The Hurricane and Severe Storm Sentinel (HS3) comprises a set of aircraft and payloads ideally suited for the study of hurricanes and other severe weather systems. Using data from two long-duration unmanned airborne systems (UASs) augmented by data from multiple satellites, global meteorological analyses, and computer simulations, the HS3 goal is to better understand the physical processes that control hurricane intensity change. HS3 is a five-year mission specifically targeted to enhance our understanding of the processes that underlie hurricane intensity change in the Atlantic Ocean basin. We define intensity change broadly, including the intensification of a tropical disturbance into a tropical cyclone, further intensification into a hurricane (including the more specific case of rapid intensification), and significant decreases in intensity. Important science questions that HS3 will address include:
1. What impact does the large-scale environment, particularly the Saharan Air Layer (SAL), have on intensity change?
2. What is the role of storm internal processes such as deep convective towers?
3. To what extent are these intensification processes predictable?
HS3 addresses the key NASA Earth Science Enterprise (ESE) Science Goal to study Earth to advance scientific understanding and meet societal needs and NASA’s research objective to “enable improved predictive capability for weather and extreme weather events.” In particular, HS3 will reduce the considerable uncertainty that exists about the factors that influence hurricane intensity change including whether it is primarily a function of the storm environment or storm internal processes. HS3 will obtain the measurements needed to improve scientific understanding and serve as a driver behind the transfer of that understanding into improved intensity prediction.