Decadal variability of the East Asian Summer Monsoon and its interplay with atmosphere temperature over the last millennium: stalagmite records Ming Tan 1, Chaoyong Hu 2, Pingzhong Zhang 3, Binggui Cai 1, Xuemei Shao 4 1 Institute of Geology and Geophysics, CAS, Beijing , China 2 China University of Geosciences, Wuhan , China 3 Lanzhou University, Lanzhou , China 4 Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing , China

stalagmite stalactite column Cave formation —— speleothem

How speleothems form and contain climate signal? CaCO 3 + H 2 CO 3 → Ca HCO 3 - soil stalagmite column stalactite flowstone Ca HCO 3 - → CaCO 3 + H 2 O + CO 2 H 2 O + CO 2 →H 2 CO 3 rain

1.What we have done with stalagmites? (1) High precision dating by annual layer counting and Th-230 dating (2) Quantitatively reconstructing climate with annual layer thickness 2.Large-scale climate signal: stalagmite oxygen isotopes (SOI) 3.Calibrating the SOI with the East Asian Summer Monsoon Index (EASMI) 4.Reconstructing temperature over the last millennium for China 5. Comparison of the EASMI and the temperature over the last millennium Outline

Shihua Cave Dongge Cave Qilian tree ring site Sample Sites Heshang Cave Wanxiang Cave Water Cave Xiangshui Cave Hulu Cave 1000km

1. What we have done with stalagmites? (1) High precision dating by annual layer counting and Th-230 dating (2) Quantitatively reconstructing climate with annual layer thickness

± ± ± ± ± ± ± ± VS. 230 Th dating Layer counting (years before 2007 AD)

6cm Stalagmite annual layers from Beijing Shihua Cave 1mm

2650-year warm season temperature reconstruction for Beijing （ BC665-AD1985) derived by calibrating the stalagmite annual layer thickness with meteorological records

2. Large-scale climate signal: stalagmite oxygen isotopes (SOI)

The oxygen isotope of stalagmite from Dongge Cave is consistent with that from Hulu Cave within 5000 years （ Yuan et al. Science, 2004) Large Scale Climate Signal !

Synthesized 1000-year temperature record derived by calibrating the BQ with the bm. The thick line shows 11- year running mean value. δ 18 O (PDB‰) Year before 2000AD Xiangshui Cave 25°15‘N Shihua Cave 39°47‘N Water Cave 41°17‘N Dongge Cave 25°17‘N Comparison of stalagmite oxygen isotope records from the south to the north of China, the oxygen isotope ratios become lighter from south to north This pattern matches the observed pattern of the summer monsoon. Starting from the South China Sea and going northward, the summer monsoon supplies rainfall from the south to the north, and oxygen isotope ratios become lighter with precipitation. All of them contain a multi- millennial trend towards heaver ratios since 9000 Yr BP, this suggests that the change in patterns recorded in these ratios in Eastern China results from a single water source.

Stalagmite oxygen isotopes Temperature ? Precipitation ? Monsoon ? δ 18 O

3. Calibrating the SOI with the East Asian Summer Monsoon Index (EASMI)

1. 郭其蕴，东亚夏季风强度指数及其变化的分析. 地理学报， 1983 ， 38(3) ， 施能，杨永胜, 年东亚冬、夏季风强度指数及其主要特征, 南京气象学院学报,1998,21(2), 黄刚，严中伟，东亚夏季风环流异常指数及其年际变化，科学通报， 1999 ， 44(4) ， 祝从文, 何金海, 吴国雄. 东亚季风指数及其与大尺度热力环流年际变化关系. 气象学报, 2000,58(4): 王亚非，张雁，陈菊英，一个能反映梅雨现象的东亚夏季风指数，气候与环境研究， 2001 ， 6 （ 2 ）， 乔云亭，陈烈庭，张庆云，东亚季风指数的定义及其与中国气候的关系，大气科学， 2002 ， 26 （ 1 ） Jianping Li and Qingcun Zeng, A unified monsoon index. GEOPHYSICAL RESEARCH LETTERS, 2002, 29(8), /2001GL013874, 8. 琚建华，钱诚，曹杰，东亚副热带夏季风指数研究，中国气象学会 2003 年年会 9. 张庆云，陶诗言，陈烈庭，东亚夏季风指数的年际变化与东亚大气环流，气象学报， 2003 ， 61 （ 5 ） 廉毅，沈柏竹，高枞亭，关于确定东亚夏季风强度指数的探讨，气象学报， 2004 ， 62 （ 6 ） 11. HUANG Gang, An Index Measuring the Interannual Variation of the East Asian Summer Monsoon—The EAP Index, ADVANCES IN ATMOSPHERIC SCIENCES, 2004, 21(1) 41– 李建平，曾庆存, 一个新的季风指数及其年际变化和与雨量的关系, 气候与环境研究， 2005, 10(3) ， 赵平，周自江，东亚副热带夏季风指数及其与降水的关系，气象学报， 2005 ， 63 （ 6 ）， 梁萍，汤绪，何金海，陈隆勋，用水汽输送表征的东亚副热带夏季风指数研究，热带气象学报， 2007 ， 23 (5) ， So many East Asian summer monsoon indices (EASMI)

Studies on the Variations of East- Asian Summer Monsoon during AD1873~2000 Guo Qiyun, Cai Jingning, Shao Xuemei and Sha wanying Chinese Journal of Atmospheric Sciences, 2004 Year AD Summer monsoon index

Annual temperature of China by Wang et al EASMI by Guo et al Comparison the EASM and the temperature of China over the last century (different decadal trends) Year AD Temperature anomaly ( ℃ ) Summer monsoon index

Oxygen isotopes of stalagmites both from Guizhou (blur) and Beijing (red) show a trend of heavier over the last century Thick lines: 3d-polynomial δ 18 O of stalagmite from Dongge Cave (PDB‰) δ18O of stalagmite from Shihau Cave (PDB‰) Year AD

Oxygen isotopes of stalagmites both from Hubei (blue) and Beijing (red) show a trend of heavier over the last 200 years δ 18 O (PDB‰) Year AD

r = － n = 49 TS9501 EASMI Relationship between the oxygen isotope of the stalagmite TS9501 from Shihua Cvae and the EASMI δ 18 O (PDB‰) Year AD Summer monsoon index

r = － 0.50 n = 99 ( ) EASMI HS-4 5-year running: year running: Relationship between the oxygen isotope from the stalagmite HS4 and the EASMI δ 18 O (PDB‰) Year AD Summer monsoon index

Heshang Cave stalagmite Variability of the EASM over the last millennium EASMI Year AD Equation ln(Y) = * X Residual sum of squares = Regression sum of squares = Coef of determination, R-squared = Residual mean square, sigma-hat-sq'd =

4. Reconstructing temperature over the last millennium for China

References: Liu Xiaohong, Qin Dahe, Shao Xuemei et al. Millennial temperature variations recorded in tree ring in the mid-Qilin Mountains. Science in China (Series D), 34, , Tan, M., T. Liu, J. Hou, X. Qin, H. Zhang, T. Li, Cyclic rapid warming on centennial-scale revealed by a 2650-year stalagmite record of warm season temperature, Geophysical Research Letters, 30, , Layer thickness (um) Tree ring index Year AD Comparison between the stalagmite layer thickness chronology (yellow) from Beijing Shihua Cave and the 1000-year tree ring width chronology from Qilian Mountain (green)

1000-year temperature record for China by combining and calibrating the Qilian tree rings and Shihua stalagmite layers (The thick line shows 11-year running mean value) Year AD Temperature anomaly ( ℃ )

1000-year temperature of China derived by combining Qilian tree rings and Shihua Cave stalagmite layers 1000-year temperature of China simulated derived by ECHO-G model r=0.44, yearly, n=986 r=0.58, 11-year running mean r=0.63, 31-year running mean Relationship between the reconstructed (red) and simulated (blue) temperatures of China for the last millennium Year AD Temperature anomaly ( ℃ ) Temperature anomaly (k)

5.Comparison of the EASM and the temperature over the last millennium

The EASM and the China Temperature is out phase in most periods at decadal and multi-decadal scales Year AD Temperature anomaly ( ℃ ) EASMI Sp Ö rer Minimum Thick lines: 11-year running mean

Moberg NH T Temperature anomaly (ºC) δ 18 O (PDB‰) Year AD Oxygen isotope of stalagmite from Shihua Cave r= － 0.35, n=107, p<0.001 Comparison of oxygen isotope of stalagmite and the NH temperature over the last two millennium This shows that the EASM and the NHT possess similar pattern at millennial or longer scales

Conclusions 1.The stalagmite oxygen isotopes (SOI) from China mostly consistent with the EASM, which derived from sea level pressure. Thus the SOI can be used to extend the EASMI in some cases. 2. The EASM and the China Temperature is out phase in most periods at decadal and multi-decadal scales over the last millennium.

Thanks for your attention

Similar patterns on century scale in the isotopes of the stalagmites from Heshang Cave (red) and Shihua Cave (blue)

TS9501 WX42-B 11-year running mean Similar patterns on century-millennium scale in the isotopes of the stalagmites from Wanxiang Cave (blue) and Shihua Cave (red)

Equation Y = * X Number of data points used = 99 Average X = Average Y = Residual sum of squares = Regression sum of squares = Coef of determination, R-squared = Residual mean square, sigma-hat-sq'd = Fit 1: Exponential Equation ln(Y) = * X Alternate Y = exp( * X) * Number of data points used = 90 Average X = Average ln(Y) = Residual sum of squares = Regression sum of squares = Coef of determination, R-squared = Residual mean square, sigma-hat-sq'd =

Year AD Summer monsoon index

Moberg NH T 贵州荔波石笋氧同位素 Temperature anomaly (ºC) δ 18 O (PDB‰) Year AD 中国南方中世纪缺失温暖期的更长气候记录 （与 Moberg NHT 对比） 文献数据来源： Moberg et al., Nature, 2005; Wang et al., Science, 2005 从小冰期到温暖期的变化幅度已经接 近末次冰期中冰阶 / 间冰阶的变化幅度 (H6 底到 D/O17 顶氧同位素差 2‰PDB) 南方在中世纪温暖期与北方不同, 意味着什么 ?

EASMI PDO of Aug. 9-year running mean

bm (temperature anomaly ( ℃ ) BQ (index) Year AD Comparison between the meteorological temperature sequence combining observed Beijing warm-season mean temperature (May to August) and Minle annual mean temperature (bm, dashed line) and the proxy index synthesized with the Beijing stalagmite layers and the Qilian tree rings (BQ, solid line).

SMI PDO-April North China Temperature