View
213
Download
0
Tags:
Embed Size (px)
Citation preview
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)
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
World Ocean Atlas 2001 Annual SST
x
x
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
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.
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
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