[Coral-List] HotSpots and WarmSpots

Thomas Goreau goreau at bestweb.net
Wed Sep 27 17:04:43 EDT 2006

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The concept has been widely misused by those who do not cite the  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  
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.


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