Agenda
• Project overview (brief)• Modeling update (preliminary results)• Next steps…• Integration pathways
Modeling status update: 11/13/2012
Land-cover, meteorology, and desert dust Explore hydrologic impacts and sensitivities
www.nsf.org
Snow Water Equivalent (SWE)Discharge (Q) magnitude and timing
Domain: catchments with range of MPB and dust impacts; varying hydro-climatology,
Distributed hydrology soil vegetation model (DHSVM)
Q (m
3 /s)
Month
Boulder Cr.Fish Cr.
Snake R.
Uncompaghre R.
Painter et al., 2010
Current modeling status
• Snake R. set-up complete – other (3) river basins nearly ready…
• Local precip./temperature still open issues; Spatial improvements in cold-season precip. from Molotch et al. (SWE recon.).
• **Preliminary** sensitivities complete• Calibrations hinge upon resolving
precip./temperature issues… (examining individual years)
Modeling system
Relevant Details:
Dust-on-snow: Observation-based dust loading/snow albedo scenarios
MPB: Satellite derived LAI-change
MPB: Vegetation classification
100 m spatial resolution
-Courtesy Jeff Deems
Example: Snake R.• Flows into Dillon Reservoir – Denver
Water• Changes in leaf-area index (LAI) used to
characterize beetle kill• Explore ‘end-points’, 2000 - 2011
Snake R.Max. LAI: 2003
Max. LAI: 2006
-Courtesy Jeff Deems -Courtesy Brian Buma
500m MODIS satellite imagery (2002-2011)
MPB Scenario: Apply maximum MPB impact to Evergreen areas, reducing canopy LAI
Dust scenarios: Alter modeled snow albedos based on observed dust impacts.
Preliminary results
Model Results: Snake R.
SWE (m)
PRISM
SWE 1 Apr., 2005
• Considerable increase in spatial detail when using Molotch et al. SWE reconstruction to distribute winter precip (versus PRISM).
SWE (m)
SWE 1 Apr., 2005
Molotch et al. SWE recon. Cold season precip distribution
Model Results: Snake R.
SWE (m)
CONTROL: Moderate dust, no beetle impact
Avg. SWE 1 Apr.
• MPB leads to higher accumulation of Snow Water Equivalent (SWE)
• Considerable variation between wet and dry years (not shown)
SWE change (m)
Difference Map
Less MoreSWE (m)
Scenario: Maximum MPB impact
Avg. SWE 1 Apr.
Residual
Relative model sensitivities
LowModerate
Extreme
WY2006
SWE
(mm
)
NoneFull MPB
Month
• Dust enhances snowmelt• Opposing effect of MPB on
SWE, non-uniform, asynchronous…
Low & Full MPBModerate
Extreme & Full MPB
MonthMonth
Relative dust impacts Relative MPB impacts Combined MPB & Dust
Photo: Chris Landry www.denverpost.org
WY2006 WY2006
Preliminary Model Streamflow Results
Averaged 2000-2011 water years
LowModerate
Extreme
Dis
char
ge @
Mon
tezu
ma
(m3 /
s) Relative dust impacts Relative MPB impactsNone
Full MPB
• Changes in melt rate control peak runoff timing and magnitude (dust)• MPB impacts also affect warm-season flow (reduced evapotranspiration)
Month
Wat
er Y
ield
(a
c-ft
/yea
r)
Low & Full MPBModerate
Extreme & Full MPB
Combined MPB & Dust
Month Month
Averaged 2000-2011 water years Averaged 2000-2011 water years
Wat
er Y
ield
(a
c-ft
/yea
r)
Wat
er Y
ield
(a
c-ft
/yea
r)
+1.8% +1.1%+9.1% +11.6% +9.9%
Preliminary Conclusions• Dust-on-snow enhances snowmelt, causing earlier
peak streamflow• MPB leads to higher SWE accumulation• Model sensitivities from Snake R. show reduction of
canopy cover increases water yield on the order of 10%
• Work in progress – compare other 3 basin responses, incorporate satellite-based MPB propagation patterns, greater spatial extents
• Potential points of integration with CBRFC: – Adjust melt factors?– Adjust ET demand?
