Formaldehyde from Space: Unexplored

regions, New Data, New Challenges.

Paul Palmer University of Edinburgh

A modest beginning….

Thomas et al, GRL, 1998

NO2HCHO

Vertical column retrievals

8 x 1016 molec cm-2T

ransm

issi

on

Chance et al, GRL, 2000

337-356 nm (O3, NO2, BrO, O2-O2)

1) Direct fit of observed radiances: slant columns

AMF = AMFG w() S() d1

0

Radiative transfer

Normalised HCHO profile

Palmer et al, JGR, 2001

2) Air-mass factor calculation: vertical columns

Estimated Error Budget

Slant column fitting: 4x1016 molec cm-2

AMF:

1) UV albedo (8%)

2) Model error (10%)

3) Clouds (20%)

4) Aerosols (20%)

Subtotal 30%

For a vertical column of 2x1016 molec cm-2 and AMF of 0.7

TOTAL = 9x1015 molec cm-2

biogenic, pryogenic, anthropogenic

pryogenicanthropogenic

biogenicanthropogenic

pryogenicpyrogenicanthropogenic

biogenicanthropogenic

Th

om

as

Kuro

su,

Harv

ard

-Sm

ithso

nia

n

HCHO August 2006Ozone Monitoring Experiment

Global distribution of HCHO, OMI August 2006

Continent 2

Direct intercontinental transport of pollutants O

3

NOx, RH, CO

Continent 1

O3

Ocean physics, chemistry, biology

Pyro-convection

HO2

O3

NO

OH

NO2

hv

Visibility

A simplistic view of tropospheric chemistry

Environmental factors:• temperature• solar irradiance• leaf area index• leaf age

July2003

MEGAN Isoprene Emission Inventory

North AmericaPalmer et al, JGR, [2001, 2003,

2006] Abbot et al, GRL, 2003 Chance et al, GRL, 2000

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 CTM and MEGAN isoprene emission model

Palmer et al, JGR, 2003.

Net

May 2001

Jun 2001

Jul 2001

Aug 2001

Sep 2001[1012 C cm-2 s-1]

Isoprene Monoterpenes MBO

Isoprene largely from broadleaf (e.g., poplar, sweetgum, aspen and oak)

Monoterpenes primarily from coniferous tree (pine, cedar, redwood)

Master Chemical Mechanism yield calculations

Cu

mu

lati

ve 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 age;

LAI; Temperature; Fixed Base factors

GEIAMonoterpenes; MBO;Acetone; Methanol

MODEL BIOSPHERE

GEOS-CHEM Modeling Overview

GEOS-CHEM global 3Dchemistry transport model

PAR, T

Emissions

MCM: parameterized HCHO source from monoterpenes and MBO

model without isoprene

Isoprene emission [1013 atomC cm-2 s-1]

Mod

el H

CH

O

colu

mn

[1

01

6

mole

c cm

-2]

SE USA

ΩHCHO= S EISOP+B

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.

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

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

1996

1997

1998

1999

2000

2001

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

Palm

er

et

al, JG

R,

2006.

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

NCEP Surface Temperature [K]

GO

ME Iso

pre

ne E

mis

sions

[1

012 a

tom

s C

cm

-2s-

1] G98 fitted to

GOME data

G98 Modeled curves

Time to revise model parameterizations of isoprene emissions?

Palm

er

et

al, JG

R,

2006.

EuropeCurci et al, in prep, 2007

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)

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

Isoprene c/o Ally Lewis

Only continent where ANTHRO > BIO emissions

[Simpson et al., JGR 1999]

A = hot; B = warm temperate; C = cool temperate

What Controls HCHO Columns Over Europe?

GEOS-CHEM HCHO Column in

Summer

BIOGENIC CONTROL

NO ISOP/NO ANTHRO

Biogenic control of HCHO column:

• Eastern Europe

• Northern Europe

• Iberian Peninsula

• Turkey(GEIA Emissions)

0.4

1.2

1

ANTHROPOGENIC CONTROL

v7-01-02

EMEP DataGEIA

MEGAN

EMEP stations, Aug 2000

Comparison between GEOS-CHEM and EMEP data

Isop

ren

e

(pp

b)

HC

HO

(p

pb

)

Day, Aug 2000

Donon

•Some (limited) evidence that HCHO signal is biogenic

•MEGAN consistently too low

Aug 1996 1996-2000 Aug Mean

GOME HCHO Columns Over Europe

2.52.01.51.00.5[1016 molec cm-

2]

Data on a regular 0.5 x 0.5 degree grid

Isop

ren

e

em

issi

on

GEIA = Guenther et al, JGR (1995)

Spatial separation method used for North America was not clean over Europe

Work in progress: inverting as a function of NOx rather than

geographyGEOS-CHEM NO2 Columns, Aug 2000 [1015 molec cm-

2]GEOS-CHEM: Isoprene vs

HCHO columns over Europe

L, M and H NOx a bit arbitrary

Resulting inversion does not distinguish properly biogenic vs anthropogenic HCHO

ΩHCHO= S EISOP+B

EISOP [1012 molec cm-2s-1]

Ω H

CH

O [

10

16 m

ole

c cm

-2]

GOME isoprene flux have an uncertainty < 200%, comparable, if not less, that bottom-up inventories

Tropical Ecosystems Barkley and Palmer, WIP

Tropical ecosystems represent 75% of biogenic NMVOC emissions

What drives observed variability of tropical BVOC emissions?

Sla

nt

Colu

mn H

CH

O [

10

16 m

ole

c cm

-2]

Sep 1997

Nov 1997

19971998199920002001

X = Active Fire (ATSR)

Mon

thly

ATS

R F

irecou

nts

Day of Year

Significant pyrogenic HCHO source over tropicsGood: Additional trace gas measurement of biomass burning; effect can be identified largely by firecounts (see below)

Bad: Observed HCHO a mixture of biogenic and pyrogenic – difficult to separate without better temporal and spatial resolution

GOME

HCHO and Isoprene over the Amazon

In situ isoprene 2002

Tro

stdorf e

t al,

200

4

19971998199920002001

GOME

ATSR Firecounts used to remove HCHO from fires

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

1

2

3

4

5

6

limonene myrcene b-pinene a-pinene sabinene

500

1000

1500

00:0006:00

12:0018:00

00:0006:00

12:0018:00

00:00

0

2

4

local time [hh:mm]

10

20

30

40

tem

pera

ture

[°C

]

0

2

4 G

93

for

isop

.[s

um

of

mon

ote

rpen

es]

tran

sp

irati

on

(mm

ol m

-2 s

-1)

monoterpene emission of Apeiba tibourbou

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48 19:12 21:36 00:00

Time bin midpoint

Co

nce

ntr

atio

n (

pp

b)

0

1

2

3

4

5

6

00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48 19:12 21:36 00:00

Time bin midpoint

Co

nce

ntr

atio

n (

pp

b)

0

0.5

1

1.5

2

2.5

3

3.5

00:00 02:24 04:48 07:12 09:36 12:00 14:24 16:48 19:12 21:36 00:00

Time bin midpoint

Co

nce

ntr

atio

n (

pp

b)

Isoprene

Limonene

Beta-pinene

[pp

b]

Time of DayC/o J. Kesselmeier

C/o J. Saxton A. Lewis

Amazon

AfricaCan isoprene explain the observed magnitude and variance of HCHO columns over the tropics?

The future?Newer orbits….better spatial and temporal resolution…

Bu

rrow

s et

al,

20

04

Biomass Burning: emissions and injection heights

OMI HCHO c/o T. Kurosu

ATSR Firecounts

October 2006ACE HCHO c/o P. Bernath

•Pyro-convective transport is difficult to model accurately.

•Two (or more) pieces of independent information allows a simultaneous inversion of surface emission and injection height.

Schoeberl et al, 2006