[Coral-List] Present Bleaching Event - PR & USVI etc.

Alan E. Strong Alan.E.Strong at noaa.gov
Fri Sep 30 21:46:48 EDT 2005

Hi Scott,

Thanks for that relevant overview of hurricane 
development/growth....keep your eyes open for next week's EOS.  One of 
our Branches here at NESDIS/ORA has a paper on the explosive development 
of Katrina [also Rita!] as they moved through the Gulf..over the DEEP 
warm waters  (fuel supply) of the Loop Current....


PS....I have CCed two Christopher's on this for their possible comments: 
one with NHC and the other my son at the DC Forecast Office in Sterling, VA

scott.stripling wrote:

> Kristen, Alan-
> To answer Kristen's question, atmospheric conditions, as well as 
> oceanic conditions, must be favorable
> for tropical cyclones to form. So a very warm ocean will not 
> necessarily lead to tropical cyclone
> development all by itself. Due to the oceanography of the local 
> region, every year the upper layer
> waters are warm enough to support the development of tropical cyclones 
> here in the NE Caribbean.
> The anomalously warm SST's that aid in setting up the biological 
> conditions for bleaching can be assumed
> to be connected to weaker than normal trades across or very near the 
> region in question, and/or
> other significant low level atmospheric changes that result in 
> significant changes in oceanic currents.
> Both of these conditions now appear at play in our region. Surface 
> pressure across the W Atlantic and into
> the northern Caribbean have generaly been below normal since the 
> beginning of the year. This has helped
> to produce a displaced, or much weakened "Bermuda High", with the 
> dominant high pressure cell
> in the Atlantic meandering closer to the Azores in the central and NE 
> Atlantic. This has caused a reduced
> trade wind flow across the tropical Atlantic, leading to less mixing, 
> and slower regional currents. Too,
> another factor at play is the larger scale horizontal circulation of 
> the Atlantic. During the past 2 years, there
> have been  extended periods (on the order of several weeks) with 
> greatly reduced transport or flow in the
> Gulf Stream off of Florida. This has to contribute to a slower than 
> normal Atlantic Basin circulation and
> other such anomalies in the circulation patterns.
> It has been my contention that NOAA will never be able to accurately 
> model the coupled global
> ocean-atmosphere system unless there is a more comprehensive in situ 
> oceanic observing network
> established, with highest importance placed in regions of the major 
> currents. In the case of the Atlantic,
> the Gulf stream is the major heat input to the hemisphere, and all the 
> water flowing through the Gulf stream
> originates in the Caribbean. So to accurately model the entire 
> Atlantic circulation, one would assume
> that in situ measurements would be needed of both the input and the 
> output of the Gulf stream. That
> would mean monitoring the flow through the major passages into the 
> Caribbean, as well as key segments
> along the Gulf stream flow. So...while I am on my soap box, may I ask 
> of you on the coral list, and
> in NOAA to help point out this important issue to NOAA policy makers. 
> One of NOAA's big
> strategic goals for the next decade is monitoring and modeling of 
> climate change. I argue that if
> we don't have the proper input into the models, how can we accurately 
> model this complex system?
> Scott Stripling
> NOAA-NWS San Juan
> Alan E. Strong wrote:
>> Hi Kristen -- Now that would be an interesting survey....we have 
>> often observed that once an overall bleaching tendency has 
>> established itself over a certain region as hurricanes move though 
>> that region SSTs are brought down by mixing and upwelling.  
>> Obviously, this extra "fuel" available for the tropical storm has the 
>> ability to enhance these tropical storms...so much more is necessary 
>> from the atmosphere to first permit a tropical depression to first 
>> develop...therein lies the key....
>> Right now we are witnessing a large pool of anomalously high SSTs 
>> centered around the Virgin Islands...but no hurricanes have actually 
>> formed or been enhance, to my knowledge, over that area yet this year...
>> Cheers,
>> Al
>> Kristen Hoss wrote:
>>> Hello,
>>> I was wondering if anyone has ever studied the correlation of coral 
>>> bleaching episodes as possible indicators of what hurricane activity 
>>> may be like during the year?  I was wondering if there was a 
>>> connection that could be used as a prediction tool, or if the 
>>> correlation would just be related to the already known water 
>>> temperatures and weather patterns, etc....
>>> -Kristen Hoss
>>> Marine Researcher
>>> and Wildlife Biologist-USDA/APHIS/WS
>>> */"scott.stripling" <scott.stripling at noaa.gov>/* wrote:
>>>     With the NE Caribbean currently located underneath an elongated
>>>     area of
>>>     low pressure,
>>>     light and variable winds will continue to dominate the region 
>>> for the
>>>     next 1 to 2 weeks.
>>>     Computer models are forecasting only brief (6-12 hour periods) of
>>>     anything
>>>     approaching normal trade wind flow during this time. Thus the
>>>     stagnant
>>>     mixing conditions will
>>>     persist regionally through the first week of October, at the least.
>>>     Scott Stripling
>>>     NOAA/NWS San Juan
>>>     Alan E Strong wrote:
>>>     > *NOTICE - Bleaching continues to evolve throughout Eastern
>>>     Caribbean*
>>>     >
>>>     > Beginning in the central Keys during August (Sombrero Key
>>>     especially)
>>>     > the warm water episode and accompanying bleaching for this 
>>> year is
>>>     > progressing south and eastward through Cuba, Puerto Rico and the
>>>     > Virgin Islands. This can visually be seen in our recen t 12-week
>>>     > composite of HotSpot accumulations - Degree Heating Weeks (DHWs):
>>>     >
>>>     > http://www.osdpd.noaa.gov/PSB/EPS/SST/data2/dhwa.9.19.2005.gif
>>>     >
>>>     > and HotSpots:
>>>     >
>>>     > http://www.osdpd.noaa.gov/PSB/EPS/SST/data/hotspotwnc.gif
>>>     >
>>>     > Extremely high DHWs above "8" in much of the Virgin Islands are
>>>     quite
>>>     > worrisome as these levels in past bleaching events typically 
>>> bring
>>>     > some mortality to corals. This evolving episode continues to 
>>> be at
>>>     > near unprecedented levels of thermal stress for this region
>>>     since our
>>>     > satellite records began in the mid-80s. From the chart one can
>>>     observe
>>>     > that eastern Puerto Rico is under higher levels of thermal
>>>     stress at
>>>     > present than western PR....hence the recent reports of 
>>> considerable
>>>     > bleaching. Until some reduced solar radiation and/or wind & 
>>> mixing
>>>     > comes to the "rescue" we worry about prospects along much of the
>>>     > Windward Islands toward South America over the next month or so.
>>>     >
>>>     > Sorry our repot couldn't be more positive.
>>>     >
>>>     > Regards,
>>>     >
>>>     > Al Strong
>>>     > NOAA's Coral Reef Watch
>>>     > http://coralreefwatch.noaa.gov/satellite/index.html
>>>     >
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**** <>< ******* <>< ******* <>< ******* <>< ******* 
Alan E. Strong  
Branch Chief, Marine Ecosystem and Climate Branch (MECB)
Coral Reef Watch Project Coordinator
Phys Scientist/Oceanographer 
  NOAA Science Center -- RM 601 
  5200 Auth Road
  Camp Springs, MD 20746-4304 
        Alan.E.Strong at noaa.gov
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