Lower atmospheric regions

In summary, large variations in the pressure, composition and temperature exist in the atmosphere, the greatest variations occurring in the lower atmospheric regions which, as will be seen, are reflected by the much more complex chemistry occurring in these regions, a chemistry which is thought to be dominated by the minor neutral constituents, doubtlessly some of which have yet to be identified. 

Ozone (O3) is formed in the tropical stratosphere, around 12 to 30 miles above the ground, where solar radiation is intense it then migrates to the polar regions. The O3 concentration can be as high as 10 ppm in the stratosphere there, it absorbs a large part of the harmfirl ultraviolet radiation from the sun, thereby protecting life on Earth. CFCs are volatile and persist in the lower atmosphere (the troposphere) because of their inert nature they resist chemical degradation reactions. It is estimated that... 

Fig. 4. The ionized regions of the Earth s atmosphere. The F, E and D regions are designated according to the ledges observed in the electron density. Typical altitudinal profiles of the various positive ion densities in the positive ion-electron plrtsma (from Refs.20 and 2I)) are also shown. The negative ion types in the positive ion-negative ion plasma of the lower D-region are known but the detail altitudinal profiles of density are not well characterised and so only the approximate total negative ion density, N, (dashed line) as obtained from Refs.22) and 23) is shown. The profiles of the electron density, Ne, and the total positive ion density, N+, are also included. It is assumed that quasi-neutrality exists throughout the atmosphere, that is Ne N+ in the thermosphere, Ne + N N+ in the mesosphere, and N N+ in the stratosphere and troposphere...

The assemblage of regions of the Earth that support life, including the lower atmosphere, the Earth s surface and aquatic environments. The term may also define a system rich in feedback loops that link life with non-living aspects of the environment. 

One important point should be emphasized here. This is the paucity of spacecraft data on the chemical composition and thermal structure of Venus lower atmosphere below —22 km altitude (von Zahn et al., 1983). About 80% of Venus atmospheric mass is below this altitude. Furthermore, altitudes of 0-12 km span the region where the atmosphere is interacting with the surface. However, with three exceptions we have no data on the chemical composition of Venus nearsurface atmosphere. First is the older measurements of CO2 and N2 from crude chemical experiments on the Venera 4-6 landers. Second, the water-vapor profile measured by the Pioneer Venus large probe neutral mass spectrometer. Third, the measurements of water-vapor and gaseous sulfur by spectrophotometer experiments on the Venera II-I4 landers. The gas chromatograph and mass spectrometer experiments on... 

Although most evidence indicates that the measured BrO is located in the free troposphere, these data do not exclude other contributions, e.g., from the marine boundary layer. Especially over ocean regions the sensitivity of GOME to BrO in lower atmospheric layers in reduced and a contribution of BrO in the MBL as measured by Leser et al. (2003) cannot be excluded (see, e.g.. 

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