Parameterization of the Non-Local Thermodynamic Equilibrium Source Function with Chemical Production by an Equivalent Two-Level Model  

作　　者：Xun ZHUThe Johns Hopkins University Applied Physics Laboratory, MD 20723-6099, USA 

出　　处：《Advances in Atmospheric Sciences》2003年第4期487-495,共9页大气科学进展（英文版）

基　　金：This research was supported by NSF grant ATM-0091514;in part by NASA grant NAG5-11962 to The Johns Hopkins University Applied Physics Laboratory.

摘　　要：The classic two-level or equivalent two-level model that includes only the statistical equilibrium of radiative and thermal processes of excitation and quenching between two vibrational energy levels is extended by adding chemical production to the rate equations. The modifications to the non-local thermodynamic equilibrium source function and cooling rate are parameterized by &#981;<SUB>c</SUB>, which characterizes the ratio of chemical production to collisional quenching. For applications of broadband emission of O<SUB>3</SUB> at 9.6 &#956;m, the non-LTE effect of chemical production on the cooling rate and limb emission is proportional to the ratio of O to O<SUB>3</SUB>. For a typical [O]/[O<SUB>3</SUB>], the maximum enhancements of limb radiance and cooling rate are about 15%–30% and 0.03–0.05 K day<SUP>&#8722;1</SUP>, respectively, both occurring near the mesopause regions. This suggests that the broadband limb radiance above &#8764;80 km is sensitive to O<SUB>3</SUB> density but not sensitive to the direct cooling rate along the line-of-sight, which makes O<SUB>3</SUB> retrieval feasible but the direct cooling rate retrieval difficult by using the O<SUB>3</SUB> 9.6 &#956;m band limb emission.The classic two-level or equivalent two-level model that includes only the statistical equilibrium of radiative and thermal processes of excitation and quenching between two vibrational energy levels is extended by adding chemical production to the rate equations. The modifications to the non-local thermodynamic equilibrium source function and cooling rate are parameterized by &#981;<SUB>c</SUB>, which characterizes the ratio of chemical production to collisional quenching. For applications of broadband emission of O<SUB>3</SUB> at 9.6 &#956;m, the non-LTE effect of chemical production on the cooling rate and limb emission is proportional to the ratio of O to O<SUB>3</SUB>. For a typical [O]/[O<SUB>3</SUB>], the maximum enhancements of limb radiance and cooling rate are about 15%–30% and 0.03–0.05 K day<SUP>&#8722;1</SUP>, respectively, both occurring near the mesopause regions. This suggests that the broadband limb radiance above &#8764;80 km is sensitive to O<SUB>3</SUB> density but not sensitive to the direct cooling rate along the line-of-sight, which makes O<SUB>3</SUB> retrieval feasible but the direct cooling rate retrieval difficult by using the O<SUB>3</SUB> 9.6 &#956;m band limb emission.

关 键 词：non-LTE radiative transfer ozone cooling ozone retrieval space weather 

分 类 号：P434.1[天文地球—大气科学及气象学]