The files within this .zip file comprise the uncrewed aerial systems (UASs) flight data from the calibration/intercomparison conducted as part of the ISARRA SCALES flight campaign, hosted in Oklahoma in September 2024.  These flights were all conducted on September 8, 2024 at the Kessler Atmospheric and Ecological Field Station near Purcell Oklahoma.  

Each intercomparison flight was designed to consist of an ascent, descent and hover at 18m a.g.l..  However, given the different natures of the participating systems, the actual flight patterns were are all slightly differnent than the proposed flight path.

The intercomparison/calibration was conducted by comparing each individual UAS to reference Coptersonde UAS supplied by the NOAA National Severe Storms Laboratory and Doppler lidars.  The Coptersonde UAS provided the primary reference for temperature (T) and relative humidity (RH) with wind speed (U) and direction (phi) referenced against the CLAMPS Doppler lidar at heights above 100 m and a Windcube Doppler lidar at heights between 40 m and 300 m, with the NOAA National Severe Storms Laboratory Coptersonde UAS providing a third reference for instances where there is disagreement.  The reference systems were calibrated using combinations of chamber and field calibrations and the description of this process, as well as all reference data, will also be uploaded to this hosting service.

The zip file contains three folders.  The 'UAV Data' folder contains the raw data provided by each UAS operator following the calibration flight.  Each UAS data file follows the World Meteorological Organization UAS Demonstration Campaign (UAS-DC) UAS Data Representation Standards, which uses netCDF formatting.   Details can be found here (https://community.wmo.int/site/knowledge-hub/programmes-and-initiatives/wmo-uncrewed-aircraft-systems-demonstration-campaign/uas-demonstration-campaign-uas-data-representation-standards) and in the pdf file included in the zip file.

File naming convention for these files is as follows:
UASDC_AAA_BBBBB_YYYYMMDDHHmmSSZ.nc
where
AAA - Operator ID, as assigned for WMO-DC
BBBBB - Aircraft ID, as assigned by operator
YYYY - Year of flight
MM - Month of flight
DD - Day of flight
HH - Hour of flight
mm - Minute of flight
SS - Seconds of flight
Z - Indicates UTC (Zulu) time
where the time in the filename indicates the start of the measurement takeoff.


The data in the 'UAV Data' folder is the raw, uncalibrated data from each system. However, we have also provided calibrations for each system.  These calibrations are provided in the form of calibration reports for each individual system, provided as .pdf files with the same name as the .nc file.  Two folders with reports are provided.  The temperature and relative humidity calibrations are provided in 'T and RH Calibration Reports'. The wind speed and wind direction calibrations are provided in 'Wind Speed and Direction Calibration Reports'.  The contents of each report is detailed as follows:

Temperature and RH Calibration Reports
--------------------------------------
There are 6 panels in each report.  The functions to correct the measured value as determined by calibration are shown in the middle figures with:
T_c and RH_c  the corrected temperature and relative humidity
T_m and RH_m  the measured temperature and relative humidity
for most cases, the correction applied was a simple bias correction, but some RH values were found to better correct when a sensitivity correction was also applied.

As some sensors calibrated to the reference better than others, to allow the user to review the calibrations themselves, we also provide figures comparing the uncorrected and corrected measurements to the corresponding reference.

Temperature:
- The upper left panel shows a time-height path of the UAS flight compared to the UAS reference, identifying when the aircraft was ascending or hovering.  The contours indicate the approximate temperature during the calibration flight.  The top middle panel shows the temperature as a function of time as measured during the flight.  This panel shows the reference UAS measurement in red, the original, uncorrected UAS measured value in grey (T_m), and the corrected value in black (T_c).    The upper right panel shows the same data, but compares the measured and corrected temperature values compared to the reference as a function of  altitude.
Relative Humidity:
- The lower left panel shows a time-height path of the UAS flight compared to the UAS reference, identifying when the aircraft was ascending or hovering.  The contours indicate the approximate relative humidity during the calibration flight.  The lower middle panel shows the relative humidity as a function of time as measured during the flight.  This panel shows the reference UAS measurement in red, the original, uncorrected UAS measured value in grey (RH_m), and the corrected value in black (RH_c).  The lower right panel shows the same data, but compares the measured and corrected relative humidity values compared to the reference as a function of  altitude. 

Wind Speed and Direction Calibration Reports
--------------------------------------
There are 6 panels in each report.  The functions to correct the measured value as determined by calibration are shown in the lower middle figures with:
U_c and \phi_c  the corrected wind speed and direction
U_m and \phi_m  the measured wind speed and direction
For direction, the correction applied was a simple bias correction, whereas wind speed was corrected using a sensitivity correction.

As some sensors calibrated to the reference better than others, to allow the user to review the calibrations themselves, we also provide figures comparing the uncorrected and corrected measurements to the corresponding reference.

Wind Speed:
- The upper left panel shows a time-height path of the UAS flight compared to the UAS reference, a 9 m sonic, and the lidar heights, identifying when the aircraft was ascending or hovering.  The contours indicate the wind speed as measured by the lidars over the course of the calibration flight.  The top middle panel shows the wind speed as a function of time as measured during the flight.  This panel shows the reference lidar wind speed (extracted at the UAS height) in two different shades of red, the reference UAS measurement of wind speed in yellow, the original, uncorrected UAS measured value in grey (U_m), and the corrected value in black (U_c).    The upper right panel shows the same data, but compares the measured and corrected wind speed values to the references as a function of  altitude.

Wind Direction:
- The lower left panel shows a time-height path of the UAS flight compared to the UAS reference, a 9 m sonic, and the lidar heights, identifying when the aircraft was ascending or hovering.  The contours indicate the wind direction measured by the lidars during the calibration flight.  The lower middle panel shows the wind speed as a function of time as measured during the flight.  This panel shows the reference lidar wind direction (extracted at the UAS height) in two different shades of red, the reference UAS measurement of wind direction in yellow, the original, uncorrected UAS measured value in grey (\phi_m), and the corrected value in black (\phi_c).    The lower right panel shows the same data, but compares the measured and corrected wind direction values to the references as a function of altitude.




