"IOW, estmating the tail of the distribution at an
80,000 year return period from ~100 years
of data is simply silly" --- Russell

No, it is people who make statements without
either data or calculation to back them up that
gives the field of statistics a bad name. Do
you have either numbers or calculation to back
your conjecture, Russell? Just because you
are a bit giddy does not alter facts.

But it is, over a 126 years, a statistically significant slice of the
globe, Paradigm.

"Epsilon formed and persisted in fairly cold waters (around 24C),
for a tropical cyclone.

It may well be that shear has been more significant than temperatures
in this extraordinary year." --- Paradigm

I have tried, with my 8-year old Power PC and a single column
atmosphere model, to explore just this relationship. (Great
minds seek parallel roads . . .) The model may indicate that
increased greenhouse forcing leads to increased vertical air
movement, which competes with the shear winds, and reduces
them. I wish I had more floating-point and graphics display
'horsepower.' Anyone got a spare NEC World Simulator?

Roger Coppock wrote:
"Epsilon formed and persisted in fairly cold waters (around 24C),
for a tropical cyclone.

It may well be that shear has been more significant than temperatures
in this extraordinary year." --- Paradigm

I have tried, with my 8-year old Power PC and a single column
atmosphere model, to explore just this relationship. (Great
minds seek parallel roads . . .) The model may indicate that
increased greenhouse forcing leads to increased vertical air
movement, which competes with the shear winds, and reduces
them. I wish I had more floating-point and graphics display
'horsepower.' Anyone got a spare NEC World Simulator?


Just for fun,

You can look at individual years:

Check out this year:

http://www.osdpd.noaa.gov/PSB/EPS/SS...84.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...84.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...84.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...84.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...84.anomaly.gif

Colder than normal temps in the formation regions.
Fewer Tropical Storms?
No, about average year:

http://weather.unisys.com/hurricane/...984/index.html

Check out this year (yes, it was El Nino, but makes the point):

http://www.osdpd.noaa.gov/PSB/EPS/SS...97.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...97.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...97.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...97.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...97.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...97.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...98.anomaly.gif
http://www.osdpd.noaa.gov/PSB/EPS/SS...98.anomaly.gif

Warmer than normal temps in the formation regions.
More Tropical Storms?
No, far fewer:

http://weather.unisys.com/hurricane/...997/index.html

"Scott" escribió en el mensaje
...

You are being unclear.

TS Epsilon itself is not a 1 in 80K year event. After all,
tropical storms in early December aren't exactly rare. See
TS Otto from last year for example. It is the accumulation
of all the previous storms before Eps that is unusual.


Scott



Roger Coppock wrote:
Atlantic TS Epsilon Is About a 1 in 80,000 Year Event!!!!!


[snip rest]

BTW, has anyone an explanation for the following :

Sometime in recent historical times, Greenland was, well : green. So there
was not much ice on it at this time, and this period is dated between 800 AC
and 1000 AC, and it is the period when the Vikings ventured in Northern
Atlantic. Then later weather grew colder, and Greenland was not green
anymore (and the Vikings settlements in Vinland - Nova Scotia ? Newfoundland
? - disappeared)
So if the Greenland ice sheet did shrink at the time, why on earth isn't
there a clue of a 10 to 20 feet variation of the sea level between 800 AC
and 1000 AC ? Was the ice thicker at the time in Kamtchatka ? Alaska ? the
Antarctic ?

leto2 wrote:
"Scott" escribió en el mensaje
...

You are being unclear.

TS Epsilon itself is not a 1 in 80K year event. After all,
tropical storms in early December aren't exactly rare. See
TS Otto from last year for example. It is the accumulation
of all the previous storms before Eps that is unusual.


Scott



Roger Coppock wrote:

Atlantic TS Epsilon Is About a 1 in 80,000 Year Event!!!!!


[snip rest]


BTW, has anyone an explanation for the following :

Sometime in recent historical times, Greenland was, well : green. So there
was not much ice on it at this time, and this period is dated between 800 AC
and 1000 AC, and it is the period when the Vikings ventured in Northern
Atlantic. Then later weather grew colder, and Greenland was not green
anymore (and the Vikings settlements in Vinland - Nova Scotia ? Newfoundland
? - disappeared)
So if the Greenland ice sheet did shrink at the time, why on earth isn't
there a clue of a 10 to 20 feet variation of the sea level between 800 AC
and 1000 AC ? Was the ice thicker at the time in Kamtchatka ? Alaska ? the
Antarctic ?

The Vikings lied.

josh halpern

Roger Coppock wrote:
"IOW, estmating the tail of the distribution at an
80,000 year return period from ~100 years
of data is simply silly" --- Russell

No, it is people who make statements without
either data or calculation to back them up that
gives the field of statistics a bad name.

You're wrong about that. People who make statements
without data to back them up are not doing statistics at
all. People who do statistics wrong or abuse the process
of drawing conclusions based on statistics are the people
who give it a bad name.

Do you have either numbers or calculation to back
your conjecture, Russell?

I don't need to do a calculation to know that, any more
than I would need to do a calculation to say that some-
one's claim of inventing a perpetual motion machine
is bogus. You should read the first few chapters of
_Statistics of Extremes_ by Gumbel. If you don't
believe me, try posting your result to sci.stat.math or
sci.stat.consult and see what they say. If you do I
suggest you pay particular attention to the comments
of Prof. Rubin and Reef Fish, if they reply, although
several other people there are quite knowledgeable.
I'd be happy to put my statement against yours and let
those more expert in statistics than either of us decide
which of us is closer to correct.

Just because you
are a bit giddy does not alter facts.

Extrapolating a model far beyond the range that the
data supports does not establish the facts, it just looks
like poor science. I'm not giddy, I'm the one who is
acting grounded. You're acting giddy if you think you
can say that an event observed once in 129 years of
imperfect data, or even perfect data, can be used to
*reliably* infer an 80,000 year return period. Instead
of arguing with someone like me, a scientist who wants
good science done in the process of establishing the
facts, you should spend your time learning about things
when they are pointed out to you. Read Gumbel, which
is a classic and IMO quite readable as statistics texts
go. If you really do understand the reasoning behind
statistics then you know that your stated conclusion is
far too strong. The event was rare and it *might* even
be about an 1 in 80,000 year event, but the data simply
are insuffcient to draw a conclusion that precise.

Cheers,
Russell

I see. We don't need facts or calculations; we've got Russell.

"leto2" wrote in message
...


BTW, has anyone an explanation for the following :

Sometime in recent historical times, Greenland was, well : green. So there
was not much ice on it at this time, and this period is dated between 800
AC and 1000 AC, and it is the period when the Vikings ventured in Northern
Atlantic. Then later weather grew colder, and Greenland was not green
anymore (and the Vikings settlements in Vinland - Nova Scotia ?
Newfoundland ? - disappeared)
So if the Greenland ice sheet did shrink at the time, why on earth isn't
there a clue of a 10 to 20 feet variation of the sea level between 800 AC
and 1000 AC ? Was the ice thicker at the time in Kamtchatka ? Alaska ? the
Antarctic ?

Why they chose the name Greenland is an interesting question, perhpas (as
Josh implied) it was an early example of "spin" by Erik the Red to try to
attract more settlers. But clearly, Greenland has been almost entirely ice
covered for 100Kyrs. The best archealogical analysis indicates that the
Vikings settled in two locations, eeked out a rather harsh existence for
several centuries, deforested the small forests that were there, damaged the
fragile landscape with sheep and finally starved to death (one settlement at
a time) when they hit some bad winters. I think it is fair to say that was
a part of the onset of the Little Ice Age. They shared the island with some
Inuit, but apparently had almost nothing to do with them, not even learning
some of their useful survival skills. The only written account of contact
is a description of how differently "wretches" bleed to death.

This diplomatic skill is apparently why they never actually settled in
Vinland (North America). Apparently they landed, encountered a band of 9
Native Americans and promptly killed 8 of them. I guess the 9th one did not
speak highly of these new arrivals so they were unwelcomed after that.

--
Coby Beck
(remove #\Space "coby 101 @ bigpond . com")

Roger Coppock wrote:
I see. We don't need facts or calculations;

We don't need overdrawn conclusions like yours, that's for sure.

we've got Russell.

No, we've got books. Try reading one like I suggested and quite
acting like an ass, Roger. It isn't my job to do your research for
you anymore than I'm expected to fix the problems I see in an
article I review for a journal. My job in that case is to point out
errors and raise questions FOR THE ORGINAL AUTHOR TO
DEAL WITH. If I have a suggestion that I want to make along
those lines it is nice, but not required. The author can complain
and the editor can choose to ignore my review or not. He can
also decide I'm a poor reviewer and never send my another paper
to review. That's how science works. If you don't like it, don't
post to sci.* NGs. However, to save you the trouble of referring
the question to sci.stat.math like I also suggested, I'll do that.
The thread will be titled "Defending statistics".

Cheers,
Russell