Numerical weather predicition and climate models require accurate and continuous measurements of the atmosphere. Radiosoundings conducted daily all over the world provide the backbone for these measurements thanks to their accuracy and high spatial resolution. However they are expensive and thus are limited to only a few profile measurements per day. Especially within boundary layer this is not enough and to fill this gap a new type of drone-based measurement system has been developed. The recent emergence of drones has brought new opportunities in atmospheric research and in this study their utilization in meteorological profiling is investigated.
The measurement system consists of an octocopter with a Vaisala RD41 dropsonde attached underneath for temperature and humidity measurements. This drone is accompanied by a custom-build ground station that allows autonomous operation. With the drone measurements up to 450m were possible.
To investigate the capabilities of drone-borne setups for vertical profiling, the temperature and humidity measurements were compared between ascending and descending legs of the flight as well as collocated radiosonde measurements. Statistical analysis on the differences between the measured profiles was conducted and individual case studies were performed for better understanding of the effects caused by the drone and the different atmospheric conditions.
The results indicate a warm bias in the drone measurements when compared against radiosonde measurements, and this bias is higher during the ascend leg. Ascend leg shows a bias of 0.4 !C when compared against the radiosonde measurements and the descend leg shows a bias of 0.2 !C. The ascend leg shows a bias of 0.3 !C when compared against the descend leg. The relative humidity measurements with the drone show a dry bias when compared against radiosonde measurements. The ascending leg has a bias of −1.9% and the descending leg −0.3 %. The difference between ascend and descend legs is −1.4 %. Thus the descending leg agrees better with the radiosonde measurements, but also the ascending leg generally agrees with the radiosonde measurements within half a degree in temperature and two percentage relative humidity
