Dear Tom,
I have given some more detail. ENSO for instance is positive or in
the El Nino state. It will change relatively soon to the La Nina
state - I don't know whether the El Nino will hang on for a while or
chsange this year. The PDO is a related phenomenon - it is a litle
positive now but what matters is the decadal trend. It is in a cool
phase since 2000. It is associated with ENSO in that there are more
frequent and intense La Nina in the cool mode and vice versa. La Nina
cool the atmosphere as cold upwelling water picks up heat from the
atmosphere. The SOI is strongly negative over the past year which
suggests that the current El Nino might hang on for a bit - warming
the planet with a large area of warm surface water across the central
Pacific. You can click on any of these indices and see the 'longer
series'. There are decadal changes - not simply point values.
ENSO and the PDO result from a dynamic balance between upwelling
fridig water and a warm layer that suppresses upwelling. I believe
that the decadal changes are driven by cloud changes and resultant
changes in short wave radiation at the surface. Froim the ISCCP
records - google Project Earthshine - a 4 W/m2 increase in SWR from
1984 (start of records) to 1998 and a 2.7 W/m2 decrease since. It is
related to changes in Earth albedo.
The Bermuda/Labrador Transport Index is more recently positive (past
year) - but is near the low points in the short record. Presumably
this means lower heat transport to the northern regions. The Arctic
was as warm in the late 1930's as it is now.
The Artic Oscillation is negative - 'over most of the past century,
the Arctic Oscillation alternated between its positive and negative
phases. Starting in the 1970s, however, the oscillation has tended to
stay in the positive phase, causing lower than normal arctic air
pressure and higher than normal temperatures in much of the United
States and northern Eurasia.’ The USA was as warm in the 1930's as
today.
The Southern Annular Index is positve but the trend is down -
influencing storm tracks - anf therefore temperatures - in the
Southern Hemisphere.
Some of these are simply oddly shifting patterns of sea surface
temperature that influence rainfall.
Cheers
Robert
On Jan 16, 12:09 am, Tom Adams <[email protected]> wrote:
> Robbo wrote:
> > In the shorter term, all of the ocean/climate indices -
> >http://ioc-goos-oopc.org/state_of_the_ocean/all/- are indicating
> > cooling this year and over the next decade or so.
>
> Why do you say they *all* indices indicate cooling? Some are
> tabulated as positive on the web page you cite.
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