Effect of surface albedo, water vapour, and atmospheric aerosols on the cloud-free shortwave radiative budget in the Arctic

• Published in: Climate Dynamics
• Main Authors: Di Biagio, C., Di Sarra, A., Eriksen, P., Ascanius, S. E., Muscari, G., Holben, B.
• Other Authors: Di Biagio, C.; ENEA, Laboratory for Earth Observations and Analyses, Via Anguillarese 301, 00123 Rome, Italy, Di Sarra, A.; ENEA, Laboratory for Earth Observations and Analyses, Via Anguillarese 301, 00123 Rome, Italy, Eriksen, P.; DMI, Danish Meteorological Institute, Danish Climate Centre, Lyngbyvej 100, 2100 Copenhagen, Denmark, Ascanius, S. E.; DMI, Danish Meteorological Institute, Qaanaaq, Greenland, Muscari, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, Holben, B.; NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA, ENEA, Laboratory for Earth Observations and Analyses, Via Anguillarese 301, 00123 Rome, Italy, DMI, Danish Meteorological Institute, Danish Climate Centre, Lyngbyvej 100, 2100 Copenhagen, Denmark, DMI, Danish Meteorological Institute, Qaanaaq, Greenland, Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Verlag GMBH Germany 2012
• Subjects: Arctic radiative balance; Surface albedo; Atmospheric aerosols; Water vapour; Direct radiative forcing; Arctic amplification; 01. Atmosphere::01.01. Atmosphere::01.01.02. Climate; 01. Atmosphere::01.01. Atmosphere::01.01.05. Radiation; Arctic; Greenland; Thule Air Base; albedo; Thule Air; Thule
• Online Access: http://hdl.handle.net/2122/8022; https://doi.org/10.1007/s00382-011-1280-1

This study is based on ground-based measurements of downward surface shortwave irradiance (SW), columnar water vapour (wv), and aerosol optical depth (s) obtained at Thule Air Base (Greenland) in 2007–2010, together with MODIS observations of the surface shortwave albedo (A). Radiative transfer model calculations are used in combination with measurements to separate the radiative effect of A (∆SWA), wv (DSWwv), and aerosols (∆SWs) in modulating SW in cloud-free conditions. The shortwave radiation at the surface is mainly affected by water vapour absorption, which produces a reduction of SW as low as -100 Wm-2 (-18%). The seasonal change of A produces an increase of SW by up to +25 Wm-2 (+4.5%). The annual mean radiative effect is estimated to be -(21–22) Wm-2 for wv, and +(2–3) Wm-2 for A. An increase by +0.065 cm in the annual mean wv, to which corresponds an absolute increase in ∆SWwv by 0.93 Wm-2 (4.3%), has been observed to occur between 2007 and 2010. In the same period, the annual mean A has decreased by -0.027, with a corresponding decrease in ∆SWA by 0.41 Wm-2 (-14.9%). Atmospheric aerosols produce a reduction of SW as low as -32 Wm-2 (-6.7%). The instantaneous aerosol radiative forcing (RFs) reaches values of -28 Wm-2 and shows a strong dependency on surface albedo. The derived radiative forcing efficiency (FEs) for solar zenith angles between 55 and 70 is estimated to be (-120.6 ± 4.3) for 0.1<A<0.2, and (-41.2 ± 1.6) Wm-2 for 0.5<A<0.6. Published 953-969 1.10. TTC - Telerilevamento 3.7. Dinamica del clima e dell'oceano JCR Journal restricted