Post on 03-Jan-2016
transcript
Snow Machine Testing
• Current Tasking– Laboratory testing of
Heavy rates (> 2.5mm/h) and very light rates (< 0.4 mm/h)
– Indoor testing time versus outdoor testing time variations
– Snowfall pattern distribution improvement within the machine
Frost Detection and Diagnosis
• Complete testing of various sensing techniques at Marshall– Leaf wetness sensor– Infrared camera– Other methods
• Integration into LWE system
Future Checktime
• Integrate WSDDM one-hour nowcast or precipitation rate to nowcast holdover/checktime times
• Integrate high-resolution model output (HRRR) data into Checktime to forecast holdover times beyond one hour
Measurement of Liquid Fraction during Wet Snow
using a dual Hotplate
Roy Rasmussen and Scott Landolt
National Center for Atmospheric Research (NCAR)
Dual Hotplate System
Temperature = 30 C Temperature = 80 C
Estimates the ice mass in snow over 5 minutes by melting the ice only.
Estimates the total precipitation mass (ice +water) over 5 minutes by sublimating ice +water
Benefits of the new system• Improved holdover
time during the most common deicing condition: wet snow
• The fraction of ice in wet snow will cool the wing by taking heat out of the wing to melt the ice. The performance of the deicing fluid depends on the temperature of the fluid, and therefore the fraction of ice present.
High Resolution Simulations of the Colorado Headwaters snowfall, snowpack and runoff
1. Perform past climate simulations using high resolution WRF model Grid spacing: 4 km. Continuous eight years: 2000 – 2008
2. Verified results of WRF integrations using NRCS SNOTEL data and showed that grid spacing of at least 6 km needed to faithfully reproduce the spatial pattern and amount of precipitation (Rasmussen et al. 2011, J. Climate).
3. Investigate enhancement of water cycle by adding CCSM 10 year mean temperature and moisture perturbation from 50 year future A1B simulations from AR4 runs to NARR boundary conditions
Full DomainHeadwaters
domain
SNOTEL sites
Model Verification with SNOTEL Model Verification with SNOTEL datadata
Full model domain
Snow pillow
Precipitation gauge
Verifications performed using 93-112 Snowpack Telemetry (SNOTEL) sites over the Headwaters domain. SNOTEL typically located at elevations between 2600 and 3600 m
Global Historical Climatology Network (GHCN) data at lower elevations for rainfall
Headwaters Domain
3/14/12 11 Orographic Precipitation and Climate Change Workshop, Boulder, CO
SNOTEL
7-year average cool-season precipitation :
1 October – 31 May
4/12/12
USBR-USACE meeting12
36 km 4 km OBSERVATIONS1000
900
800
700
600
500
400
300
200
100
0
Prec
ipit
atio
n (m
m)
(1360 x 1016 grid points)
Four kilometer horizontal resolution climate simulations will be conducted for 13 years in the past and 13 years in the future
(centered on 2050) over the domain below using the WRF model using the Thompson et al. microphysics allowing precipitation
type and rate to be determined with good accuracy