 |
| Titel |
Theoretical implication of reversals of the ozone weekend effect systematically observed in Japan |
| VerfasserIn |
A. Kannari, T. Ohara |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 10, no. 14 ; Nr. 10, no. 14 (2010-07-23), S.6765-6776 |
| Datensatznummer |
250008652
|
| Publikation (Nr.) |
 copernicus.org/acp-10-6765-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Systematic changes of the ozone weekend effect are found over broad areas of
Japan. These changes are characterized by (1) spatial reversals from a
weekend increase in the vicinity of huge precursor source areas to a weekend
decrease in the surrounding rural areas, and (2) temporal reversals from a
weekend increase under relatively unsuitable meteorological conditions for
ozone formation to a weekend decrease under relatively suitable conditions.
We developed a simple numerical advection–reaction model to explain the
relationship between the duration of advection and the supplied solar
energy, which causes the daily maximum ozone concentration to be lower near
the precursor source. Ozone isopleth diagrams for individual advection
durations (equivalent to the distance from the source) for a wide range of
initial precursor conditions show that both VOC-limited and NOx-limited
regimes exist for each advection duration, but the area of NOx-limited
regime becomes dominant as the advection duration increases because of the
increased exposure of the air mass to solar energy. For given initial VOC
and NOx concentrations, the area remote from the source becomes a
NOx-limited regime even if the precursor source area is in the VOC-limited
regime. The rate of reduction of weekend emissions of NOx is larger than
that of VOC, causing a weekend increase in ozone inside an area of
VOC-limited regime near the source, but a weekend decrease in remote areas
with a NOx-limited regime. The boundary between these two ozone formation
regimes depends on meteorological conditions: when sunlight intensity and
temperature are relatively low, the change from a VOC-limited to a
NOx-limited regime occurs at a point more remote from the source than when
they are relatively high, which causes a prevailing ozone weekend increase
over a wide geographical area on days with lower ozone potential. Therefore,
observations of ozone weekend changes can be interpreted in light of the
theoretical implications of our model; they can be used for determination of
ozone formation regimes, which change in different locations and under
different meteorological conditions. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|