Astrid Lampert

Optical properties and sulfate scattering efficiency of boundary layer aerosol at coastal Neumayer Station, Antarctica

[1] We measured optical properties and ionic composition of the aerosol at Neumayer Station from 2004 through 2006 by an integrating nephelometer and chemical analysis of daily aerosol samples, respectively. From this unique data set, we discussed the seasonality of optical parameters along with the chemical composition of the aerosol. Austral summer (November through March) was characterized by mean particle number concentrations of 472 ± 260 cm -3 compared to 168 ± 160 cm -3 during winter (April through October), mean scattering Angstrom exponents of 1.5 ± 0.6 compared to 1.2 ± 0.5 during winter, and mean hemispheric backscattering ratios at 700 nm of 0.21 ± 0.13 compared to 0.17 ± 0.08 during winter. In contrast, light scattering coefficients (σ sp ) showed a broad maximum during winter (4.8 ± 5.3 Mm -1 for σ sp (550)). The mean single scattering albedo was 0.99 ± 0.01 0.02 at 550 nm. We further derived mass scattering and mass backscattering efficiencies for biogenic sulfate aerosol (BSA) at 450 nm, 550 nm, and 700 nm for relative humidities between 5% and 11%. At 550 nm, the scattering efficiency for biogenic sulfate aerosol α S BSA (550) was 8.9 ± 0.7 m 2 g -1 with a corresponding backscattering efficiency α bs BSA (550) of 1.0 ± 0.08 m 2 g -1 . From the seasonality of the aerosol composition, we inferred a dominant contribution of sulfate aerosol regarding radiative forcing in the lower troposphere from December through January, while the impact of sea salt aerosol prevailed for the rest of the year at Neumayer.

An Observational Case Study on the Influence of Atmospheric Boundary-Layer Dynamics on New Particle Formation

We analyze the influence of atmospheric boundary-layer development on new particle formation (NPF) during the morning transition. Continuous in-situ measurements of vertical profiles of temperature, humidity and aerosol number concentrations were quasi-continously measured near Melpitz, Germany, by unmanned aerial systems to investigate the potential connection between NPF and boundary-layer dynamics in the context of turbulence, temperature and humidity fluctuations. On 3 April 2014 high number concentrations of nucleation mode particles up to

First in situ evidence of wakes in the far field behind offshore wind farms

6.0 \times 10^4~\text {cm}^{-3}

A three‐dimensional characterization of Arctic aerosols from airborne Sun photometer observations: PAM‐ARCMIP, April 2009

6.0×104cm-3 were observed in an inversion layer located about 450 m above ground level. The inversion layer exhibited a spatial temperature structure parameter

Microphysical and radiative characterization of a subvisible midlevel Arctic ice cloud by airborne observations – a case study

C_T^2

Microphysical and optical properties of Arctic mixed-phase clouds. The 9 April 2007 case study.

CT2 15 times higher and a spatial humidity structure parameter