Electron content, global mean

21.4 TECU

2026-10-25 18:15:00 UTC

area-weighted (cos latitude)

GloTEC global total electron content (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26 Current

Mean anomaly

-1.6 TECU

departure from the recent quiet background: positive during ionospheric storms

Radio absorption, highest frequency

0.0 MHz

2026-10-25 18:29:00 UTC

no significant absorption

D-Region Absorption Prediction (D-RAP), highest affected frequency (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26 Current

X-ray and proton status (NOAA)

X : Normal X-ray Background

p⁺ : Normal Proton Background

messages issued with the D-RAP model

Total electron content (TEC) of the ionosphere GloTEC global total electron content (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26

Number of electrons above one square metre of ground, in TECU (10¹⁶ electrons per m²), assimilated by NOAA from ground GNSS receivers and COSMIC-2 radio occultations. The maximum follows the Sun and forms two crests on either side of the magnetic equator (equatorial anomaly, fountain effect). Each TECU delays a GPS signal by about 16 cm: the largest error source of single-frequency satellite positioning.

Electron content anomaly GloTEC global total electron content (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26

Departure of TEC from its recent quiet background, in TECU: red, more electrons than usual (positive phase of an ionospheric storm); blue, fewer (negative phase, often the day after a geomagnetic storm). Of little value where receivers are missing (oceans, poles).

Shortwave absorption (D region) D-Region Absorption Prediction (D-RAP), highest affected frequency (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26

Highest frequency absorbed by 1 dB on a path (MHz) according to the NOAA D-RAP model: below it, shortwave (HF, 3 to 30 MHz) radio links of aviation, shipping and radio amateurs are cut. X-ray flares switch it on over the day side within minutes; solar protons over the polar caps for days. Transparent: no absorption.

Mean electron content and anomaly since the first import (TECU) GloTEC global total electron content (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26 Current

Show the data as a table

Area-weighted global mean every 10 minutes; the record builds up from 25/10/2026. The daily cycle comes from the distribution of the continents (more sunlit area at some hours); the background trend follows solar activity.

Highest absorbed frequency (MHz) D-Region Absorption Prediction (D-RAP), highest affected frequency (NOAA SWPC) · U.S. Government work, public domain; credit NOAA SWPC · 10/25/26 Current

Show the data as a table

Maximum of the D-RAP grid at each import. Peaks come with X-ray flares (see the GOES X-rays on the “now” page); plateaus of several days with proton events.

Method and sources

GloTEC: every 10 minutes NOAA assimilates, with a Gauss–Markov Kalman filter inherited from the USU-GAIM model (Scherliess et al., 2006), the slant electron content measured by ground GNSS receivers and COSMIC-2 radio occultations; grid of 5° in longitude and 2.5° in latitude. The global mean is weighted by the cosine of latitude. D-RAP: D-region absorption model driven by the GOES X-ray and proton fluxes (Sauer and Wilkinson, 2008), 4° × 2° grid. The maps are reprojected to Mercator from the regular grid.

Reading these data

These are model products: GloTEC leans on its background model where measurements are missing; D-RAP computes the absorption from GOES fluxes, it does not measure it. The series only start at the first import: no record yet to study the link between geomagnetic storms and ionospheric storms.

SOURCES OF THIS PAGE

GloTEC global total electron content (NOAA SWPC): NOAA SWPC, GloTEC (Global Total Electron Content) operational product: Gauss–Markov Kalman filter assimilation of ground GNSS and COSMIC-2 radio occultation TEC, after the USU-GAIM filter of Scherliess et al. (2006), J. Geophys. Res., 111, A11315. · doi:10.1029/2006JA011712 · source page ↗
Licence : U.S. Government work, public domain; credit NOAA SWPC · retrieved on Oct 25, 2026 · SHA-256 3df296f81e2b…
D-Region Absorption Prediction (D-RAP), highest affected frequency (NOAA SWPC): NOAA SWPC, D-Region Absorption Prediction model (D-RAP2), driven by GOES X-ray and proton fluxes (Sauer and Wilkinson, 2008, doi:10.1029/2008SW000399). · doi:10.1029/2008SW000399 · source page ↗
Licence : U.S. Government work, public domain; credit NOAA SWPC · retrieved on Oct 25, 2026 · SHA-256 375db3b56e5d…

Ionosphere Electron content and radio absorption, mapped every 10 minutes