58 research outputs found
Recommended from our members
CCN measurements at the Princess Elisabeth Antarctica research station during three austral summers
For three austral summer seasons (2013-2016, each from December to February) aerosol particles arriving at the Belgian Antarctic research station Princess Elisabeth (PE) in Dronning Maud Land in East Antarctica were characterized. This included number concentrations of total aerosol particles (N CN ) and cloud condensation nuclei (N CCN ), the particle number size distribution (PNSD), the aerosol particle hygroscopicity, and the influence of the air mass origin on N CN and N CCN . In general N CN was found to range from 40 to 6700cm -3 , with a median of 333cm -3 , while N CCN was found to cover a range between less than 10 and 1300cm-3 for supersaturations (SSs) between 0.1% and 0.7%. It is shown that the aerosol is dominated by the Aitken mode, being characterized by a significant amount of small, and therefore likely secondarily formed, aerosol particles, with 94% and 36% of the aerosol particles smaller than 90 and ≈35nm, respectively. Measurements of the basic meteorological parameters as well as the history of the air masses arriving at the measurement station indicate that the station is influenced by both marine air masses originating from the Southern Ocean and coastal areas around Antarctica (marine events - MEs) and continental air masses (continental events - CEs). CEs, which were defined as instances when the air masses spent at least 90% of the time over the Antarctic continent during the last 10 days prior to arrival at the measurements station, occurred during 61% of the time during which measurements were done. CEs came along with rather constant N CN and N CCN values, which we denote as Antarctic continental background concentrations. MEs, however, cause large fluctuations in N CN and N CCN , with low concentrations likely caused by scavenging due to precipitation and high concentrations likely originating from new particle formation (NPF) based on marine precursors. The application of HYSPLIT back trajectories in form of the potential source contribution function (PSCF) analysis indicate that the region of the Southern Ocean is a potential source of Aitken mode particles. On the basis of PNSDs, together with N CCN measured at an SS of 0.1%, median values for the critical diameter for cloud droplet activation and the aerosol particle hygroscopicity parameter ° were determined to be 110nm and 1, respectively. For particles larger than ĝ‰110nm the Southern Ocean together with parts of the Antarctic ice shelf regions were found to be potential source regions. While the former may contribute sea spray particles directly, the contribution of the latter may be due to the emission of sea salt aerosol particles, released from snow particles from surface snow layers, e.g., during periods of high wind speed, leading to drifting or blowing snow. The region of the Antarctic inland plateau, however, was not found to feature a significant source region for aerosol particles in general or page276 for cloud condensation nuclei measured at the PE station in the austral summer
CCN measurements at the Princess Elisabeth Antarctica research station during three austral summers
For three austral summer seasons (2013–2016, each from December to February)
aerosol particles arriving at the Belgian Antarctic research station Princess
Elisabeth (PE) in Dronning Maud Land in East Antarctica were characterized.
This included number concentrations of total aerosol
particles (NCN) and cloud condensation nuclei (NCCN),
the particle number size distribution (PNSD), the aerosol particle
hygroscopicity, and the influence of the air mass origin on NCN
and NCCN. In general NCN was found to range from
40 to 6700 cm−3, with a median of 333 cm−3, while
NCCN was found to cover a range between less than 10 and
1300 cm−3 for supersaturations (SSs) between 0.1 % and 0.7 %. It is
shown that the aerosol is dominated by the Aitken mode, being characterized by a
significant amount of small, and therefore likely secondarily formed, aerosol
particles, with 94 % and 36 % of the aerosol particles smaller than
90 and ≈35 nm, respectively. Measurements of the basic
meteorological parameters as well as the history of the air masses arriving
at the measurement station indicate that the station is influenced by both
marine air masses originating from the Southern Ocean and coastal areas
around Antarctica (marine events – MEs) and continental air masses
(continental events – CEs). CEs, which were defined as instances when the air
masses spent at least 90 % of the time over the
Antarctic continent during the last 10 days prior to arrival at the measurements station, occurred during 61 % of the time during which
measurements were done. CEs came along with rather constant NCN
and NCCN values, which we denote as Antarctic continental
background concentrations. MEs, however, cause large fluctuations
in NCN and NCCN, with low concentrations likely caused
by scavenging due to precipitation and high concentrations likely originating
from new particle formation (NPF) based on marine precursors. The application
of HYSPLIT back trajectories in form of the potential source contribution
function (PSCF) analysis indicate that the region of the Southern Ocean is a
potential source of Aitken mode particles. On the basis of PNSDs, together
with NCCN measured at an SS of 0.1 %, median values for the
critical diameter for cloud droplet activation and the aerosol particle
hygroscopicity parameter κ were determined to be 110 nm and 1,
respectively. For particles larger than ≈110 nm the Southern Ocean
together with parts of the Antarctic ice shelf regions were found to be
potential source regions. While the former may contribute sea spray particles
directly, the contribution of the latter may be due to the emission of sea salt
aerosol particles, released from snow particles from surface snow layers,
e.g., during periods of high wind speed, leading to drifting or blowing snow.
The region of the Antarctic inland plateau, however, was not found to feature a
significant source region for aerosol particles in general or for cloud condensation nuclei measured at the PE station in
the austral summer.</p
Mneme. Past and memory in the Aegean Bronze Age. Proceedings of the 17th international Aegean Conference
Physis. L'environnement naturel et la relation homme-milieu dans le monde égéen protohistorique. Proceedings of the 14e Rencontre égéenne internationale/14th International Aegean Conference, held in Paris, at the Institut National d'Histoire de l'art (INHA), on 11-14 December 2012
International audienceThe volume proposes the proceedings of the 14e Rencontre égéenne internationale/14th International Aegean Conference, held in Paris, at the Institut National d'Histoire de l'art (INHA), on 11-14 December 2012, on the theme PHYSIS. L'environnement naturel et la relation homme-milieu dans le monde égéen protohistorique (568 pages, 176 plates). 50 contributions were presented in seven sections: "Cadre naturel", "Ressources naturelles", "Paysage et climat", "Iconographie", "Agriculture", "Ressources animales", "Peuplement et population". 23 short presentations are included as posters
MNHMH / MNEME. Past and memory in the Aegean Bronze Age (Proceedings of the 17th International Aegean Conference, Udine – Venice, 17-21 April 2018), (AEGAEUM 43), Leuven-Liège 2019.
Disjunct eddy-covariance as a tool for biogenic volatile organic compounds flux estimation at the ecosystemscale.
- …