Land based sources of pollution//source estimates

Alan E Strong Alan.E.Strong at noaa.gov
Thu Oct 4 13:26:31 EDT 2001


Bob/William/list:

All the more reason for an integrated activity for considering/utilizing many types of
observations that have a bearing on reefs:

SST
Insolation
Winds [QuickScat, etc.]
Cloud cover
Chlorophyll/turbidity
Water level
...
'

Cheers,
Al

Bob Buddemeier wrote:

> William/list:
>
> Thanks -- I suspect this will be mirrored in other places when people look (by the
> way, it is analogous to findings that in some areas there has been a significant
> increase of the fraction of the total precipitation falling in relatively intense as
> opposed to mild and moderate events).
>
> Question -- relevance to bleaching is likely to depend on the seasonal distribution
> of the effect -- if it increases mixing in the normally warm and calm period of the
> year it could be really important, but if the changes primarily effect the seasons
> when things don't bleach anyway, not so.  Do you have statistics on the wind
> distributions and pattern shifts relative to SST?
>
> Comment -- this has general implications for connectivity and disturbance, as well as
> the sediment resuspension and turbidity context in which the point was originally
> made.
>
> Bob
>
> Alan E Strong wrote:
>
> > William,
> >
> > A silver lining??...wonder how global change models are treating this?
> >
> > Al
> >
> > William Skirving wrote:
> >
> > > Hi Al and others,
> > >
> > > Yes we have found that the wind in the GBR region has been increasing
> > > (we've only looked at summer winds over the past 50 years).  We think that
> > > it is because we are getting more highs and lows over our region during the
> > > summer, rather than having dominant lows.  The transition between a high
> > > and low gives rise to increased pressure gradients and hence increased
> > > winds.  This has been a steady increase over the past 50 years and seems to
> > > be correlated with increased temperatures (ie global warming).  This is
> > > only statistical yet, and we have yet to put our finger on the exact cause.
> > >
> > > The high pressure events seem to be associated with increased ridging up
> > > the east coast of Australia, which is also a typical ENSO response.
> > >
> > > Now for the interesting stuff.  There is a significant decrease in winds
> > > 0-10 km/h, a slight decrease in winds 11-20 km/h, a significant increase in
> > > winds 21-30 km/h, a slight increase in winds 31-40 km/h and no detectable
> > > change in winds greater than 40 km/h.
> > >
> > > So yes, we are seeing a change in winds which seems to be associated with
> > > global warming.
> > >
> > > This has interesting implications for coral bleaching, since more wind
> > > means more mixing, more mixing can mean less extreme SSTs and therefore
> > > potentially less coral bleaching!
> > >
> > > William Skirving
> > >
> > > At 01:25 PM 10/3/01 -0400, Alan E Strong wrote:
> > > >Alina -- An interesting observation.....Folks we have been working with in
> > > >the GBR
> > > >see evidence of increased pressure offshore in the recent decade....does
> > > >this mean
> > > >greater sea-breezes from increased ocean-land temperature/pressure
> > > >differences?  It
> > > >may also have something to do with PDO...that the latest GRL tells us is
> > > >equatorally
> > > >driven!?
> > > >
> > > >We hope to be looking at this more closely in the years ahead...
> > > >
> > > >Cheers,
> > > >Al
> > > >
> > > >"Alina M. Szmant" wrote:
> > > >
> > > > > Bob and others:
> > > > > ...
> > > > > I have a hypothesis that I have been bandying around for a few years that
> > > > > it's been more windy since the mid 1980s and 1990s which could be an effect
> > > > > of global warming (more heat, more wind) [this is based on a gut impression
> > > > > that in spite of having bigger and better boats than I had access to in the
> > > > > 1970's, we have more days that we are weathered out now than a few decades
> > > > > back].   More frequent or more severe storms all year long could result in
> > > > > lower overall water clarity in areas like the Florida Keys where there is
> > > > > lots of sediment to resuspend (I gave a presentation about all this in
> > > > > Bali, but mea culpa, mea culpa I haven't written it up yet).  If those of
> > > > > you that like to work with climate data would have access to good wind
> > > > > records, I suggest someone look at the frequency and duration of higher
> > > > > wind events over the past 50 years or more, by passing the data thru some
> > > > > kind of filter that looks for the higerh energy events (e.g. 15+ knots for
> > > > > 24+ hrs):  it takes a minimum period of high winds to really get things
> > > > > stirred up, but if the rough conditions persist for too long, suspended
> > > > > sediments are likely flushed out of the system).  Thus, not enough
> > > > > resuspension could result in fine sediments building up to eventually
> > > > > become a problem (nutrients will also build up); frequent moderate energy
> > > > > events may make the system turbid a lot of the time depending on whether
> > > > > net flow rids the system of the resuspended fines; occasional major events
> > > > > help flush the system of both sediments and nutrients.  Thus wind regimes
> > > > > (and their change over time as climate changes) could make a big difference
> > > > > in the environment conditions reefs have to deal with, and their "health".
> > > > > ...
> > > > >
> > > > > Alina Szmant
> > > >
> > > >**** <>< ******* <>< ******* <>< ******* <>< *******
> > > >Alan E. Strong
> > > >Acting Chief, Oceanic Research & Applications Division
> > > >Team Leader, Marine Applications Science Team (MAST)
> > > >Phys Scientist/Oceanographer
> > > >   NOAA/NESDIS/ORA/ORAD -- E/RA3
> > > >   NOAA Science Center -- RM 711W
> > > >   5200 Auth Road
> > > >   Camp Springs, MD 20746-4304
> > > >         Alan.E.Strong at noaa.gov
> > > >              301-763-8102 x170
> > > >               FAX: 301-763-8572
> > > >   http://orbit-net.nesdis.noaa.gov/orad
> > > >
> >
> > ~~~~~~~
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>
> --
> Dr. Robert W. Buddemeier
> Kansas Geological Survey
> University of Kansas
> 1930 Constant Avenue
> Lawrence, KS 66047 USA
> Ph (1) (785) 864-2112
> Fax (1) (785) 864-5317
> e-mail:  buddrw at kgs.ukans.edu

--
**** <>< ******* <>< ******* <>< ******* <>< *******
Alan E. Strong
Acting Chief, Oceanic Research & Applications Division
Team Leader, Marine Applications Science Team (MAST)
Phys Scientist/Oceanographer
  NOAA/NESDIS/ORA/ORAD -- E/RA3
  NOAA Science Center -- RM 711W
  5200 Auth Road
  Camp Springs, MD 20746-4304
        Alan.E.Strong at noaa.gov
             301-763-8102 x170
              FAX: 301-763-8572
  http://orbit-net.nesdis.noaa.gov/orad

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