Data Assimilated Global Ionosphere Specification (GIS) - raw 3-D electron densities from DOY 221 to 365 in 2019 and DOY 001 to 009 in 2020

The ionospheric data (electron density) used in this study are from GIS (Lin et al., 2015, 2017), which is an observational product based on the Gauss‐Markov Kalman filter to assimilate the slant TECs from ground‐based GPS receivers and space‐based radio occultation receivers onboard recently launched FORMOSAT-7/COSMIC-2 mission (Lin et al., 2020).<br><br>The global 3-D ionospheric electron density data are stored in NetCDF format.<br>Each tar file contains a folder named as ("YYYY.DOY") for a specified day. There are 24 ("*.nc") files inside the folder.<br>[YYYY is the year][DOY is the day of year]<br>For each day, the data files are named as "GIS_Ne_RO_GPS_YYYY_DOY_XX.nc"<br><br>[XX is Universal Time in hour]<br>Each file consists the global 3-D electron densities of 5° × 2.5° × 20 (km) grid in geographic longitude, latitude and altitude (from 100-1000 km).<br>References:Lin, C. Y., Matsuo, T., Liu, J. Y., Lin, C. H., Tsai, H. F., &amp; Araujo‐Pradere, E. A. (2015). Ionospheric assimilation of radio occultation and ground‐based GPS data using non‐stationary background model error covariance. Atmospheric Measurement Techniques, 8(1), 171–182. https://doi.org/10.5194/amt-8-171-2015Lin, C. Y., Matsuo, T., Liu, J. Y., Lin, C. H., Huba, J. D., Tsai, H. F., &amp; Chen, C. Y. (2017). Data assimilation of ground-based GPS and radio occultation total electron content for global ionospheric specification. Journal of Geophysical Research: Space Physics, 122, 10,876–10,886. https://doi.org/10.1002/2017JA024185Lin, C. Y., C. H. Lin, J. Y. Liu, P. K. Rajesh, T. Matsuo, M. Y. Chou, H. F. Tsai, W. H. Yeh, and Bodo Reinisch (2020), The Early Results and Validation of FORMOSAT-7/COSMIC-2 Space Weather Products: Global Ionospheric Specification and Ne-Aided Abel Electron Density Profile, accepted by J. Geophys. Res. Space Physics<br><br>