D Baumgardner et al 2008 Environ. Res. Lett. 3 025010 doi:10.1088/1748-9326/3/2/025010
D Baumgardner1, G Kok2, M Krämer3 and F Weidle4
Show affiliationsPart of Focus on Aerosol-Cloud Interactions
In situ measurements have been made in the upper troposphere of the properties of particles containing light absorbing carbon (LAC). These measurements, made in late November 2006 over northern Europe, show that the average LAC mass concentration varies between 1 and 5 ng m−3 over a latitude range 50° to 70°N, with maxima at 50° and 66°. The relative fraction of all particles larger than 0.1 µm that contain LAC decreases at higher latitudes. The derived extinction coefficient, which also increases with latitude, reaches a maximum of 1.4 Mm−1 at 66°.
The air mass histories associated with the LAC were evaluated with back trajectory analysis using wind field analysis from the European Center for Median-Range Weather Forecast (ECMWF). A positive correlation exists between the fraction of particles containing LAC and the maximum relative humidity (RH), minimum temperature and maximum number of hours of cloud experienced by the air mass in the 5–10 days prior to being sampled by the aircraft. Air masses arriving from lower altitudes and with trajectories over North America also had larger concentration fractions of LAC.
The average LAC mass is in good agreement with previous measurements made over North America for the same latitude range, and the span of values fits best with model predictions of LAC distributions that assume that the LAC transported from surface sources is hydrophobic.
92.60.Mt Particles and aerosols
92.60.Gn Winds and their effects
92.60.hv Pressure, density, and temperature
92.60.Nv Cloud physics; stratus and cumulus clouds
92.60.hf Tropospheric composition and chemistry, constituent transport and chemistry
Issue 2 (April-June 2008)
Received 15 January 2008, accepted for publication 12 May 2008
Published 30 May 2008
D Baumgardner et al 2008 Environ. Res. Lett. 3 025010
A Schneider et al 2009 Environ. Res. Lett. 4 044003
Scott F. Anderson et al. 2008 The Astronomical Journal 135 2108
Marco Fatuzzo and Fulvio Melia 2003 ApJ 596 1035
Kurtis A. Williams and Michael Bolte 2007 The Astronomical Journal 133 1490
Y. Damerdji et al. 2007 The Astronomical Journal 133 1470
Béla Szilágyi et al 2007 Class. Quantum Grav. 24 S275
Basmah Riaz et al. 2009 ApJ 705 1173
Kim D Anderson 2009 J. Neural Eng. 6 055003
W.-C. Müller and A. Busse 2007 EPL 78 14003