CCT-13, new entries for data category 2, upper-level temperature/humidity/wind reports with re-used radiosondes

[SibylleK]

Initial request

Background
The Czech Hydrometeorological Institute (CHMI) have been re-using radiosondes since 2019 for testing, and started using them operationally in 2022. They receive radiosondes which have been found or tracked down by members of the public, re-condition them, and re-use them. Re-used radiosondes now make up a significant proportion of total radiosondes used by CHMI: their most recent order for new radiosondes with their supplier was 23% lower than previous years due to this re-use programme.
Of the radiosondes that are returned to CHMI, approximately 75% can be re-used.

Data quality
CHMI have carried out two studies comparing new radiosondes to used radiosondes: one where ‘paired’ flights were used to directly compare the sensors, and one where re-used and new sensors were compared to NWP data.
These two studies showed that re-used radiosondes generally performed better than the WMO ‘goal’ requirements for temperature, wind and humidity measurements. Humidity measurements showed the largest RMSE between re-used and new instruments, but were still within the WMO goal.

Future use
Given the cost savings that are possible by re-using radiosondes, and the reduction in environmental impact, it is likely that more national meteorological and hydrological services will consider similar re-use programmes. For example, GeoSphere Austria started re-using some sondes in Vienna in summer 2023.

Impact on data users
In June 2023, the EUMETNET Observations Scientific Expert Team (OBS SET) was consulted on the possible impacts on data users of more re-used radiosondes being launched. OBS SET would like it to be possible to carry out further research into differences between data from used and re-used radiosondes. Currently there is no way of knowing from the BUFR message whether a re-used radiosonde has been used.

Proposal
EUMETNET Working Group for radiosounding (WG-RS) has been consulted. WG-RS is made up of technical experts in upper air measurement from most EUMETNET Members, and currently has around 30 members. WG-RS would like to propose new entries in Common Code Table 13, under data category 2 - “Vertical soundings (other than satellite)”.

Amendment details

New entries in CCT 13:

Data Category	Data Category name	International Subcategory	International Subcategory name
2	Vertical soundings (other than satellite)	104	Upper-level temperature/humidity/wind reports from fixed-land stations (TEMP) with re-used radiosondes
2	Vertical soundings (other than satellite)	105	Upper-level temperature/humidity/wind reports from ships (TEMP SHIP) with re-used radiosondes
2	Vertical soundings (other than satellite)	106	Upper-level temperature/humidity/wind report from mobile land stations (TEMP MOBIL) with re-used radiosondes
2	Vertical soundings (other than satellite)	114	Upper-level temperature/humidity/wind reports from descent radiosondes originally launched from fixed-land stations with re-used radiosondes
2	Vertical soundings (other than satellite)	115	Upper-level temperature/humidity/wind reports from descent radiosondes originally launched from ships with re-used radiosondes
2	Vertical soundings (other than satellite)	116	Upper-level temperature/humidity/wind reports from descent radiosondes originally launched from mobile land stations with re-used radiosondes

Comments

No response

Requestor(s)

Alex Priestley, EUCOS Network Manager
Sibylle Krebber (DWD)

Stakeholder(s)

EUMETNET Observations Scientific Expert Team (OBS SET)
All users of radiosonde data

Publication(s)

Manual on Codes (WMO-No. 306), Volume I.2, Common Code Table C-13

Expected impact of change

None

Collaborators

EUMETNET Working Group for radiosounding (WG-RS)

References

No response

Validation

No response

[amilan17]

@SibylleK Do you want this to be included in FT2024-1 or FT2024-2?

[SibylleK]

@amilan17 If it is not too late, FT2024-1 would be good.

[amilan17]

https://github.com/wmo-im/CCT/wiki/Teleconference.10.January.2024 notes:

@SibylleK update the branch; @amilan17 to verify branch

[SibylleK]

@amilan17, the branch is updated.