Measurements of UV aerosol optical depth in the French Southern Alps

[摘要] Routine measurements of global and diffuse UV irradiances at Briançonstation (1310 m a.s.l.) are used to retrieve the direct solar irradiance and theaerosol optical depth (AOD), for cloudless days. Data of three years (2003,2004, 2005) are analyzed; the results confirm those of a preliminaryanalysis for 2001, 2002.

The atmosphere is very clear in winter, with AODs between 0.05 and 0.1. Theturbidity increases slowly in spring, starting end of February, with AODsaround 0.2–0.3 in mid summer, some values reaching 0.4. A similar behaviouris observed for all years, with somewhat higher values in late summer forthe year 2003.

[学科分类] 大气科学