Data from: Spatial variation of the rain-snow temperature threshold across the Northern Hemisphere
Data files
Jan 31, 2019 version files 1.21 GB
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jennings_et_al_2018_file1_station_locs_elev.csv
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jennings_et_al_2018_file2_ppt_phase_met_observations.csv
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jennings_et_al_2018_file3_temp50_observed_by_station.csv
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jennings_et_al_2018_file4_temp50_raster.tif
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jennings_et_al_2018_file5_temp50_linregr_raster.tif
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jennings_et_al_2018_file6_precipphase_station_observations_code.R
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jennings_et_al_2018_file7_precipphase_phasemethods_code.R
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jennings_et_al_2018_file8_precipphase_merra_threshold_simulation_code.R
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jennings_et_al_2018_file9_precipphase_merra_snowfall_frequency_sensitivity_code.R
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README_for_jennings_et_al_2018_file1_station_locs_elev.txt
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Abstract
We present the first continuous map of rain-snow air temperature thresholds over the Northern Hemisphere land surface, underlining the spatial variability of precipitation phase partitioning. Land surface models typically discriminate between rain and snow using a simple, spatially uniform air temperature threshold, but observations indicate the threshold is not static. Our analysis of a 29-year observational dataset (n = 17.8 million) shows the threshold varies significantly, averaging 1.0°C and ranging from -0.4°C to 2.4°C for 95% of Northern Hemisphere stations, with continental climates exhibiting the warmest thresholds and maritime the coolest. Relative humidity exerts the strongest control on phase partitioning, while surface pressure plays a secondary role. Simulations indicate the selection of a rain-snow threshold introduces significant uncertainty to snowfall frequency and that including relative humidity as a predictor variable provides the greatest improvement to precipitation phase prediction between 0.6°C and 3.4°C, the interval where phase partitioning is most uncertain.