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MetadataConventions for post-processed aircraft based data files.  

I have drawn on the following documents, which are netCDF-centric, but should apply to any data format.  

 I've only made a guess at the required/recommended/optional field.

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Global Attributes

Name


Description

Conventions

required

Identifies this file to follow our conventions.

title

highly recommended

Something to describe the dataset

institution

required

Specifies where the original data was produced.

source

required

The method of production of the original data. "Aircraft". Do we prefer "Platform"?

project

highly recommended


cdm_datatype = "Trajectory"

required if

we choose to follow UnidataObsConvention

Per-variable Attributes

units

required

udunits compatable?

long_name

required

description of variable

standard_name

highly recommended

if a name exists for this parameter

data_quality

highly recommended


missing_value

highly recommended


valid_range

optional


source

optional

instrument source for this measurement

CF standard name table
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Global attributes for Data Discovery

Do we recommend the DataDiscovery Draft above? 

There are several reasons for the need of variable data discovery:

  • Variable names can be cryptic.
  • There can be multiple measurements of the same type.
  • Automation - Software which wants to find its way into a file. Any track plot or SkewT program should be able to open a file and produce their image without user intervention.

I talked with Jon Caron about the variable discovery.

  • He suggested that CF conventions prefer one variable name per attribute, instead of a list of variables in one attribute.
  • After more discussion we thought reversing the "standard_names" to list the variables at the global level was a good way to do it.
  • He suggested using a colon to add a namespace feel, so that all these attributes looked similar (if we liked).

    latitude

    highly recommended

    longitude

    highly recommended

    altitude

    highly recommended

    wind_speed

    recommended

    wind_direction

    recommended

    upward_air_velocity

    recommended

    air_temperature

    recommended

    platform_speed_wrt_air

    recommended

    This is true airspeed

    dew_point_temperature

    recommended

    air_pressure

    recommended

    platform_roll_angle

    recommended

    platform_pitch_angle

    recommended

    platform_orientation

    recommended

    This is true heading

    ground_speed_east_west

    recommended

    ground_speed_north_south

    recommended

Sample netCDF. I added the "reference" as an example namespace.

:reference:latitude = "LATC"
:reference:longitude = "LONC"
:reference:altitude = "GGALT"
:reference:air_temperature = "ATX"
....

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