Ground Deicing Update

Scott Landolt, Roy Rasmussen and Jenny Black

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)

6

Hotplate at Marshall Test Site, Boulder Colorado

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.

Deicing in a Future Climate

Roy Rasmussen and Kyoko Ikeda, NCAR

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

March

RUN2

PRISM

RUN1

Test 4 km WRF model estimate of precipitation for March, 2001