Surface Transportation Weather Research CenterUniversity of North Dakota

Pavement Precipitation Accumulation

Precipitation Data Sources

Presenter:

Mark Askelson

University of North DakotaDepartment of Atmospheric

Sciences/RWIC/STWRC

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 2

Precipitation Data Sources

Primary sourcesSurface observationsRadarSatelliteAnalyses/models

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 3

Precipitation Data Sources

Surface GaugesStrengths

Accuracy (but wind contamination)

Weakness—limited capacity for indicating snowfall in real time

ASOS: Automated Surface Observing System Tipping bucket gauges—not presently useful for

measuring snowfall. Visibility → snowfall rate (significant variability) Manual intervention stations

→ Useful information, but not enough of them.

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 4

Precipitation Data Sources→ North Dakota ASOS/AWOS stations.

→ Manual intervention stations circled.

→ Not shown (KRDR—GF AFB, a manual intervention station).

→ Only some of these provide real time snowfall amounts.

ND ASOS/AWOS stations (from http://www.faa.gov/asos/map/nd.cfm).

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data Sources→ South Dakota ASOS/AWOS stations.→ Manual intervention stations circled.→ Not shown (KRCA—Ellsworth AFB, a manual intervention station).

→ Only some of these provide real time snowfall amounts.

SD ASOS/AWOS stations (from http://www.faa.gov/asos/map/nd.cfm).

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data Sources

AWOS: Automated Weather Observing System AWOSIII-P has a precipitation identification sensor,

but does not record amounts. RWIS: Road Weather Information System

DOT 14 in North Dakota; 35 in South Dakota Indicate precipitation occurrence

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 7

Precipitation Data Sources

RAWS: Remote Automated Weather Stations United States Forest Service 9 in North Dakota; 5 in South Dakota Uncertain regarding utility for snowfall estimation

Citizen Weather Observer Program (CWOP) Forecast Systems Laboratory Private weather stations

PRIMENet EPA and NPS 1 station in North Dakota Uncertain snowfall measurement potential

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 8

Precipitation Data Sources

High Plains Regional Climate Center Automated Weather Data Network (HPRCC-AWDN)

NDAWN: North Dakota Agricultural Weather Network

→ NDSU

→ 55 in North Dakota

→ Tipping bucket rain gauge South Dakota

→ 11 in South Dakota

→ Tipping bucket rain gauges

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 9

Precipitation Data Sources

South Dakota Television Stations KOTA-TV WeatherNet KELO WeatherNet KMEG Weather Net Uncertain snowfall measurement utility

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data Sources

Non real-time networks NWS Cooperative Observer Program NOAA/NWS 15 Minute Cooperative Observer

Program

→ 55 in North Dakota; 40 in South Dakota

→ Weighing rain gauges. North Dakota Atmospheric Resource Board

Cooperative Observer Network

→ Principally concerned with rainfall.

→ Operates from April to September.

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data Sources

Cost of setting up surface gauges for South Dakota

75,885 square miles Yankee Sensor

Estimated ~$10,000 each (for sensor alone) Minimizes wind contamination of amounts

Estimates 1 gauge/900 mi2: ~$850,000 1 gauge/400 mi2: $1.9 million 1 gauge/100 mi2: $7.6 million

Infrastructure and maintenance?

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data SourcesRadar

Strengths Good spatial and temporal coverage

Park River Basin example courtesy of Scott Kroeber

RADAR Estimated Precipitation (2 km resolution)

NDAWN Interpolated

COOP Interpolated NDARB Interpolated

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data Sources

Weaknesses Accuracy

40-50% error common for storm total accumulation Can reach 100% for < 1” snowfalls.

Overshooting 0.5˚ beam reaches 5.0 km at ~225 km range.

Surface Transportation Weather Research CenterUniversity of North Dakota

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Precipitation Data Sources Ground Clutter and Anomalous Propagation

Ground Clutter: Commonly observed return owing to radar beam bouncing off buildings, towers, etc.

Anomalous Propagation: Radar beam bends downward towards the Earth more than normal…produces anomalous returns to the radar.

Surface Transportation Weather Research CenterUniversity of North Dakota

STWRC--Precipitation Data Sources 15

Precipitation Data SourcesSatellite

Strengths—Expands coverage area.Weaknesses

Been applied more to rain than snow. Probably more effective for heavy snow (identify cloud

patterns) May not resolve light snow (clouds cannot be

discriminated from snow on the ground).