North American Isoprene Emissions Measured from Space Paul Palmer Harvard University ACD seminar...
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Transcript of North American Isoprene Emissions Measured from Space Paul Palmer Harvard University ACD seminar...
North American Isoprene Emissions
Measured from Space
Paul PalmerHarvard University
ACD seminar series, NCAR, January 14, 2002
Talk Overview
• Relating HCHO columns to VOC emissions
• Global 3d model analysis
• GOME HCHO columns
• Are different HCHO data consistent? •
• GOME isoprene emissions
Overall Approach
Talk Overview
• Relate HCHO columns to VOC emissions
• Global 3d model analysis
• HCHO from GOME
• Are different HCHO data consistent?
• GOME isoprene emissions
HCHO + h 2HO2 + CO
H2 + CO
HCHO + OH HO2 + CO + H2O
VOC + OH ... ... n HCHO + OTHER PRODUCTS
VOCs, HCHO and tropospheric O3
VOC
EPA BEIS2 isoprene
GEIAisoprene
ppb
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
Relating HCHO columns to VOC emissions
•Absence of
transport = Yi Ei
iVOCi Emission Ei
kHCHO
kHCHO
HCHO yields from VOCsSpecies
Emission[TgC month-
1]
HCHO Yield[C-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 0.8 0.06 0.53
HCHO 0.15 1.0 1.64
CH3OH 2.1 1.0 23.0 Total: 86%
VOC YiHCHO
•Define a displacement length scale
and smearing length scale
ki
Horizontal transport displaces and smears HCHO signal
Limiting values:Ls,i U/ki when ki«kHCHO
Ls,i U/kHCHO when kHCHO«ki
midmorning eg values KHCHO = 0.5h-1; U = 20kmh-1; [OH]=5E6 mol cm-3
ISOP Ld,i & Ls,i 40 km
CH4 Ld,i & Ls,i = many 1000s km
CH3OH Ld,i =250 km; Ls,i = 1000 km
~ GOME obs
GEOS-CHEM global 3D model:
101
•Driven by GEOS met data
•2x2.5o resolution/26 vertical levels
•O3-NOx-VOC chemistry
•GEIA isoprene emissions
•Aerosol scattering: AOD:O3
Dickerson et al, [1997]
GEOS-CHEM HCHO columnsJuly 1996
[1016 molec cm-2]
GEIA isoprene emissions
NW NE
SESW
Isoprene emission [1013 atomC cm-2 s-1]
Mod
el H
CH
O c
olu
mn
[101
6 m
ole
c c
m-2
] July 1996 (25-50oN, 65-130oW)
Slope S = Y/kHCHO
n S[103 s]
r2 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 1.48 0.24
Yields consistent with photochemical model
• 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
Global Ozone Monitoring Experiment
HCHO slant column fitting
3 x 1016 molec cm-2
8 x 1016 molec cm-2
1 fitting uncertainty 4 x 1015 molec cm-2
Chance et al [2000]
O3
NO2
BrO
O2-O2
vertical column = slant column /AMF
Palmer et al, [2001]
AMF example - Tennessee
GEOS-CHEM S()
w()
S() w()
AMFG
2.08
AMF
0.71
AMF calculation every GOME July 1996 scene...
GOME HCHO – July 1996
Chance et al, 2000; Palmer et al, 2001
Filtered for cloudy scenes (cf > 40%)
GOME HCHO – July 1996
Bias = 11%
r2 = 0.7 n = 756
GEOS-CHEM
GO
ME
GOME HCHO(T) vs ISOP(T)
ISOP(T) [Guenther et al, 1995]
300.5
Ozarks
Overall Approach
EPA BEIS2
GEIA
ppb
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
Modeling in situ dataGEIA BEIS2
r2 = 0.53
Bias -3%
r2 = 0.65
Bias -30%
NW NE
SESW
Isoprene emission [1013 atomC cm-2 s-1]
Mod
el H
CH
O c
olu
mn
[101
6 m
ole
c c
m-2
]Model Transfer functions
GOME isoprene emissions
BEIS2 fine structure
Consistency: GOME and in situ data
r2 = 0.77
Bias -12%
Summary
New methodology for VOC emission from space-based HCHO columns
Isoprene is dominant VOC for North American summertime
GOME shows Ozarks isoprene volcano
EPA BEIS2 too low?
GOME consistent with in situ data
Daily VOC emissions: the future?
Acknowledgements
Daniel Jacob, Arlene Fiore, Randall Martin (Harvard University)
Kelly Chance, Thomas Kurosu (Harvard-Smithsonian Observatory)