 |
| Titel |
A discussion on the determination of atmospheric OH and its trends |
| VerfasserIn |
P. Jöckel, C. A. M. Brenninkmeijer, P. J. Crutzen  |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 3, no. 1 ; Nr. 3, no. 1 (2003-02-07), S.107-118 |
| Datensatznummer |
250000713
|
| Publikation (Nr.) |
 copernicus.org/acp-3-107-2003.pdf |
|
|
|
|
|
| Zusammenfassung |
| The oxidation efficiency of the troposphere is largely determined by the
hydroxyl radical and its global distribution. Its presence limits the lifetime of most trace gases.
Because of the great importance of several of these gases for climate, ozone budget and
OH itself, it is of fundamental importance to acquire knowledge about atmospheric
OH and possible trends in its concentrations. In the past, average concentrations of
OH and trends were largely derived using industrially produced CH3CCl3 as a chemical
tracer. The analyses have given valuable, but also rather uncertain results. In this paper we
describe an idealized computer aided tracer experiment which has as one of
its goals to derive tracer concentration weighted, global average <k(OH)>, where
the temporal and spatial OH distribution is prescribed and k is the
reaction rate coefficient of OH with a hitherto never produced (Gedanken) tracer, which is injected at a number of surface sites in the atmosphere in
well known amounts over a given time period. Using a three-dimensional (3-D)
time-dependent chemistry transport model, <k(OH)> can be accurately determined
from the calculated 3-D tracer distribution. It is next explored how well
<k(OH)> can be retrieved solely from tracer measurements at a limited number of
surface sites. The results from this analysis are encouraging enough to actually think about the feasibility to carry out a global dedicated tracer
experiment to derive <k(OH)> and its temporal trends. However, before that, we
propose to test the methods that are used to derive <k(OH)>, so far largely
using CH3CCl3, with an idealized tracer experiment, in which a
global chemistry transport model is used to calculate the ``Gedanken'' tracer distribution,
representing the real 3-D world, from which <k(OH)> is derived, using only
the tracer information from a limited set of surface sites. We propose here
that research groups which are, or will be, involved in global average OH studies to participate in such an inter-comparison of methods, organized and
over-seen by a committee appointed by the International Global Atmospheric
Chemistry (IGAC) program. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|