Transcript Estimation of Ozone Production Efficiency from Space

Estimating
Ozone Production Efficiency
from Space
Matthew Cooper1, Randall Martin1,2, Bastien Sauvage3,
Chris Boone4, Kaley Walker4,5,Peter Bernath4,6,
Chris McLinden7, Doug Degenstein8,
Andreas Volz-Thomas9, Catherine Wespes10
5th International GEOS-Chem Meeting
Harvard University
May 2, 2011
1. Dalhousie University
2. Harvard-Smithsonian Center for Astrophysics
3. University of Waterloo
4. University of Toronto
5. University of York
7. University of Saskatchewan
8. Université de Toulouse
9. Forschungszentrum Juelich
6. Environment Canada
10. Université Libre de Bruxelles
Ozone Production Efficiency
PO3
Convective outflow:
No HNO3,
some initial O3, NOx
NO
LNO x
NO2
HNO3
P(O3 )
P(O3 )
O3
OPE 


L( NOx ) P( HNO3 ) HNO3
• OPE represents the nonlinear dependence of O3 on NOx
• GEOS-Chem predicts high ozone production efficiency
– This has not been confirmed by measurements in the tropical troposphere
– We can estimate OPE using satellite retrievals of O3 and HNO3 concentrations
Observations
ACE-FTS
• Solar occultation instrument measuring IR
• Global coverage in tropics over several years (2004-2010)
• Measures O3, HNO3, 30+ others
• Evaluation against aircraft, ozonesondes
[Cooper et al., JGR, in press]
– 10-13% high bias for O3
– 15% for HNO3
Aircraft
• PEM Tropics A (1996) and B (1999)
• PRE-AVE (2004) and CR-AVE (2006)
• Tropospheric O3 and HNO3 observations
between 8-12 km used here
Testing the Method using GEOS-Chem
PO3
O3
OPE 

PHNO3 HNO3
• How does calculating OPE from concentrations
compare to direct calculation from production rates?
PO3
OPE 
 130 mol / mol
PHNO3
O3
OPE 
 190 mol / mol
HNO3
• Assumed similar O3, HNO3 loss
• Some HNO3 scavenging occurs, leads to OPE overestimation
• OPE from concentrations is an upper limit estimate!
Ozone Production Efficiency from ACE-FTS
• OPE given by slope
• OPE = 196 (+34, -61)
mol/mol
ACE-FTS (11.5 km) in Tropics (±20°)
• Agrees with tropical mean
OPE from GEOS-Chem (190
mol/mol)
• First estimate of OPE using
satellite data
• Uncertainty sources
–
–
–
–
Slope error ± 8
ACE bias ± 5
Method (upper limit) -53
Regional pollution ±33
∆𝑂3
𝑂𝑃𝐸 =
∆𝐻𝑁𝑂3
OPE from ACE-FTS, Aircraft and GEOS-Chem
• Over South Pacific region:
ACE-FTS
OPE (mol/mol)
223 (+41, -69)
Aircraft
232 (+41, -71)
GEOS-Chem
188 (+42, -63)
• GEOS-Chem agree with
both data sets within
uncertainties
Tropics (±20° at 11.5 km)
GEOS-Chem
ACE-FTS
Aircraft
OPE Variability
0
50
100
150
200
Ozone Production Efficiency (mol/mol)
250
300
Whole Tropics
Tropical Atlantic
Tropical Pacific
OPE from GC P-rates
131
93
196
OPE from ACE –FTS
196 (+34, -61)
146 (+16, -41)
249 (+21, -68)
Number of Points
368
62
65
Error – slope (mol/mol)
8
14
19
Error –variability (mol/mol)
32
6
4
Summary
• Estimation of Ozone Production Efficiency possible from ACEFTS measurements
– A new application for satellite measurements
• Upper limit tropical mean OPE = 196 (+34,-61) mol/mol using
ACE-FTS measurements
• In agreement with values calculated from GEOS-Chem output
• Regionally defined values possible from ACE-FTS – show same
features seen in GEOS-Chem