Upper air intercomparison campaigns are organized on the mandate of the World Meteorological Organization (WMO) for the purpose of getting an overview of the performance of the various operational upper air systems that are currently available . Such campaigns provide important information to national meteorological services (NMHS), who partially base the selection of an operational upper air system for their network on the outcome of these campaigns. Furthermore, these campaigns improve the quality and cost-effectiveness of upper air observing systems by providing recommendations on system performances, improvements of instruments and methods of observation and suitable working references, to WMO Members and instrument manufacturers. The focus of the Upper Air Instrument Intercomparison 2022 (UAII2022) is on radiosonde systems and aims to include as many manufacturers as possible. One of the additional aims of this campaign is to involve a variety of other measurement techniques such as remote sensing, aircraft and satellite observations to assess the added value of these instrument systems for upper-air observations.
Goal of the campaign
The main objective of the upper-air intercomparison campaign is to test the performance of operational radiosonde systems and to provide guidance on their performance relative to each other, as well as to evaluate the current capabilities of surface-based and space-based remote sensing instruments, and aircraft-based observations. Its results shall help WMO Members in selecting observing systems according to their requirements and will allow them to evaluate the potential offered by remote sensing instruments to complement the in situ information provided by the radiosondes.
The primary goals of the campaign are:
- To test and evaluate as many operational radiosonde systems as possible at the same location and time.
- To characterize the individual radiosondes with respect to their reproducibility and to determine the uncertainty of the different measured parameters.
- To compare the different radiosonde systems to characterized reference systems employed in the GCOS Reference Upper Air Network (GRUAN).
- To characterize measurement errors and uncertainties of radiosonde sensors under laboratory conditions.
- To demonstrate the added-value of surface-based remote-sensing systems for upper-air measurements and to develop a methodology to compare the measurements of radiosondes with remote-sensing instruments.
To evaluate the capability of each system participating in the intercomparison to reach the uncertainty targets as defined in OSCAR.
Planning, location and organisation
The campaign will take place in 2022 at DWD’s Meteorological Observatory Lindenberg (Germany), and will be organized under the auspices of WMO, with DWD and MeteoSwiss as project co-leads and local organizers. The campaign will consist of two distinct parts, a laboratory campaign and a field campaign. The field campaign is scheduled for August-September 2022, whereas the laboratory campaign will take place between January and December of 2022. During the field campaign, for each radiosonde model, approximately 15 daytime and approximately 15 night-time soundings will be performed. A key aspect of the project is the selection and application of reference in-situ instruments for temperature and water vapour, the characterization of radiosondes under laboratory conditions and the application of manufacturer-independent checks of the radiosondes prior to launch. Lindenberg Observatory has an extensive and unique collection of remote sensing instrumentation, which will be included in the campaign to assess and characterize the added-value of remote sensing instruments for upper-air measurements.