Near-infrared thermal emissivity from ground based atmospheric dust measurements at ORM

摘要

We present an analysis of the atmospheric content of aerosols measured atObservatorio del Roque de los Muchachos (ORM; Canary Islands). Using a laserdiode particle counter located at the Telescopio Nazionale Galileo (TNG) wehave detected particles of 0.3, 0.5, 1.0, 3.0, 5.0 and 10.0 um size. Theseasonal behavior of the dust content in the atmosphere is calculated. TheSpring has been found to be dustier than the Summer, but dusty conditions mayalso occur in Winter. A method to estimate the contribution of the aerosolsemissivity to the sky brightness in the near-infrared (NIR) is presented. Thecontribution of dust emission to the sky background in the NIR has been foundto be negligible comparable to the airglow, with a maximum contribution ofabout 8-10% in the Ks band in the dusty days.