Transcript Workshop on common metrics to calculate the CO2 equivalence of anthropogenic greenhouse gas emissions by sources and removals by sinks Radiative Forcing.

Workshop on common metrics to calculate the CO2 equivalence of anthropogenic
greenhouse gas emissions by sources and removals by sinks
Radiative Forcing and Global Warming
Potentials due to CH4 and N2O
Hua Zhang Ruoyu Zhang
National Climate Center
China Meteorological Administration
April 3-4, 2012
Bonn, Germany
1
Backgrounds
2
Data & Methods
3
Radiative forcings
4
GWPs & GTPs
5
Discussion
CH
(pptv)
C0
(pptv)
N
24(ppmv)
20
Concentrations of main GHGs before 2005
10000
5000
year（before 2005）
0
Concentrations of main GHGs under SRES scenarios
气候变化的一种机制
通过辐射传输过程
TH
RF of GHG x
GWPx 
RF of CO2
TH
 RF (t )dt  a [ x(t )]dt
x
 RF (t )dt
r
0
x

0
TH
Timedecaying
functions
0
TH
 a [r (t )]dt
r
0
Radiative
efficiency
1 GWP is related to emission process of GHG;
2 GWP can convert any kind of GHG equivalently to
CO2 emission, which makes the comparison easily
among different gases;
3 GWP denotes the cumulative climate effect of the
GHG during a period of time.
T changes with
time
dT (t )
T (t )
C
 F (t ) 
dt

TH
x
GTP
T arrives at
balance not
varying
T

T
TH
x
TH
r
Surface
temperature
changes
T    F
1 GTP refers to emission process of GHGs too ;
2 GTP can convert any kind of GHGs equivalently to
CO2 emission too;
3 GTP denotes the effect of GHG on the temperature
changes of the earth-atmosphere system.
Radiative Transfer Model
(Zhang et al., 2003; 2006a,b)
• 998-band longwave radiative transfer
scheme (high resolution)
• 10~49000cm-1 (0.2~1000µm) is divided into 998
bands
• longwave region 10~2500cm-1(4~1000µm）
is 498 bands with intervals of 5cm-1
Gas
molecular spectrum data
辐射传输模式
辐射传输模式
HITRAN2004
Atmosphere profiles data
6 kinds of typical model atmosphere :
TRO、MLS、MLW、SAS、SAW、USS
Clouds
ISCCP D2 products
Temperature profile T0(L)
Radiative Transfer Model
(Zhang et al.，2006)
kn=0
Radiative Transfer Model
(Zhang et al.，2006)
Heating rate for zero
concentration: htr0(L)
Heating rate for 0.1 ppbv
concentration: htr1(L)
Criterion: to kn=0
Heating rate judge whether Instantaneous
the
Htrdif（L）=htr1(L) - htr0(L)
system reaches RF
to balance
htrdif（L）<ξ
Y
Adjusted RF
N
iteration
kn=kn+1
Tnew（L）=Told（L）+htrdif（L）×△t
L：from Tropopause to TOA
Doubled CO2 , H2O increase by
20%
Doubled CO2
Model
layer
998band
AOGCMs
LBL
998-band
AOGCMs
LBL
TOM
3.03
2.45
2.8
3.26
3.75
3.78
200 hPa
5.6
5.07
5.48
4.13
4.45
4.57
Surface
1.7
1.12
1.64
11.14
11.95
11.52
（1）CO2 concentration is doubled from 287 ppmv to
574 ppmv；
（2）With doubled CO2 concentration (574 ppmv), H2O
content is increased by 20% of its concentration of
1860 year
Radiative efficiency
Clear sky
Cloudy sky
Gas
IPCC
2007
IRE
ARE
ARE
ARE after lifetimeadjustment
ARE
CO2
1.99E-5
1.88E-5
1.64E-5
1.57E-5, +11.9%
1.4E-5
CH4
5.13E-4
5.06E-4
4.14E-4
3.73E-4, +0.8%
3.7E-4
N 2O
3.87E-3
3.79E-3
3.13E-3
2.98E-3, -1.4%
3.03E-3
* unit：W·m-2·ppbv-1
** Lifetime : CO2 : 120a ; CH4 : 12a ; N2O : 114a
Radiative forcings (ARF)
2005
Gas
2010
before
After
Before
adjustment adjustment adjustment
IPCC
After
adjustment
2007
CO2
1.89
1.81
2.04
1.95
1.66±0.17
CH4
0.581
0.523
0.583
0.525
0.48±0.05
N 2O
0.185
0.177
0.187
0.179
0.16±0.02
* unit：W·m-2
** Lifetime : CO2 : 120a ; CH4 : 12a ; N2O : 114a
Climate sensitivity parameter : λ
Its typical value is chosen as 0.5K·(W·m-2)-1
Original concentration of CO2 : 385.2 ppmv
Then:
T   F
IPCC :
1.5~4.5K

Concentration
ARF
/ W m-2
Temperature
Changes / K
CO2×1.5
2.8
1.4
CO2×2.0
4.8
2.4
CO2×2.5
6.4
3.2
CO2×3.0
7.8
3.9
CO2×3.5
9.0
4.5
CO2×4.0
9.8
4.9
ARF fitting formula
ARFCO2    ln( C / C0 )   ( C  C0 )
C : CO2 concentration;
C0 : background CO2 concentration,
C0 = 385.2 ppmv;
fitting parameters : α=6.2554, β=5.2783×10-2
6种大气廓线下
ARF fitting formula
ARFCH 4   ( M  M 0 )   (M  M 0 )   N ( M  M 0 )    N (M  M 0 )
CH4 background concentration M0=1797ppbv;
0≤M0,N0≤10000 ppbv ;
fitting parameters : α=0.03195, β=1.439×10-4,
γ=-1.133×10-3, δ=1.221×10-7
ARFN 2O   ( N  N 0 )   ( N  N 0 )   M ( N  N 0 )    M ( N  N 0 )
N2O background concentration N0=321.8ppbv
0≤M0,N0≤10000 ppbv;
fitting parameters : α=0.08801, β=0.0011
γ=-3.7167×10-4, δ= 2.0116×10-9
Test of fitting
Test issue
Model results
/ W m-2
Formula results
/ W m-2
Absolute
error
/ W m-2
CO2×2 + CH4×2 + N2O×2
6.07
6.05
0.02
CO2×2 + CH4×1 + N2O×1
4.70
4.76
0.06
CO2×2 + CH4×2 + N2O×1
5.36
5.30
0.06
CO2×1 + CH4×2 + N2O×2
1.32
1.29
0.03
* Shi et al., absolute error≤0.05 W m-2
before atmospheric lifetime adjustment
Gas
CH4
GWP
GWP
IPCC 2007
GTPP
GTPS
20 / 100 / 500
20 / 100 / 500
20 / 100 / 500
20 / 100 / 500
50 / 17 / 5.3
72 / 25 / 7.6
41 / 0.26 / ~0
56 / 19 / 5.4
289 / 298 / 153
268 / 233 / 11
250 / 269 / 139
N2O 258 / 265.7 / 137
after atmospheric lifetime adjustment
GWP
GWP
IPCC 2007
GTPP
GTPS
20 / 100 / 500
20 / 100 / 500
20 / 100 / 500
20 / 100 / 500
CH4
47 / 16 / 5
72 / 25 / 7.6
39 / 0.24 / ~0
53 / 18 / 5
N 2O
257 / 266 / 136
289 / 298 / 153
268 / 233 / 11
250 / 268 / 138
气体
For comparison :
Shine（2005）results
Analytical calculation
Gas
EBM
GTPP
GTPS
GTPP
GTPS
20 / 100 / 500
20 / 100 / 500
20 / 100 / 500
20 / 100 / 500
CH4
52 / 0.35 / 0
69 / 24 / 7
46 / 5 / 0.8
66 / 25 / 8
N 2O
290 / 270 / 13
260 / 290 / 160
290 / 270 / 35
270 / 290 / 160
After the lifetime-adjustment
Gas
Atmosphere lifetime
/a
AGWP / 10-14·W·m-2·kg-1
CO2
120
2.72 / 9.57 / 31.5
CH4
12
127.7 / 157.3 / 157.4
N2O
114
700.3 / 2542 / 4298
HFC-32
4.9
6613 / 6727 / 6727
HFC-125
29
19971 / 38808 / 40083
HFC-134
10
12962 / 14990 / 14991
HFC-134a
14
12320 / 16191 / 16204
HFC-143a
52
24107 / 64468 / 75499
HFC-152a
1.4
1573 / 1573 / 1573
C2F6
10000
28168 / 140277 / 68757
CF4
50000
12527 / 62553 / 311520
SF6
3200
52193 / 257734 / 1211774
20 / 100 / 500
Before atmospheric lifetime adjustment
AGTPP / 10-16·K·kg-1
AGTPS / 10-14·K·kg-1
20 / 100 / 500
20 / 100 / 500
CH4
372 / 1.62 / ~0
73.8 / 139.5 / 139.7
N 2O
2419 / 1465 / 43.9
328.9 / 1972 / 3593
CO2
9.04 / 6.28 / 3.89
1.31 / 7.34 / 25.9
Gas
After atmospheric lifetime adjustment
AGTPP / 10-16·K·kg-1
AGTPS / 10-14·K·kg-1
20 / 100 / 500
20 / 100 / 500
CH4
336 / 1.46 / ~0
66.5 / 125.7 / 125.9
N 2O
2312 / 1401 / 41.9
314 / 1884 / 3434
CO2
8.64 / 6.01 / 3.72
1.26 / 7.02 / 24.8
Gas
AGTPP / 10-16·K·kg-1
AGTPS / 10-14·K·kg-1
20 / 100 / 500
20 / 100 / 500
HFC-32
16834 / 10.2 / ~0
5209 / 7118 / 7119
HFC-125
80622 / 7321 / 0.008
12550 / 40266 / 42393
HFC-134
35691 / 59.9 / ~0
8093 / 14012 / 14021
HFC-134a
44445 / 361 / ~0
8322 / 17108 / 17160
HFC-143a
46423 / 12837 / 5.9
13945 / 62032 / 75986
HFC-152a
2755 / 1.5 / ~0
1376 / 1669 / 1669
C2F6
124990 / 146336 / 140610
16213 / 131366 / 705206
CF4
51547 / 60720 / 60241
6683 / 143168 / 296248
SF6
233196 / 268627 / 237083
30283 / 243422 / 1253570
Gas
AGTPP of CH4 & N2O
Temperature Change (10-13K)
400
300
200
N2O
N2O ( life-adjusted )
CH4
100
CH4 ( life-adjusted )
0
AGTPS of CH4 & N2O
0
100
200
300
Time (a)
400
500
10
AGTPP
adjustedAGTPP
9
8
7
6
28
5
4
3
0
100
200
300
年份/a
Time (a)
AGTPS of CO2
400
500
-14K)
(10
Temperature
14
温度 changes
/10 K
-16
(10
changes
Temperature
温度
/10-16
K K)
AGTPP of CO2
AGTPS
adjustedAGTPS
24
20
16
12
8
4
0
0
100
200
300
年份/a
Time (a)
400
500
The lifetimes of CH4 are relatively short-lived
GHGs; GWP greatly over-estimates the
effects of their pulse emission on climate
changes.
GTPp is an optimal metric for assessing the
long-term effects of CH4 emissions on global
climate change, by considering practical
emissions of these gases.
• Climate sensitivity parameter λ can affect
AGWP and AGTP greatly, this should be
considered as a large uncertainty in
estimating process.
• AGWPs and AGTPs of long-lived GHGs are
sensitive to time horizon; while AGTPp of
short-lived GHGs is sensitive to time
horizon greatly.
• Clouds is another large factor of
uncertainties in estimating GWP or GTP
and should be clarified in IPCC AR5 report.
Thanks！