# A Survey on Unmanned Surface Vehicles for Disaster Robotics: Main Challenges and Directions
## 3 USVs for Natural Disasters
### Hurricanes
With the success of such measurements, the authors conclude that the glider allows an extensive use of this technology in measuring air-sea interaction processes in extreme conditions. [PERSON] et al. [68] describe the results of a 100-days journey of a Wave Glider platform in the Gulf of Mexico. During this period, the glider collected surface weather, water temperature, wave, and ocean current profile data within tropical cyclones. It collected data from the tropical storm Hanna in the Caribbean Sea to validate the data against that from nearby buoys. Numerical models were created to predict tropical cyclones and their intensity. Also, collected data was used to understand the Wave Glider maneuverability capabilities in different wave and current conditions. Results indicate an agreement between data measured with the USV and data from the nearby buoys in fair conditions and on the periphery of the tropical cyclone. Lessons learned suggest that tampering or possible collisions can be addressed by using more visible signage on the glider, by deploying the USV in minimally trafficked regions, and by increasing the distance from buoys during loitering exercises. [PERSON] and [PERSON] [69] also use a Wave Glider to monitor surface winds and currents to understand oceanic responses to tropical cyclones. Such monitoring gives a more comprehensive view of actual atmosphere-ocean interactions in a typhoon, as well helps to accurately model air-sea coupled processes. The authors affirm that the Wave Glider was chosen since the onboard weather station is designed to work properly on a moving platform, under severe sea conditions. Such gliders demonstrated an ability to weather more than 10-foot seas and more than 40 kt winds [80], surviving five hurricanes and three tropical cyclones and traveling more than 560,000 km (300,000 nautical miles) [59]. The USV is equipped with an acoustic Doppler current profiler (ADCP)and a conductivity-temperature-depth sensor, while the weather station collects air temperature, wind speed and direction, and barometric pressure. Observations using the glider were conducted on the ocean surface 150 km east of Okinawa, Japan during the Typhoon Danas (2013), which is equivalent to a category 4-hurricane. The glider entered the typhoon eye area collecting a time series of surface winds and currents in typhoon cores to examine the balance between wind-induced energy and the increased kinetic energy of the upper ocean. [PERSON] et al. (2016, 2017) present the development and testing of a monohull USV called EMILY for exploration of bathymetry, littoral mapping, and tracking hurricanes. EMILY can operate autonomously and is equipped with meteorological sensors for measuring atmospheric conditions and water temperature in the ocean. Collected data can be stored on board or be transmitted via radio or satellite communication links. According to the authors, the data collected by the USV can be used for extending hurricane landfall times, improving storm forecast accuracy, and providing information to emergency managers and the public. Simulations are performed to test ways to enhance the possibility of the USV approach a hurricane. Considering the application of robotics to disasters in general, [PERSON] et al. (2018) summarize the activities and lessons learned from a set of four responses (La Conchita Mudslides, Hurricane Dennis, Hurricane Katrina, and Hurricane Wilma). Lessons learned include the low performance of vision systems under low temperatures, the requirement of careful placement of cameras to avoid collisions, the recording of Human-Robot Interface data for future analysis, and the need for more realistic simulations for training purposes.