Observations from a Passive Microwave Sounder on the Global Hawk: HAMSR during SHOUT and EPOCH

We will present observations from the High-Altitude MMIC Sounding Radiometer (HAMSR) during two hurricane campaigns: SHOUT in 2016 (Sensing Hazards with Operational Unmanned Technology) and EPOCH in 2017 (East Pacific Origins and Characteristics of Hurricanes).

HAMSR is a Microwave Sounding Radiometer with 25 channels near the 60- and 118-GHz oxygen lines and the 183-GHz water-vapor line. The selection of channels allows the retrieval of temperature and water vapor profiles below the airplane under almost all weather conditions. An additional large scan width allows us to cover a large area of observations during the flight. This makes HAMSR and ideal instrument for hurricane observations.

The observations during SHOUT in 2016 cover Hurricanes like Hermine, Gaston and Matthew, the observations in 2017 focus on Harvey, which was observed during its intensification period in the Gulf of Mexico. We will present data from these observations with a new post-processing retrieval algorithm that includes scattering. The algorithm allows us not only to retrieve water vapor and temperature, but also to estimate of the amount of liquid water and rain. The hurricane observations allow us to look on the retrieval under extreme conditions and test boundaries of our retrieval. We will present results from this retrieval for several flights during both campaigns and show comparisons with the AVAPS dropsonde system and radar information. The combination of instruments allows us to compare and validate our retrieved data with respect to temperature and water vapor, but also with respect to clouds and rain.