Exploring the spatial patterns of changing surface ocean conditions in the Tropical Atlantic and Pacific

Kilbourne, K.H., D. E. Black, J. Nyberg, T. M. Quinn, R. S. Webb, A. Winter

Main Points

• Don’t forget the rest of the tropics.

• Interactions between the ocean basins can be important

• Atlantic Perspective on the LIA

Questions

• What is the state of knowledge of Caribbean climate history?

• How do the spatial patterns tie into the Pacific climate history

• Are the patterns consistent with known inter-basin connection mechanisms?

• Earlier work in Tropical Atlantic SST– Centennial resolution – Short records– Indicated cooler conditions during the Maunder

Minimum– Some hint of changes in seasonal range

• Examples:– Keigwin et al., 1996 (Bermuda)– Winter et al., 2000 (Puerto Rico)– Watanabe et al., 2001 (Puerto Rico)– Nyberg et al., 2002 (Puerto Rico)

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World Ocean Atlas 2001 Annual SST

x

x

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23.00

24.00

25.00

26.00

27.00

28.00

1000 1200 1400 1600 1800 2000

SST-August

SST-February

Date

Example of Resolution

Nyberg et al., 2002 - Artificial Neural Network

24

25

26

27

28

29

Cariaco Mg/Ca - SST

1000 1200 1400 1600 1800 2000Date

-4.8

-4.4

-4.0

-3.6Puerto Rico Coral d18OPuerto Rico Coral d18O

9.3

9.6

9.9

1000 1200 1400 1600 1800 2000

Jamaican Sponge Sr/Ca (mmol/mol)Hasse-Schramm et al., 2003

Black et al., 2007

Kilbourne et al in process 2007

Temperature

Higher

Lower

New SST data:High resolution

Centennial-scale Puerto Rico Coral 18O driven by SST

8.9

9.0

9.1

9.2

9.3

Sr/Ca (mmol/mol)Puerto Rico Coral Sr/Ca

1000 1200 1400 1600 1800 2000

-4.8

-4.4

-4.0

-3.6Puerto Rico Coral d18OPuerto Rico Coral d18O

1000 1200 1400 1600 1800 2000

SST proxy

SST and SSS proxy

24

25

26

27

28

29

Cariaco Mg/Ca - SST

1000 1200 1400 1600 1800 2000Date

-4.8

-4.4

-4.0

-3.6Puerto Rico Coral d18OPuerto Rico Coral d18O

9.3

9.6

9.9

1000 1200 1400 1600 1800 2000

Jamaican Sponge Sr/Ca (mmol/mol)Hasse-Schramm et al., 2003

Black et al., 2007

Kilbourne et al in process 2007

Temperature

Higher

Lower

PacificMCA

New SST data:High resolution

Galapagos P>E

All agree 2˚C cooler

Local and Regional Surface Temperature Anomalies Track

Hemispheric Anomalies

-1.0

0.0

1.0

1900 1920 1940 1960 1980 2000

SST anomaly (˚C)

La Parguera SSTA sw Puerto Rico SSTA

WHWP SSTA N.Hem Avg. (Mann et al., 1999)

CorrelationCoefficient (r) WHWP Puerto Rico La Parguera

Northern Hemisphere 0.78 0.66 0.70WHWP 0.89 0.79

Puerto Rico 0.75

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

World Ocean Atlas 2001 Annual SST

x

xxx

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

24

25

26

27

28

29

Cariaco Mg/Ca - SST

1000 1200 1400 1600 1800 2000Date

-4.8

-4.4

-4.0

-3.6Puerto Rico Coral d18OPuerto Rico Coral d18O

9.3

9.6

9.9

1000 1200 1400 1600 1800 2000

Jamaican Sponge Sr/Ca (mmol/mol)

Hasse-Schramm et al., 2003

Black et al., 2007

Kilbourne et al in process 2007

Temperature

Higher

Lower

PacificMCA

Seasonal Perspective

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1994 1996 1998 2000 2002 2004

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1900 1902 1904 1906 1908 1910 1912

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1664 1666 1668 1670 1672 1674 1676

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1618 1620 1622 1624 1626 1628 1630

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1750 1752 1754 1756 1758 1760 1762

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1850 1852 1854 1856 1858 1860 1862

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1558 1560 1562 1564 1566 1568 1570

-5.0

-4.5

-4.0

-3.5

-3.0

8.6

8.8

9.0

9.2

9.4

1484 1486 1488 1490 1492 1494 1496

LPTA 2004 - 1751 E1P ~1673 - 1446

Monthly Coral Data

Seasonal Range in 18O-0.60

-0.40

-0.20

0.00

0.20

0.40

0.60

Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar

Coral

18 (‰ )O VPDB

14891564162416691757185419071999

•No large changes in seasonality evident from the 18O

•Coral 18O = f( SST and 18Ow) so a seasonally resolved independent temperature proxy is needed to confirm.

Atlantic -Pacific Linkages

Atmospheric Link • Zhang and Delworth (2005)

– Modeled a shut down of THC– Resulted in Anomalous Hadley Circulation– Cooling in tropical Atlantic => SLP– Across the Isthmus, SLP too

Atmospheric Link• Chunzai Wang (2006) “An overlooked feature of

tropical climate: Inter-Pacific-Atlantic variability”– Examined the effects of SST gradient between Pacific

and Atlantic equatorial regions– Resulted in anomalous Walker Circulation– Positive feedback– Far field effects in Pacific

South AmericaColdWarm

Wind Anomalies

Colder

Convergence

Amplification of Pacific Walker Anomalies

Coral Data from NCDC

Site Name Longitude LatitudeEarly Period

Late PeriodDiff. Sr/Ca (mmol/mol)

Diff. 18 O(‰ )VPDB

Reference

Abraham Reef 153.0 -22.1 1749-1799 1900-1950 - 0.09 Druffel and Griffin 1993

Alina's Reef 279.8 25.4 1751-1799 1900-1950 - 0.14 Swart et al., 1996

Amedee 166.5 -22.5 1700-1799 1900-1950 -0.033 0.08 Delong and Quinn unpublished data

Britomart Reef 146.7 -18.2 1748-1798 1903-1953 -0.026 0.15 Hendy et al 2002

Ifaty Reef 43.6 -23.2 1750-1799 1900-1950 - -0.07 Zinke et all 2004

La Parguera 293.0 17.9 1751-1799 1900-1950 0.05 0.26 This study

Montego Bay 282.0 18.5 1747-1795 1904-1954 0.149 0.12 Haase-Schramm et al., 2003

Rarotonga 200.2 -21.2 1750-1799 1900-1950 -0.090 - Linsley et al 2000

Ras Umm Sidd 34.3 27.9 1751-1799 1900-1950 - 0.16 Felis et al 2000

Ribbon Reef #10 145.7 -14.7 1748-1796 1900-1950 - 0.01 Wörheide, G., 1998

Savusavu Bay 179.2 -16.8 1776-1799 1900-1950 - 0.18 Bagnato et al., 2005

Secas Island 278.0 8.0 1750-1798 1900-1950 - 0.18 Linsley et al 1994

Urvina Bay 268.8 -0.4 1750-1799 1900-1950 - -0.11 Dunbar et al 1994

Difference ~1750-1800 from ~1900-1950

Coral data available from NCDC

Summary of Tropical LIA Spatial Pattern

• Cooler Caribbean and Gulf of Mexico

• Warmer and Drier in Southwestern Pacific

• Potentially warmer/wetter in cold Tongue

Enhanced SST Gradient between Atlantic and Pacific

Could This Mechanism Be Working During the LIA?

What other processes could be at work?

South AmericaColdWarm

Wind Anomalies

Colder

Convergence

Amplification of Pacific Walker Anomalies

Suggestion

The way to really get at processes and mechanisms is data assimilation

•Despite best efforts, data are often chosen because they fit a story

•Need an objective way to handle the errors in proxies and dating - cost functions

Selected Previous work in the Caribbean

• Keigwin et al., 1996 (Bermuda)– ~1˚C cooler during the Little Ice Age

• Winter et al., 2000 (Puerto Rico)– Coral 18O in 5-year segments – 2-3˚C cooler during Maunder Minimum – The 18O is a combined signal of SST and 18Ow

• Watanabe et al., 2001 (Puerto Rico)– Paired Mg/Ca and 18O – Found 2-3˚cooler during 1699-1705 (really ~1499-1505)– Hiatus visible in core x-ray - dating off by ~200 years

• Nyberg et al., 2002 (Puerto Rico)– Foraminiferal abundances - artificial neural network– Increased seasonal SST range ~1600-1400