Short-lived pollutants contribute to the regional amplification of global warming in the Arctic. In the project CLIMSLIP-NyA we will examine two important aspects of short-lived pollutants in the Arctic. We will study how black carbon in the atmosphere and in the snow contribute to an enhanced absorption of solar radiation in the atmosphere and in the snow. The aerosol-cloud interactions will be also investigated by the simultaneous characterization of the microphysical and optical properties of clouds and aerosols. The field experiments include observations of black carbon concentrations in the atmosphere in springtime and the determination of black carbon concentrations in the snow using a single particle soot photometer. The observations will contribute to a better quantification of the behavior of black carbon in springtime in the Arctic and its deposition to the snowpack.
Three months of continuous measurements of cloud and aerosol properties will be performed at Mount Zeppelin station using the LAMP instrumentation (CPI, Polar Nephelometer, FSSP/Nevzorov probes). These observations will allow us to study the link between the aerosols properties and composition (IN, CCN...) and the microphysical and optical properties of clouds during the Winter-Spring transition period in the Arctic.
Finally, the results will be exploited in modeling studies to determine the impact of climate-relevant processes on regional changes in the Arctic.

Campaign 2012

Simultaneous measurements of BC in the FT, in the BL, and in the snow will be used to better characterize the dry deposition of BC. BC measurements are performed using a newly acquired Single Particle Soot Photometer, which provides true BC concentrations contrary to other filter-based absorption photometers. The deposition of BC to the snow can better be quantified since a new SP2 technique allows a better and faster quantification of the BC content in the atmosphere. Since the same technique will also be applied for the analysis of snow samples, concentrations in the atmosphere and in the snow can directly be related. At the same time, the SP2 technique allows a better vertical resolution of the BC content in the snow enabling the determination of the BC content in different snow layers. Further continuous BC measurements at the Zeppelin station will help to determine the exchange between the BL and the FT. BC concentrations in fresh snow samples will be used to determine the input of BC by wet deposition. The observations of vertical profiles of absorbing impurities and physical properties in the snow will be combined with snowpack modelling to investigate the impact of the presence of absorbers on the radiative properties and the thermal budget of the entire snowpack. Moreover, the snowpack model will be used to investigate the impact of BC on snow metamorphism and further physical properties of the snow.
The BC measurements will be accompanied by high-volume sampling of aerosols to determine their chemical composition. Key tracers like sea salt components or levoglucosan will be determined to characterize the origin of the different air masses arriving at Svalbard. The determination of the same species in the snowpack including vertical profiles will be used to attribute and quantify the origin of different air masses throughout the past winter season and the impact of bimoass burning on the aerosols and snow composition.
Continuous cloud measurements are needed to study the variability of microphysical and optical properties of arctic clouds during the winter-spring transition period. Simultaneous measurements of aerosol properties (Concentration, PSD and BC for example) are also highly valuable in order to describe the aerosol-cloud interaction during that period. We intend to perform a field experiment at Mount Zeppelin station to link the expected high variability of cloud properties to the aerosol properties.
The experimental set-up will consist in the coupling of the LAMP CPI instrument (for microphysical and morphological characterization of ice particles) with the Polar Nephelometer (for the measurement of optical properties of particles) and the FSSP-100/Nevzorov probes (for the microphysical properties of water droplets/and ice) at the Zeppelin station. The synergy of these instruments will provide a description of arctic cloud particles within a size range varying from a few micrometers (typically 3 micrometer for the PN) to about two millimetres (for the CPI probe). These measurements will be statistically analyzed in order to capture the variability of cloud properties during a time period where cloud properties are expected to change dramatically (from pure ice cloud in March to pure liquid cloud in May). These analysis will be supported by light scattering modeling in order to quantify the influence of the shape of particles and the liquid water / ice water partitioning on the optical properties. Additionally, the BC measurements performed by the LGGE, and the station aerosol measurements will be exploited to study the aerosol-cloud interaction. Indeed, the variability of the microphysical properties observed in the sampled clouds is expected to be linked to changes of aerosol composition.