Relative Merits of Using Spaceborne GNSS-R Observations For Improving Storm Surge Simulations

  • Al-Khaldi, Mohammad (The Ohio State University)
  • Johnson, Joel (The Ohio State University)
  • Kang, Younghun (The Ohio State University)
  • Kubatko, Ethan (The Ohio State University)

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The monitoring of cyclone intensification and propagation inland using spaceborne sensors has had a long history of investigation beginning with the TIROS-3 satellite in 1961 and evolving over time into more mature systems like ASCAT ((Advanced SCATerometer) series of satellites first launched in 2006. The increased reliance on spaceborne observatories for providing accurate meteorological input wind fields is motivated, to a large extent, by their global coverage. This in turn enables more comprehensive monitoring and characterization of storm structure and variability spanning their development from tropical disturbances into categorized hurricanes. Traditional spaceborne wind sensors nonetheless can experience limitations caused by the high rain rates around storm eye walls that compromise their ability to accurately characterize storms. Cloud cover can pose a similar limitation in some cases as well. In contrast, the more recent GNSS-R (Global Navigation Satellite System Reflectometry) sensing methodology [1] can reduce the sensitivity of spaceborne wind measurements to the confounding effects of rain and cloud cover by operating at lower microwave frequencies. Their utility for improving hurricane characterization [2, 3] is therefore explored in this work using observations made by NASA’s CYGNSS (Cyclone Global Navigation Satellite System) GNSS-R mission. Results from a data record that extends over a 5 year period spanning ~40 storms will be reviewed. As a further step, the impact of using CYGNSS retrieved parametric storm profiles in storm surge simulations is also assessed through their use as input meteorological wind fields in ADvanced CIRCulation (ADCIRC) storm surge hindcasting simulations. An assessment of the relative merits of their incorporation into the ADCIRC framework relative to results using Best Track wind fields will also be discussed, including comparisons with in situ gauge measurements of storm surge properties.