WORLD METEOROLOGICAL
ORGANIZATION
CT-MTDCF/ET-DR&C/Doc.
3.5(5)
ITEM: 3.5
COMMISSION FOR BASIC SYSTEMS
JOINT MEETING OF COORDINATION TEAM ON
MIGRATION TO TABLE DRIVEN CODE FORMS
AND EXPERT TEAM ON DATA
REPRESENTATION AND CODES
(11. 8. 2008)
ENGLISH ONLY
GENEVA, 1-5 SEPTEMBER 2008
New Descriptors for Surface Aviation Observations
Submitted by Yves Pelletier (Canada)
________________________________________________________________
Summary and Purpose of Document
The document contains new Table B descriptors, proposed
for validation.
________________________________________________________________
ACTION PROPOSED
The meeting is invited to approve the descriptors for
validation.
Proposed descriptors
Table
Reference
Element Name
Unit
Scale
Reference Data
Value
Width
0 10 012
Density Altitude
0
-5000
14
0 11 029
Variable Wind State
Feet
Code
Table
0
0
3
1. Density Altitude
Density altitude is a parameter derived from air density at a particular location. It
indicates the altitude in the ICAO Standard Atmosphere corresponding to a given air
density.
2. Proposed Code Table 0 11 029 (Variable Wind State) was devised in accordance with
the Manual on Codes, sections 15.5.2 and 15.5.3.
Code Table 0 11 029
Variable Wind State
0 - Calm
1 - V002 (variable 2 kt)
2 - Vsss (variable with wind speed)
3 - not variable
4-6 - reserved
7 – missing