Land based sources of pollution//source estimates

[Bob Buddemeier]

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the sediment resuspension and turbidity context in which the point was originally
made.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


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