scholarly journals The return of radio waves from the middle atmosphere—I

1937 ◽  
Vol 161 (905) ◽  
pp. 181-196 ◽  
Keyword(s):  
Physical Characteristic ◽  
Middle Atmosphere ◽  
Upper Atmosphere ◽  
Radio Waves ◽  
Sharp Distinction ◽  
Fundamental Significance ◽  
High Ionization ◽  
Collisional Damping

One of us introduced the name “Ionosphere” to designate that region of the upper atmosphere of which the most prominent physical characteristic was the occurrence of sustained high ionization densities, and which was, in consequence, of fundamental significance in the propagation of radio waves. The name, after finding its way into many languages, has been formally adopted by the Union Radio Scientifique Internationale for international use, and is now commonly applied to the region of the atmosphere above the first 90 km. It is an object of this present paper to show that this sharp distinction, although very broadly justified, is less happy than might have been hoped. It has been customary to regard the return of radio waves of measurable intensity from regions sensibly below 90-100 km. as very improbable in any save exceptional conditions, the collisional damping at lower levels being believed to ensure severe attenuation of such waves as might otherwise be returned from any temporarily densely ionized regions at moderate levels, while at still lower levels the rate of recombination seemed likely to prevent the maintenance of substantial ionization densities.

scholarly journals Radio Waves in the Upper Atmosphere

Nature ◽  
1938 ◽  
Vol 141 (3566) ◽  
pp. 407-407
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves

scholarly journals Dissociation, recombination and attachment processes in the upper atmosphere—I

1937 ◽  
Vol 163 (915) ◽  
pp. 542-553 ◽  
Keyword(s):  
Reaction Rates ◽  
Upper Atmosphere ◽  
Radio Waves ◽  
Ionization Density ◽  
Pressure Discharge ◽  
Mechanical Methods ◽  
Order Of Magnitude ◽  
Quantitative Manner ◽  
The Individual ◽  
Atmospheric Ionization

The study of the properties of the earth’s upper atmosphere has now progressed so far as to provide what should be a sufficient basis for the development of a detailed theory. Since the state of the upper atmosphere approximates closely to that of the gas in a low-pressure discharge tube (except for the absence of solid boundaries), it is clear that such a theory must deal with the individual collision processes which can occur in such a system. Until the last few years no satisfactory theory of these phenomena was available, but it is now possible to apply quantum mechanical methods with reasonable expectation of results accurate at least as regards order of magnitude. We therefore propose to make use of these methods to obtain a deeper understanding of the physics of the ionosphere. In this paper we confine ourselves particularly to the qualitative study of certain problems associated with the two upper ionized layers (the E and F regions), making use of information already available concerning the probabilities of the various collision reactions which are important. The detailed evaluation of these reaction rates is being carried out, and in later papers it is hoped to deal with the various problems in a more nearly quantitative manner. The two main strata of atmospheric ionization are the E region extending roughly from 120 to 160 km. and the F region from 180 to 300 km., at night. During the day each splits into two distinct strata forming the E 1 and E 2 and the F 1 and F 2 regions. The ionization density in each region, as determined from experiments with radio waves, exhibits characteristic annual and diurnal variations besides irregular variations of considerable magnitude. The first problem which arises is the reason for the existence of the stratification. This being understood it is then necessary to account for the observed variations of density, the daytime splitting of the layers, and so on.

Return of Radio Waves from the Middle Atmosphere

Nature ◽  
1936 ◽  
Vol 137 (3473) ◽  
pp. 867-867 ◽  
Author(s):  
S. K. MITRA
Keyword(s):  
Middle Atmosphere ◽  
Radio Waves

Refraction of short radio waves in the upper atmosphere

1926 ◽  
Vol 45 (6) ◽  
pp. 535-539 ◽  
Author(s):  
William G. Baker ◽  
Chester W. Rice
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves

scholarly journals Influence of gravity waves on the climatology of high-altitude Martian carbon dioxide ice clouds

2018 ◽  
Author(s):  
Erdal Yiğit ◽  
Alexander S. Medvedev ◽  
Paul Hartogh
Keyword(s):  
Carbon Dioxide ◽  
High Altitude ◽  
Gravity Waves ◽  
General Circulation ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Upper Atmosphere ◽  
Cloud Formation ◽  
Ice Clouds ◽  
Ice Cloud

Abstract. Carbon dioxide (CO2) ice clouds have been routinely observed in the middle atmosphere of Mars. However, there are still uncertainties concerning physical mechanisms that control their altitude, geographical, and seasonal distributions. Using the Max Planck Institute Martian General Circulation Model (MPI-MGCM), incorporating a state-of-the-art whole atmosphere subgrid-scale gravity wave parameterization (Yiğit et al., 2008), we demonstrate that internal gravity waves generated by lower atmospheric weather processes have wide reaching impact on the Martian climate. Globally, GWs cool the upper atmosphere of Mars by ~10 % and facilitate high-altitude CO2 ice cloud formation. CO2 ice cloud seasonal variations in the mesosphere and the mesopause region appreciably coincide with the spatio-temporal variations of GW effects, providing insight into the observed distribution of clouds. Our results suggest that GW propagation and dissipation constitute a necessary physical mechanism for CO2 ice cloud formation in the Martian upper atmosphere during all seasons.

Refraction of short radio waves in the upper atmosphere

1926 ◽  
Vol 45 (6) ◽  
pp. 571-572
Author(s):  
Baker ◽  
Rice
Keyword(s):  
Upper Atmosphere ◽  
Radio Waves
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