air quality forecast feedback: los angeles air basin · 2016. 9. 15. · sang-mi lee, ph.d and...
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South Coast Air Quality Management District
Air Quality Forecast Feedback: Los Angeles Air Basin
NOAA Forecast Working Group Meeting September 15-16, 2016
Sang-Mi Lee, Ph.D and Scott Epstein, Ph.D
South Coast Air Quality Management District
21865 Copley Dr, Diamond Bar, CA 92886
South Coast Air Quality Management District
Overview
• 12 UTC cycle Forecast Products • Retrieved for Los Angeles Air Basin • 2nd day forecast variables were evaluated:
– Daily Max 8-hour Ozone – Average 24-hour PM2.5 – Meteorological variables (Wind Speed, Temperature and Humidity)
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South Coast Air Quality Management District
Performance Evaluation Zone
3
Los Angeles Downtown
Pacific Ocean
Redlands
South Coast Air Quality Management District
Daily Max 8-hour Ozone
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South Coast Air Quality Management District
Average 24-hour PM2.5
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PM2.5 measurements were made with automated Beta Attenuation Method samplers
South Coast Air Quality Management District
Daily Max 8-hour Ozone at Crestline
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South Coast Air Quality Management District
Daily Max 8-hour Ozone at Glendora
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South Coast Air Quality Management District
Month to Month Variation
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Daily Max 8-hour Ozone at Glendora: June & July 2016
South Coast Air Quality Management District
Performance Statistics by Month
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-40
-20
0
20
40
60
80
100
Daily
-Max
Mea
n Pr
ed.
Unp
aire
d [p
pb]
Daily
-Max
Mea
n O
bs.
[ppb
]Da
ily-M
ax B
ias E
rr.
Unp
aire
d [p
pb]
Daily
-Max
Gro
ss E
rr.
Unp
aire
d [p
pb]
Nor
m D
aily
-Max
Bia
sEr
r. U
npai
red
[%]
Nor
m D
aily
-Max
Gro
ssEr
r. U
npai
red
[%]
Peak
Pre
dict
ion
Accu
racy
Unp
aire
d[p
pb]
UrbanReceptor
UrbanReceptor
May Jun Jul
South Coast Air Quality Management District
Geographical Variation
10
-80
-60
-40
-20
0
20
40
60
80
100Da
ily-M
ax M
ean
Pred
.U
npai
red
[ppb
]
Daily
-Max
Mea
n O
bs.
[ppb
]
Daily
-Max
Bia
s Err
.U
npai
red
[ppb
]
Daily
-Max
Gro
ss E
rr.
Unp
aire
d [p
pb]
Nor
m D
aily
-Max
Bia
s Err
.U
npai
red
[%]
Nor
m D
aily
-Max
Gro
ss E
rr.
Unp
aire
d [%
]
Peak
Pre
dict
ion
Accu
racy
Unp
aire
d [p
pb]
Daily Max 8-hour O3
Coastal
UrbanSource
UrbanReceptor
Foothills
South Coast Air Quality Management District
METEOROLOGICAL FACTOR
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South Coast Air Quality Management District
Wind Speed Prediction Performance: Monthly
12
-60
-40
-20
0
20
40
60
80
May Jun Jul
[%]
Wind Speed Normalized Bias and Gross Error in "Urban Receptor"
South Coast Air Quality Management District
Wind Speed Prediction : Geographical Variation
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-80
-60
-40
-20
0
20
40
60
80
UrbanReceptor Foothills_UrbSrc Coastal
(%)
Wind Speed
South Coast Air Quality Management District
Anaheim and Crestline
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Wind Over Prediction Ozone under Prediction
Wind under
Prediction Ozone Over
Prediction
Wind Over Prediction Ozone under Prediction
Wind under
Prediction Ozone Over
Prediction
South Coast Air Quality Management District
NOAA VS. SOUTH COAST AQMD Spatial Grid resolution WRF Forecast vs. Hindcast Chemical mechanism > SCAQMD uses SAPRC07
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South Coast Air Quality Management District
NOAA vs. SCAQMD Predictions
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NOAA
SCAQMD
South Coast Air Quality Management District
NOAA vs. SCAQMD Predictions
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NOAA
SCAQMD
South Coast Air Quality Management District
NOAA vs. SCAQMD at Crestline site
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South Coast Air Quality Management District
Summary and Conclusions
• NOAA forecast still tends to under-predict high ozone episodes in the Basin especially urban receptor areas where the peak concentrations are recorded.
• The bias grows bigger in June and July. However, meteorological prediction does not show the same trend.
• The errors in ozone prediction do not correlate with wind prediction bias directly. (i.e. wind under prediction appeared in ozone under prediction)
• SCAQMD’s modeling product which has higher spatial resolution, improved WRF predictions, and SAPRC-07 chemical mechanism shows reasonably good performance to capture high ozone episodes and meteorology vs. chemistry correlation.
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