Vol. 22, issue 08, article # 11

Fomin B. A., Falaleeva V. A. Recent advance of spectroscopy and its effect on line-by-line calculations for validation of radiation codes for climate models. // Optika Atmosfery i Okeana. 2009. V. 22. No. 08. P. 803-806 [in Russian].
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The evolution of spectroscopic data from 1992 to 2008 and its effect on Line-by-Line (LBL) calculations for validation of radiation codes for climate models is the subject matter of this paper. The authors have made use of the standard mid-latitude summer (MLS) atmosphere in all the numerical experiments. The long-wave calculations with the current (2008) and previous (2002) HITRAN editions revealed a very good agreement: discrepancies are less than 0.1 W/m2 in flux calculations (H2O lines and continuum, CO2, O3). The replacement of the latest (MT CKD-2.1) version by the previous one (CKD-2.4) has given the discrepancies of up to ~ 0.9 W/m2. The short-wave calculations with the same HITRAN editions, on the contrary, have revealed a disagreement greater than that observed during the previous decade: the additional absorption only by the water vapor lines in downward fluxes reached 2.6 and 1.1 W/m2 ( ~ 1.5 and 1.3%) for the Solar Zenith Angles (SZA) of 30° and 75°, respectively. The additional absorption with the latest and previous HITRAN editions along with the continuum models reached in total 2.3 and 2.0 W/m2 for SZA of 30° and 75°, respectively (H2O lines and continuum, CO2, O2, O3). It has been found that total neglect of the line-mixing effect can produce essential errors: up to ~ 2.5 W/m2 (1.5%) in the long-wave flux calculations. Nevertheless, its usual treatment with the use of the line shape correction or the first order approximation gave satisfactory result: errors in the long-wave flux calculations were below ~ 0.14 W/m2 (~ 0.1%) and ~ 0.03, W/m2 respectively.