High-energy Electrons at Earth Orbit - Baseline Data for One Year
This plot shows the averaged intensities of 30-1100 keV (1 keV=1000 electron volts) electrons at Low-Earth Orbit altitudes using the last year of observations by NOAA/TIROS. Click here to see current data for energetic electron levels at Low-Earth Orbit today.
The red region of enhanced radiation over South America at the center of the map is called the South Atlantic Anomaly. This has been referred to as the Sargasso sea of satellite navigation. This perilous region, reaching a peak just off the coast of Brazil, results because the Earth's magnetic core is shifted from the center of the planet by about 500 kilometers. Because of this shift, the magnetic field is weaker over South America. Trapped radiation belt particles penetrate much deeper in the atmosphere here (within a few hundred kilometers of the surface) intersecting the paths of satellites in low-earth orbit, burying themselves in sensitive electronics and disrupting the onboard computers. Narrow yellow bands that stretch across the map at mid-latitudes (in the northern hemisphere, across the middle of the U.S. and, in the southern hemisphere, skimming the bottom of the South Atlantic Anamoly) are high-energy electrons from the outer radiation belts. They are separated by a narrow white region from thicker brighter yellow bands at higher latitude. These highest-latitude (brightest yellow) bands are electrons associated with the auroral oval.