Morphology and mixing state of aged soot particles at a remote marine free troposphere site

implications for optical properties

Swarup China (Author), Barbara Scarnato (Author), R. Chris Owen (Author), Bo Zhang (Author), MarianT. Ampadu (Author), Sumit Kumar (Author), Katja Džepina (Author), Michael P. Dziobak (Author), Paulo Fialho (Author), Judith A. Perlinger (Author)

Abstract

The radiative properties of soot particles depend on their morphology and mixing state, but their evolution during transport is still elusive. Here we report observations from an electron microscopy analysis of individual particles transported in the free troposphere over long distances to the remote Pico Mountain Observatory in the Azores in the North Atlantic. Approximately 70% of the soot particles were highly compact and of those 26% were thinly coated. Discrete dipole approximation simulations indicate that this compaction results in an increase in soot single scattering albedo by a factor of <= 2.17. The top of the atmosphere direct radiative forcing is typically smaller for highly compact than mass-equivalent lacy soot. The forcing estimated using Mie theory is within 12% of the forcing estimated using the discrete dipole approximation for a high surface albedo, implying that Mie calculations may provide a reasonable approximation for compact soot above remote marine clouds.

Keywords

atmospheric aerosol;soot;long-range transport;free troposphere;single scattering albedo;

Data

Language:	English
Year of publishing:	2015
Typology:	1.01 - Original Scientific Article
Organization:	UNG - University of Nova Gorica
UDC:	54
COBISS:	59042307
ISSN:	0094-8276
Views:	1396
Downloads:	0
Average score:	0 (0 votes)
Metadata:

Other data

URN:	URN:SI:UNG
Pages:	str. 1243-1250
Volume:	ǂVol. ǂ42
Issue:	ǂiss. ǂ4
Chronology:	2015
DOI:	10.1002/2014GL062404
ID:	12757734