Identification

Title

On the use of nonmethane hydrocarbons for the determination of age spectra in the lower stratosphere

Abstract

On 9 April 2001, while approaching the West Coast of the North American continent, flight 20 of the NASA TRACE P campaign penetrated deeply into a stratospheric intrusion. From measurements aboard that flight we derive vertical profiles of nonmethane hydrocarbons (NMHCs) and other short-lived trace gases in the lower stratosphere using Dichlorofluoromethane, CF₂ Cl₂, as the altitude scale. All profiles show an exponential decrease, which permits the description of their vertical distribution by a single parameter, the scale height. These scale heights are shown to be related to the respective lifetimes in a unique fashion. Using the approximation of a 1-D diffusive model with a constant eddy diffusion coefficient, K, and assuming constant lifetimes, we establish an analytical solution for this relation. By fitting this theoretical expression to the experimental data we can estimate K and thus obtain an approximate age spectrum of the form given by Hall and Plumb (1994). A much better fit to the experimental scale heights is obtained, when we allow the lifetimes to be height-dependent and calculate the theoretical scale heights numerically from a 1-D model. An optimization also suggests a constant K, but with a value of 0.46 m²/s, larger than those obtained from the fit of the analytical solution. The obtained age spectra should be valid for transit times not longer than 300 days.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7wq0420

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

2007-06-23T00:00:00Z

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