1. North American Hydrocarbon Emissions Measured from Space
Paul Palmer
Division of Engineering and Applied Sciences
Harvard University

2. Talk Overview Why are accurate hydrocarbon emissions important?
How is it possible to relate measured HCHO columns to specific hydrocarbon emissions?
Are satellite observations consistent with in situ data?
The future?

3. O3 O2 hv O3 hv OH HNO3 NO2 NO OH HO2 H2O2 hv, H2O
STRATOSPHERE
TROPOSPHERE hv OH
HNO3
NO2 NO O3 OH
HO2
H2O2
hv, H2O
CO, hydrocarbons, NOx
HCHO + h  2HO2 + CO (radical channel)
HCHO + OH  HO2 + CO + H2O lifetime = few hrs

4. Global 3d model of chemistry
How do we validate satellite observations?
GOME,
MOPITT,
SCIAMACHY
TES, OMI
Global 3d model of chemistry

5. Summertime in situ HCHO datasets
Fried et al 1997
Harris et al 1989
Kleindienst et al 1988
Lee et al 1995, 1998
Martin et al 1991
McKeen et al 1997
OZIE -Guenther
Reimer et al 1998
Shepson et al 1991
ppb

6. Aircraft HCHO profile data
North Atlantic Regional Experiment 1997
Southern Oxidant Study 1995
measurements
GEOS-CHEM model
Altitude [km]
Altitude [km]
[ppb]
Continental outflow
Surface source (mostly isoprene+OH)

7. Relating HCHO columns to hydrocarbon emissions
Chemical loss kHCHO
Absence of transport  = Yi Ei
HCHO 
HC oxidation ki (HCHO yield Yi) i
Emission Ei
kHCHO
HCi

8. HCHO yields from HCs Total: 86% Species Emission [TgC month-1]
Potential HCHO production [%]
CH4
2.6
1.0
28.5
ISOP
7.3
0.45
32.0
 -pinenes
1.1
0.8
0.019
0.045
0.23
0.39
MBO
0.06
0.53
HCHO
0.15
1.64
CH3OH
2.1
23.0
Total:
86%

9. ( ) L d,i = U ki ln ki -kHCHO kHCHO midmorning eg values
Horizontal transport displaces HCHO signal
Displacement length scale
L d,i = U ki
( ) ln
ki -kHCHO
kHCHO
midmorning eg values
KHCHO = 0.5h-1; U = 20kmh-1; [OH]=5E6 mol cm-3
ISOP Ld,i  40 km
CH Ld,i = many 1000s km
CH3OH Ld,i =100s km

10. GEOS-CHEM global 3D model: 101
Driven by DAO GEOS met data
2x2.5o resolution/26 vertical levels
O3-NOx-VOC chemistry
GEIA isoprene emissions
Aerosol scattering: AOD:O3
Dickerson et al, [1997]

11. GEOS-CHEM HCHO columns July 1996
GEIA isoprene emissions
GEOS-CHEM HCHO columns July 1996
[1016 molec cm-2]

12. Model HCHO column [1016 molec cm-2] model without isoprene
July 1996 (25-50oN, oW) NW NE
Slope S = Y/kHCHO
Model HCHO column [1016 molec cm-2] SW SE
model without isoprene
Isoprene emission [1013 atomC cm-2 s-1]

13. Yields consistent with photochemical modelr2
lifetime
[hours] Y
[C-1] NW
1810
2.04
0.51
1.67
0.34 NE
2193
1.90
0.43
1.76
0.30 SE
1913
2.09
0.65
1.48
0.39 SW
1750
1.27
0.49
0.24
Yields consistent with photochemical model

14. Global Ozone Monitoring Experiment
Nadir-viewing SBUV instrument
Launched April 1995
Pixel 320 x 40 km2
10.30 am cross-equator time
Global coverage in 3 days
O3, NO2, BrO, OClO, SO2, HCHO, H2O, & cloud coverage

15. HCHO columns – July 1996 r2 = 0.7 n = 756 Bias = 11%
GEOS-CHEM
r2 = 0.7 n = 756
Bias = 11%
[1016molec cm-2]
GOME
HCHO fitted in UV (~340 nm)
1 uncertainty: x 1015 molec cm-2

16. Isoprene “volcano” GOME GEOS-CHEM [1016 molec cm-2] July 7 1996

17. The Ozarks Dissected plateau - 129,500 sq km
Oak forests – good isoprene emitters
Cambridge, MA
"Trees cause more pollution than automobiles do."

18. Ozark Isoprene Experiment 1998
Enclosure measurements
Result Summary
Type Spec ppb Alt [m] Local time
Balloon Isop
Plane Isop
Surface HCHO 7-15(11)
Plane HCHO 3-11(7)
Balloon-borne measurements
Photos c/o Alex Guenther, NCAR

19. HCHO data over the Ozarks
SOS 1999
Aircraft 350 m during July 1999
Illinois
Missouri
Kansas
OZARKS
[ppb]
c/o Y-N. Lee, Brookhaven National Lab.

20. Isoprene “volcano” GOME GEOS-CHEM [1016 molec cm-2]
Temperature dependence of isoprene emission
July
Slant column HCHO [1016 mol cm-2]
Surface temperature [K]
July
[1016 molec cm-2]

21. Global 3d model of chemistry

22. GEIA
EPA BEIS2

23. Summertime in situ HCHO datasets
Fried et al 1997
Harris et al 1989
Kleindienst et al 1988
Lee et al 1995, 1998
Martin et al 1991
McKeen et al 1997
OZIE -Guenther
Reimer et al 1998
Shepson et al 1991
ppb

24. Modeling in situ data GEIA BEIS2 r2 = 0.65 Bias -30% r2 = 0.53

25. Model Transfer functionsNW NE
Model HCHO column [1016 molec cm-2] SW SE
model without isoprene
Isoprene emission [1013 atomC cm-2 s-1]

26. GOME isoprene emissions – July 1996
[1012 atom C cm-2 s-1]

27. Consistency: GOME and in situ data
r2 = 0.77
Bias -12%

28. Global HCHO from GOME: July 1996
[1016 molec cm-2]

29. ATSR Firecounts – July 1996

30. Global HCHO from GOME: Oct 1996
[1016 molec cm-2]

31. Summary New methodology for HC emission from space-based HCHO columns
Isoprene is dominant HC for North American summertime
GOME shows Ozarks isoprene volcano
GOME data consistent with in situ data
The future?

32. Acknowledgements
Daniel Jacob, Arlene Fiore, Randall Martin (Harvard University)
Kelly Chance, Thomas Kurosu (Harvard-Smithsonian Observatory)