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Evaluating Radio Occultation (RO) Constellation Designs Using Observing System Simulation Experiments (OSSEs) for Ionospheric Specification
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  • Nicholas Dietrich,
  • Tomoko Matsuo,
  • Chi-Yen Lin,
  • Brandon diLorenzo,
  • Charles C. H. Lin,
  • Tzu-Wei Fang
Nicholas Dietrich
Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder

Corresponding Author:[email protected]

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Tomoko Matsuo
Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder
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Chi-Yen Lin
National Central University
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Brandon diLorenzo
Ann and H.J. Smead Department of Aerospace Engineering Sciences, University of Colorado Boulder
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Charles C. H. Lin
National Cheng Kung University
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Tzu-Wei Fang
NOAA SWPC
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Abstract

Low Earth orbit (LEO) radio occultation (RO) constellations can provide global electron density profiles (EDPs) to better specify and forecast the ionosphere-thermosphere (I-T) system. To inform future RO constellation design, this study uses comprehensive Observing System Simulation Experiments (OSSEs) to assess the ionospheric specification impact of assimilating synthetic EDPs into a coupled I-T model. These OSSEs use 10 different sets of RO constellation configurations containing 6 or 12 LEO satellites with base orbit parameter combinations of 520 km or 800 km altitude, and 24 degrees or 72 degrees inclination. The OSSEs are performed using the Ensemble Adjustment Kalman Filter implemented in the Data Assimilation Research Testbed and the Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIEGCM). A different I-T model is used for the nature run, the Whole Atmosphere Model-Ionosphere Plasmasphere Electrodynamics (WAM-IPE), to simulate the period of interest is the St. Patrick’s Day storm on March 13-18, 2015. Errors from models and EDP retrieval are realistically accounted for in this study through distinct I-T models and by retrieving synthetic EDPs through an extension Abel inversion algorithm. OSSE assessment, using multiple metrics, finds that greater EDP spatial coverage leading to improved specification at altitudes 300 km and above, with the 520 km altitude constellations performing best due to yielding the highest observation counts. A potential performance limit is suggested with two 6-satellite constellations. Lastly, close examination of Abel inversion error impacts highlights major EDP limitations at altitudes below 200 km and dayside equatorial regions with large horizontal gradients and low electron density magnitudes.
25 Apr 2024Submitted to ESS Open Archive
26 Apr 2024Published in ESS Open Archive