Vertical levels (METRo)

From Documentation

This article is about the number of vertical levels in the model of METRo.

The choice of the grid depends on the kind of road for which the road forecast is attempted.

Contents 1 Road 2 Bridge and overpass 3 Proposition of output 3.1 Example

[edit] Road

For normal roads, a variable-resolution grid is used. The grid contains 29 levels under the surface, is computed at the run time and is based on the number and the composition of layers of the road. For a given composition of road, the same grid will always be used.

The grid is chosen to give a maximum resolution of 0.01 m at the surface and about 0.05 m at a depth of 0.5 m. The bottom of the variable grid is at 1.4 m, and 24 out of 29 levels lie above 0.5 m.

For more information about how the levels are disposed into the ground, please refer to the METRo article.

[edit] Bridge and overpass

In the case of a bridge, a uniform grid of 0.01 m (1 cm) is used, starting at 0.5 cm.

[edit] Proposition of output

It has been proposed to add all the levels of sub surface temperature in the output roadcast of METRo. This would be the version 1.6 of METRo roadcast. Please check if there is any back compatibility issues.

A flag should be added to have all the levels in the output. Something like --levels.

The output would have the following values:

Field description	Element name	Unit
Depth of level	depth	Meter
Temperature at level	lev-temp	Celsius
Grid level	(attribute) num="n"	Integer without units, 0 is the surface

[edit] Example

Number are fictives.

<?xml version="1.0"?>
<roadcast>
  <header>
      <filetype>roadcast</filetype>
      <version>1.5</version>
      <road-station>oaa</road-station>
      <production-date>2004-08-26T01:00Z</production-date>
      <first-roadcast>2004-08-25T23:12Z</first-roadcast> 
      <vertical-levels>
          <depth num="0">0.00</depth>
          <depth num="1">0.01</depth>
          <depth num="2">0.02</depth>
          ...
      </vertical-levels>
  </header>
  <prediction-list>
      <prediction>
       <forecast-time>2004-08-26T00:00Z</forecast-time>
         <hh>20.0</hh>
         <at>-7.03</at>
         <td>-11.96</td>
         <ws>22.11</ws>
         <sn>0.0</sn>
         <ra>0.0</ra>
         <qp-sn>0.0</qp-sn>
         <qp-ra>0.0</qp-ra>
         <cc>7</cc>
         <sf>35.81</sf>
         <ir>298.06</ir>
         <fv>0.0</fv>
         <fc>-128.07</fc>
         <fa>10.0</fa>
         <fg>-71.37</fg>
         <bb>-287.17</bb>
         <fp>0.0</fp>
         <rc>1</rc>
         <st>-0.79</st>
         <sst>-7.02</sst>
         <tl>
            <lev-temp num="0">-8.4</lev-temp>
            <lev-temp num="1">-8.2</lev-temp>
            <lev-temp num="2">-8.3</lev-temp>
            ...
          </tl>
      </prediction>
      <prediction>
        <forecastime>
          ...
  </prediction-list>
</roadcast>

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