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National Center for Atmospheric Research

Boulder, COOctober 21, 2005

Andy SternConsulting Meteorologist

Mitretek Systems

Metadata for RWIS

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What is Metadata?

• Metadata is defined as “data about data”

• Metadata is a necessary component for observations to be included in data collecting networks (such as MADIS)

• Some portions of metadata can change frequently, so it is important for end users to understand the circumstances under which the data were collected

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What is Metadata used for?

• Metadata can describe almost any quality about an observation. Some examples include:– Platform location & elevation– The types & makes of sensors– Calibration records– Maintenance records– Site exposure

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Minimum Metadata for ESS

• From a MADIS data table:– |MN001|Twin Lakes I-35 Mile Post 1– |371.1000|43.50833|-93.35406|GMT|

• Station Name/Identifier (5 characters)• Long Name String (35 characters)• Station Latitude/Longitude (to 5 digits)• Station Elevation (to 4 digits)• Time Basis (Greenwich Mean Time)

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State DOTs Providing Data to MADIS

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Expanded Metadata - Identification• Platform ID/Site Number• Plain Text Location• Latitude/Longitude/Elevation• Access Directions• Datum• RPU Make• Nearest AWOS/ASOS Site• Advanced Traffic Management

Systems ID

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Metadata - Instrumentation

• Type & Model of each instrument• Number of road sensors• Puck layout diagram• Location of sub-grade temperature

probe• Sensors in bridge decks/ramps• Maintenance/Calibration Records

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Graphical Metadata

RWIS

I-80

EB

Puck Layout Diagram

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Metadata – Site Exposure

• Digital Image of Site• Digital Panoramic View of Site• Distance to center of road• Obstructions (direction & distance)• Landscape Features• Four Quadrant Site Layout• Terrain Slope (degrees & direction)• Base Height Above/Below the

Roadway

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Example of Digital Panorama

Interstate 80 @ Wahsatch, Utah

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Metadata value to the community• Other communities (such as

weather, energy, CVO, agriculture) can use metadata to determine if the observations are:– representative for their task– have appropriate exposure– have a robust maintenance policy– have an established climate record

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Additional Information

• New Publication from FHWA– “Road Weather Information System

Environmental Sensor Station Siting Guidelines”

– Partnership between FHWA, Aurora Pooled Fund Program and the AASHTO Snow and Ice Cooperative Program

– Available from http://ops.fhwa.dot.gov/publications/ess05/