Hurricane Imaging Radiometer Wide Swath Simulation for Wind Speed and Rain Rate

There is a strong national interest in the observation of ocean surface winds with high spatial and temporal resolution for understanding tropical cyclones and their effects on weather and climate and in forecasting storms making landfall. Current satellite and aircraft based remote sensing capability is limited in wind speed dynamic range and in the ability to retrieve wind information in the presence of rain, or in temporal and spatial coverage, respectively. The Hurricane Imaging Radiometer (HIRAD) is capable to capture all the hurricane features and dynamics from a high altitude aircraft preserving high resolution measurements. A detailed description of the methods used in simulating the HIRAD instrument surface sampling of wind speed, in intense rain, from various aircraft platforms with realistic operational flight patterns through a time evolving hurricane will be provided in this paper. A noise model used to simulate the effects of rain for various observation path lengths over the swath will also be described. Results will demonstrate the extent of spatial and temporal coverage available from currently available aircraft platforms. © 2008 IEEE

The Proof of Concept of The Hurricane Imaging Radiometer: Hurricane Wind Speed and Rain Rate Retrievals

This dissertation presents the proof of concept for the Hurricane Imaging Radiometer (HIRAD), where remote sensing retrievals of the 2-dimensional wind and rain fields for several hurricanes are validated with independent measurements. A significant contribution of this dissertation is the development of a novel statistical calibration technique, whereby the HIRAD instrument is radiometrically calibrated, using modeled brightness temperatures (Tb) generated using a priori hurricane wind and rain fields that are statistically representative of the actual hurricane conditions at the time of the HIRAD brightness temperature measurements. For this calibration technique, the probability distribution function of the measured HIRAD Tb\u27s is matched to the modeled Tb distribution. After applying this Tb calibration, hurricane wind speeds and rain rates are retrieved for six hurricane surveillance flights between 2013-2015. These HIRAD results are compared with available, statistically independent, surface measurements from in-situ GPS dropwindsondes and remote sensing: Stepped Frequency Microwave Radiometer (SFMR), and the High-Altitude Imaging Wind and Rain Aerial Profiler (HIWRAP). Since there is good agreement in the intercomparisons, it is concluded that the HIRAD hurricane measurement technique performs as intended, after the corresponding Tb images are properly calibrated. Furthermore, based upon the above comparisons, it is concluded that the retrieved HIRAD 2-dimensional wind field improves upon the a priori calibration source, regardless of quality of this model used in the calibration. This shows that HIRAD is not simply replicating results of the calibration source, but rather, it adds useful information