Publication Date:
2020-03-05
Description:
In this paper impact of intensive biomass burning (BB) in North America in July 2015, on
aerosol optical and microphysical properties measured in the European Arctic is discussed.
This study was made within the framework of the Impact of Absorbing Aerosols on radiating
forcing in the European Arctic (iAREA) project. During the BB event aerosol optical depth
(AOD) at 500 nm exceeded 1.2 in Spitsbergen and 0.7 in Andenes (Norway). Ångström
Exponent (AE) exceeded 1.4 while the absorbing Ångström Exponent (AAE) varied between
1 and 1.25. BB aerosols were observed in humid atmosphere with a total water vapor column
between 2 and 2.5 cm. In such conditions aerosols are activated and may produce clouds at
different altitudes. Vertical structure of aerosol plumes over Svalbard, obtained from
ceilometers and lidars, shows variability of range corrected signal between surface and
middle and upper troposphere. Aerosol backscattering coefficients show values up to 10
-5m-1sr-1at 532 nm. Aerosol surface observations indicate chemical composition typical for
biomass burning particles and very high single scattering properties. Scattering and
absorption coefficients at 530 nm were up to 130 and 15 Mm-1, respectively. Single scattering
albedo at the surface varied from 0.9 to 0.94. The averaged values over the entire atmospheric
column, ranged from 0.93 to 0.99. Preliminary statistics of model and sunphotometer data as
well as previous studies indicate that this event, in the Arctic region, must be considered
extreme (such AOD was not observed in Svalbard since 2005) with a significant impact on
energy budget.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf
