[Coral-List] HotSpots and WarmSpots
goreau at bestweb.net
Thu Sep 28 09:57:52 EDT 2006
We seem to have crossed emails, as I had just replied to your earlier
message covering many of the same points below.
The principle of the current method is the same as that we had
originally proposed in integrating the temporal excess over the
historical maximum temperature average, but of course it increases
the resolution somewhat to take weekly averages instead of monthly
ones. But due to the thermal inertial of the ocean, average
temperatures normally change slowly unless there is a hurricane
induced upwelling event, and in fact the gain in predictive capacity
by using weeks instead of months is very minor. To be sure a 5 degree
positive anomaly for a week, surrounded by 2 weeks of colder than
average temperatures on either side could cause bleaching that would
not be detected by the monthly HotSpot, but such events are
exceedingly rare and I don't know of a single major bleaching event
that has been missed by looking at the monthly data. Given the
variability of cloud cover, the monthly average is much more stable
and robust statistically than the weekly average. At any rate, I
think all of this is of interest to coral list bleaching types.
Do you plan to post it?
Thanks, you are right, that is a good idea. I will be glad to provide
the citations. I'm a bit pressed for time right now because I have to
make urgent bookings to get to the World Premiere of my film on
Tourism, Water Quality, and Coral Reef Health (when we post the video
on the web, we'll send the url to the list server).
Al does seem to have been misquoted. Journalists make mistakes all
the time and never think they should check with their sources to make
sure they really got it right. Then your colleagues all notice and
they never forgive you! The bleaching alert that Mark issued earlier
this year on the list server when in fact it was cool seems to have
been a genuine mistake. But he is right that there is no question it
has gotten very hot in the eastern Caribbean in the last week.
Hopefully this will not remain long enough to cause bleaching because
this is the time when temperatures should be dropping, if we lived in
The NOAA Hot Spot site is a very valuable resource, but I think a
discussion of how to interpret is needed, because I get a strong
feeling most people are looking only at the instantaneous HotSpots
without realizing the need to time integrate the values.
On Sep 28, 2006, at 9:40 AM, Jim Hendee wrote:
> Hi, Tom,
> I think quite often it's the media who are misinterpreting or
> misrepresenting the message that is sent out by NESDIS. Mark
> Eakin's recent messages via Coral-List (see the archives at http://
> clearly have said that this year things are cooler in the Caribbean
> than last year. I have also seen (and been victim of) misquotes
> from the media! "Same 'ol same ol'" doesn't sell newspapers!
> Also, the NESDIS HotSpot tools do not claim to be the same concept
> you originally envisioned, thus there is no need for them to follow
> your original idea of one straight month. They have just continued
> on with the concept since the paper you wrote ten years ago, so of
> course they're going to improve. And besides, it's all so
> physiologically complex anyway--with light, CDOM and winds all
> possibly playing a part, depending upon the location--that the tool
> should only be considered just what they have always claimed--that
> this is a management decision tool only. Apparently their track
> record is pretty good, though I have not seen a definitive history
> of hits/misses.
> Thomas Goreau wrote:
>> To all serious coral bleaching researchers,
>> A very serious misconception continues to plague the interpretation
>> of Coral Bleaching HotSpots, which I am forced to clarify because I
>> invented the term.
>> The HotSpot concept was developed through a combination of field
>> observations, in-situ measurements, and analysis of regional and
>> global satellite SST data in Goreau (1990), Goreau, Hayes, Clark,
>> Basta, & Robertson (1993), Goreau & Hayes (1994), Goreau, Hayes, &
>> Strong (1996), Goreau & Hayes (2005a,b,c).
>> The concept has been widely misused by those who do not cite the
>> original literature. A HotSpot is defined as an area where the
>> monthly average temperature is 1 degree C above the historical
>> baseline average for the warmest month of the year. It is not the
>> same as a short term 1 C anomaly, it must remain for a month to be a
>> HotSpot. A HotSpot is a time integrated anomaly over a one month
>> period, NOT an instantaneous short term fluctuation. We do not issue
>> bleaching alerts until AFTER ONE STRAIGHT MONTH OF EXCESSIVE
>> TEMPERATURES. If the anomaly duration is less than that it is a
>> WarmSpot, not a HotSpot.
>> The NOAA HotSpot site, based on our work, does not explain the
>> difference, or cite the original literature, and lately misleading
>> bleaching alerts have been issued based on WarmSpots (see message
>> below). These are jumping the gun, causing much confusion, and much
>> more care is needed in following the original prescription. The
>> problem is serious enough that we should not be crying wolf
>> prematurely and damaging the credibility of the method, which when
>> correctly used, has correctly predicted all major bleaching events
>> since 1982.
>> Best wishes,
>> Thomas J. Goreau, PhD
>> Global Coral Reef Alliance
>> 37 Pleasant Street, Cambridge MA 02139
>> goreau at bestweb.net
>> Date: Tue, 26 Sep 2006 13:45:14 -0400
>> From: Mark Eakin <Mark.Eakin at noaa.gov>
>> Subject: Re: [Coral-List] Areas of Potential Bleaching in Caribbean
>> To: Coral Listserver <coral-list at coral.aoml.noaa.gov>
>> Message-ID: <274DF87D-DF85-4861-BB2A-2535A9069B2C at noaa.gov>
>> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>> Warming continues in the area around the northern Lesser Antilles.
>> While it looks like the Florida Keys has probably dodged the bullet
>> this year, there is a strong potential for low-level bleaching in the
>> northeastern Caribbean this year. We have begun to accumulate Degree
>> Heating Weeks in most of this region. The good news is that we have
>> only now reached the level of temperature stress that we had reached
>> by early August in 2005. That means that it is highly unlikely that
>> we will accumulate substantial thermal stress before temperatures
>> begin to cool.
>> Coral-List mailing list
>> Coral-List at coral.aoml.noaa.gov
Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net
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