## 3 UAV Applications in Climate Change Research
### Building Envelope Performance  
UAVs empowered with infrared sensors have emerged as an essential tool for building envelope inspections and building energy audits. One major application is using thermographic cameras mounted on drones to detect heat leaks, air infiltration, exfiltration, and insulation deficiencies in roofs and facades. UAVs can be easily deployed to survey every side of a building's structure from optimal proximity compared to the ground-based thermography providing more accurate insights into the thermal performance of building envelopes [155]. A study by [PERSON] et al. [156] presented a comprehensive exploration of the utilization of UAVs for real-time structure detection and tracking, focusing on linear structures, such as roads, highways, and canals, based on the visual feedback. The research tackled two critical components of this challenge: vision-based structure detection and controlling the UAV to follow the structure accurately. The insights provided by this paper have broad applications in different domains. For instance, in infrastructure monitoring, the paper highlights the potential for autonomous UAVs to inspect and monitor structures, such as pipelines, roads, and power grids. This capability can enhance safety and reduce the operational costs. The paper also emphasizes the significance of this technology in disaster responses. Following events, such as earthquakes or natural disasters, where infrastructures can be severely affected, autonomous UAVs can rapidly assess the damage and provide real-time visual feedback, aiding in efficient recovery efforts. Additionally, the ability to autonomously monitor the critical infrastructure can have implications for homeland security, ensuring the integrity of key assets, such as bridges, roads, railways, and power transmission corridors  
Producing orthorectified thermal maps reveals the location and severity of envelope flaws causing energy waste, which can be addressed through suitable retrofit strategies. A study by [PERSON] and [PERSON] [157] explored the use of drones for facade inspections and building envelope pathology diagnoses. Drone technology proved to be an effective and promising alternative methodology for supporting the technical inspection and diagnosis of building envelope pathologies. UAVs also enable low-cost frequent inspections to monitor repairs or catch new leaks as they emerge post-occupancy or post-retrofit. Moreover, UAVs can help facilitate rapid scanning to map cracking and spalling that undermine structural integrity. The photogrammetry processing of visual imagery can construct 3D point clouds capable of millimeter-scale crack detections [158]. Utilizing infrared sensors also highlights areas of moisture intrusion within wall systems signaled by temperature differentials [119]. A study by [PERSON] et al. [159] presented a promising approach to automating sloped roof inspections using UAVs and deep learning. It highlighted the significance of such technology in enhancing efficiency, reducing safety risks, and providing accurate assessments of roof conditions. While acknowledging the limitation of a small dataset, the paper suggested that, with more data, the model's accuracy could be further improved. Overall, this study contributed to the advancement of automated inspection techniques, paving the way for more efficient and safer practices in the construction and insurance industries. Detailed UAV-based envelope inspections enable proactive maintenance to avoid expensive repairs and enhance resilience to climate impacts. In addition, hyperspectral data can detect moisture content and vegetation health in green roofs [160]. Photogrammetry models produced from UAV data help quantify surface buckling, blistering, and deformation over large areas. For a moisture intrusion diagnosis, combining thermal and visible imagery allows a precise inspection. Thermal sensors lack a visual context, while moisture below surfaces remains invisible in visible bands.