Post on 16-Dec-2015
Quantifying uncertainties in modelling global isoprene
emissions: the role of satellite data
Paul Palmerhttp://www.geos.ed.ac.uk/eochem
)(inputs1
0 x
n
xEE
Climate models tend to use simple isoprene emission models
E0(t) is typically fixed in climate models.
T
PPFD
CO
2
CO2 [ppm] T [K]
PPFD transmission
T and PPFD equations based on MEGAN; CO2 is from Arneth et al
)exp((
)exp(xCCC
xCCE
TTT
TToptT
212
12
1
1)Assume functional form is correct
2)Time-dependent variables x and Eopt and empirical coefficients CT1 (=95) and CT2 (=230).
Focus on temperature dependence model
Fractional perturbation of CT1
Fract
ional p
ert
urb
ati
on
of
CT2
T
X
T is most sensitive to CT1
A2
B1C
O2 [
pp
m]
TS [
K]
SW
[W
/m2] Decrease due to
increased cloudiness
CAVEAT: I have not accounted for direct and diffuse PPFD partitioning
Hadley Centre IPCC model runs
Eis
op [
Tg/y
r/d
eg
] fr
om
20
00
T PPFD
2050 ---- 2100 ____
Eis
op [
Tg
/yr/
deg
] fr
om
20
00
CO2 T
PPFDA2
B1
Use MEGAN with Hadley model data
Eis
op [
Tg/y
r/d
eg
] fr
om
20
00
T PPFD
2050 ---- 2100 ____
Eis
op [
Tg
/yr/
deg
] fr
om
20
00
CO2 T
PPFDA2
B1
Use MEGAN with Hadley model data
Economic pressures shift natural ecosystems to agricultural and biofuel crops
Foley et al, 2005
-2
0
2
4
6
8
10
12
14
00:00 06:00 12:00 18:00 00:00
mg
m-2
h-1
Isoprene Flux Oil Palm
Isoprene Flux Rainforest
daily mean oil palm
daily mean rainforest
Isoprene Flux Results Rainforest vs Oil Palm over Borneo c/o Langford, Miztal, Nemitz and Hewitt
Eis
op [
Tg/y
r/d
eg
] fr
om
20
00
Eis
op [
Tg/y
r/d
eg
] fr
om
20
00
2050 ---- 2100 ____
A2
B1
Even a modest (crude) land-use change scenarios completely changes our main result
-2050: double Y2K emissions over Borneo
-2100: 25% emission increase over 5S-5NT PPFD CO2 T
PPFD
Eis
op [
Tg/y
r/d
eg
] fr
om
20
00
Eis
op [
Tg/y
r/d
eg
] fr
om
20
00
2050 ---- 2100 ____
A2
B1
Even a modest (crude) land-use change scenarios completely changes our main result
-2050: double Y2K emissions over Borneo
-2100: 25% emission increase over 5S-5NT PPFD CO2 T
PPFD
Time to parameterise acclimatisation for decadal model calculations?
But what about acclimatisation?M
onso
n e
t al, 1
99
2
grown at 26C
grown at 34C
Velvet Bean
Relating HCHO Columns to Isoprene Emissions
VOC HCHOhours
OH
hours
h, OH
Net
• HCHO is significant product of isoprene oxidation
• Isoprene emissions are typically main driver of variability in HCHO columns observed from space 12 years of HCHO
Where WhenImportance
Statistical reduction of 12-year dataset
Barkley et al, 2009
Scenes influences by fires and cloud have been removed
Barkley et al, 2009
Amazonian leaf flushing consistent with large-scale
reduction of HCHO
Working hypothesis: leaf drop and flush in preparation for sunnier, dry conditions in dry season
Barkley et al, 2009
SPARE SLIDES
What drives isoprene emission variability?
What drives isoprene emission variability?