Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)

One hundred and sixty–nine years of weather station data were analyzed to quantify the changing nature of the winter season precipitation phase in the downtown area of Toronto (Canada). The precipitation variables examined were rainfall, snowfall water equivalent, total precipitation, rain days, sno...

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Main Authors: Micah J. Hewer, William A. Gough
Format: Article
Language:English
Published: MDPI AG 2020-08-01
Series:Atmosphere
Subjects:
Online Access:https://www.mdpi.com/2073-4433/11/8/867
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author Micah J. Hewer
William A. Gough
author_facet Micah J. Hewer
William A. Gough
author_sort Micah J. Hewer
collection DOAJ
description One hundred and sixty–nine years of weather station data were analyzed to quantify the changing nature of the winter season precipitation phase in the downtown area of Toronto (Canada). The precipitation variables examined were rainfall, snowfall water equivalent, total precipitation, rain days, snow days, and precipitation days. From these precipitation variables, three precipitation phase metrics were constructed for further analysis: the fraction of total precipitation that fell as snow, the fraction of precipitation days that recorded snow, and finally, the precipitation phase index (PPI) derived from comparing the rainfall to the snowfall water equivalent. Snowfall and snow days were decreasing at the most significant rate over this time period, and although rain days were increasing, total precipitation and precipitation days were also decreasing at a statistically significant rate. All three precipitation phase metrics suggest that winters are becoming less snowy in Toronto’s urban center. We also looked at trends and changes in average winter season temperatures to explore correlations between warming temperatures and changes in the winter season precipitation phase. Of the three precipitation phase metrics considered, the ratio of snow days to precipitation days recorded the strongest time series trend and the strongest correlation with warming temperatures.
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spelling doaj.art-8d2e87f41858407b824846920bdef6c82023-11-20T10:17:59ZengMDPI AGAtmosphere2073-44332020-08-0111886710.3390/atmos11080867Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)Micah J. Hewer0William A. Gough1Department of Physical and Environmental Sciences, University of Toronto at Scarborough, Scarborough, ON M1C 1A4, CanadaDepartment of Physical and Environmental Sciences, University of Toronto at Scarborough, Scarborough, ON M1C 1A4, CanadaOne hundred and sixty–nine years of weather station data were analyzed to quantify the changing nature of the winter season precipitation phase in the downtown area of Toronto (Canada). The precipitation variables examined were rainfall, snowfall water equivalent, total precipitation, rain days, snow days, and precipitation days. From these precipitation variables, three precipitation phase metrics were constructed for further analysis: the fraction of total precipitation that fell as snow, the fraction of precipitation days that recorded snow, and finally, the precipitation phase index (PPI) derived from comparing the rainfall to the snowfall water equivalent. Snowfall and snow days were decreasing at the most significant rate over this time period, and although rain days were increasing, total precipitation and precipitation days were also decreasing at a statistically significant rate. All three precipitation phase metrics suggest that winters are becoming less snowy in Toronto’s urban center. We also looked at trends and changes in average winter season temperatures to explore correlations between warming temperatures and changes in the winter season precipitation phase. Of the three precipitation phase metrics considered, the ratio of snow days to precipitation days recorded the strongest time series trend and the strongest correlation with warming temperatures.https://www.mdpi.com/2073-4433/11/8/867precipitation phasesnowfall fractionsnow day fractionregional warmingclimate changeToronto (Canada)
spellingShingle Micah J. Hewer
William A. Gough
Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)
Atmosphere
precipitation phase
snowfall fraction
snow day fraction
regional warming
climate change
Toronto (Canada)
title Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)
title_full Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)
title_fullStr Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)
title_full_unstemmed Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)
title_short Quantifying the Changing Nature of the Winter Season Precipitation Phase from 1849 to 2017 in Downtown Toronto (Canada)
title_sort quantifying the changing nature of the winter season precipitation phase from 1849 to 2017 in downtown toronto canada
topic precipitation phase
snowfall fraction
snow day fraction
regional warming
climate change
Toronto (Canada)
url https://www.mdpi.com/2073-4433/11/8/867
work_keys_str_mv AT micahjhewer quantifyingthechangingnatureofthewinterseasonprecipitationphasefrom1849to2017indowntowntorontocanada
AT williamagough quantifyingthechangingnatureofthewinterseasonprecipitationphasefrom1849to2017indowntowntorontocanada