Hurricane and Severe Storm Sentinel (HS3): Summary of the 2012 deployment

The Hurricane and Severe Storm Sentinel (HS3) objectives are: 1) To obtain critical measurements in the hurricane environment in order to identify the role of key factors such as large-scale wind systems (troughs, jet streams), Saharan air masses, African Easterly Waves and their embedded critical layers (that help to isolate tropical disturbances from hostile environments). 2) To observe and understand the three-dimensional mesoscale and convective-scale internal structures of tropical disturbances and cyclones and their role in intensity change. The mission objectives will be achieved using two Global Hawk (GH) Unmanned Airborne Systems (UASs) with separate comprehensive environmental and over-storm payloads. The GH flight altitudes (>16.8 km) allow overflights of most convection and sampling of upper-tropospheric winds. Deployments from Goddard's Wallops Flight Facility and ~26-hour flight durations will provide coverage of the entire Atlantic Ocean basin, and on-station times up to 5-22 h depending on storm location. Deployments will be in September of 2012 and from late-August to late-September 2013-2014, with up to eleven 26-h flights per deployment. Measurements from the Environmental GH Payload 1) Continuous sampling of temperature and relative humidity in the clear-air environment from the scanning High-resolution Interferometer Sounder (S-HIS). 2) Continuous wind profiles in clear air from the TWiLiTE instrument beginning in 2013. 3) Full tropospheric wind, temperature, and humidity profiles from the Advanced Vertical Atmospheric Profiling System (AVAPS) dropsonde system, which is capable of releasing up to 89 dropsondes in a single flight. 4) Aerosol and cloud layer vertical structure from the Cloud Physics Lidar (CPL). Measurements from the Over-Storm GH Payload 1) Three-dimensional wind and precipitation fields from the High-altitude Wind and Rain Airborne Profiler (HIWRAP) conically scanning Doppler radar. 2) Surface winds and rainfall from the Hurricane Imaging Radiometer (HIRAD) multi-frequency interferometric radiometer. 3) Temperature, water vapor, and liquid water profiles, rain rates, and vertical precipitation profiles from the High-Altitude MMIC Sounding Radiometer (HAMSR). A summary of the 2012 deployment will be discussed.