CYGNSS SMALLSAT CONSTELLATION FOR SEVERE STORM AND HYDROLOGIC SCIENCE APPLICATIONS

Randall Rose ^1,5 Chris Ruf ² Mahta Moghaddam ³ Derek Posselt ⁴

¹Space Science and Engineering, Southwest Research Institute, San Antonio, Texas, USA
²Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI, USA
³Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
⁴Department of Atmospheric Physics and Weather, Jet Propulsion Laboratory/Caltech, Pasadena, CA, USA
⁵Division of Space Science and Engineering, Southwest Research Institute, San Antonio, Texas, USA

The NASA Cyclone Global Navigation Satellite System (CYGNSS) mission consists of a constellation of eight microsatellites successfully launched into low Earth orbit on 15 December 2016. Each observatory carries a radar receiver to measure GPS signals scattered by the Earth surface. Over ocean, the reflected GPS signals are used to estimate surface wind speed and air-sea latent heat flux. Over land, estimates of near-surface soil moisture, wetland extents, and imaging of flood inundation are possible. The measurements are able to penetrate through all levels of precipitation and heavy vegetation due to the GPS frequency of operation. The density and revisit time of sampling afforded by the number of satellites in the constellation makes possible reliable detection of short time scale weather events such as flood inundation dynamics immediately after a tropical cyclone landfall and rapid soil moisture dry down immediately after major precipitation events. Engineering commissioning of the constellation was completed in March 2017 and the mission is currently in its extended science operations phase.

Science data products are being generated for ocean surface scattering cross section, near surface (10 m referenced) ocean wind speed and mean square slope. The impact of CYGNSS wind speed data assimilation into hurricane weather prediction model is being investigated. Measurements over land are used for terrestrial science applications, including near-surface soil moisture content and flood inundation extent.

The COSPAR 2019 presentation will include an overview, current mission status, and highlights of scientific applications related to its ocean wind and terrestrial water cycle measurements.