future precipitation and snowpack along the wasatch range
TRANSCRIPT
Future precipitation and snowpack along the Wasatch Range
Court Strong
University of Utah
Department of Atmospheric Sciences
Outline
• Study region (Great Basin and Wasatch Range)
• Projected climate change (big picture)
• Climate modeling framework
• Precipitation and snowpack 1950-2100
Study region
Annual mean precipitation (cm)
Great Basin UT
WY
Elevation (m)
“Wasatch Range”
UT
ID
Projected climate change (big picture)
Warming
• Increased moisture content of atmosphere
• Wet years become wetter
Jet stream shifts north
• Wetter north / drier south
• Increased variability
Climate modeling framework • Three greenhouse gas emission
scenarios were considered
High emission (A2) Moderate emission (A1B) Low emission (B1)
Image from IPCC AR4 Report
Climate modeling framework Coarse-scale simulations (100 to 200 km)
dynamical downscaling
statistical downscaling
12-14 km
Precipitation 2000-2049
minus 1950-1999
2050-2099 minus 1950-1999
High emission (A2)
Moderate emission (A1B)
Low emission (B1)
Change in annual precipitation
cm
Moderate emission (A1B) Wasatch Range annual mean precipitation
Precipitation: Wasatch
mean of all simulations
Moderate emission (A1B)
annual precipitation
Moderate emission (A1B) Moderate emission (A1B) Wasatch Range annual mean precipitation
Moderate emission (A1B) Wasatch Range annual mean precipitation
Moderate emission (A1B)
annual precipitation
Precipitation: Wasatch
mean of all simulations
Temperature: Wasatch Moderate emission (A1B)
average maximum air temperature: March-April
mean of all simulations
Moderate emission (A1B) Moderate emission (A1B)
snowpack (SWE) April 1
Snowpack: Wasatch
mean of all simulations
Based on 14-km model projections May not represent highest-elevation changes
Precipitation: Wasatch
Amplified seasonality • Increased
precipitation during high snow months
• Decreased precipitation during May-June
precipitation trend
1950-2099 (% change)
precipitation seasonality
(cm)
Summary • Drier over southern Great Basin and wetter
over northern Great Basin (jet stream wetter and shifted north)
• Wasatch Range trends (to 2100) – Increase in annual mean precipitation (~ 7%)
– Overall increase in precipitation variability
– Snowpack declines due to warming
– Amplified precipitation seasonality (wetter snow season, drier in May and June)
• New data (released last week)
Precipitation and snowpack: historical
Extremely high and very low years just occurred back to back.
Snowbird SNOTEL 1989-2012
Annual precipitation (cm)
Average maximum air temperature
March-April (°C)
Snowpack SWE April 1 (cm)
Wasatch Range
Future projections: Wasatch