A far-wing line shape theory based on the binary collision and quasistatic approximations that is applicable for both the low- and high-frequency wings of the vibration-rotational bands has been developed. This theory has been applied in order to calculate the frequency and temperature dependence of the continuous absorption coefficient for frequencies up to 10,000 cm−1 for pure H2O and for H2O-N2 mixtures. The calculations were made assuming an interaction potential consisting of an isotropic Lennard-Jones part with two parameters that are consistent with values obtained from other data, and the leading long-range anisotropic part, together with the measured line strengths and transition frequencies. The results, obtained without the introduction of adjustable parameters, compare well with the existing laboratory data, both in magnitude and in temperature dependence. This leads us to the conclusion that the water continuum can be explained in terms of far-wing absorption. Current work in progress to extend the theory and to validate the theoretically calculated continuum will be discussed briefly
Attention is given to all processes extending from the earth surface to the tropopause, but special emphasis continues to be devoted to the physics of clouds and precipitation, i.e. atmospheric aerosols; microphysical processes; cloud dynamics and thermodynamics; numerical simulation of cloud processes; clouds and radiation; meso- and macrostructure of clouds and cloud systems, and weather modification.
As the world’s leading publisher of science and health information, Elsevier serves more than 30 million scientists, students, and health and information professionals worldwide. We are proud to play an essential role in the global science and health communities and to contribute to the advancement of these critical fields. By delivering world-class information and innovative tools to researchers, students, educators and practitioners worldwide, we help them increase their productivity and effectiveness. We continuously make substantial investments that serve the needs of the global science and health communities.
We have carried out a detailed analysis of several long pathlength transmission measurements in the 8–12-µm atmospheric window in order to determine the extinction coefficient due to the water vapor continuum. Our results indicate that three modifications to the current LOWTRAN atmospheric transmission model are required. The first two corrections involve an improved fit to the pure water vapor continuum absorption together with the elimination of the atmospheric broadened continuum term. Finally, and most critically, a strong measured temperature dependence must be included in the water vapor continuum absorption coefficient. For pathlengths ranging from 10 km to 50 km, failure to incorporate these corrections can lead to errors in the computed transmission ranging from factors of 2 to more than 10,000.
