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

Abstract

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.

Impact of Spatial Resolution on Wind Field Derived Estimates of Air Pressure Depression in the Hurricane Eye

“…The swath for a typical HIRAD pass through the eye (with the aircraft at 20 km) would extend to cover the full eyewall region of a strong compact storm. Because of its wide-swath, high resolution imaging capability, HIRAD provides the opportunity to examine the detailed structure of the near surface (10 m height) wind field [3]. In particular, we consider the information contained in the wind field and its dependence on the spatial resolution of the image.…”

Performance Simulations for a Synthetic Aperture Radiometer Measuring Peak Surface Wind Speed in Hurricanes

“…The HIRAD simulation constructs cross-track scans at each model grid point, and contiguous scans along the track [6]. Thus, the spatial resolution over the HIRAD field-of-view is the same as the model grid in both cross-track and along track.…”