Photooxidants formation and transport over Europe during the heat wave period in July 2006

1
Photo-oxidants formation and transport over
Europe during the heat wave period in July 2006
Joanna StruzewskaWarsaw University of
Technology, Warsaw, Poland Jacek Kaminski York
University, Toronto, Canada
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Outline

• July 2006 case study
• GEM-AQ model description and experiment setup
• Result analysis heat wave development
• Impact on photochemical pollution
• Summary
• Future plans

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July 2006 case study

• Prolonged heat wave period over Europe
• The hottest July since official measurements
  begun
• Two sub-periods might be distinguished
• Impacts
• Droughts
• Increased mortality
• Air quality problem over entire continent
• Extreme events over Western Europe

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Heat wave development

• Based on weather services reports
• July 3rd - Heat wave in Western Europe (France)
• July 4th - Hot air reached Central Europe
• July 6th - Severe thunderstorms over Western
  Europe
• July 7th - Hot air from over Africa passing
  towards Lithuania and Latvia
• July 13th High air temperature across Europe
  African air from the south-west and air from Asia
  from the east

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Aim of the study

• Analysis of photochemical pollution during first
  heat wave period over Central Europe in July 2006
  (July 3 14)
• Analysis based on GEM-AQ model simulation over
  Europe
• Meteorological situation over Europe used for the
  interpretation of air quality indices
• GEM-AQ model evaluation
• Meteorological and air quality measurements - 14
  stations from Poland
• Ozone measurements - 5 UK and 4 French stations
  (Airparif)
• Station type rural / background

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GEM-AQ model description

• The Canadian operational weather forecast model,
  the Global Environmental Multiscale (GEM) (Côté,
  et al., 1998) is used as a host meteorological
  model for inclusion of tropospheric air quality
  processes
• Gas phase chemistry
• Aerosol chemistry and physics (not used in this
  study)
• Heterogenous chemistry (not used in this study)
• Antropogenic and biogenic emissions
• Dry and wet removal
• Vertical diffusion of gas and aerosol trace
  species

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GEM-AQ experiment setup

• Grid global variable resolution mode
• 0.135 deg (15 km) over Europe (core)
• 400 x 350 (core)
• Time span 3 - 14 of July 2006
• Time step 450 s.
• Modelling strategy
• OA every 6 hours used to produce trial fields
• Chemical initial conditions from 5-year run with
  GEM-AQ, 1.5x1.5 deg. uniform resolution

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Model domain - core
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Results analysis - meteorology

• Meteorological analysis
• Synoptic situation (pressure patterns,
  circulation)
• Average temperature 10 17 LT (each day and
  averaged for the simulation period)
• Number of hours with the temperature exceeding
  30oC
• Cloudiness (averaged for the period)

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Synoptic situation July 4th

• Low pressure system forced transport of hot air
  masses towards Western Europe

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Synoptic situation July 6th

• Mutual location of pressure systems over Africa
  and Central Europe allowed for transport of hot
  air masses to the north

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Synoptic situation July 13th

• Circulation patterns causing the transport of hot
  air masses towards Europe from the south and east

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Air temperature (8 hour average)
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Number of hours with air temperature exceeding
30oC
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Average cloud cover
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Result analysis - ozone

• Air quality indices - ozone
• Maximum 8-h moving average each day (area
  exposed to gt 120 ug/m3)
• Number of hours exceeding information treshold
  (180 µg/m3)
• Number of hours exceeding alert treshold (240
  µg/m3)
• Average 8-hour concentration for the period (10
  17 LT)

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O3 - maximum 8-h moving average
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Information threshold exceedings
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8-hour average temperature and O3
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Comparison with O3 measurements
Wicken Fen - UK
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Comparison with O3 measurements
Ramboulliet - France
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Comparison with O3 measurements
Widuchowa - Poland
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Comparison with O3 measurements
Mscigniew - Poland
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Summary 1/4

• The on-line GEM-AQ model reproduced correctly
  development of pressure systems and inflow of hot
  air masses towards Europe
• Good agreement with surface synoptic maps and
  meteorological measurements
• Heat wave during the first week of July 2006 was
  connected with the development of low pressure
  system over France and favourable anticyclonic
  circulation over Central Europe

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Summary 2/4

• Inflow of humid and relatively cooler air from
  over Atlantic Ocean towards Western Europe
  generated instability, causing severe
  thunderstorms and gales over France and Germany
• Stable high over Central-Eastern Europe blocked
  the front movement and transported hot air masses
  towards north-eastern Europe
• During the second week of July frontal systems
  over Westren Europe dissipated and hot air was
  transported from over Africa and Asia

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Summary 3/4

• The GEM-AQ model reproduced high ozone
  concentrations during heat wave period
• Good agreement with O3 measurements
  (rural-background station type)
• Ozone variability better reproduced for UK and
  French monitoring stations
• Emission data might be less accurate for
  Central-Eastern Europe
• Bigenic emission used for this study might not be
  representative for heat wave period
• For some Polish stations ozone concentrations
  slightly overestimated especially during
  nighttime

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Summary 4/4

• High concentration of ozone affected most of
  European continent
• Air quality standards were exceeded especially in
  Central Europe (120 µg/m3 8-h moving average and
  the information threshold exceeded)
• High pressure system allowed for persisting of
  hot and polluted air mass, clear sky and weak
  wind conditions enhanced photochemical production
• Ozone pollution in northern part and Baltic
  countries might be connected with transport but
  might has been enhances by biogenic VOC emisions
  during heat wave period

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Future plans

• Numerical simulation for the period 15 31 of
  July
• Air mass ageing index analysis
• Analysis of biogenic VOC emissions (especially in
  Baltic countries)
• Comparison with other available AQ measurements
  and available satellite images