Spectral aerosol optical depth prediction by some broadband models. Validation with AERONET observations

Abstract

A comprehensive investigation on the performance of aerosol optical depth at 500 nm (AOD500) predictions using broadband physical and statistical models is detailed here. Seven simple models and one more complicated model were selected. A special database with more than 26 000 broadband (direct solar beam) and spectral (AODλ) instantaneous observations at clear solar disc during 10 years (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011) at Tõravere (Estonia) was compiled for the intercomparison. The database allows analysing the variability and climatological behaviour of several column parameters: coefficient of broadband transparency, precipitable water, AOD500, and the Ångström wavelength exponent (α). A statistical AOD500 model is finally recommended. It uses only two input parameters: coefficient of column broadband transparency and precipitable water. Two models from the set enabled variation of Ångström α. However, consideration of a priori known instantaneous α values did not improve predictions.

Atmosphere aerosol microphysical model for Belarus and adjacent regions

“…Íà ðèñ. 4, à ïîêàçàíû àýðîçîëüíûå îï-òè÷åñêèå òîëùèíû, îñðåäíåííûå ïî ìåñÿöó íà ðàçíûõ äëèíàõ âîëí, ïî äàííûì ñòàíöèé AERONET â ã. Ìèíñê, Áåëüñê è Òûðàâåðå (Ýñòîíèÿ) [9]. Âèäíî, ÷òî ñåçîííûé õîä ÀÎÒ äëÿ ýòèõ ðåãèîíîâ î÷åíü ïîõîae.…”

“… ÷àñòíîñòè, îáðàùàåò íà ñåáÿ âíèìàíèå ìèíèìóì â èþíå è ìàêñèìóìû â àïðåëå è àâãóñòå, êîòîðûå íàáëþäàþòñÿ âî âñåõ òðåõ ðåãèîíàõ. Êàê îòìå÷àëîñü â ðàáîòå [9], èþíüñêèé ìèíèìóì ÀÎÒ â Ýñòîíèè íàáëþäàëñÿ åùå ñ 1994 ã.  [9] îí îáúÿñíÿåòñÿ î÷èùåíèåì àòìîñôåðû, âñëåäñòâèå ïîÿâëåíèÿ ñâåaeåé ðàñòèòåëüíîñòè, îãðàíè÷èâàþùåé îáðàçîâàíèå ïûëåâîãî àýðîçîëÿ, è íåáîëüøèì ÷èñëîì ëåñíûõ ïîaeàðîâ.…”