REASoN Multi-Resolution Snow Products for the Hydrologic Sciences University of California, Santa...
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Transcript of REASoN Multi-Resolution Snow Products for the Hydrologic Sciences University of California, Santa...
REASoN Multi-Resolution Snow Products for the
Hydrologic Sciences
University of California, Santa BarbaraUniversity of California, Merced
• Long term commitment for snow remote sensing products– Mandate to work with applications community
UC Merced team
• Roger Bales– 4 yrs with Regional Earth Science Applications Center
(RESAC)
• Bob Rice, research scientist• Programmer• Grad student for modeling & analysis
Data access via www
http://hydis.hwr.arizona.edu/resac
1995-2001 on CD
RESAC output & outcomes
– fractional SCA product for Colorado & Rio Grande basins 1995-2002
– blended SWE product: interpolated SNOTEL & AVHRR SCA
– near-real-time product delivered via map server & archived product via CD
– SWE volume estimates evaluated by SRP (AZ), CO, NM
– SWE assimilation into PRMS for upper Salt & upper Rio Grande (in progress)
– formal user workshop to introduce & evaluate products; multiple stakeholder meetings
Expected REASoN outcomes
– create new demands for RS snow products within water resources community
– demonstrate usefulness of RS products in various ways to applications community
– demonstrate improved ways of using RS products for hydrologic forecasts & water resources decisions
– enhance dialog between research & applications communities on the topic of snow RS products
Applications planAim: connect the snow remote sensing products w/
applications in water resourcesApproach:– cooperative efforts w/ research community
– specify & analyze snow products – develop & implement strategies to use the products for
both model input & model evaluation
– working directly w/ applications community– develop approaches to use & evaluate products in
existing Decision Support Systems– assimilate products into available snowmelt runoff
models to do hindcasts (USGS, Scripps, LLNL, LBL…)– use products to make forecasts of basin-scale runoff
Sierra Nevada 1998 SCA animation
Red: cloudsBlack: no snowGreyscale: SCA
R. Davis, CRREL
1
2
3
4
5
AVHRR bands
Geographic mask
Thermal mask
Masked fractional snow covered
area map
Composite cloud mask
Build Cloud Masks using several spectral-
based tests
Snow map algorithm output: mixed clouds, high reflective bare ground, & sub-pixel snow cover
Execute sub-pixel snow cover algorithm:
AVTREE using bands 1,2,3 (reflectance) as
input
Build thermal mask
Application of cloud, thermal &
geographic masks to raw AVTREE output
Scene evaluation:
•degree of cloud cover
•Coverage over study basins
Topography Ground measured snow water equivalent
Total snow water equivalent map
Interpolate usinghypsometric method
Combine sub-pixel SCA and ground-based
interpolated SWE to produce total basin
water maps
Execute atmospheric corrections, conversion
to engineering units using AVREF
AVHRR (HRPT FORMAT)pre-processed at UCSB[NOAA-12,14,16]
Snow cover mapping process
Georegister image using GEOREG script.
x
Product design studies (forward and backward)SCA
map
cloud mask
aggregating
subsetting
canopy corrections
SWE/SCA blending
NOHRSC products
ground data•SNOTEL
•Snowcourse
Modeling
(PRMS..)
applications community
evaluation
•MODIS
•500m resolution
•Fractional snow cover
•AVHRR
Rio Grande SCA & SWE: average for March
1995 1998 1999 2000 2001 20021996 1997
SCA
SWE
National Operational Hydrological Remote Sensing Center (NOHRSC)
• AVHRR(Advanced Very High Resolution Radiometer) -Available since 1986-1-km resolution-fractional snowcover-blended SWE product
MODIS(Moderate Resolution Imaging
Spectroradiometer) snow cover, western U.S.
Image Color Legend:
white snow
pink cloud
grey no data / night
green snow/cloud free land
blue water
-Available since 2000/2001-1-km spatial resolution-36 bands, 0.620-14.385 m-Binary mapping
Western Snow Conference- 2005
Workshop (3hrs.)
Objectives• Introduce project• Generate interest• Initiate dialogue between research and apps
communitiesOverriding Objective • generating a demand and usefulness for RS
products
*User prospective on Remote Sensing • (DWR rep 10 min?)