ReRe: [Coral-List] Link between ENSO and Caribbean SST

[Martin Pêcheux]

Dear John,

My first advice is to ask the climatic research communauty (surely Hadley and
Reading center in UK) rather than the coral reef one, which lack crually of
people connecting our problematics with climate dynamic.

The link of ENSO with climatic signatures outside tropical Pacific is a wolf
in the litterature. People speak of "teleconnections", but there are no clear
explanations (but SW USA) given the complexity. It is mainly statistical
correlation. I didn't  monitor all the publications on the topic these last 5
years, but I think that the book of Philander 1990, El Niño, La Niña, etc, San
Diego Acad Press, 293p. as still a good chapter on teleconnections for an
introduction.
I know that for the Indian Ocean, there is a similar, but independant, mode of
oscillation, the Indian Dipole, with maybe 1/8 of EOF SST variance. ENSO will
explain crudly a third of the SST variance. But it correspond to an uniform
warming, whereas the ID is a E-W gradient. The 1998 event was a coincidence
between the two (still the best is : Nature, 1999, 401, 356-360, and 360-363).

Most of ENSO, a part of ID, involve equatorial currents and atmospheric trade
winds and jets. The Atlantic is particular in this respect as its equator is
short and with deviation along the Brazil coast. Nonetheless, there is also an
E-W oscillation, though a weak one (I have no ref under hand but see below an
email received today). A priori, or the Caribbean, as trade winds are
East-West, the correlation with ENSO will not be evident, but, but, influence
is to be search in pressure anomalies and patterns, I guess with EOF
(Empirical Orthogonal Functions = 2D-factor analysis). Also, teleconnections
involves clouds and precipitations (opposed to anticyclones) as much as, or
more than, temperatures. Warming causes high pressure causing weaker winds
causing warming, egg and duck.
Try also lag of ENSO from Caribbean. And lag of Caribbean with moosoon.....the
Earth is round, the Walker circulation.
For fun, I suspect also some influence of the stratospheric 2.4 year
Quasi-Biennal Oscillation of the sens of the equatorial jet, with downwelling
waves, but almost nothing have been published.
At easiest ,try to search with www.scholar.google.com.


> Dr. Martin Pêcheux

Institut des Foraminifères Symbiotiques
16, rue de la Fontaine de l'Espérance, 92160 Antony, France
martin.pecheux at free.fr
+33(0) 8711 804 32
Publications at  www.reefbase.org

Negociations at the Subsidiariess Body on Scientic, Technic Assessment, Bonn,
16-27 May
Event convened on Thursday, 26 May 2005
Title: Simulations of global climate change commitment for the
IPCC AR4
William Collins, National Center for Atmospheric Research,
introduced simulations for the IPCC's fourth assessment report
(AR4). He presented the Community Climate System Model (CCSM) and
explained that the models used for the AR4 have produced realistic
predictions and can simulate: mean sea-surface temperatures to
within 0.03C; ocean heat uptake to within 25%; and ocean uptake of
tracers to within 10%.
Collins then discussed projected climatic changes based on a
combined analysis of 12 climate models in the IPCC archive,
including: an increase in global surface temperature by 0.5C over
the 21st century; an average sea level rise of 10cm; polar
amplification; and the possibility of an "El Niño-like signature,"
where the eastern Atlantic Ocean warms more than the western part.
His site at http://www.cgd.ucar.edu/cms/wcollins/


John McWilliams a *crit :

> Dear Coral-list
>
> I'm interested in the link between ENSO and its impacts on sea surfaces
> temperatures in the Caribbean (and subsequent impacts on coral bleaching).
>
> To investigate this I'm trying to correlate ENSO indices (e.g. Southern
> Oscillation Index or Multivariate ENSO index) with SST anomalies in the
> Caribbean, using time lags (at monthly intervals) of up to three years.
> However, I know relatively little about the underlying mechanisms that link
> these two variables. Can anyone shed some light on how a strong El Nino
> (e.g. in 1998) can result in high SST in the Caribbean? For example, does
> it involve changes in tradewinds or oceanic circulation?
>
> In addition, does anyone know if there is an appropriate time lag? If, for
> example, I get a significant correlation using a lag of 12 months, I need
> to know if this result is sensible or just a coincidence with no meaning in
> the real world.
>
> Any thoughts would be much appreciated.
> Kind regards
>
> John
>
> Dr John McWilliams
> School of Biological Sciences
> University of East Anglia
> Norwich
> NR4 7TJ
> United Kingdom
>
> _--

Mon but dans la vie, c'est d'aller dans l'autre sens de nulle part. Ca évite
d'aller n'importe où (live from Paris U-bahn)
Goal in my life is to go other way of nowhere. To avoid any where (expérience
du métro de Paris)

L'homme descend