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Sea Surface Temperature anomalies during 1987 El Ni ño. (SOURCE: IGOSS nmc ship, buoy & satellite data; http://ingrid.ldgo.columbia.edu/). UPLIFTED CORAL REEFS AT HUON PENINSULA:. Last Interglacial, ~ 125 ka. CORAL AND INSTRUMENTAL RECORDS OF ENSO SINCE 1880
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Sea Surface Temperature anomalies during 1987 El Niño (SOURCE: IGOSS nmc ship, buoy & satellite data; http://ingrid.ldgo.columbia.edu/)
UPLIFTED CORAL REEFS AT HUON PENINSULA: Last Interglacial, ~ 125ka
CORAL AND INSTRUMENTAL RECORDS OF ENSO SINCE 1880 all records treated with a 2.5-7 year bandpass filter to reveal ENSO variability
Sea Surface Temperature anomalies during 1987 El Niño (SOURCE: IGOSS nmc ship, buoy & satellite data; http://ingrid.ldgo.columbia.edu/)
Laguna Pallcacocha, Ecuador (Moy et al., 2002)
Laminated sediments from Laguna Pallcacocha, Ecuador: Rodbell et al., 1999
Ecuadorian lake sediment record: (Moy et al., 2002)
LIVING AND HOLOCENE CORAL d18O seasonal and 9pt binomial filter 2.5-7 year bandpass filtered strong ENSO ‘GRADUAL’ or ‘ABRUPT’? weak ENSO (Tudhope et al, unpublished)
Plankton: proxy indicators of climate change in the ocean. Carbonate shells of foraminiferans (top left) and coccoliths (bottom left), and silica skeletons of diatoms (top right) and radiolarians (bottom right)
PALAEO ENSO: • What we are pretty sure about: • Zonal E-W SST gradient initiated about 2-3 Myrs BP • Interannual ENSO variability present by 130 kyrs BP (possibly much earlier) • ENSO variability occurs in both ‘glacial’ and ‘interglacial’ conditions, but Modern ENSO appears to be relatively strong • ENSO was weak or absent in early-mid-Holocene (~10-6 kyrs BP)
PALAEO ENSO: • What we still argue about: • What were mean conditions like in the equatorial Pacific during early-mid-Holocene when ENSO was weak ….. El Niño-like? …. La Niña-like?.... or neither? • Just how weak was the early-mid-Holocene ENSO? …. Separating SST from rainfall and salinity effects. • Glacial ENSO variability. • Relationship between interdecadal (PDO) variability, ENSO variability and mean state. • Relatonship, if any, between changes in mean conditions in the tropical Pacific and millennial variability in the extratropics, e.g., SW US drought in the MWP; D-O cycles in Greenland
When ENSO was weak in the early-mid-Holocene, what were mean conditions like in the equatorial Pacific? Koutavas and Lynch-Stieglitz, 2004
PD: std. dev. = 0.81°C MH: std. dev. = 0.71°C
Palaeo-ENSO Work of: Tudhope et al, 2001; Ravelo et al., 2004, Moy et al., 2003, Cobb et al., 2003 Koutavas and Lynch-Stieglitz, 2004 Linsley et al., 2006, 2008
Development of equatorial zonal SST gradient about 2 million years ago: Ravelo et al, Nature, 2004
ENVIRONMENTAL RECORDS FROM MASSIVE CORALS:
WHAT WE WOULD LIKE TO RECONSTRUCT: • VARIANCE …. interannual-interdecadal • BACKGROUND STATE of the tropical Pacific • TELECONNECTION PATTERNS ….. extra-tropical and extra-Pacific • Within ‘climate regime’ … little or no change in external forcing, e.g., late Holocene • Between ‘climate regimes’ ….. significant changes in climatic boundary conditions, e.g., glacial vs. interglacial
ENSO ARCHIVES: • Ideal attributes: • seasonal resolution • continuous • from core regions of ENSO dynamics • Potential Archives (and attributes met): • deep sea sediments (2, 3) • laminated sediments, marine and lacustrine (?1, 2, ?3) • tropical ice cores (1, 2) • trees (1, 2) • cave deposits (?1, 2, ?3) • corals (1, 3)