CRAZ Ozone Analysis Xin Qiu, Ph.D., ACM, EP May 3 rd, 2011.
Post on 13-Jan-2016
213 Views
Preview:
Transcript
CRAZ Ozone Analysis
Xin Qiu, Ph.D., ACM, EP
May 3rd, 2011
Objectives• Perform an analysis of the factors
contributing to high ozone days in CRAZ
• Identify and assess the drivers for local and regional ozone formation
• Understand ozone formation mechanism as NOx-Limited vs VOC-Limited
• Provide additional support to identify “back-out” situations
AQ Issues
Primary Emissions
Secondary Pollutants
CASA Action Levels
Source: Alberta Environment, Particulate Matter and Ozone Assessment for Alberta 2001- 2007
Data and ModelsNine Years of data (2001 -2009)
• Meteorological Data– The National Climatic Data Center archives of surface
and upper air data in North America
• Air Quality Data– CASA measurements of ambient concentrations of ozone
in/out of CRAZ
Tools• HYSPLIT Back Trajectory Model• Synoptic Classification• Statistical Analysis
CRAZ Area & Its Monitoring Stations
CRAZ High Ozone Days 2001 – 2009
2009 2008 2007 2006 2005 2004 2003 2002 2001
12-Apr-09
12-May-07 12-May-06
17-May-04 09-Apr-03 14-Apr-02 13-May-01
18-Apr-09
02-Jun-07 23-Jul-06
03-Jun-04 25-May-03 13-Jun-02 26-May-01
01-May-09
04-Jun-07 08-Aug-06
04-Jun-04 29-May-03 21-Jun-02 29-May-01
23-May-09
15-Jul-07 06-Sep-06
30-Jun-03 22-Jun-02 12-Aug-01
24-May-09
03-Aug-07
22-Jul-03 13-Jul-02
25-May-09
23-Jul-03 16-Jul-02
03-Jun-09
24-Jul-03 17-Jul-02
25-Jul-09
08-Aug-03 18-Jul-02
27-Aug-09
09-Aug-03
01-Sep-09
13-Aug-03
14-Aug-03
15-Aug-03
Threshold: O3 8-hr mean > 58 ppb
Back Trajectory Model
• The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model developed by the National Oceanic and Atmospheric Administration (NOAA)
• By incorporating receptor location coordinates, altitudes, run time, and meteorological data, the model provides back trajectory history from the receptor to the source over a given period of time.
Definitions• Long-range: Clear stretch of trajectories from one direction;
high ozone due to long-range transport from emission sources outside of Alberta. This is the case can be “backed out”.
• Local: trajectories are mostly localized, particularly at low and middle altitude. High ozone mainly due to local emissions and the Management Plan should be in place.
• Mixed-Range: trajectories are slightly beyond local (CRAZ) area, or the transport within province (e.g., transport from Edmonton). This is usually a complicated situation and we further look into case by case.
• Dominated Wind Direction: defined as the direction where air mass moves from according to the majority of back-trajectories.
• Long-range
• Local - 1
• Local - 2
• Mixed range
Summary TableWeather Pattern
Long Range (25/48)
Local Transport
(14/48)
Mixed Range (10/48)
Direction of Coming Air Mass
Maximum Temp.
(οC)
Daily Mean Wind Speed
(m/s)
Pressure System Type
Low Medium High
DM-P (2 1/48)
Apr 18, 2009 May 27, 2009
W N
W W
W W
13.8 20.2
5.4 5.4
High High
Jun 3, 2009 ALL ALL N,NW 22.2 2.7 High Jul 25, 2009 ALL ALL SW 28.8 2.4 High
Aug 27, 2009 W SW SW 24.7 2.3 High
May 11, 2007 Sep 1,2009 SE
W SE W
S SW
27.6 21.7
2.9 2.6
High High
Jun, 2, 2007 NE SW SW 26.5 2.9 High Jun, 4, 2007 NE W S 24.1 5.1 High Jul, 23, 2006 ALL ALL SW 31.1 3.3 High Sep 6, 2006 ALL ALL SW 26.9 2.9 High
May, 17, 2004
NNW N N 18.2 2.7 High
Jun, 3, 2004 W W W 21.0 2.8 High Jun, 4, 2004 W,SW SW SW 24.3 3.3 High
Aug 9, 2003 Jul, 23, 2003 SW
SW SW SE
SW NE
29.8 25.4
3.6 3.8
High High
Jun 13, 2002 N N NW 23.7 1.9 High Jun 22, 2002 ALL S SW 26.1 4.1 High Jul 16, 2002 W SW S,SW 28.8 3.3 High May, 26, 2001 NE E W 21.6 3.8 High Aug, 12, 2001 N,NW
NW
W
30.4
2.5
High
DM-T (11/48)
Apr 12, 2009
May 12, 2007
May 12, 2006 May 29, 2003 July 22, 2003 Jul 18, 2002
May 13, 2001 Jul 24, 2003
May 25, 2009
May 24,2009
Aug 3, 2007
W S
ALL W W
SW S,SW SW SW W W
W W W W W SW SW SW SW SW SW
W W W
SW W
SW SW SW SW SW SW
14.2 21.6 19.3 23.1 27.0 16.3 22.4 31.0 29.9 22.7 22.8
3.9 2.7 4.5 4.2 4.8 6.8 5.7 2.9 4.1 4.8 6.3
low low low low low low low low low low low
DP (5/48)
May 1, 2009 N,NW N,NW NW 13.2 3.8 High May 23, 2009 NW SW W 20.4 4.3 High
May, 25, 2003 S SW SW 26.1 3.6 High Aug, 8, 2003 ALL ALL SW 23.4 2.9 High
Jun, 21, 2002 W W W 24.4 1.9 High DT
(7/48)
Aug, 8, 2006 Aug, 13, 2003 Aug, 14, 2003
Jul, 13, 2002 Jul, 17, 2002 Jul, 15, 2007
Aug, 15, 2003
SW SS SW 31.8 4.2 Low SW SW ALL SW SW S
SW SW SW SW SW S
NW SW S S
SW SW
28.4 29.1 32.4 34.0 32.8 28.7
3.8 3.2 3.9 3.3 3.2 3.1
low Low low Low low Low
TR
(4/48) Apr, 9, 2003 SW SW W 15.1 5.8 High to Low Jun, 30, 2003 SW SW SW 28.0 5.7 Low to High Apr, 14, 2002 W,SW NW NW 16.6 9.1 Low to High May, 29, 2001 SW SW W 14.4 7.1 Low to High
The Concept of Air Mass
• What is an air mass?
• How is it related to basic meteorological parameters (temperature, pressure, winds, etc.)?
• How is it different from analysis of basic meteorological parameters?– Source– Duration– Spatial coverage
Weather Pattern
DM-P
Synoptic Air Mass Types**
• Dry Polar (DP): Low temperature, clear sky, stable and dry air. Air mass is generally advected from cold north polar regions.
• Dry Tropical (DT): The hottest and driest weather condition. Air is either advected from the USA, or produced by rapidly descending air.
• Dry Moderate Polar (DM-P): Mild and dry, as modified dry polar air from the anticyclone system that dominates Alberta.
• Dry Moderate Tropical (DM-T): Mild and dry, and usually as modified from tropical air mass originating from the United States.
• Transitional (TR): During these days one weather type yields to another.
• Moist Tropical (MT): Hot and humid. Typically found in summer warm sectors of mid-latitude cyclones or in a return flow of an anticyclone.
• Moist Moderate (MM): Mild, cloudy, and unstable. Generally close to a warm front, as modified moist polar or moist tropical air.
• Moist Polar (MP): Cool, humid, overcast. Winds are usually from the north or northwest.
**Sheridan Spatial Synoptic Classification system (2001) (http://sheridan.geog.kent.edu/ssc.html)
Frequencies in Calgary
%
SCC DM-P DM-T DP DT TR Total Long-Range 5 8 2 6 4 25
Local 10 1 1 1 13 Mixed-Range 6 2 2 10
Total 21 11 5 7 4 48
67%
10%
15%
8%
• Dry Moderate (DM), Dry Tropical (DT), and the Dry Polar (DP), are always among the top three circulation patterns associated with the high Ozone concentrations.
• DM shows highest frequency associated with ozone concentrations.
• DM has westerly or southwesterly flow• No high ozone event found in MT, MM &MP• Local and Mixed-range mostly associated
with DM
Air Mass/ Air Quality
• 83% of total high ozone days were associated with temperatures greater than 18οC
• 100% local high ozone events are associated with temperature higher than 18οC
• 80% mixed-range high ozone events are associated with temperature higher than 18οC
Temperature
SCC Daily Maximum Temperature
> 18οC
Daily Maximum Temperature
< 18οC
Total
Long-Range 19 6 25 Local 13 13
Mixed-Range 8 2 10 Total 40 8 48
Ozone Isopleths
NOx Limited
VOC Limited
NOx/VOC Ratios
1/8
NOx/VOC Ratios
• NOx/VOC ratios in Calgary were much higher than in Red Deer;
• NOx/VOC ratios in Calgary were greater than 1/8, VOC-Limited
• Most NOx/VOC ratios in Red Deer were less than 1/8 NOx-Limited
• Larger variations in NOx/VOC ratios were found in Calgary than in Red Deer
Summary - 1
• Long-range transport: 52%
(”back-out”)
• Local: 27%
• Mixed range: 21%
Summary - 2• More than 66% of the high ozone days occurred under
DM-T and DM-P weather patterns, with 40% long-range transport, 35% local and 25% mixed range accounted for 35% and 25%.
• Local transport is strongly related to DM-P weather patterns
• Mixed-range transport is mostly related to DM weather types. Required further investigation.
Summary -3• CRAZ has both VOC-limited and NOx-limited
ozone formation regimes. • In urban area (City of Calgary), a VOC-limited
mechanism dominated mostly• In rural area, it’s likely a NOx-limited
mechanism• In suburban area, it’s depended upon air
mass and urban plume (uncertainty remains)
Uncertainties/Limitations
• HYSPLIT has limitations• Only 3 CRAZ monitoring stations & located in
urban area• Anthropogenic emissions were not included in
the analysis• Biogenic VOC emissions were not included in
the analysis• Lack of data to identify ozone formation in
sub-urban area
top related