Event Title

Sensitivity of Wasatch Snowpack to Temperature Changes

Presenter Information

John Horel

Location

ECC 303/305

Event Website

https://water.usu.edu/

Start Date

3-31-2008 11:00 AM

End Date

3-31-2008 11:15 AM

Description

Potential changes to snowpack in the Wasatch Mountains resulting from global warming are examined. Since global climate simulations are unable to resolve narrow mountain ranges such as the Wasatch, limited confidence is generally ascribed to model estimates of precipitation changes in Utah due to global warming. The observed sensitivity of high elevation precipitation to temperature during each storm within the past 25-30 years is proposed as a proxy metric to estimate the potential impact of increased temperature during the winter. The methodology follows from that applied for other regions; Casola et al. (2008) suggest that a 1o C increase in winter seasonal temperature could lead to reductions in spring snowpack of order 20% for the lower elevation Cascades. NRCS daily precipitation records at Ben Lomond Peak and the nearby lower elevation site at Ben Lomond Trail provide a relatively unique opportunity to examine the elevational dependence of precipitation to temperature. Two approaches are used: (1) histograms of daily precipitation as a function of estimated temperature at the station elevation and (2) simple estimates of the amount of precipitation falling as rain or snow along the east slope of the Wasatch as a function of the temperature profile. Both of these approaches yield reductions in winter season precipitation of order 10% per 1o C increase in winter seasonal temperature. The smaller potential reduction due to increasing temperature for the Wasatch relative to the Cascades is not too surprising given the higher base elevation of the Wasatch. Our plans for using such proxy indicators to examine climate simulations of current and future climate scenarios will be discussed.

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Mar 31st, 11:00 AM Mar 31st, 11:15 AM

Sensitivity of Wasatch Snowpack to Temperature Changes

ECC 303/305

Potential changes to snowpack in the Wasatch Mountains resulting from global warming are examined. Since global climate simulations are unable to resolve narrow mountain ranges such as the Wasatch, limited confidence is generally ascribed to model estimates of precipitation changes in Utah due to global warming. The observed sensitivity of high elevation precipitation to temperature during each storm within the past 25-30 years is proposed as a proxy metric to estimate the potential impact of increased temperature during the winter. The methodology follows from that applied for other regions; Casola et al. (2008) suggest that a 1o C increase in winter seasonal temperature could lead to reductions in spring snowpack of order 20% for the lower elevation Cascades. NRCS daily precipitation records at Ben Lomond Peak and the nearby lower elevation site at Ben Lomond Trail provide a relatively unique opportunity to examine the elevational dependence of precipitation to temperature. Two approaches are used: (1) histograms of daily precipitation as a function of estimated temperature at the station elevation and (2) simple estimates of the amount of precipitation falling as rain or snow along the east slope of the Wasatch as a function of the temperature profile. Both of these approaches yield reductions in winter season precipitation of order 10% per 1o C increase in winter seasonal temperature. The smaller potential reduction due to increasing temperature for the Wasatch relative to the Cascades is not too surprising given the higher base elevation of the Wasatch. Our plans for using such proxy indicators to examine climate simulations of current and future climate scenarios will be discussed.

https://digitalcommons.usu.edu/runoff/2008/AllAbstracts/13