Drone-derived datasets in the assessment of the 2024 cut-off low event in Valencia

[Description of methods used for collection/generation of data] Three different UAV platforms were used for data acquisition, each chosen based on their payload capacity and compatibility with various sensors:: 1) DJI Matrice 300 RTK (M300). This quadcopter supports a maximum payload of 2.5 kg and has a maximum take-off weight (MTOW) of 9 kg. It was equipped with several sensors to capture multispectral imagery, RGB data, and gas concentration measurements: - DJI Zenmuse H20T. A multi-sensor payload featuring a 20 MP RGB zoom camera (1/2.7” CMOS) and a 12 MP wide-angle RGB camera (1/2.3” CMOS). It includes a detachable gimbal and offers a maximum shutter speed of 1/8000 s. Under controlled conditions, the manufacturer specifies an accuracy of 0.2 m plus 0.15% of the target distance. - MicaSense RedEdge-MX. A multispectral dual sensor that captures 10 bands across the visible and near-infrared (NIR) spectrum, including blue (444, 475 nm), green (531, 560 nm), red (650, 668 nm), red edge (705, 717, 740 nm), and NIR (842 nm). The system integrates a Downwelling Light Sensor (DLS) with GPS to account for changes in solar irradiance, along with a radiometric calibration panel (RP04-1924106-0B) to ensure radiometric accuracy. - Sniffer4D V2 RS (Soarability). A multi-gas sensing and mapping system capable of simultaneously detecting total volatile organic compounds (TVOC, ppm), sulfur dioxide (SO₂, μg/m³), ozone and nitrogen dioxide (O₃ + NO₂, μg/m³), particulate matter (PM1.0, PM2.5, PM10, μg/m³), flammable gases (CxHy, %), and hydrogen sulfide (H₂S, μg/m³). It provides real-time visualization in both 2D and 3D. In addition, it was integrated with the Sniffer4D Multi-pass TDLAS Hyper-local Methane Module, enabling quantitative methane detection with a resolution of 1 ppm. 2) DJI Mavic 3E (M3E). A lightweight quadcopter equipped with a 20 MP wide-angle RGB camera (4/3” CMOS) and a 12 MP telephoto RGB camera with 56× hybrid zoom. It has an MTOW of 1,050 g and a maximum flight endurance of 45 minutes. 3) DJI Mavic 2 Enterprise Advanced (M2EA). This UAV features a 48 MP RGB optical sensor with a 1/2” CMOS sensor. It has an MTOW of 1,100 g and a maximum flight duration of 31 minutes.