[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....
Cheers,
Al
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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>>> >
>>> >
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>>
>>
>>
>>
--
**** <>< ******* <>< ******* <>< ******* <>< *******
Alan E. Strong
Branch Chief, Marine Ecosystem and Climate Branch (MECB)
Coral Reef Watch Project Coordinator
Phys Scientist/Oceanographer
NOAA/NESDIS/ORA/SOCD -- E/RA3 {formerly NOAA/NESDIS/ORA/ORAD}
NOAA Science Center -- RM 601
5200 Auth Road
Camp Springs, MD 20746-4304
Alan.E.Strong at noaa.gov
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