andrea fraser – october 2011 andrea fraser, geoff dollard, paul willis, trevor davies, justin...
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Andrea Fraser – October 2011
Andrea Fraser, Geoff Dollard, Paul Willis,
Trevor Davies, Justin Lingard
UK Air Quality Forecasting of Particulate Matter Spring 2011
Presentation outline
Brief outline of the UK air quality forecast
Air Quality Forecast Spring 2011
PM episodes
PM Speciation during the episodes
Summary
AEA – UK Air Quality Forecast
AEA have been providing daily forecasts to protect public health and to meet specific EC Directive Requirements since 1990.
AEA’s approach is to use a team of air quality experts to compile the forecasts based on a portfolio of inputs.
Inputs Include:
• WRF-CMAQ AQ forecasting models.• Back Trajectories• Pan-European model results.• Latest UK & European monitoring data.• Weather forecasts.• Satellite imagery.• Expert judgement based on analyses of
historical air pollution episodes.
Meteorology Data produced using WRF (Weather Research and Forecasting) Model
• 50km and 10km resolution for Europe and the UK.
• 48 vertical layers.
Using GFS initial and boundary conditions
WRF-CMAQ for UK Air Quality Forecast
Emissions data
Europe – EMEP - 50km UK - NAEI - 1km Biogenic Potential Inventory - 50km
CMAQ (Community Multiscalar Air Quality) ModelVersion 4.7.1CB05 Chemistry with aerosol and aqueous extensions (AE5) Boundary conditions are from the STOCHEM global modelCMAQ uses the same resolution as WRF, with a slightly smaller grid and 25 vertical layers, with 12 layer below 800M
Extract values at monitoring stationsDaily and Monthly evaluation with monitoring data
Create ImagesAnimations and plots of daily maximum – O3 NO2 SO2 CO PM10 PM2.5
Ozone Daily max PM10 Daily Max
SO2 Daily Max
Air Quality Forecast
AQ forecasting has a few more challenges than a retrospective modelling study.
Retrospective model
• Weather is modelled using boundary conditions from models that have assimilated measurements.
• Emissions from the inventory for the year being simulated.• Boundary conditions may be taken from a variety of sources including models
that have assimilated measurement and satellite data.
Forecast model
• The weather is modelled using boundary conditions from a weather model projecting into the future.
• The emission are based on the last available year – 2009.• Generic modelled boundary conditions.
Air Quality Forecast
When making an air quality forecast you need to use your experience of model performance to decide how reliable the forecast is.
Retrospective model• Evaluate over long time periods - often months, years.• Detailed studies of specific time periods often associated with intensive
measurement campaigns. • Uses ratified measurements from automated and specialised networks and
campaigns.
Forecast model• Everyday for a over a 24 and 48 hour period.• Need to know how well the model will perform over the next few days. • Evaluated with provisional data from the Automated Urban and Rural Network
(AURN).
• We can learn about the seasonal performance from evaluation of the forecast over longer time scale.
• Use more specialised measurements for evaluation and model development
WRF-CMAQ Performance – 2010
Ozone (10km) PM10 (10km)
Ozone 2010
In 2010 Ozone had a positive bias and PM10 negative. Particularly at the Urban and Urban Background sites
PM10 (10km)
PM10 2010
“Summer-Smog” April 2011
This was the first ‘smog warning’ for two years. The unusual weather caused by a high pressure system above the UK, and pollution drifting over from Europe, combined to breach European safety limits.
High pollution episode warning: First “summer-smog” of 2011
The high pressure system persisting over the UK is forecast to bring warm and still conditions to the UK over the Easter weekend. These conditions mean it is likely that the UK will experience a high pollution episode this weekend.
Elevated levels of PM10 and ozone reaching high or moderate are expected from now until at least Sunday.
Friday 22nd April 2011
http://uk-air.defra.gov.uk/ http://www.londonair.org.uk/
Earth Observatory NASALooking more like summer than spring, the United Kingdom was wreathed in smog on April 22, 2011, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this image. According to UK Air, much of the pollution is coming from continental Europe, and some of that transport is evident in the image.
http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=50214&src=nha
March 2011 – PM10 (24hr running mean)
0
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24-
ho
ur
run
nin
g m
ean
PM
10co
nce
ntr
atio
ns
acr
oss
AU
RN
sit
es
(mgm
-3 g
rav.
eq
uiv
)
Birmingham Tyburn
Birmingham Tyburn Roadside
Bristol St Paul's
Bury Roadside
Camden Kerbside
Cardiff Centre
Chepstow A48
Chesterfield
Chesterfield Roadside
London Bloomsbury
Salford Eccles
Glasgow Kerbside
Harwell
Stanford-le-Hope Roadside
London Harlington
Hull Freetown
London N. Kensington
Leamington Spa
Leeds Headingley Kerbside
Leeds Centre
Liverpool Speke
Middlesbrough
London Marylebone Road
Norwich Lakenfields
Nottingham Centre
Newport
Oxford St Ebbes
Plymouth Centre
Portsmouth
Port Talbot Margam
Reading New Town
Rochester Stoke
Scunthorpe Town
Sheffield Centre
Southwark A2 Old Kent Road
Southampton Centre
Stoke-on-Trent Centre
Storrington Roadside
Thurrock
Warrington
Index 4
Index 5
Index 6
Index 7
Index 4
Index 5
Index 6
Index 7
0
5
10
15
20
25
30
35
40
45
50
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5
10
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20
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30
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40
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50
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Nu
mb
er
of
sta
tio
ns
wit
h m
od
era
te l
ev
els
o
r a
bo
ve
du
e t
o P
M1
0a
t e
ach
pa
rticu
lar
ho
ur
Nu
mb
er
of
AU
RN
sta
tio
ns
wit
h d
ail
y m
ea
n P
M1
0a
bo
ve
50mm
g-3
(re
pre
sen
ted
in r
ed
do
t)
No. of stations Index 7 each hour
No. of stations Index 6 each hour
No. of stations Index 5 each hour
No. of stations Index 4 each hour
No. AURN dlyMean above 50
ModerateIndex 4 – 65 μgm-3 Index 5 – 75 μgm-3 Index 6 – 87 μgm-3
HighIndex 7 – 97 μgm-3
March 2011
Rural sites (4) Urban Background (16)
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24-h
our
runn
ing
mea
n PM 1
0co
ncen
trati
ons
acr
oss
AU
RN
sit
es
(mgm
-3 g
rav.
eq
uiv
)
Birmingham Tyburn
Birmingham Tyburn Roadside
Bristol St Paul's
Bury Roadside
Camden Kerbside
Chepstow A48
Chesterfield
Chesterfield Roadside
London Bloomsbury
Salford Eccles
Glasgow Kerbside
Harwell
Stanford-le-Hope Roadside
London Harlington
Hull Freetown
London N. Kensington
Leamington Spa
Leeds Headingley Kerbside
Liverpool Speke
Middlesbrough
London Marylebone Road
Norwich Lakenfields
Nottingham Centre
Newport
Oxford St Ebbes
Plymouth Centre
Portsmouth
Port Talbot Margam
Reading New Town
Rochester Stoke
Scunthorpe Town
Sandy Roadside
Sheffield Centre
Southampton Centre
Stoke-on-Trent Centre
Storrington Roadside
Thurrock
Warrington
Index 4
Index 5
Index 6
Index 7
Index 4
Index 5
Index 6
Index 7
April 2011 – PM10 (24hr running mean)
0
5
10
15
20
25
30
35
40
45
50
0
5
10
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20
25
30
35
40
45
50
01/0
4/20
11
02/0
4/20
11
03/0
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11
04/0
4/20
11
05/0
4/20
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06/0
4/20
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07/0
4/20
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4/20
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4/20
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10/0
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4/20
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4/20
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4/20
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4/20
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4/20
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4/20
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25/0
4/20
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4/20
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27/0
4/20
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28/0
4/20
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29/0
4/20
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30/0
4/20
11
Num
ber o
f sta
tions
with
mod
erat
e le
vels
or
abov
e du
e to
PM 10
at e
ach
parti
cula
r ho
ur
Num
ber o
f AU
RN s
tatio
ns w
ith d
aily
mea
n PM 1
0ab
ove
50m
mg-3
(rep
rese
nted
in r
ed d
ot)
No. of stations Index 7 each hour
No. of stations Index 6 each hour
No. of stations Index 5 each hour
No. of stations Index 4 each hour
No. AURN dlyMean above 50
ModerateIndex 4 – 65 μgm-3 Index 5 – 75 μgm-3 Index 6 – 87 μgm-3
HighIndex 7 – 97 μgm-3
UK Met. Office UK overview April 2011
With areas of high pressure over or near to the UK for much of the month, there was plenty of fine, warm weather.
Temperature
The UK mean temperature was 3.7 °C above the 1971–2000 average and it was the warmest April in the series from 1910.
The daily maximum temperatures in particular were well above average, by as much as 6 °C in south-east England.
A maximum temperature of 27.8 °C was recorded at Wisley, Surrey on 23rd.
In central England, it was the warmest April for over 350 years.
Sun
It was a sunny month across all of the UK, with amounts generally close to 150% of normal, making it the sunniest April in the series from 1929.
Rainfall
Rainfall was close to or above normal over much of western Scotland, but elsewhere it was dry — exceptionally so over much of southern, central and eastern England where less than 10% of normal rainfall was recorded
http://www.metoffice.gov.uk/climate/uk/2011/april.html
WRF ForecastSurface Conditions 19th to 24th April at 12:00
23rd April
Back Trajectories
Urban Background
19th – 26th April 2011
Back Trajectories
Urban Background
Elevated PM April 2011
Evaluation of CMAQ forecast with hourly PM10 provisional data from 16 AURN Urban Background sites 12-26th April 2011
Rural and Remote Urban Background UrbanNo. of Sites 4 16 12
Normal Mean Bias (%) 8 -14 -24
Normal Mean Error (%) 44 37 41
% of pairs within a factor of 2 68 73 68
Forecast the hourly PM10 exceeding 65 μgm-3
Proportion Correct 0.96 0.91 0.97Odds Ratio Skill Score 0.98 0.90 0.64
Typical Episodes result in higher nitrate
Daily average (μg m-3)
Provisional anion measurement from NPL
Dharsheni Muhunthan (NPL) Sonya Beccaceci (NPL) David Green (Kings College London)
PM2.5 Species
Provisional AURN measurement
PM2.5 Species
Provisional AURN measurement
PM2.5 Species
Provisional AURN measurement
Summary
The UK CMAQ air quality forecast generally underestimates PM10 pollution.
During the period of moderate to high pollution in April 2011 model performance was better than in previous years.
Can we identify why model performance was better during the ‘summer smog’ of April 2011?
It was an unusual period and was challenging for the air quality forecast.
Weather – hot, dry and sunny.
Emissions:• Two four day holiday weekends with only 3
‘normal’ working days• Holidays and daytrips• Biogenic emissions
Thank you
The air quality forecast is produce on behalf of the Department for the Environment, Food and Rural Affairs and the Devolved Authorities.