Isotope Simulation of the Evolution of East Asian
Monsoon since the LGM: A Preliminary Analysis
对LGM以来同位素气候模拟的初步分析
Xinyu Wen & Zhengyu Liu
Dept of Atmospheric and Oceanic Sciences, Peking University
Contributors: Esther Brady & Otto-Bliesner Bette
CCR/CGD, NCAR
Jun/29/2012 @ Nanjing
Overview
1.
2.
3.
4.
Model-Data Comparison
Interpretation of d18O
Appropriate Indices for Paleo-EASM/EAWM
Improve Understanding of Monsoon Dynamics
Picture of the Problem
WARM
-10%
COLD
-10%
-16%
-26%
-34%
Evaporation
0%
SMOW
EQ
0%
Cumulus
Parameterization
-4%
-12%
Large-scale condensation
With cloud microphysics
-20%
North
Pole
Benefits from Using Isotope-enable Model？

Model-Data Comparison？
气候态偏差；格点-站点的代表性；统计降尺度；

Reanalysis d18O？
用准确的Reanalysis做Nudging

Proxy Assimilation？
利用Isotope模式结果，寻找更准确的Transfer functions；再
利用此关系，同化Proxy以进行更好的古气候模拟
(Sturm, 2010)
Annual Mean d18O in Water Vapor & Precip.
CAM
CAM
GNIP
(Lee, et al., 2007)
10-yr Spin-up
50-yr Integration with Fixed BC
Experiment Design
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21
20
19
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15
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10
9
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3
2
• Model: CAM3 with Isotope-enable module
• Each slice was integrated for 50 years, with first 10-year truncated as spin-up
• Outputs: Atm/Monthly; Winds/Daily; Water Isotope/Monthly
Water Isotopes:
• d18O in precipitation and in water vapor
• deuterium (dD) in precipitation and in water vapor
1
0 (ka)
Forcing:
• GHGs (CO2; CH4; N2O)
• Orbital Parameters
• Terrain/Sea Level
• SST/SICE
• Water Isotopes at Sea Surface
DJF
H218O (per mil)
Terrain, Sea Level, SST/SICE are
derived from Drs Liu and Feng’s
TraCE simulations, which is a fullycoupled transient simulation for the
period 22ka-Present.
JJA
1,0018
1,0016
1,0014
1,0012
1,0010
1,0008
1,0006
1,0004
1,0002
1,0000
0,9998
22 21 20 19 18 17 16 15 14 13 12 11 10 9
Age (ka)
8
7
6
5
4
3
2
1
0
ANN DJF JJA
d18O in Precip.
JJA
Hulu Cave (Wang, 2001)
Dongge Cave (Wang, 2005)
d18O in Precip.
DJF
?
Hulu Cave (Wang, 2001)
Dongge Cave (Wang, 2005)
Temperature Effect vs. Amount Effect
Temperature Effect
Corr( d18O, Ts )
ANN
ANN
DJF
DJF
JJA
JJA
Inter-Millennium
Inter-Annual
较松的标准
较严的标准
Amount Effect
Corr( d18O, Precip )
ANN
ANN
DJF
DJF
JJA
JJA
Inter-Millennium
Inter-Annual
较松的标准
较严的标准
温度效应 vs 数量效应
Corr( d18O, Ts )
Corr( d18O, Precip )
ANN
ANN
DJF
DJF
JJA
JJA
Local vs. Regional
d18O的空间代表性如何？
ANN
ANN
DJF
DJF
JJA
JJA
Inter-Millennium
Inter-Annual
较松的标准
较严的标准
Corr( d18O, d18O )
(Pausata, Battisti, et al, 2011)
Precip (Local) vs. d18O (Regional)
ANN
ANN
DJF
DJF
JJA
JJA
Inter-Millennium
Inter-Annual
较松的标准
较严的标准
Corr( Precip, d18O )
Summary
Hints from CAMiso:
 d18O来源于Indian Ocean
 JJA d18O与OBS中很相似
 d18O和Temp是大尺度；Precip是小尺度
 d18O与Temp关系更好；而与Precip关系小
Fig 1. Time series
Fig 1 (Supplement Material)
JJA Time Series @ each point
V1000
V850
SAT
Prec.
Fig 1 (Supplement Material)
DJF Time Series @ each point
V1000
V850
SAT
Prec.
Fig 1 (Supplement Material)
ANN Time Series @ each point
V1000
V850
SAT
Prec.