Identification

Title

Growth rates of freshly nucleated atmospheric particles in Atlanta

Abstract

During the Atlanta ANARChE Study of July and August 2002, atmospheric aerosol size distributions from 3 to 2000 nm were measured continuously with 5-min resolution. Sulfuric acid vapor concentrations were also measured. During regional nucleation events these data showed the presence of a nucleation mode that grew at rates ranging from 3 to 20 nm h(-1). In this paper we compare these measured modal growth rates with calculated rates that account for sulfuric acid condensation, intramodal coagulation of nucleation mode particles, and extramodal coagulation of nucleation mode particles with preexisting particles. Data collected during six time intervals were amenable to analysis. Calculated and measured growth rates were in reasonable agreement for the four events that involved growth below 40 nm ( ratios of measured to calculated growth rates = 1.0, 2.1, 0.68, 0.60). Two of the three afternoon events involved growth above 40 nm, and in these cases, measured rates substantially exceeded calculated rates by factors of four to five, suggesting that our model did not account for all growth processes. We also compared observed rates of change in nucleation mode number concentration with calculated coagulation rates during these six time intervals. During the sub-40 nm growth events, particle concentrations changed at rates that were significantly below calculated coagulation rates. In two of these cases, particle concentrations increased during the growth period, suggesting that a source of particles was present. Measured size distributions suggest that particle production by nucleation continued during these events and contributed to this discrepancy. Concentrations during the super-40 nm events decreased at rates that exceeded calculated coagulation rates.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7v69jx3

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

2005-11-09T00:00:00Z

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