Input observation (METRo)

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Description Edit

This file contains the latest RWIS station observations (minimum 3 hours, optimally 12 hours).

Version and revision date Edit

  • Version: 1.0
  • Revision date: Novembre 3rd 2004

Default location Edit

No default location. Observation file must be specified as an argument to the command line.

Contents Edit

The measurements taken by the RWIS station (air temperature, dew point, wind speed, etc.) as well as the date they were taken. This file must contain at least 1 valid observation, and each element in this observation must also be valid (you must have at least one sub-surface observation).

In the case that observations are not available from a site, pseudo-observations must be used. For example, some sites may not have a subsurface sensor. In this case, an estimate of the subsurface temperature may be used in the input observation file. If METRo is to be used in an iterative manner, the user can estimate the subsurface temperature for the initial run, and then use the output subsurface temperature from METRo's roadcast as input for the next run.

Mandatory fields Edit

Header Edit

Field description Element name
Version number version

Observations Edit

Field description Element name Unit
Date and time of observation observation-time ISO 8601
Air temperature at Celsius
Dew point td Celsius
Presence of precipitation pi 0: No -- 1: Yes
Wind speed ws km/h
Road condition sc SSI code
Road surface temperature st Celsius
Road subsurface temperature (40 cm) sst Celsius


  • Missing values are coded with the value: 9999
  • All road condition values are considered wet except for 33 which is the SSI code for dry road.
  • In the case of a bridge, METRo uses air temperature as the subsurface temperature.
  • Road subsurface sensor may be on other depth than 40 cm. In these case, METRo source code should be changed. See METRo mailing list for details.

Minimum Requirements for a Valid Observations FileEdit

METRo performs a variety of tests on the observation input XML file. The following conditions must all be met for METRo to run:

  • At least one observation must include both a valid 'sst' and 'st' entry
  • The observation containing both 'sst' and 'st' must be within 4 hours of another valid 'st' observation
  • There must be at least two valid 'st' entries
  • At least one 'st' entry must be at or after the time of the first atmospheric forecast

Data source Edit

Canada Edit

Transport is mainly a provincial jurisdiction in Canada. Most of the RWIS stations providing observation to create a road forecast are the property of the Departement of Tranport of the province where it belongs.

Some cities also possess RWIS stations.

Please contact the corresponding authority if you want to get access to the observation.

Example Edit

<?xml version="1.0"?>

METRo I/O files
Station | Observation | Forecast | Roadcast | Configuration
METRo I/O specification
Schema | | Flowchart | Format | Date | Observation QA/QC | Road condition | Station type | Time zone | Layer type | Latitude and longitude
METRo I/O examples
Station | Observation | Forecast | Roadcast | Graphical display

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This page is part of the documentation of the METRo software. Back to the table of content.

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