xinyu wen & zhengyu liu dept of atmospheric and oceanic sciences, peking university

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 LiuDept of Atmospheric and Oceanic Sciences, Peking University

Contributors: Esther Brady & Otto-Bliesner BetteCCR/CGD, NCAR

Jun/29/2012 @ Nanjing

Overview1. Model-Data Comparison2. Interpretation of d18O3. Appropriate Indices for

Paleo-EASM/EAWM4. Improve Understanding of Monsoon

Dynamics

EQNorthPole

0%

-10% -10%-16%

-26%-34%

0% -4% -12%-20%

WARM COLD

SMOW

Picture of the Problem

CumulusParameterization

Large-scale condensationWith cloud microphysics

Evap

orat

ion

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

GNIP

CAM

(Lee, et al., 2007)

22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 (ka)

50-y

r In

tegr

atio

n w

ith F

ixed

BC

10-y

r Sp

in-

up

Experiment Design

• 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

Forcing:• GHGs (CO2; CH4; N2O)• Orbital Parameters• Terrain/Sea Level• SST/SICE• Water Isotopes at Sea Surface

Terrain, Sea Level, SST/SICE are derived from Drs Liu and Feng’s TraCE simulations, which is a fully-coupled transient simulation for the period 22ka-Present.

22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 00.9998 1.0000 1.0002 1.0004 1.0006 1.0008 1.0010 1.0012 1.0014 1.0016 1.0018

Age (ka)

H21

8O (

per

mil)

DJF

JJA

ANNDJF JJA

Hulu Cave (Wang, 2001)Dongge Cave (Wang, 2005)

d18O in Precip.JJA

d18O in Precip.DJF

?Hulu Cave (Wang, 2001)

Dongge Cave (Wang, 2005)

Temperature Effect vs. Amount Effect

Temperature EffectCorr( d18O, Ts )

Inter-Millennium较松的标准 Inter-Annual较严的标准

ANN ANN

DJF DJF

JJA JJA

Amount EffectCorr( d18O, Precip )

Inter-Millennium较松的标准 Inter-Annual较严的标准

ANN ANN

DJF DJF

JJA JJA

ANN

DJF

JJA

ANN

DJF

JJA

温度效应 vs 数量效应Corr( d18O, Ts ) Corr( d18O, Precip )

Local vs. Regional

ANN

DJF

JJA

ANN

DJF

JJA

Corr( d18O, d18O )

Inter-Millennium较松的标准 Inter-Annual较严的标准

d18O的空间代表性如何？

(Pausata, Battisti, et al, 2011)

ANN

DJF

JJA

ANN

DJF

JJA

Corr( Precip, d18O )

Inter-Millennium较松的标准 Inter-Annual较严的标准

Precip (Local) vs. d18O (Regional)

SummaryHints 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.