Readme file for: SnowClim Data This .txt file was generated on 5 Jan 2022 by A.C. Lute. Summary: ------------------------------------------------------------------------ The SnowClim Data contains snow climate metrics for pre-industrial, historical, and future climate scenarios at ~210 m for the Western United States. The SnowClim Dataset was developed following the methods presented in Lute et al., (in review). Briefly, historical climate data was developed downscaling raw WRF data (Rasmussen & Liu, 2017) consisting of 4 km spatial resolution hourly simulations for 1 October 2000 to 30 September 2013. Future climate data was downscaled from a pseudo-global warming run performed by perturbing ERA-Interim by average differences from a suite of climate models participating in the Fifth Coupled Model Intercomparison Project (CMIP5) between 1976-2005 and 2071-2100 under the RCP 8.5 scenario (Rasmussen & Liu, 2017). Pre-industrial climate data was developed by perturbing the downscaled historical WRF data by monthly climatological differences in climate between pre-industrial (1850-1879) and the historical period using a pattern scaling approach based on spatially varying differences in variables from the CMIP5 models. 4-hourly climate forcings for the three time periods were used to force the SnowClim Model. Downscaled climate data and snow model outputs were summarized into climate and snow metrics at ~210 m spatial resolution for the western US. Additional details about the climate forcing data preparation, model physics, model calibration and application to the western US domain can be found in Lute et al., (in review). File Organization: ------------------------------------------------------------------------ Snow and climate metrics are available in separate netCDF files. GeoTIFF versions of the same files and subsetting capabilities can be found on HydroShare at https://www.hydroshare.org/resource/36895c3a2c53409893f5ba02ee142767/. The suffix '_PRE' indicates that the data represents conditions under pre-industrial climate. The suffix '_CTRL' indicates that the data represents conditions under the control scenario (aka historical climate). The suffix '_PGW' indicates that the data represents conditions under the future, pseudo-global warming scenario. Metrics with values for each month have values for January through December. Metrics with values for each year use snow years, which we define as September 1 - August 31. For example, snow year 2001 is the year starting on September 1, 2000 and ending on August 31, 2001. Metrics: ------------------------------------------------------------------------ - downwelling shortwave units: W m-2 Monthly mean downwelling shortwave radiation at the surface, downscaled from WRF (Rasmussen and Liu, 2017; which accounts for cloud cover) using the R insolvent package to correct for aspect, self-shading, and shading by adjacent terrain. - minimum air temperature (tmin) units: °C Monthly mean of daily minimum 2m air temperatures, downscaled from WRF (Rasmussen and Liu, 2017) using local lapse rates. - maximum air temperature (tmax) units: °C Monthly mean of daily maximum 2m air temperatures, downscaled from WRF (Rasmussen and Liu, 2017) using local lapse rates. - mean air temperature (tmean) units: °C Monthly mean of daily mean 2m air temperatures, downscaled from WRF (Rasmussen and Liu, 2017) using local lapse rates. - mean dew point temperature (tdmean) units: °C Monthly mean of daily mean 2m dewpoint temperatures, downscaled from WRF (Rasmussen and Liu, 2017) using local lapse rates. - precipitation (ppt) units: meters (m) Monthly total precipitation, downscaled from WRF (Rasmussen and Liu, 2017) using local lapse rates and bias corrected using PRISM precipitation data (PRISM Climate Group, 2015). - number of temperature sign changes (tschange) units: count Annual number of times that temperature (°C) changes sign. Calculated from 4-hourly air temperatures downscaled from WRF (Rasmussen and Liu, 2017) using local lapse rates. - annual maximum SWE units: meters (m) Annual maximum snow water equivalent (m), averaged across years. - date of annual maximum SWE units: Julian day of year Julian day of annual maximum snow water equivalent (m), averaged across years. - largest snowfall event units: meters (m) Liquid water equivalent thickness of the largest three consecutive day snowfall total each year (m). - date of largest snowfall event units: Julian day of year Julian day of the largest three consecutive day snowfall total each year. - snow cover days units: days Monthly number of days with snow depth greater than 10 mm, averaged across years. - snow duration units: days Number of days between the start and end of snow cover, averaged across years. The start of snow cover is defined as the first day of the first period of 5 consecutive days with snow depth greater than 10 mm, and day of snow cover end is defined as the last day of the last period of 5 consecutive days with snow depth greater than 10 mm. - snow free days units: days Annual number of days with snow depth less than 10 mm between the start and end of snow cover, averaged across years. The start of snow cover is defined as the first day of the first period of 5 consecutive days with snow depth greater than 10 mm, and day of snow cover end is defined as the last day of the last period of 5 consecutive days with snow depth greater than 10 mm. - date of snow cover start units: Julian day of year Julian day of beginning of snow cover, averaged across years. The day of beginning of snow cover is defined as the first day of the first period of 5 consecutive days with snow depth greater than 10 mm. - date of snow cover end units: Julian day of year Julian day of end of snow cover, averaged across years. The day of the end of snow cover is defined as the last day of the last period of 5 consecutive days with snow depth greater than 10 mm. - min snow depth: units: meters (m) Monthly minimum snow depth (m), averaged across years. - mean snow depth units: meters (m) Monthly mean snow depth (m), averaged across years. - max snow depth units: meters (m) Monthly maximum snow depth (m), averaged across years. - min SWE units: meters (m) Monthly minimum snow water equivalent (m), averaged across years. - mean SWE units: meters (m) Monthly mean snow water equivalent (m), averaged across years. - max SWE units: meters (m) Monthly maximum snow water equivalent (m). averaged across years. - snowfall units: meters (m) Monthly total snowfall water equivalent (m), averaged across years. Sharing and access information: ------------------------------------------------------------------------ 1. Licenses/restrictions placed on the data: This resource is shared under the Creative Commons Attribution CC0. 2. Links to publications that cite or use the data: none yet 3. Links to other publicly accessible locations of the data: https://www.hydroshare.org/resource/acc4f39ad6924a78811750043d59e5d0/ 4. Links/relationships to ancillary data sets: SnowClim Model and Dataset (https://www.hydroshare.org/resource/acc4f39ad6924a78811750043d59e5d0/) SnowClim Model Code (https://www.hydroshare.org/resource/dc3a40e067bf416d82d87c664d2edcc7/) SnowClim Pre-industrial Climate Data (https://www.hydroshare.org/resource/0c852b12f668438fb9f0188a1cc6e8a9/) SnowClim Pre-industrial Snow Data (https://www.hydroshare.org/resource/fc621d75985c4695b6758ade312241c6/) SnowClim Present Climate Data (https://www.hydroshare.org/resource/7e3678f00ad74bfd881f91d6f6f81494/) SnowClim Present Snow Data (https://www.hydroshare.org/resource/2dbd6e849a754c0981b99ee7c09031eb/) SnowClim Future Climate Data (https://www.hydroshare.org/resource/36895c3a2c53409893f5ba02ee142767/) SnowClim Future Snow Data (https://www.hydroshare.org/resource/96cba44cd74843639f855d7c9e22024b/) 5. Was data derived from another source? yes. Climate data was downscaled from the dataset of Rasmussen and Liu, 2017. 6. To cite this data, please reference both of the following: Lute, A., J. Abatzoglou, T. Link (2021). SnowClim Model and Dataset, HydroShare, http://www.hydroshare.org/resource/acc4f39ad6924a78811750043d59e5d0 Lute, A. C., Abatzoglou, J., and Link, T.: SnowClim v1.0: High-resolution snow model and data for the western United States, Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2021-407, in review, 2021. Authors: ------------------------------------------------------------------------ A.C. Lute, University of Idaho John Abatzoglou, University of California, Merced Timothy Link, University of Idaho Contact Information: ------------------------------------------------------------------------ Please contact A.C. Lute with questions, concerns, or comments. Current contact information is available on the webpage this file was downloaded from. References: ------------------------------------------------------------------------ Lute, A. C., Abatzoglou, J., and Link, T.: SnowClim v1.0: High-resolution snow model and data for the western United States, Geosci. Model Dev. Discuss. [preprint], https://doi.org/10.5194/gmd-2021-407, in review, 2021. PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu, created 27 May 2015. Rasmussen, R., and C. Liu. 2017. High Resolution WRF Simulations of the Current and Future Climate of North America. Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory. https://doi.org/10.5065/D6V40SXP. Accessed 24 Sep 2018.