MISR observed cloud-tracked winds over tropical cyclones and their positive forecast impact in NAVGEM simulation of Hurricane Sandy

The Multi-angle Imaging SpectroRadiometer (MISR) retrieves cloud-tracked winds from the parallax and motion of cloud features sequentially observed by multiple camera view angles during a single overpass. With 275 m image resolution, and less than a minute between consecutive images during an overpass, MISR provides a unique, densely gridded (17.6 km resolution), near-instantaneous snapshot of the wind field. MISR winds are similar and similarly accurate, but possess key distinctions from atmospheric motion vectors (AMV) provided by geostationary instruments. We will show examples and assess the frequency of MISR providing wind information not available from other instruments. Additionally, we will demonstrate the information content of MISR winds, showing their capacity to measure wind speed variations in a hurricane eye, divergence associated with rapid convection, and vertical wind shear for several example tropical cyclones including Alberto, Sinlaku, and Ida. Lastly, we will review recent simulations of Hurricane Sandy by the NAVy Global Environmental Model that assimilated MISR winds in addition to standard operational inputs. MISR winds showed a strong positive per-observation impact on 24-hr forecast error.