1. Impact of adjusting the times of radiosonde launches
Proposed studies:
Impact of adjusting the times of
radiosonde launches
John Eyre, on behalf of Stuart Goldstraw, Chair WMO/CBS ET-SBO
WMO Impact Studies Workshop; Shanghai, China; May 2016
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2. Proposed studies: Impact of adjusting the times of radiosonde launches
Background
Possible NWP impact studies
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3. Background (1)
Under present WMO regulations, radiosondes are launched mainly at 00 and 12 UTC
Implementation Plan for the Evolution of Global Observing Systems (EGOS-IP) says:
Action G10:
Investigate possibility to optimize the radiosonde network
… to make upper-air conventional observation coverage more uniform
… taking into account all user requirements in terms of space and time distribution;
… and make relevant recommendations to the CBS for updating Technical Regulations accordingly.
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4. Background (2)
Expected impact on WMO Application Areas of changing radiosonde launch times:
Nowcasting – positive – launch times adjusted to be most favourable to support the forecasting of local meteorological phenomena. This will vary widely around the world.
NWP – neutral/positive? [see next slide]
Climate monitoring – potentially negative – some stations must be protected
Other applications areas?
Costs – potentially positive for some countries (staff time)
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5. Background (3) Expected impact on NWP - issues:
Global NWP is now relatively insensitive to observation times
… if they are distributed approximately uniformly in time.
HOWEVER,
other observations are not uniform in time …
e.g. minimum in AMDAR data around local midnight,
AND SO
what is the impact on NWP of changing launch times?:
to complement other observation types for NWP,
to improve impact on other applications and/or costs.
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6. Possible NWP impact studies
Data denial studies – possible in regions where there are currently more than 2 launches per day
Special campaigns – launch additional sondes for a period of time – study their impact
OSSEs
Others?
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7. Summary
Question:
If NMSs had the freedom to optimise cost:benefit of radiosonde launch times,
… what would be the impacts on applications of these observations,
… including NWP?
NWP impact studies encouraged to address this question
WMO/CBS ET-SBO will be studying this, and they have requested help from NWP centres.
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8. Thank you! Questions?
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