Identification

Title

Investigating carbonaceous aerosol and its absorption properties from fires in the Western United States (WEâ€�CAN) and Southern Africa (ORACLES and CLARIFY)

Abstract

Biomass burning (BB) produces large quantities of carbonaceous aerosol (black carbon and organic aerosol, BC and OA, respectively), which significantly degrade air quality and impact climate. BC absorbs radiation, warming the atmosphere, while OA typically scatters radiation, leading to cooling. However, some OA, termed brown carbon (BrC), also absorbs visible and near UV radiation; although, its properties are not well constrained. We explore three aircraft campaigns from important BB regions with different dominant fuel and fire types (Western Wildfire Experiment for Cloud Chemistry, Aerosol Absorption, and Nitrogen [WE-CAN] in the western United States and ObseRvations of Aerosols above CLouds and their intEractionS and Cloud-Aerosol-Radiation Interactions and Forcing for Year downwind of southern Africa) and compare them with simulations from the global chemical transport model, GEOS-Chem using GFED4s. The model generally captures the observed vertical profiles of carbonaceous BB aerosol concentrations; however, we find that BB BC emissions are underestimated in southern Africa. Our comparisons suggest that BC and/or BrC absorption is substantially higher downwind of Africa than in the western United States and, while the Saleh et al. (2014, https://doi.org/10.1038/ngeo2220) and FIREX parameterizations based on the BC:OA ratio improve model-observation agreement in some regions, they do not sufficiently differentiate absorption characteristics at short wavelengths. We find that photochemical whitening substantially decreases the burden and direct radiative effect of BrC (annual mean of +0.29 W m(-2) without whitening and +0.08 W m(-2) with). Our comparisons suggest that whitening is required to explain WE-CAN observations; however, the importance of whitening for African fires cannot be confirmed. Qualitative comparisons with the OMI UV aerosol index suggest our standard BrC whitening scheme may be too fast over Africa.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7n301dv

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2021-08-16T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact