Fixed-wing UAS wind and turbulence measurements at GM Falkenberg during FESSTVAL 2020 and 2021

Abstract: This data set contains in-situ airborne measurements of atmospheric parameters by unmanned aircraft system (UAS) of type fixed-wing conducted with the multi-purpose airborne sensor carrier "MASC-3" (Rautenberg et al., 2019b). The UAS recorded in-situ meteorological parameters of the three-dimensional wind vector, temperature and humidity at high temporal resolution with a sampling rate of 100 Hz. The data was obtained at the boundary layer-measurement site (Grenzschichtmessfeld (GM)) Falkenberg during two intensive observational periods (IOPs): 07 July - 31 July 2020 and 06 June - 02 July 2021, in the framework of the VALUAS project. The project is funded by the German Meteorological Service (DWD) to validate Doppler wind lidar measurements. The measurements in 2021 took place in parallel to the Field Experiment on submesoscale spatio-temporal variability in Lindenberg (FESSTVAL) campaign. The data set contains 53 flights and has been processed by the Environmental Physics group at the University of Tübingen, Germany.

TableOfContents: eastward wind component u; standard deviation of eastward wind component uu; northward wind component v; standard deviation of northward wind component vv; upward air velocity w; standard deviation of upward air velocity ww; wind speed; standard deviation of wind speed; wind direction; standard deviation of wind direction; air pressure; air temperature; relative humidity; turbulent kinetic energy tke; momentum flux mfs

Note: For each flight the netCDF file contains the median time, latitude, and longitude and the mean height above ground of the respective legs together with a leg ID and the bounds for latitude and longitude of every leg.

Technical Info: dimension: total number of legs (varies between flights); temporalExtent_startDate: 2020-07-07 09:50:18; temporalExtent_endDate: 2021-07-02 18:18:03; temporalResolution: none (depends on flight duration per leg i.e. variable time_bnds); temporalResolutionUnit: none; spatialResolution: none (depends on leg length i.e. variables lat_bnds and lon_bnds); spatialResolutionUnit: none; horizontalResolutionXdirection: none; horizontalResolutionXdirectionUnit: none; horizontalResolutionYdirection: none; horizontalResolutionYdirectionUnit: none; verticalResolution: none (depends on leg height above ground i.e. variable zsl); verticalResolutionUnit: none; verticalStart: 90; verticalStartUnit: meters; verticalEnd: 580; verticalEndUnit: meters; instrumentName: multi-purpose airborne sensor carrier MASC-3; instrumentType: five-hole probe, fine wire platinum resistance thermometer; instrumentLocation: Fixed-wing unmanned aircraft system; instrumentProvider: University of Tübingen, Germany

Methods: For measuring the three-dimensional wind vector MASC-3 uses a five-hole probe (Rautenberg et al., 2019a; Wildmann et al., 2014), for temperature a fine wire platinum resistance thermometer (Wildmann et al., 2013), and for positional measurements an INS with a GPS sensor. The MASC-3 can resolve turbulence down to an eddy size of about 1 m (Rautenberg et al. 2019b).

The overall atmospheric conditions during the campaign were typical summer-time atmospheric boundary layers with strong convection. The overall duration of a flight is 1 – 1.5 h in an altitude band of 90 m - 580 m above ground. Each measurement flight of the presented data set comprises flight sections, which are straight and leveled (called legs), with a length of approx. 2.5 km. Flights took place only in good weather conditions (visual contact with the aircraft, no flying in rain, thunderstorms, above clouds or at night). The maximum measurable wind speed is approx. 12 - 15 m/s.

All flights have been quality controlled and filtered for systematic errors. The uncertainties of the measurement principle are described in detail in van den Kroonenberg et al. (2008). The uncertainty of absolute wind measurements was validated to below 0.4 m/s. Only straight and level flight sections (legs) are used during post-processing. The median values (u-, v-, and w-component of the wind), mean values (all other variables except time, latitude and longitude) and standard deviations are calculated for each variable, resulting in the data set archived here, i.e. all values are median or mean values of the specific flight legs. All meteorological equations are based on the Python package “PARMESAN” (https://tue-umphy.gitlab.io/software/parmesan/)

Units: m/s; m/s; m/s; m/s; m/s; m/s; m/s; m/s; degrees; degrees; Pa; K; 1; m²/s²; N/m²

geoLocations: westBoundLongitude: 14.1024 degrees East; eastBoundLongitude: 14.1401 degrees East; southBoundLatitude: 52.1539 degrees North; northBoundLatitude: 52.1780 degrees North; Germany, UTM zone 33U

Size: Data are organized per flight leg. Data from all flights of individual years (here: 2020: 25 flights and 2021: 28 flights) are packed into separate tar archives = 2 archives. Total size: < 200 KByte

Format: netCDF

DataSources: Fixed-wing unmanned aircraft system (UAS) based in-situ airborne measurements using the multi-purpose airborne sensor carrier MASC-3

Contact: saskia.jung (at) uni-tuebingen.de

Web page: https://www.cen.uni-hamburg.de/en/icdc/data/atmosphere/samd-st-datasets/samd-st-fesstval/fval-ekut-masc3-l2-wind.html , see also: https://www.cen.uni-hamburg.de/en/icdc/research/samd/observational-data/short-term-observations/fesstval.html