English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Aerosol light scattering (σsp), backscattering (σbsp) and absorption (σap) were measured at Montsec (MSC; 42°3' N, 0°44' E, 1570 m a.s.l.), a remotehigh-altitude site in the western Mediterranean Basin. Mean (±SD)σsp, σbsp and σap were18.9 ± 20.8, 2.6 ± 2.8 and 1.5 ± 1.4 Mm−1,respectively at 635 nm during the period under study (June 2011–June 2013). Meanvalues of single-scattering albedo (SSA, 635 nm), the scatteringÅngström exponent (SAE, 450–635 nm), backscatter-to-scatter ratio(B / S, 635 nm), asymmetry parameter (g, 635 nm), black carbon mass absorptioncross section (MAC, 637 nm) and PM2.5 mass scattering cross section(MSCS, 635 nm) were 0.92 ± 0.03, 1.56 ± 0.88, 0.16 ± 0.09,0.53 ± 0.16, 10.9 ± 3.5 m2 g−1 and2.5 ± 1.3 m2 g−1,respectively. The scattering measurements performed at MSC were in themedium/upper range of values reported by Andrews et al. (2011) for othermountaintop sites in Europe due to the frequent regional recirculationscenarios (SREG) and Saharan dust episodes (NAF) occurring mostly inspring/summer and causing the presence of polluted layers at the MSCaltitude. However, the development of upslope winds and the possiblepresence of planetary boundary layer air at MSC altitude in summer may alsohave contributed to the high scattering observed. Under these summerconditions no clear diurnal cycles were observed for the measured extensiveaerosol optical properties (σsp, σbsp and σap). Conversely, low σsp and σap at MSC weremeasured during Atlantic advections (AA) and winter regional anticyclonicepisodes (WREG) typically observed during the cold season in the westernMediterranean. Therefore, a season-dependent decrease in the magnitude ofaerosol extensive properties was observed when MSC was in the freetroposphere, with the highest free-troposphere vs. all-data difference observed in winter and the lowestin spring/summer. The location of MSC station allowed for a reliablecharacterization of aerosols as a function of the main synoptic meteorologicalpatterns. The SAE was the lowest during NAF and showed an inversecorrelation with the outbreak intensity, indicating a progressive shifttoward larger particles. Moreover, the strength of NAF episodes in theregion led to a slope of the scattering vs. absorption relationship among thelowest reported for other mountaintop sites worldwide, indicating that MSCwas dominated by dust aerosols at high aerosol loading. As a consequence,SSA showed a nearly monotonic increase with increasing particleconcentration and scattering. The SAE was the highest during SREG, indicatingthe presence of polluted layers dominated by smaller particles.Correspondingly, the asymmetry parameter was lower under SREG compared withNAF. The MAC and MSCS were significantly higher during NAF and SREG comparedto AA and WREG, indicating an increase of absorption and scatteringefficiencies associated with the summer polluted scenarios. The opticalmeasurements performed at the MSC remote site were compared with thosesimultaneously performed at a regional background station in the westernMediterranean Basin located at around 700 m a.s.l. upstream of the MSC station

atmospheric chemistry and physics

Climatology of aerosol optical properties and black carbon mass absorption cross section at a remote high-altitude site in the western Mediterranean Basin