The effect of pyro- convective fires on the global troposphere: comparison of TOMCAT modelled fields with observations from ICARTT Sarah Monks Outline: • Brief introduction to the relevance of the work done • Discuss the effect of forest fires on the troposphere • Present some of the results from comparing the global chemical transport model to observations
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The effect of pyro-convective fires on the global troposphere: comparison of TOMCAT modelled fields with observations from ICARTT Sarah Monks Outline:
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The effect of pyro-convective fires on the global troposphere:
comparison of TOMCAT modelled fields with observations from ICARTT
Sarah Monks
Outline:
• Brief introduction to the relevance of the work done
• Discuss the effect of forest fires on the troposphere
• Present some of the results from comparing the global chemical transport model to observations
Introduction• Over recent years it has become accepted that emissions from one
region can be easily transported to another
• Intercontinental transport can affect regional air quality
• The International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) 2004 took place over the Atlantic Gain a better understanding of:
- Regional air quality
- Intercontinental transport of Ozone and it’s precursors
• O3 is formed photochemically from NMHC and CO in the presence of NOX.
• Ozone (O3) is an important trace gas: It is a greenhouse gas Its distribution affects the oxidising capacity of the troposphere It is harmful to living organisms
Biomass Burning in Alaska, 2004
• Extensive forest fires in Alaska in 2004 during ICARTT
• Forest fires emit a wide variety of reactive trace gases into the atmosphere including:- CO, hydrocarbons and NOX (=NO + NO2)
• In the summer of 2004 the Alaskan forest fire emissions dominated the distributions of trace species over the Atlantic
• Pyro-convection lifts the trace species up to the free troposphere – effect global troposphere
Projects Aims
• Test whether a global chemical transport model (CTM) can reproduce ICARTT in situ observations of trace species
The effect of model resolution The effect of convection and vertical diffusion Comparison of Eulerian and Lagrangian models (see poster) Test TOMCAT’s treatment of mixing and chemistry (see poster)
• Quantify the impact of the forest fires
TOMCAT MODEL• Eulerian 3D global chemical transport model (CTM)
• Forced by meteorological analyses from ECMWF
• 31 vertical levels (1000 hPa – 10 hPa)
• Variable horizontal resolution: used 5.6° x 5.6° and 2.8° x 2.8°
• Chemistry scheme: 41 chemical species, 118 chemical reactions
• Subgrid-scale processes: convection and vertical diffusion are parameterised