 |
| Titel |
Impacts of intercontinental ozone transport on Northern Hemisphere yields of six major crop types. |
| VerfasserIn |
Michael Hollaway, Stephen Arnold, Andrew Challinor, Lisa Emberson |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250054962
|
|
|
|
|
|
| Zusammenfassung |
| Tropospheric ozone concentrations have increased steadily since pre-industrial times, driven
by in-situ production from anthropogenic emissions of nitrogen oxides (NOx) and organic
compounds. Ozone in the troposphere is a global air pollution problem, and has harmful
effects on human health and vegetation. Transport of ozone and its precursors between
continents has been shown to contribute to surface ozone concentrations in many developed
and developing regions of the northern hemisphere. Enhanced surface ozone concentrations
are known to be harmful to vegetation and may significantly reduce crop growth and yields in
many regions. We have used the TOMCAT global atmospheric chemistry model to
quantify intercontinental contributions to crop ozone exposure and yield reduction
in the Northern Hemisphere. We apply the use of 3 metrics (AOT40/M7/M12)
to assess the impacts of NOx emissions from each of the Northern Hemisphere’s
three major industrialised regions (North America, Europe and South East Asia) on
global and regional exposure of 6 major agricultural crop types to harmful ozone
concentrations, and the resultant yield losses during the 2005 growing season. The AOT40
metric relates vegetation damage to exceedence of a 40ppbv threshold concentration,
while M7 & M12 (Mx) are based on mean surface ozone concentrations. Using
the 3 metrics, model calculations show that for 4 of the major crops considered
(wheat, rice, cotton and potato) 90% reductions in SE Asian anthropogenic NOx
emissions tend to produce the greatest reduction in crop yield losses (45.1% to
94.9%) on a global scale with the same cuts to N American emissions resulting in the
greatest global impact on crop yield reductions for maize and soybean (55.9% to
85.5%). N American NOx emissions tend to produce the largest transboundary
impact, resulting in European yield loss reductions of between 32.9% and 41.1%
with the AOT40 threshold metric and 9.3% to 17.8% with the mean ozone Mx
metric, when a 90% cut is applied to NOx emissions from the N American receptor
region. European NOx emissions tend to produce a greater local impact on crops
rather than a transboundary impact, due to inefficiency of export of ozone and its
precursors from the European domain. We find that due to the threshold nature of
the AOT40 index, inferred non-local contributions to ozone-induced yield loss
have a strong dependence on local ozone concentrations. Mx-derived non-local
contributions also have a small dependence on local ozone concentrations, due to
the non-linear dependence of yield loss on mean ozone. The results demonstrate
that local air quality and emission control strategies over each of the regions have
the potential to partly alleviate non-local ozone-induced yield loss, in addition to
effectively mitigating local ozone-induced yield losses for six major crop types. |
|
|
|
|
|
|