ozone transport analysis using back-trajectories and camx probing tools
DESCRIPTION
Ozone Transport Analysis Using Back-Trajectories and CAMx Probing Tools. Sue Kemball -Cook, Greg Yarwood , Bonyoung Koo and Jeremiah Johnson, ENVIRON Jim Price and Mark Estes, TCEQ 2010 CMAS Conference, October 11-13, 2010 Chapel Hill, North Carolina. Background. - PowerPoint PPT PresentationTRANSCRIPT
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Ozone Transport Analysis Using Back-Trajectories and
CAMx Probing Tools
Sue Kemball-Cook, Greg Yarwood, Bonyoung Koo and Jeremiah Johnson, ENVIRONJim Price and Mark Estes, TCEQ
2010 CMAS Conference, October 11-13, 2010Chapel Hill, North Carolina
Ozone Transport Presentation for CMAS
Background
• Lowering the 8-hour standard increases the importance of background ozone and transport
• Simulation of ozone transport in photochemical models will be critical for development of ozone control strategies
• CAMx probing tools can be used to quantify background ozone
Ozone Transport Presentation for CMAS
Objectives
• Investigate ozone transport into Texas– Which source regions contribute to high ozone in Texas?– What effect do emissions changes in those source regions
have on Texas ozone?
• Use a suite of independent tools to analyze ozone transport– HYSPLIT back trajectories
Show pathways for air arriving at Texas monitors on high ozone days
New MM5CAMx-to-ARL tool reformats CAMx winds for input to HYSPLIT and calculates vertical velocities using CAMx algorithm
– CAMx probing tools APCA (Anthropogenic Precursor Culpability Assessment) HDDM (Higher order Decoupled Direct Method)
Ozone Transport Presentation for CMAS
Using APCA and HDDM to Study Modeled Transport
• CAMx APCA and HDDM probing tools provide complementary information for transport analysis
• APCA– Can quantify contributions by source region and source
category to ozone at a given receptor and time– Does not give information about how such a contribution may
change if emissions change
• HDDM– Can provide estimates of model response to changes in
emissions
Ozone Transport Presentation for CMAS
APCA/HDDM Source Region Maps
• APCA emissions source regions shown in red
• HDDM emissions source regions shaded– Ohio and Tennessee
Valleys (blue)– Southeastern U.S.
(pink)
• 3 emissions source categories – Elevated anthropogenic
emissions– Biogenic emissions– All other emissions
• Buffer around Texas, roughly corresponding to 12 km Texas domain
Ozone Transport Presentation for CMAS
Episode Selection
• Modeled three Texas high ozone episodes during 2005-6
• Episode selection based on monitoring network and model performance evaluation results– More rural ozone monitors in Texas during 2006 than 2005
• Focus on periods of high diagnosed and modeled transport from Ohio and Tennessee Valleys and Southeastern U.S. – June 13-15, 2006
Good model performance in both 12 km grid and in source regions in 36 km grid; transport from OH-TN Valleys and SE diagnosed using HYSPLIT back trajectories
Ozone Transport Presentation for CMAS
June 13-15, 2006 Transport Episode
• Back trajectories from TCEQ analysis using EDAS meteorological inputs to HYSPLIT
• Transport from OH-TN Valleys and SE into Texas
7
June 13 June 14 June 15
Ozone Transport Presentation for CMAS 8
June 9-15, 2006: MPE for Source Regions
• Good model performance with small positive bias
Ohio/Tennessee Valleys
SoutheastNormalized Bias
-40
-30
-20
-10
0
10
20
30
40
6/9
6/10
6/11
6/12
6/13
6/14
6/15
(%)
SE
+15%
-15%
Normalized Bias
-40
-30
-20
-10
0
10
20
30
40
6/9
6/10
6/11
6/12
6/13
6/14
6/15
(%)
OH+TN
+15%
-15%
Transport
Ozone Transport Presentation for CMAS
Monitors Used in APCA/HDDM Analysis
• Used rural monitors sited upwind of non-attainment areas
• Selected monitors based on location and MPE
• During transport episodes, evaluated source contributions with APCA at these receptors at the time of daily max 8-hour average ozone (DM8)
Ozone Transport Presentation for CMAS
San Augustine, TX: June 14, 2006
• Largest contributions from Louisiana, Tennessee, BCs, other states in OH-TN Valley source region
• APCA and HYSPLIT back trajectories are consistent in assessment of source regions
Ozone Transport Presentation for CMAS
Ozone Sensitivity to Change in Elevated Anthro NOx Emissions in
the Source Regions• Sensitivity of DM8 to elevated anthropogenic NOx
(eaNOx) emissions in the OH-TN and SE source regions when > 60 ppb
• For eaNOx only, calculate sensitivities
S1OH-TN~∂O3 _____, S1
SE ~ ∂O3_____,
∂(eaNOxOH-TN) ∂(eaNOxSE)
S2
OH-TN~ ∂2O3________, S2SE ~ ∂2O3 ____,
∂(eaNOxOH-TN)2 ∂(eaNOxSE)2
where OT=Ohio and Tennessee Valleys, SE=Southeastern U.S.
• How sensitive is East Texas ozone to emissions in these source regions?
Ozone Transport Presentation for CMAS
June 13-15, 2006: Average S1OT
and S2
OT
• S1OT generally positive and largest in source regions
– Emissions increase generally would increase ozone; emissions reduction would decrease ozone
– S1OT negative near large NOx sources; i.e. NOx reduction increases ozone (NOx disbenefit)
• East-west S1OT gradient across Texas, 1-4 ppb on average over episode in East TX
• S2OT largest in vicinity of large coal-fired power plants along the Ohio River
Ozone Transport Presentation for CMAS
Sensitivity of Texas Ozone to Reductions in Source Region eaNOx
• For a given monitor, calculate ozone change from emissions perturbation Δε using Taylor series expansion about unperturbed state, C(0)
• C=ozone concentration, S(i) are sensitivities
• Where Δε=-0.20 for 20% emissions reduction in the source region, for example, and C(0)=DM8 at the monitor in the unperturbed case
– Neglecting higher order terms Rn+1
• Plot emissions change Δε versus change in ozone C(Δε)-C(0) at the monitor (next slide)
Ozone Transport Presentation for CMAS
Change in Texas Ozone from Emissions Reduction in OH-TN Valley
Source Region
• Shows change in DM8 at rural TX monitors that would result from reducing eaNOx in OH-TN source region
• NEWT and SAGA show largest ozone reductions
-8
-7
-6
-5
-4
-3
-2
-1
0
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%Chan
ge in
Dai
ly M
ax 8
-Hou
r O
zone
(pp
b)
Karnack
Temple
Greenville
Newton
San Augustine
June 14, 2006
Change in Daily 8-Hour Max Ozone with NOx Emission Reduction in
OH-TN Valley Elevated Anthro NOx
% Reduction in OH-TN Valley Elevated Anthro NOx Emissions
Ozone Transport Presentation for CMAS
Zero-Out Contribution
• HDDM coefficients can be used to estimate effect on ozone of removing (zeroing out) one or more emissions sources
• For 2 emitters j and k, zero out contribution (ZOC) is calculated
• For the OH-TN and SE source regions, ZOC is given by
ZOC(OT+SE)=(S(1)OT-½S(2)
OT,OT)+ (S(1)SE-½S(2)
SE,SE)- S(2)OT,SE
• Here, we calculate components of ZOC for OH-TN and SE eaNOx emissions and present them separately, as cross term was negligible
Ozone Transport Presentation for CMAS
Comparison of APCA and HDDM ZOC Estimates for eaNOx
• The APCA and HDDM tools agree on the relative importance of these two source regions in contributing to high ozone in Texas
• APCA and HDDM consistent with the HYSPLIT back trajectories
0
2
4
6
8
10
12
APCA HDDM
Ozo
ne (p
pb)
Comparison of APCA Source Region Contributions and HDDM Zero-Out Contribution: San Augustine at Time of 8-Hour Max
ea NOx SE
ea NOx OT
June 14, 2006
HYSPLIT Back Trajectories
APCA/HDDM
Ozone Transport Presentation for CMAS
Conclusions
• HYSPLIT, APCA and HDDM provide complementary information on – model winds that define transport pathways from source
regions to receptor regions– ozone source apportionment– sensitivity of receptors to emissions changes in the source
regions
• Because their formulations are independent of one another, each of these tools can serve as a way to evaluate information provided by the others
• Used in combination, these tools can provide a valuable resource for control strategy development.
Ozone Transport Presentation for CMAS
Questions?