Code Table 4.2, discipline 0, category 19: new entries for persistent contrails

[SibylleK]

Initial request

DWD is requesting two new contrail parameters.

The existing entries in code table 4.2:

Name	Product Discipline	Parameter Category	Parameter Number	Units
Contrail top	0	19	15	m
Contrail base	0	19	16	m

stand for top and base of condensation trails in general.
We request two new parameters for top and base of persistent contrails.
Persistent contrails, which may persist for several hours (Cirrus homogenitus, Cirrus homomutatus, [1]) are of special interest, for instance, as they increase the general cloudiness of the atmosphere (see, e.g. [2]).
In addition, aviation is very interested in information on these clouds.
Persistent contrails may be diagnosed using the method described in [3].
Currently, however, we do not have the possibility to distinguish explicitly between persistent and non-persistent contrails with respect to GRIB metadata, as the existing "contrail" parameters may be interpreted as including both types, persistent and non-persistent.

Amendment details

Add new entires in code table 4.2 dicipline 0, category 19:

Name	Product Discipline	Parameter Category	proposed Parameter Number	Units
Top of persistent contrails	0	19	48	m
Base of persistent contrails	0	19	49	m

Comments

No response

Requestor(s)

Sebastian Borchert (DWD)
Sibylle Krebber (DWD)
Petra Baumann (MeteoSwiss)

Stakeholder(s)

Enter list of stakeholder(s).

Publication(s)

Manual on Codes (WMO-No. 306), Volume I.2, GRIB code table 4.2, discipline 0, category 19

Expected impact of change

MEDIUM

Collaborators

No response

References

[1] WMO International Cloud Atlas
[2] Fereral Aviation Administration (USA), Aircraft Contrails Factsheet
[3] Appleman H. (1953) The formation of exhausted condensation trails by jet aircraft. Bulletin American Meteorological Society, Vol. 34, 14 – 20.

Validation

No response

[amilan17]

https://github.com/wmo-im/CCT/wiki/Teleconference.6.7.June.2023 notes:

Team agrees to proposal

[amilan17]

@SibylleK Did you want this to go through FT2023-2? If so I created a branch for you to update.

[SibylleK]

Thank you very much @amilan17! Yes, it should go through FT2023-2.
Branch is updated.

[amilan17]

https://github.com/wmo-im/CCT/wiki/Teleconference.13.July.2023 notes:

ready