Yair Rosenthal Rutgers University Will briefly summarize (not on Courseworks) • Oppo, D.W., Y. Rosenthal, B. K. Linsley; 2000‐year‐long temperature and hydrology reconstrucons from the Indo‐Pacific Warm Pool; Nature, vol. 460, 1113‐1116, 2009.

Another related paper from our group to be discussed later by Y. Rosenthal • Rosenthal, Y, B. K. Linsley, D. W. Oppo, Pacific Ocean heat content over the past 10,000 years (2013), Science, vol. 342, 617‐621, November 1, 2013 a 2 430 1 insolation; Planktonic foraminifera Mg/Ca records of mixed )

0°N JJA 2 420 0 layer temperatures in the WPWP. (A) Comparison of Indonesian and WPWP -1 410 Globigerinoides ruber Mg/Ca‐based surface temperature anomaly records. Anomalies -2 calculated as departures relave to average of

SSTa (°C) 400 MD78 SSTa (Timor Sea) last 2,000 years (except for MD41, see table 1).

-3 MD81 SSTa (Mindano) Insolation JJA O°N (w/m MD41 SSTa (Sulu Sea) Bold gray curve is JJA solar insolaon at 0°N for MD76 SSTa (Banda Sea) 390 MD62 SSTa (Makassar St.) reference. (B) 200 year non‐overlapping binned -4 MD65 SSTa (Sumba Indonesia) 13GGC SSTa (Bali Basin) 70GGC SSTa (Makassar St.) averages of all 8 cores shown in A (black) and -5 380 average of just the 4 southern Makassar region 0 5000 10000 15000 20000 Age year BP cores (green). The light green and dashed bounding lines show the standard error (SE) of 1.5 b Holocene all measurements in each 200 year bin. Dark Climatic Optimum 1 gray curves are sea level reconstrucons from Tahi and Barbados. MWP 0.5

0 0 SSTa (°C) -0.5

-1 -50

-1.5 Flooding of SSTa (all 8 indonesian- Sunda Shelf WPWP cores) SSTa (just Makasar St. cores: -100 -2 13GGC, 70GGC, MD62, MD65)

SSTa from Oppo et al., 2009 Barbados RSL (m) Relative Sea Level (m) (for Makassar, SW Sulawesi) Tahiti RSL (m) -2.5 0 3000 6000 9000 12000 15000 Age year BP

Figure 2 Our Preferred Explanation in 2010 was…… : A westward shift or expansion of the WPWP would explain the early Holocene elevated SSTs. This would also be in-line with observations of a more La Niña-like mean state in the early Holocene. Mg/Ca – alkenone apparent SST discrepancy

Mg/Ca

alkenone Mg/Ca – Tex86 SST Makassar

SST 70GGC 30

29

28 SST °C

27 Tex86 Mg/Ca

26 0 2 4 6 8 10 12 Age Kyr Northern South China Sea SST Winter SST

Summer SST

Mean annual SST

Shintani et al., 2011 Wei et al., 2007 Model‐data comparison

All the models suggest temperature warming throughout the Holocene (due to increase pCO2 and decrease extent of ice sheets in contrast with available data compilaons. A seasonal ecological bias toward summer months or upwelling periods can account for some but not all of this).

Liu et al., 2014 PANS Possible mechanisms to explain SST changes in the Indonesian Seaways

1. WPWP SST are influenced by significant input of northern Pacific water and thus exhibit signatures of northern hemisphere climate as affected by insolaon Abrupt upper thermocline cooling beginning 9,500 yr BP In the Timor Sea downstream of the ITF. Xu, J., Holbourn, A., Kuhnt, W., Jian, Z. & Kawamura, H. Changes in the thermocline structure of the Indonesian outflow during Terminations I and II. Earth Planet. Sci. Lett. 273, 152–162 (2008). Thermocline temperature records along the ITF path

Gibbons et al., in prep. Makassar

Savu

Makassar

Timor

Gordon 2005

Sunda Shelf flooding Increase in the atm concentraons of greenhouse gases starng ~6000 years ago Holocene changes in the mean climate State of the tropical Ocean

Early to late Holocene southward migraon of the Atlanc ITCZ, a record from the Cariaco Basin,Western Tropical Atlanc ( Haug et al., 2001) A record of Holocene ENSO variability from Laguna Pallcacocha, Ecuador (Moy et al., 2002)

Increasing ENSO frequency or amplitude

AGE A Holocene Asian monsoon record from the Dongge Cave (southern China)

A southward shi of the ITCZ and weakening of the summer monsoon aer ~6 ka, associated with reduced northern hemisphere summer insolaon

Wang et al., (2005) Summer insolation 65°N

540

530

520

510

500 W/M^2

490

480

inso(W/m2) 470 0 5 10 15 Age Ka

Possible mechanisms to explain SST changes in the Indonesian Seaways

2. A northward shi of the ITCZ in the early Holocene led to stronger cross equatorial winds and thus stronger north‐ westward transport of warm south Pacific tropical water at the expanse of North Pacific water following Godfrey “Island Rule”. Possible implicaons for ITF:

Early Holocene warmer water and implied higher water transport. The southward migraon of the ITCZ decreases the cross equatorial transport

ITF heat transport decreases throughout the Holocene following Northern Hemisphere insolaon.

What about centennial‐millennial variability? Makassar Strait over last 2,000 years: Below shows reconstructed Makassar Strait Sea Surface 18 Temperature and δ Oseawater (Salinity) vs. Northern Hemisphere Air Temperature Medieval Warm warmer Period

Proxy for Temperature

cooler

saltier

Proxy for Salinity

fresher

From Oppo, Rosenthal and Linsley Nature, vol 460, August 27, 2009 FRESHWATER CONTROLS ON THE INDONESIAN THROUGHFLOW THERMOCLINE DURING THE LAST 2000 YEARS

Julie Kalansky PhD Thesis 2014

Temperature Proxies: Temperature(˚C) Sauer 1998

Mg/Ca of N. dutertrei planktonic foraminifera Anand et al. 2003; Depth (m)

N. dutertrei calcifies at Temperature(˚C) 80‐100 m.

Temp Error ±1.3˚C ~80 m 21

Depth (m) ITF (119˚E)

Latitude Thermocline temperature and esmated salinity changes

25 temperature MCA LIA 0.2 salinity

24 0.0 ! 23 18 O

-0.2 SW (SMOW ‰) 22

-0.4 21 thermocline temp (˚C)

-0.6 20

19 -0.8 400 800 1200 1600 2000 Year ITF ENSO response

Ffield et al. 2000 El Nino is associated with cooler temperatures and reduced flow

Susanto et al. 2012

23 Effects of interannual variability of SCS water on the ITF: ENSO connecon • El Nino: more restricve to the upper ITF Gordon et al. (2012) • La Nina: less restricve to the upper ITF Strong Luzon throughflow Weak Luzon throughflow El Niño La Niña

~100m ~100 m Mindanao Current Mindanao Current Blocked: upper ~100m 40 m 40 m Blocked: Karimata transport response upper ~40 m to local winds, slightly stronger in la nina

Mindanao surface layer leakage to ITF Mindanao surface layer leakage blocked only in blocked upper ~100 m upper ~40 m La Niña effect: Warmer ITF reaches into the Indian Ocean, potenally affecng regional sea surface temperature and climate??? ITF Seasonal Monsoon Response

high precipitaon low precipitaon deep and cool thermocline flow shallow and warm thermocline flow

A. northwest B. southeast monsoon monsoon

South China Sea

25 The 2004 to 2009 Makassar Strait mean seasonal velocity (filtered). Maximum southward velocity occurs in July to September during the southeast monsoon

The Makassar Strait temperature and salinity mean seasonal secons constructed from the January 2004 to November 2006 INSTANT mooring measurements (same filter).

Susanto et al. 2012 The Makassar Strait potenal temperature salinity curves constructed from the January 2004 to November 2006 INSTANT mooring measurements

EAWM cool/fresh/ min velocity EASM warm/salty/ mx velocity

Susanto et al. 2012 25 temperature MCA LIA 0.2 salinity

24 0.0 ! 23 18 O

-0.2 SW (SMOW ‰) 22

-0.4 21 thermocline temp (˚C)

-0.6 20

19 -0.8 400 800 1200 1600 2000 Year

28 0.4 A.

24 ! 18

0.0 O sw (SMOW ‰) 22 -0.4

20 -0.8 thermocline temp (˚C) temperature

B. -172 precipitaon thermocline temp (˚C) 24

-174

22 -176 precipitaon D leaf-wax (‰)

! -178 20

-180 400 800 1200 1600 2000 year

29 Changes in the monsoon system during the Common Era

Tierney et al., 2010 B. Zhang et al., 2008 C. Tierney et al., 2010 D. Emile‐Geay et al., 2013 E. Moy et al., 2002 F. Conroy et al., 2008 G. Steinhilber et al., 2012

31 An intermediate water exchange through the Makassar – climate implicaons

Water Masses passing the Makassar Straits

Temperature (°C)

-10 -5 0 5 10 15 20 25 30 0 0

200 7° 32'S 115° 24'E 200 4° 2'S 118° 36'E 3° 38'S 119° 9'E

1° 36'S 117° 32'E 400 400 2° 34'N 120° 40'E 1° 43'N 128° 47'E 70GGC 7.8°C PressureTemperature db (°C) -10 Pressure0 10 db20 30 0 Depth meter

Depth meters 13GGC 6.5°C 600 Pressure db 600 200 10GGC 6.1°C Pressure db 400 120 pressure N Pacific 600 120 pressure S Pacific 800 800 800 Solomon Sea 1000 7GGC 5.2°C 34 35 36 37 Philippines Salinity (psu) Makassar Strait 1000 1000 50 100 150 200 250 34 34.5 35 35.5 36 oxygen !M Salinity Hyalinea balthica

Restricted depth / temperature 6‐12°C distribuon

High temp‐sensivity

No [∆CO3] ion effect

Easy to clean

~0.64‰ offset from δ18O equilibrium

Great candidate for thermocline and intermediate water reconstrucons (when available)

Rosenthal et al., 2011 A MD04 MD88

Ocean Borneo B Indian it ra Ocean r St MD78 Borneo a ass Australia k Makassar Ma Cores Lifamatola Passage 70GGC 31MC/32GGC 47MC/48GGC D ew ak Java Sea Cores ang Sill 6MC/7GGC Banda Sea 10GGC 13GGC Flores Sea Java Ombai Strait Australia Australia Timor Passage 16 12 8 4 0

Rosenthal et al., 2013 !"#$%&!'#(% )#*%&)+#(% )'#*%&))#(% "%&'($ )%*'($

!"#$ ,,-.% Comparing Indonesia IWT records with the surface temperature compilaon of Marco

(Marco et al., 2013; Rosenthal et al., 2013) 9.::4$##%4(;4 5 =>>,4$##&4?@A@4 5 9,-30<4$##84(;4 5

# 8## "### "8## $### #78 #78 D # #

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# )/01.234

!" %#!&#'( %#!&#') *+,-.+

# 8## "### "8## $### F3.046G Tidal mixing: can the surface signal reflect mixing with the IWT?

Reduce SST by 2oC inside Observaon Indonesia Seas

Reduce Control Run precipitaon by (no dal 20% mixing)

With dal Graphics from Sprintall et al. mixing (2010), based on results of Koch‐ Larrouy et al. (2010) Rosenthal, fig4, x13p6

Changes in OHC over the past 10,000 years Implicaons to Ocean Heat Content

A

70 7500-9000 BP 3000-5000 BP 0-1000 CE 1600-1800 CE 2000-2010 CE 60 50 40 30 Joules

22 20

10 10 OHC anomaly 0 -10 B 20

10

OHC 0 ∆

Joules/century -10 22 Rosenthal et al., 2013 10 7500-2000 BP 1100-1700 CE 1600-1970 CE 1955-2010 CE Thoughts We argue that the heat transport during the MCA is >0.1 PW higher than in the LIA. While this heat anomaly is not large compared with observed interannual variability, integrated over a few centuries, it potenally translates into a large perturbaon. Based on this we would expect greater heat transport through the Leeuwin Current into the Indian Ocean thermocline and farther into the Agulhas Current during the MCA. This may have been one mechanism by which the Common Era climate anomalies were propagated across the equator into the southern hemisphere. Possible global effects: long term anomalies