Climatology of new particle formation at Izaña mountain GAW observatory in the subtropical North Atlantic [Discussion paper]

A climatology of new particle formation (NPF) events at high altitude in the subtropical North Atlantic is presented. A 4-year data set (June 2008–June 2012), which includes number size distributions (10–600 nm), reactive gases (SO2, NOx, and O3), several components of solar radiation and meteorological parameters, measured at Izaña Global Atmosphere Watch (GAW) observatory (2373 m above sea level; Tenerife, Canary Islands) was analysed. NPF is associated with the transport of gaseous precursors from the boundary layer by orographic buoyant upward flows that perturb the low free troposphere during daytime. On average, 30% of the days contained an NPF event.This study was performed within the context of several projects, supported by the Ministry of Economy and Competitiveness of Spain (POLLINDUST, CGL2011-26259), REDMAAS (CGL2011- 15008-E) and GRACCIE (CSD2007-00067) and by the European Union (FP7, ACTRIS, grant contract: 262254)