Graham Easterling wrote:
Martin Rowley wrote:
"Ron Button" wrote in message
...
As there has been some comment recently about the reappearance of the
dreaded El Nino,I thought it was worth a look at the current world sea
temp charts (see below ).
Assuming it occurs around latitude 10 south,there seems to be very
little evidence of its appearance judging by todays readings.
... Perhaps more along the equator, though signs of same should be
apparent at that latitude on the South American side.
https://www.fnmoc.navy.mil/products/...sstanomaly.gif
... I tend to look at the TOGA/ TAO data display from the array
specifically set up to monitor this region: find the main page and data
from:-
http://www.pmel.noaa.gov/tao/proj_over/proj_over.html
(also plenty of reading on what constitutes El Niņo etc.)
At the moment, I would tend to agree with you that there is no sign of a
*major* event occurring: even by the definitions found on this site, the
situation currently looks not very far from 'normal', though tending to
a 'warm' ENSO event - especially with warm 'blobs' further west in the
Pacific, which could 'slosh' back towards the east if/when the trades
fail.
The problem is that every appearance of anomalously warm waters gets
labelled as an El Niņo,
Quite.
In fact I've just looked at SST anomalies for late September (26th or
27th) in 2002, 2003, 2004 & 2005 & they are all remarkably similar. Not
just that they all seem to indicate a weak El Nino, but the north
Atlantic patterns are also remarkably similar. So all recent years have
shown a similar anamoly to the norm, so the norm is now anomolous!
I find a lot of this technical stuff tiresome especially when it comes
to numbers (that has always been a problem for me) but I had assumed
that the differences were in the region of half a degree Centigrade not
of the order of hundredths.
But that is what the link provided shows:
"GLOBAL Temperature Anomalies in .01 C."
So is it 5 to 6 degrees as he "...late 1997 when anomalies in the
equatorial east Pacific were at least +5/+6degC.,
Or is that the 0.5-6 degrees that is taken as the datum for an El Nino?
The air pressure systems of an El Nino are the same as a positive NAO
are they not? Where the air mass over one part of the Pacific or Indian
Ocean is greatly different from that over the other side?
Thus a La Nina is the equivalent of a period when the Azores high and
the Icelandic lows are of similar pressures?
And that "inter El Nino/La Nina years" are periods when the pressure
differences are marked but not great?
In other words, a cycle.
(It's ages since I read up on it but all I learned was that the
temperature differences average out to a miniscule amount, over the
time periods covered. And anyway temperatures over a period of weeks or
months, are never important compared the the type of weather. After all
we can have thunder and tornadoes even, in mid winter.
Yes these events occur with a temperature differenece that is usually
quite marked. But this is a daily change and it follows that the
temperature changes enough theother way, to make up for anomalies. Thus
rendering futile any attempt at long term analysis.)