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SUMMARY:Modelling the air-quality/climate interactions over urban areas (b
 y Peter Huszar)
DTSTART:20170504T123000Z
DTEND:20170504T140000Z
DTSTAMP:20170411T032028Z
UID:presentation-35.series-5
DESCRIPTION:There are multiple pathways urban areas impact environment: (i
 ) cities represent intense emissions source of gaseous species and aerosol
 s\, having direct impact on the composition and chemistry of the atmospher
 e\, (ii) certain gaseous and particulate material released and secondarily
  formed interact with radiation and cloud/rain microphysics\, (iii) artifi
 cial urban surfaces represent additional sinks and sources of momentum\, h
 eat and moisture affecting the mechanical\, thermodynamic and hydrological
  properties of local atmosphere and have specific impact on the meteorolog
 ical conditions. An additional pathway of urban/meteorology/air-chemistry 
 interaction arises from this third pathway: (iv) modified thermal and dyna
 mic properties of urban air directly influence the transport\, reactions a
 nd deposition of chemical species in urban air.\n\nUsing regional climate 
 chemistry modelling tool\, we analysed the listed impacts/interactions ove
 r central Europe for the period of 2001-2010. We found\, that the direct m
 eteorological forcing of urban canopy is by more than one order larger tha
 n the impact on meteorology via radiative effects of the chemical changes 
 introduced by urban emissions. In terms of temperature\, urban surfaces le
 ad to increase of day/night time values by up to 1.5 to 4°C\, while the r
 adiative effects are of order of 0.01 to 0.1°C and of opposite sign (due 
 to urban aerosols). Regarding the impact on chemistry\, the urban contribu
 tion to air pollution is significant not only over cities but over rural a
 reas as well with contributions to the background pollution by a couple of
  10%. Furthermore\, we found that chemistry is largely modulated by the pr
 eviously mentioned urban canopy meteorological effects - especially the ur
 ban induced turbulence enhancement and reduced wind have strong impact on 
 transport of urban pollutants leading to significant modifications of the 
 surface concentrations of both primary (NOx) and secondary pollutants (Ozo
 ne\, HNO3).
LOCATION:SR Wegener Center\, Brandhofgasse 5\, 1st floor
ORGANIZER;CN="Douglas Maraun";ROLE=CHAIR:MAILTO:douglas.maraun@uni-graz.at
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