Introduction Conclusions References Tables Figures Back Close Abstract Introduction Conclusions References Tables Figures Back Close Abstract A seasonal-trend decomposition technique based on a locally-weighted regression smoothing (Loess) approach has been used to decompose monthly ozone concentrations at Mace Head (Ireland) into trend, seasonal and irregular components. The trend component sh...

Regular rain and fogwater sampling in the Podocarpus National Park, on the humid eastern slopes of the Ecuadorian Andes, along an altitude profile between 1960 and 3180 m, has been carried out since 2002. The samples, accumulated over about 1-week intervals, were analysed for pH, conductivity and major ions (K, Na, NH+4 , Ca 2+, Mg2+, Cl, SO 4 , NO − 3 , PO 3− 4 ). About 35% of the weekly sampl...

Carbon monoxide and acetone measurements are presented for five aircraft measurement campaigns at midlatitudes, polar and tropical regions in the northern hemisphere. Throughout all campaigns, free tropospheric air masses, which were influenced by anthropogenic emissions, showed a similar linear relation between acetone and CO, with a slope of 21–25 pptv acetone/ppbv CO. Measurements in the ant...

Recently, two types of ice clouds (TICs) properties have been characterized using the Indirect and SemiDirect Aerosol Campaign (ISDAC) airborne measurements (Alaska, April 2008). TIC-2B were characterized by fewer (< 10 L−1) and larger (> 110 μm) ice crystals, and a larger ice supersaturation (> 15 %) compared to TIC-1/2A. It has been hypothesized that emissions of SO2 may reduce the ice nuclea...

Hygroscopic properties of atmospheric particles were studied in the marine tropospheric boundary layer over the Atlantic and Indian Oceans during two consecutive field studies: the Aerosols99 cruise (Atlantic Ocean) from 15 January to 20 February 1999, and the INDOEX cruise (Indian Ocean Experiment) from 23 February to 30 March 1999. The hygroscopic properties were compared to optical and chemi...

This work examines the effect of direct radiative forcing of aerosols in the eastern Mediterranean troposphere as a function of air mass composition, particle size distribution and hygroscopicity, and relative humidity (RH). During intensive field measurements on the island of Crete, Greece, the hygroscopic properties of atmospheric particles were determined using a Hygroscopicity Tandem Differ...

When the available statistical information is imperfect, it is dangerous to follow standard optimisation procedures to construct an optimal portfolio, which usually leads to a strong concentration of the weights on very few assets. We propose a new way, based on gener-alised entropies, to ensure a minimal degree of diversiication.

The Chinese capital Beijing is one of the global megacities where the effects of rapid economic growth have led to complex air pollution problems that are not well understood. In this study, ambient particle number size distributions in Beijing between 2004 and 2006 are analysed as a function of regional meteorological transport. An essential result is that the particle size distribution in Bei...