Troposphere, range

Seiler and Junge (226) cited measurements in the upper troposphere ranging from 0.1 to 0.15 ppm in both hemispheres, with an average value of 0.13 ppm and rather constant surface values of 0.1 to 0.12 ppm at the equator and 10°S. They found no diurnal variation, and none of their measurements dropped below 0.09 ppm. Sharply increased values approaching 0.2 ppm were reported for the air over the North Atlantic, which they attribute to an ocean source of CO. 

The part of the atmosphere of direct concern to the environment is the relatively dense lower layer called the troposphere, ranging in thickness from about 10 km at the... 

The atmosphere is divided into several layers on the basis of temperature. Of these, the most significant are the troposphere, extending in altitude from the earth s surface to approximately 11 kilometers (km) and the stratosphere, from about 11 km to approximately 50 km. The temperature of the troposphere ranges from an average of 15°C at sea level to an average of -56°C at its upper boundary. The average temperature of the stratosphere increases from -56°C at its boundary with the troposphere to -2°C at its upper boundary. The reason for this increase is absorption of solar ultraviolet energy by ozone (O3) in the stratosphere. 

The troposphere ranges form -300 km (temperature about 320 K) to 50 km (temperature about 53 K). In the pressure range of 50 to 100 bar water clouds are assumed. In the range of 20 to 40 bar clouds of ammonium hydrosulfide, between 3 and 10 bar hydrogen sulfide and at 1 to 2 bar methane clouds can be found. At the tropopause, the temperature is 53 K, then it increases in the stratosphere due to absorption of solar UV radiation by methane and other hydrocarbons. At the outermost layer of its atmosphere, the temperature is about 800 K. 

More complex ions are created lower in the atmosphere. Almost all ions below 70-80 km are cluster ions. Below this altitude range free electrons disappear and negative ions fonn. Tln-ee-body reactions become important. Even though the complexity of the ions increases, the detemiination of the final species follows a rather simple scheme. For positive ions, fomiation of H (H20) is rapid, occurring in times of the order of milliseconds or shorter in the stratosphere and troposphere. After fomiation of H (H20), the chemistry involves reaction with species that have a higher proton affinity than that of H2O. The resulting species can be... 

The turnover time of water vapor in the atmosphere obviously is a function of latitude and altitude. In the equatorial regions, its turnover time in the atmosphere is a few days, while water in the stratosphere has a turnover time of one year or more. Table 7-1 Qunge, 1963) provides an estimate of the average residence time for water vapor for various latitude ranges in the troposphere. Given this simple picture of vertical structure, motion, transport, and diffusion, we can proceed to examine the behavior of... 

Fig. 11-24 Carbon-14 in the troposphere and the ocean surface water 1962-1981. values for ocean surface water during this period range from 0-15% with no trend over time. (Modified with permission from R. Nydal and K. Lovseth (1983). Tracing bomb in the atmosphere. /. Geophys. Res. 88, 3621-3642, American Geophysical Union.)...

The transformation of arenes in the troposphere has been discussed in detail (Arey 1998). Their destruction can be mediated by reaction with hydroxyl radicals, and from naphthalene a wide range of compounds is produced, including 1- and 2-naphthols, 2-formylcinnamaldehyde, phthalic anhydride, and with less certainty 1,4-naphthoquinone and 2,3-epoxynaphthoquinone. Both 1- and 2-nitronaphthalene were formed through the intervention of NO2 (Bunce et al. 1997). Attention has also been directed to the composition of secondary organic aerosols from the photooxidation of monocyclic aromatic hydrocarbons in the presence of NO (Eorstner et al. 1997) the main products from a range of alkylated aromatics were 2,5-furandione and the 3-methyl and 3-ethyl congeners. 

Oxidation rate constant k, for gas-phase second order rate constants, kOH for reaction with OH radical, kNC,3 with N03 radical and k(), with 03, or as indicated data at other temperatures see original reference kOH = (7.49 0.39) x 10 11 cm3 molecule-1 s-1 at (298 2) K with a calculated tropospheric lifetime ranging from 1.9 to 2.4 h using a global tropospheric 12-h daytime average OH radical concentration of 2.0 x 10s molecule cm-3 (relative rate method, Phousongphouang Arey 2002)... 

Air calculated tropospheric lifetime ranging from 1.9 to 2.4 h for dimethylnaphthalenes using a global tropospheric 12-h daytime average OH radical concentration of 2.0 x 106 molecule cm-3 for the reaction with OH radical (Phousongphouang Arey 2002). 

A high-speed sensor for the assay of dimethyl sulfide in the marine troposphere based on its CL reaction with F2 was recently reported [18]. Sample air and F2 in He were introduced at opposite ends of a reaction cell with a window at one end. The production of vibrationally excited HF and electronically excited fluorohydrocarbon (FHC) produced CL emission in the wavelength range 450-650 nm, which was monitored via photon counting. Dimethyl sulfide could be determined in the 0-1200 pptv (parts per trillion by volume) concentration range, with a 4-pptv detection limit. 

Troposphere is used here to represent the lowest layer of the atmosphere, ranging from the ground to the base of the stratosphere at 10—15 km altitude. Essentially, all data on particulate organic matter is from near ground level in the lower troposphere. 

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