of Monthly Snow-Day Fraction 771m CMIP5/AR5 URL to web-accessible folder containing downloads for this data set http://onlinelibrary.wiley.com/doi/10.1002/hyp.9934/abstract WWW:LINK-1.0-http--link Statistically downscaled projections of snow/rain partitioning for Alaska Detailed information on the construction of this data and its implications http://data.snap.uaf.edu/data/Base/AK_771m/historical/CRU_TS/snow_day_fraction/snow_fraction_data_users_guide.pdf WWW:LINK-1.0-http--link User guide Detailed description of data and methodology http://data.snap.uaf.edu/data/Base/AK_771m/historical/CRU_TS/snow_day_fraction/supplementary_data_code.zip WWW:LINK-1.0-http--link Processing code ZIP archive of data processing code https://doi.org/10.5066/P9G6F51O WWW:LINK-1.0-http--link DOI for USGS ScienceBase record about this dataset https://doi.org/10.3390/w10050668 WWW:LINK-1.0-http--link Alaska Snowpack Response to Climate Change: Statewide Snowfall Equivalent and Snowpack Water Scenarios Paper with discussion and analysis of these data https://doi.org/10.3390/w10050668 WWW:LINK-1.0-http--link Littell et al., 2018: Alaska Snowpack Response to Climate Change: Statewide Snowfall Equivalent and Snowpack Water Scenarios Publication. Note that in this publication, SWE is referred to as SFE and fs is referred to as PSF.