2.7.1 https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions spase://NASA/NumericalData/ISIS2/SFS/TOPIST NASA NumericalData ISIS 2 TOPIST Produced Electron Density Profiles https://doi.org/10.48322/cm9h-qt09 2026-04-30T16:34:07Z 2021-04-27T15:38:11Z Only known prior ReleaseDate of the metadata 2025-12-04T13:29:42Z Added MetadataRightsList and RightsList(s). Added ResourceType and NamingAuthority. Updated to 2.7.1. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. ZCB 2026-04-10T09:58:46Z Added new Contact(s). ZCB 2026-04-10T10:03:44Z Added PublicationInfo. ZCB 2026-04-30T16:34:07Z Added DOI. tlk This data set from the ISIS 2 (International Satellites for Ionospheric Studies) Swept-Frequency Sounder consists of electron density profiles for the ionosphere above the F2 maximum (topside ionosphere). The data set was generated from the averaged ionogram binary data (SPIO-00318) recorded by the Topside Sounder. The data are obtained with the TOPIST program, which analyzes the data, automatically scales the ionogram traces and resonances, and inverts the traces into an electron density profile. The same program is available for use to hand-scale the data if desired. Output data items include spacecraft position, electron density profile, assessment of quality, resonance and cut-off frequencies, and both the O-trace and X-trace. Paghis, Irvine 2026-04-10T10:03:44Z Space Physics Data Facility spase://SMWG/Person/Irvine.Paghis PrincipalInvestigator spase://SMWG/Person/Dieter.K.Bilitza GeneralContact spase://VSPO/NumericalData/ISIS 2/SFS/NEPROF_TOPIST spase://VSPO/NumericalData/ISIS2/SFS/TOPIST spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb Online Open https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available NASA Heliophysics data products FTPS from SPDF (not with most browsers) ftps://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ HTTPS from SPDF https://spdf.gsfc.nasa.gov/pub/data/isis/topside_sounder/ In CDF via HTTP from CDAWeb CDF spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb Online Open https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available NASA Heliophysics data products CDAWeb https://cdaweb.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=I2_NEPROF_TOPIST&index=sp_phys I2_NEPROF_TOPIST I2_NEPROF_TOPIST Text https://cdaweb.gsfc.nasa.gov/pub/data/isis/topside_sounder/topist_ne_profile_cdf/isis2/$Y i2_neprof_topist_$Y$m$d_$v.cdf spase://SMWG/Repository/NASA/GSFC/SPDF Online Open CDAWeb Programmatic Data Access https://cdaweb.gsfc.nasa.gov/WS/cdasr/1/dataviews/sp_phys/datasets/I2_NEPROF_TOPIST/clientLibraryExample/ I2_NEPROF_TOPIST Access to this data from common programming environments. Note: this AccessInformation element was added by HDPWS. Binary spase://SMWG/Repository/NASA/GSFC/SPDF Online Open https://spdx.org/licenses/ SPDX CC0-1.0 https://spdx.org/licenses/CC0-1.0.html Creative Commons Zero v1.0 Universal CC0 1.0 Universal is the Creative Commons license applicable to all publicly available NASA Heliophysics data products CDAWeb HAPI Server https://cdaweb.gsfc.nasa.gov/hapi I2_NEPROF_TOPIST Web Service to this product using the HAPI interface. CSV spase://SMWG/Instrument/ISIS2/SFS Profile 1971-11-11T18:18:40 1984-01-04T05:15:38 Earth.NearSurface.Ionosphere