Sustainable Development Indicator Group

Working Draft Framework, Version 2, June 4, 1996

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1.2.5.2 Ionosphere

Definition: A shell of partially ionized atmosphere surrounding the Earth from approximately 60-1000 km. Absorption of short wavelength radiation from the Sun photoionizes gases in the atmosphere to produce the ionosphere. Gas dynamics and electromagnetic interactions dominate the behavior of the inoized gases. The gases ionize during daytime and recombine during night.

Definition Source: Satellite Environment Handbook

Ionosphere Categories:

1.2.5.2.1 D Region: The lowest layer of the ionosphere extending from approximately 60-85 km and dominated by NO+ ions generated by apsorption of Lyman-Alpha radiation. The D Region disappears at night. (Definition Source: Satellite Environment Handbook)

1.2.5.2.2 E Region: The layer of the ionosphere extending from approximately 85-140 km and dominated by O2+ and NO+ ions generated by the absorption of soft X-rays. (Definition Source: Satellite Environment Handbook)

1.2.5.2.3 F1 Region: The layer of the ionosphere extending from approximately 140-200 km and dominated by O2+ and NO+ ions at the lower boundry and transitioning to O+ at the upper boundry. Absorption by radiation between 200-900 angstroms generate the F1 layer. The F1 layer disappears completely at night.. (Definition Source: Satellite Environment Handbook)

1.2.5.2.4 F2 Region: The layer of the ionosphere extending from approximately 200-1000 km and dominated by O+ and some N+ ions. Ion density peaks between 200-400 km and then slowly tapers off. Unlike the F1 layer, the F2 layer does not disappear at night.. (Definition Source: Satellite Environment Handbook)