1. Paul Palmer, University of Leeds
What can we learn about the Earth system using space-based observations of tropospheric chemical composition?
Transcends many of nerc centers of excellences: DARC, CASIX, CTCD, NCAS
Paul Palmer, University of Leeds

2. Observed rise in ozone background at northern midlatitudes
Ozone exceedances of 90 ppbv,
summer 2003 (#days)
Observed rise in ozone background at northern midlatitudes 60
Model values for
preindustrial ozone }
European mountain-top observations
[Marenco et al., 1994] 50
0-1; 1-5; 5-10; >10 40 30 20 10
O3 penetrates plant foliage through the stomates into the cell walls, and subsequently decomposes to oxygen-containing molecules (e.g., H2O2), which damage plant cells. Elevated O3 concentrations lead to leaf necrosis and reduced agricultural yields [Ashmore, 2005].
1870
1890
1910
1930
1950
1970
1990
Correlation of high ozone with temperature is driven by:
1) Stagnation, 2) Biogenic hydrocarbon emissions, 3) Chemistry

3. Tropospheric O3 is an important climate forcing agentNO
HO2 OH
NO2 O3 hv
HC+OH  HCHO + products
NOx, HC, CO
Level of Scientific Understanding
Natural VOC emissions (50% isoprene) ~ CH4 emissions.
IPCC, 2001

4. Bottom-up Isoprene emissions, July 1996
E = A ∏iγi
Emissions (x,y,t); fixed base emissions(x,y); sensitivity parameters(t)
Guenther et al, JGR, 1995
GEIA
EPA BEIS2
2.6 Tg C
Pierce et al, JGR, 1998
7.1 Tg C
Guenther et al, ACP, 2006
MEGAN
3.6 Tg C
[1012 atom C cm-2 s-1]

5. Global Ozone Monitoring Experiment (GOME) & the Ozone Monitoring Instrument (OMI)
Launched in 2004
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), 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

6. GOME HCHO columns July 2001 Biogenic emissions Biomass burning
Data: c/o Chance et al
[1016 molec cm-2] 1 2
0.5
1.5
2.5
* Columns fitted: nm * Fitting uncertainty < continental signals

7. May
Jun
Jul
Aug
Sep
1996
1997
1998
1999
2000
2001
GOME HCHO column [1016 molec cm-2] 1 2
0.5
1.5
2.5
Palmer et al, JGR, 2006.

8. Relating HCHO Columns to VOC Emissions
hours OH
h, OH
VOC
Net
kHCHO
EVOC =
(kVOCYVOCHCHO)
HCHO
___________
Local linear relationship between HCHO and E
VOC source
Distance downwind
WHCHO
Isoprene
a-pinene
propane
100 km
Three/four prong attack:
Chemistry; Emissions: magnitude and controls; Transport
EVOC: HCHO from GEOS-CHEM CTM and MEGAN isoprene emission model
Palmer et al, JGR, 2003.

9. Seasonal Variation of Y2001 Isoprene Emissions
MEGAN
GOME
MEGAN
GOME
May
Jun
Aug
Sep
Jul
3.5 7
1012 atom C cm-2s-1
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
Palmer et al, JGR, 2006.

10. GOME Isoprene Emissions: 1996-2001
May
Jun
Jul
Aug
Sep
1996
1997
1998
1999
2000
2001
[1012 molecules cm-2s-1] 5 10
Relatively inactive
Palmer et al, JGR, 2006.

11. Isoprene flux [1012 C cm-2 s-1]
Sparse ground-truthing of GOME HCHO columns and derived isoprene flux estimates
Isoprene flux [1012 C cm-2 s-1]
Julian Day, 2001
MEGAN
Obs
GOME
May Jun July Aug Sep
Seasonal Variation: Comparison with eddy correlation isoprene flux measurements (B. Lamb) is encouraging
Atlanta, GA
PROPHET Forest Site, MI
Atlanta, GA
To evaluate the GOME interannual variability over the southeastern United
States we used isoprene concentration data from four EPA Photochemical
Assessment Monitoring Sites (PAMS, located
around Atlanta Georgia. Three of these sites are classed as surburban and one
is considered rural. Instantaneous concentration measurements are taken every
three hours using an automated GC with flame ionization detection. The
uncertainty of these individual measurements is 30\%
(Susan Zimmer-Dauphinee, EPA, personal communication, 2004).
Instruments are calibrated daily using an isoprene standard. Measurements that
do not agree with the standard to within a 30\% accuracy are discarded.
As with the HCHO columns, there
is a large degree of interannual variability in the observed seasonal
cycle on the continental scale (not shown).
\callout{Figure \ref{fig:pamsga}} shows that GOME HCHO column data captures
58\% of the temporal variability of the monthly mean isoprene concentrations
at all Atlanta sites, after removing one anomalous measurement (880~ppbC,
July 1996) and two outliers (June 1998 and August 1999). %
The value for the intercept (0.2$\times$10$^{16}$molec~cm$^{-2}$) in Figure
\ref{fig:pamsga},
corresponding to the HCHO column with no contribution from isoprene, is
half the background HCHO column that is expected from from CH$_4$ oxidation.
The two monthly mean outliers originate from the rural site that is sometimes
influenced by local biogenic emissions from the Kudzu vine, a known strong
emitter of isoprene (Susan Zimmer-Dauphinee, EPA, personal communication,
2004). The reason why these local biogenic emissions significantly influence
only a few months is unknown.
By comparing mean
summertime values (June$-$August) we effectively test the ability of GOME
to capture observed interannual variability in isoprene concentration. GOME
summertime columns between 1996$-$2001 capture 92\% of the observed
interannual variability.
GOME HCHO [1016 molec cm-2]
Interannual Variation: Correlate with EPA isoprene surface concentration data. Outliers due to local emissions.
PAMS Isoprene, 10-12LT [ppbC]

12. Surface temperature explains 80% of GOME-observed variation in HCHO
NCEP Surface Temperature [K]
GOME HCHO Slant Column [1016 molec cm-2]
G98 fitted to GOME data
G98 Modeled curves
Palmer et al, JGR, 2006.
Time to revise model parameterizations of isoprene emissions?

13. Tropical ecosystems represent 75% of biogenic NMVOC emissions
1996
1997
1998
1999
2000
2001
What controls the variability of NMVOC emissions in tropical ecosystems?
Kesselmeier, et al, 2002
Importance of VOC emissions in C budget?
GOME HCHO column, July

14. Challenges: Cloud cover, biomass burning, and lack of fundamental understanding of NMVOC emissions…
TES 6km, 11/04
OMI, 24/9-19/10, 2004
13x24 km2 O3
Improved cloud-clearing algorithms and better spatial resolution data help. CO
emission rate (C)
(µg g-1 h-1)
PAR
(µmol m-2 s-1)
assimilation (C)
(mg g-1 h -1) 1 2 3 4 5 6
limonene
myrcene
b-pinene
a-pinene
sabinene
500
1000
1500
00:00
06:00
12:00
18:00
local time [hh:mm] 10 20 30 40
temperature
[°C]
G93 for isop.
[sum of monoterpenes]
transpiration
(mmol m-2 s-1)
monoterpene emission of Apeiba tibourbou
A more integrated approach to understanding controls of NMVOCs, e.g., surface data, lab data,
MODIS Firecount
O3-CO-NO2-HCHO-firecount correlations import to utilize when looking at the tropics
TES data c/o Bowman, JPL

15. Some aerosol-climate effects
SEVERI AOD
CCN
Primary and secondary aerosol sources: biomass burning, biogenic, desert dust
Internally or externally mixed?
visibility
deposition
Size of desert dust and biogenic aerosol
Fe fertilization
South America
Africa D Z N P
Ocean Ecosystem
Africa

16. OP3 and OP3-APPRAISE
Figure c/o: Franz X. Meizner (MPI)

17. Compiled from UK ozone network data
“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
“Normal” airmass flow
Stagnant airmass flow
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 5 10 15 20 25 30 35 40
Temperature (C)
Isoprene (ppt)
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 is normally 2-50 ppt
No temperature dependence given!!!!
Same latitude as hudson bay!!
Isoprene c/o Ally Lewis

18. Resolution of new satellite data allows study UK AQ from space
GOME 1x1o
Aug 1997
SCIA 0.4x0.4o, Aug 2004
NAEI NOX emissions as NO2, 2002
OMI 0.1ox0.1o, Jul 2004
GOME and SCIA NO2 c/o R. Martin; OMI (unofficial) NO2 c/o T. Kurosu
Cloud cover [%], ISCCP August 83-04 30
100 70
Length of day [hours]
Day of Year
Edinburgh, 56N
Denver, 40N
Transcends many of nerc centers of excellences: DARC, CASIX, CTCD, NCAS
Challenges...

19. The increasing role of BVOCs: constraints from OMI HCHO?
1016 [molec cm-2]
OMI HCHO 2
<0.3
Stewart et al, 2003
Isoprene
Monoterpenes
BVOC fluxes for a “hot, sunny” day
Data c/o T. Kurosu
NO + RO2  NO2 + RO, Aug 2003
Isoprene HCHO
No temperature dependence on isoprene emission….spruce plantation on the borders…
Tropospheric O3 production results from NO + RO2  NO2 + RO
The influence of different VOCs on this step can be calculated
Much higher total rate of NO  NO2 conversion during the heatwave period (NB – the graphs have different scales)
Isoprene contributes substantially to O3 production
Given the short lifetime of isoprene, it must have been generated and reacted locally
BOE:
0.5-1 ppb isoprene = 1-5x1012 molec cm-2 s-1 (cf. SE USA 5-7x1012 molec cm-2 s-1)
NO2 production ppb h-1
c/o Jenny Stanton, University of Leeds

20. Space-based aerosol optical properties can help map emissions of particulate matter
MISR AOT can help estimate total PM2.5:
MISRSurface PM2.5 =
ModelSurface [PM2.5] x MISR AOT
Model AOT
2003 roadside (primary) PM10
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
Liu et al, 2004

21. Current Development in Modelling UK AQ
UK currently using MODELS 3 (MM5 + CMAQ) for AQ
1) UM mesoscale CTM
UKMO Unified Model
2) UKCA gas-aerosol chemistry scheme
AQ-climate links
AQ Model
Chem-Clim Model
Global vs urban chemistry? Subgrid scale processes?
Similar equations for data assimilation and inverse modelling
J(x) = ½(yo – H(x))T(E+F)-1(yo-H(x)) +½(x-xb)TB-1(x-xb)
Multi-species analyses – inter-species error covariance?
Radiance versus retrieved products?
Limit of linearization of non-linear oxidant chemistry?