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Since solar radio emission F at 10.7 cm wavelength is a good indicator of solar activity, one can apply the empirical formula for quiet magnetospheric conditions. [5] (2) + with T ∞ in K, F o in 10 −2 W m −2 Hz −1 (the Covington index) a value of F averaged over several solar cycles. The Covington index varies typically between 70 and ...
The density falls off to below 10 4 e/cm 3 at night. The F 1 layer merges into the F 2 layer at night. Though fairly regular in its characteristics, it is not observable everywhere or on all days. The principal reflecting layer during the summer for paths of 2,000 to 3,500 km (1,200 to 2,200 miles) is the F 1 layer. However, this depends upon ...
The thermopause is the atmospheric boundary of Earth's energy system, located at the top of the thermosphere. [1] The temperature of the thermopause could range from nearly absolute zero to 987.547 °C (1,810 °F).
The E layer is the middle layer, 90 to 150 km (56 to 93 mi) above the surface of the Earth. Ionization is due to soft X-ray (1–10 nm) and far ultraviolet (UV) solar radiation ionization of molecular oxygen (O 2). Normally, at oblique incidence, this layer can only reflect radio waves having frequencies lower than about 10 MHz and may ...
The respective mean heat flows of continental and oceanic crust are 70.9 and 105.4 mW/m 2. [1] While the total internal Earth heat flow to the surface is well constrained, the relative contribution of the two main sources of Earth's heat, radiogenic and primordial heat, are highly uncertain because their direct measurement is difficult.
The mesopause is the point of minimum temperature at the boundary between the mesosphere and the thermosphere atmospheric regions. Due to the lack of solar heating and very strong radiative cooling from carbon dioxide, the mesosphere is the coldest region on Earth with temperatures as low as -100 °C (-148 °F or 173 K). [1]
Total atmospheric mass is 5.1480 × 10 18 kg (1.13494 × 10 19 lb), [36] about 2.5% less than would be inferred from the average sea-level pressure and Earth's area of 51007.2 megahectares, this portion being displaced by Earth's mountainous terrain. Atmospheric pressure is the total weight of the air above unit area at the point where the ...
The earth atmosphere's scale height is about 8.5 km, as can be confirmed from this diagram of air pressure p by altitude h: At an altitude of 0, 8.5, and 17 km, the pressure is about 1000, 370, and 140 hPa, respectively.