Impact of Assimilating the FORMOSAT‐3/COSMIC and FORMOSAT‐7/COSMIC‐2 RO Data on the Midlatitude and Low‐Latitude Ionospheric Specification

Abstract

Global Navigation Satellite System (GNSS) Radio Occultation (RO) missions, such as the Formosa Satellite‐3/Constellation Observing System for Meteorology, Ionosphere, and Climate (FORMOSAT‐3/COSMIC) and the upcoming FORMOSAT‐7/COSMIC‐2, provide valuable profiling of the ionized atmosphere for the monitoring of space weather. This study shows that the FORMOSAT‐3/COSMIC and FORMOSAT‐7/COSMIC‐2 missions' ability to monitor highly variable ionospheric weather can be considerably extended with the help of data assimilation. The Gridpoint Statistical Interpolation (GSI) Ionosphere is a new data assimilation system designed specifically for the low‐latitude and midlatitude ionosphere. The capability of the GSI Ionosphere is first demonstrated with actual FORMOSAT‐3/COSMIC RO total electron content (TEC) data for January 2013. Features of the ionospheric equatorial ionization anomaly in a coupled plasmasphere ionosphere thermosphere model become more consistent with the TEC maps created with independent ground‐based GPS data. The consistency has improved by assimilation of FORMOSAT‐3/COSMIC RO data up to about 50% in comparison to the control simulation case without data assimilation. To evaluate the impact of future RO missions on ionospheric weather specification, comparative Observing System Simulation Experiments (OSSEs) are carried out with synthetic RO TEC data. An OSSE of FORMOSAT‐7/COSMIC‐2 shows that the GSI Ionosphere can improve the ionospheric specification within ±30° geomagnetic latitude by 67% over the control case, which is comparable to the improvement yielded by FORMOSAT‐3/COSMIC for 2009 (61%). These results indicate a great potential for improving the monitoring of realistic ionospheric weather with the help of FORMOSAT‐7/COSMIC‐2 RO TEC data.

Domain of Influence Analysis: Implications for Data Assimilation in Space Weather Forecasting

“…The DOI analysis presented here can also be combined with an Observing System Simulation Experiment (OSSE), an approach already used in ionospheric and solar dynamo studies (Hsu et al, 2018;Dikpati, 2017) to help provide a cost-effective approach to the evaluation of the potential impact of new observations. OSSE requires that DA is already implemented and uses independently simulated "data" that are ingested into a different model or a different instance of the same model.…”

The Impact of Solar Activity on Forecasting the Upper Atmosphere via Assimilation of Electron Density Data

“…They focused on assimilating over a period of 24 h under solar minimum conditions. Hsu, Matsuo, and Liu (2018) and Hsu, Matsuo, Yue, et al. (2018) presented observing system simulation experiments (OSSEs) of assimilation of synthetic data that represent both COSMIC and the follow‐on mission COSMIC‐2.…”

The Early Results and Validation of FORMOSAT‐7/COSMIC‐2 Space Weather Products: Global Ionospheric Specification and Ne‐Aided Abel Electron Density Profile

“…This often hinders the investigation of day‐to‐day ionosphere variations, making it necessary to combine several days of measurements to generate a global density map. On the other hand, numerous studies have demonstrated the capability to reconstruct global ionosphere density through data assimilation techniques (Araujo‐Pradere et al, 2007; Bust et al, 2004, 2007; Chen, Lin, Matsuo, Chen, Lee, et al, 2016; Chen, Lin, Matsuo, & Chen, 2016; Chen et al, 2017, 2019; Fuller‐Rowell et al, 2006; Hajj et al, 2004; Hsu et al, 2014; Hsu, Matsuo, Yue, et al, 2018; Hsu, Matsuo & Liu, 2018; Komjathy et al, 2010; Lee et al, 2012, 2013; Matsuo & Araujo‐Pradere, 2011; Scherliess et al, 2006; Schunk et al, 2005; Sun et al, 2015; Wang et al, 2004; Yue et al, 2014). Recently, Lin et al (2015, 2017) developed the global ionospheric specification (GIS) data assimilation system that can provide global ionospheric electron density on an hourly basis.…”