What have I learnt about tropospheric composition using space-based

observations?

Paul Palmer, University of Leedswww.env.leeds.ac.uk/~pip

Correlation of high ozone with temperature is driven by:1) Stagnation, 2) Biogenic hydrocarbon emissions, 3) Chemistry

Ozone exceedances of 90 ppbv,summer 2003 (#days)

Model values forpreindustrial ozone

}European mountain-top observations[Marenco et al., 1994]

Observed rise in ozone background at northern

midlatitudes

0-1; 1-5; 5-10; >10

60

50

40

30

20

10

01870 1890 1910 1930 1950 1970 1990

NO

HO2OH

NO2

O3hv

HC+OH HCHO + productsNOx, HC,

CO

Tropospheric O3 is an important climate forcing agent

IPCC, 2001

Level of Scientific Understanding

Natural VOC emissions (50% isoprene) ~ CH4 emissions.

Bottom-up Isoprene

emissions, July 1996

MEGAN

3.6 Tg C

GEIA

7.1 Tg C

[1012 atom C cm-2 s-

1]

Guenther et al, JGR, 1995

EPA BEIS2

2.6 Tg C

Pierce et al, JGR, 1998

Guenther et al, ACP, 2006

E = A ∏iγi

Emissions (x,y,t); fixed base emissions(x,y); sensitivity parameters(t)

Global Ozone Monitoring Experiment (GOME) &the Ozone Monitoring Instrument (OMI)

• GOME (European), OMI (Finnish/USA) are nadir SBUV instruments• Ground pixel (nadir): 320 x 40 km2 (GOME), 13 x 24 km2 (OMI)• 10.30 desc (GOME), 13.45 asc (OMI) cross-equator time • GOME: 3 viewing angles global coverage within 3 days• OMI: 60 across-track pixels daily global coverage• O3, NO2, BrO, OClO, SO2, HCHO, H2O, cloud properties

Launched in 2004

GOME HCHO columns

July 2001

[1016 molec cm-

2]

0 1 20.5

1.5

2.5

Biogenic emissions

Biomass burning

* Columns fitted: 337-356nm * Fitting uncertainty < continental signals

Data: c/o Chance et al

May

Jun Jul Aug

Sep

1996

1997

1998

1999

2000

2001

GOME HCHO column [1016 molec cm-2]

0 1 20.5

1.5

2.5

Palm

er

et

al, JG

R,

2006.

Relating HCHO Columns to VOC Emissions

VOC HCHOhours

OH

hours

h, OH

Local linear relationship between HCHO and E

kHCHO

EVOC = (kVOCYVOCHCHO)HCHO

___________

VOC source

Distance downwind

HCHO Isoprene

-pinenepropane

100 km

EVOC: HCHO from GEOS-CHEM and MCM models

Palmer et al, JGR, 2003.

Net

MCM HCHO yield calculationsC

um

ula

tive H

CH

O y

ield

[p

er

C]

0 2 4 6 8 10 12 14 16 18 20 220.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

HC

HO

YIE

LD

PE

R C

RE

AC

TE

D

DAYS

NOX= 1 PPB NOX= 100 PPT

pinene

( pinene similar)DAYS

0.4

0 20 40 60 80 100 120 1400.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55C

umm

ula

tive

HC

HO

Yie

ld fr

om

iso

pren

e o

xid

atio

n (p

er C

)

TIME (HOURS)

NOX = 0.1 PPB

NOX =1 PPB

Figure 18. Formation of HCHO from isoprene. Vertical lines denote midnight of each day

Isoprene

HOURS

0.5NOx = 1 ppb

NOx = 0.1 ppb

Parameterization (1ST-order decay) of HCHO production from monoterpenes in global 3-D CTM

Higher CH3COCH3 yield from monoterpene oxidation delayed (and smeared) HCHO production

Palmer et al, JGR, 2006.

C5H8+OH(i) RO2+NOHCHO, MVK, MACR

(ii) RO2+HO2ROOH

ROOH recycle RO and RO2

Monthly mean AVHRR LAI

MEGAN (isoprene)Canopy model

Leaf ageLAI

TemperatureFixed Base factors

MODEL BIOSPHERE

GEIAMonoterpenes

MBOAcetoneMethanol

Modeling Overview

GEOS-CHEMGlobal 3D CTM

PAR, T

Emissions

MCM: parameterized HCHO source from monoterpenes and MBO

Seasonal Variation of Y2001 Isoprene Emissions

•Good accord for seasonal variation, regional distribution of emissions (differences in hot spot locations – implications for O3 prod/loss).

•Other biogenic VOCs play a small role in GOME interpretation

May

Jun

Aug

Sep

Jul

0 3.5

7

1012 atom C cm-2s-

1

GOME MEGAN MEGAN GOME

Palmer et al, JGR, 2006.

GOME Isoprene Emissions: 1996-2001May Jun Jul Aug Sep

1996

1997

1998

1999

2000

2001

[1012 molecules cm-2s-1]0 5 10

Relatively inactive

Palm

er

et

al, JG

R,

2006.

Isop

ren

e fl

ux [

10

12 C

cm

-2 s

-1]

Julian Day, 2001

MEGANObsGOME

Sparse ground-truthing of GOME HCHO columns and derived isoprene flux estimates

Seasonal Variation: Comparison with eddy correlation isoprene flux measurements (B. Lamb) is encouraging

Atlanta, GA

May Jun July Aug Sep

PAMS Isoprene, 10-12LT [ppbC]

GO

ME H

CH

O [

10

16 m

ole

c c

m-2]

1996 1997 1998 1999 2000 2001Interannual Variation:

Correlate with EPA isoprene surface concentration data. Outliers due to local emissions.

Atlanta, GA

PROPHET Forest Site, MI

Surface temperature explains 80% of GOME-observed variation in HCHO

NCEP Surface Temperature [K]

GO

ME H

CH

O S

lant

Colu

mn

[10

16 m

ole

c cm

-2]

G98 fitted to GOME data

G98 Modeled curves

Time to revise model parameterizations of isoprene emissions?

Palm

er

et

al, JG

R,

2006.

Tropical ecosystems represent 75% of biogenic NMVOC emissions

1996

1997

1998

1999

2000

2001

What controls the variability of NMVOC emissions in tropical ecosystems?

Importance of VOC emissions in C budget?

Kesselmeier, et al, 2002

GOME HCHO column, July

Challenges: Cloud cover, biomass burning, and lack of fundamental understanding of NMVOC emissions…

em

issio

n r

ate

(C

)(µ

g g

-1 h

-1)

PA

R(µ

mol m

-2 s

-1)

assim

ilati

on

(C

)(m

g g

-1 h

-1) 0

123456

limonene myrcene b-pinene a-pinene sabinene

500

1000

1500

00:0006:0012:00

18:0000:00

06:0012:00

18:0000:00

0

2

4

local time [hh:mm]

10

20

30

40

tem

pera

ture

[°C

]

0

2

4

G93

for

isop

.[s

um

of

mon

ote

rpen

es]

tran

sp

irati

on

(mm

ol m

-2 s

-1)

monoterpene emission of Apeiba tibourbou

OMI, 24/9-19/10, 2004

13x24 km2

TES data @ 6km, 11/04

O3

CO

MODIS Firecount

O3-CO-NO2-HCHO-firecount correlations import to utilize when looking at the tropics

Improved cloud-clearing algorithms and better spatial resolution data help.

TES data c/o Bowman, JPL

A more integrated approach to understanding controls of NMVOCs, e.g., surface data, lab data,

40

45

50

55

60

65

70

- 60 - 50 - 40 - 30 - 20 - 10 0 10

“Normal” airmass flow

44

46

48

50

52

54

56

- 20 - 15 - 10 - 5 0 5 10

Stagnant airmass flow

0

200

400

600

800

1000

1200

1400

27-Jul

29-Jul

31-Jul

2-Aug

4-Aug

6-Aug

8-Aug

10-Aug

12-Aug

14-Aug

16-Aug

18-Aug

20-Aug

22-Aug

24-Aug

26-Aug

28-Aug

30-Aug

0

5

10

15

20

25

30

35

40

Tem

pera

ture

(C

)

Isop

ren

e (

pp

t)

Estimated up to 700 extra deaths attributable to air pollution (O3 and PM10) in UK during this period

O3 > 100 ppb on 6 consecutive days

2pm, 6th Aug, 2003

Compiled from UK ozone network data

Isoprene c/o Ally Lewis

“Expect harmful levels of ozone and PM2.5 over the next couple of days; please keep small children and animals inside. Transatlantic pollution represents 20% of today’s UK surface ozone.”

2010

Resolution of new satellite data allows study UK AQ from space

SCIA NO2 @ 0.4x0.4o, Aug 2004

GOME NO2 @ 1x1o

Aug 1997

NAEI NOX emissions as NO2, 2002

GOME and SCIA NO2 c/o R. Martin; OMI (unofficial) NO2 c/o

T. Kurosu

Length

of

day

[hours

]

Day of Year

Edinburgh, 56N

Denver, 40N Cloud cover [%], ISCCP August 83-04

30 10070

OMI NO2 @ 0.1ox0.1o, Jul 2004

The increasing role of BVOCs: constraints from OMI HCHO?

Stewart et al, 2003Isoprene

MonoterpenesBVOC fluxes for a “hot, sunny” day

BOE:

0.5-1 ppb isoprene = 1-5x1012 molec cm-

2 s-1 (cf. SE USA 5-7x1012 molec cm-2 s-1)10

16 [m

ole

c cm-

2]

OMI HCHO2

<0.3

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

218.

00

218.

17

218.

33

218.

50

218.

67

218.

83

219.

04

219.

21

219.

38

219.

54

219.

75

219.

92

220.

08

220.

25

220.

42

220.

58

220.

75

220.

92

221.

08

221.

25

221.

42

221.

58

221.

75

221.

92

222.

13

222.

29

222.

46

222.

63

222.

79

222.

96

JDay

Rat

e N

O2

pro

du

ctio

n p

pb

h-1

NO

2 p

rod

ucti

on

pp

b h

-1

Isoprene HCHO

c/o Jenny Stanton

NO + RO2 NO2 + RO, Aug 2003

• Unclear what PM characteristics affect health

• Secondary PM is formed from:– Oxidation of organic

compounds

– Oxidation of SO2

– Difficult to estimate offline – need models and data

MISRSurface PM2.5 =

ModelSurface [PM2.5] x MISR AOT

Model AOT2003

roadside (primary)

PM10

MISR AOT can help estimate total PM2.5:

Space-based aerosol optical properties can help map emissions of particulate matter

Liu

et

al,

2004