g'Day all
As many of you would be aware, the problem of using surface sea
temperature measurements recorded from pelagic trips is that because of
many variables, the data good for a seasonal guide but is almost useless
for meaningful scientific comparison.
Invariably data is recorded from sensors embedded in the fish finder
(depth sounder) transducer fitted below the water line of the vessel.
The sea surface temperature displayed on the instrument will nearly
always be different between two transducer sensors even when fitted to
the same vessel and also significantly different between two vessels
unless properly calibrated. The reasons are many but include the
mounting position and the depth below the sea surface of the sensors
located on a vessel hull. The quality of the sensor also comes into the
mix of considerations but will usually vary even between two new quality
sensors such as Furuno connected to the same instrument.
Picture two calibrated transducers, one stern mounted on a dinghy or
small vessel (approx 0.2m below water line), the second through hull
mounted in the deepest fwd hull section of a deep sea fishing trawler
(say 2.0m or greater below water line). At the same location when day
atmospheric temperatures are hot with calm sea conditions combined with
little water movement (gentle tide and current), surface readings will
be significantly different between the two vessels. In still water,
temperature varies by the Cm. Then there are daily variability factors
of sea water surface temperature. Apart from sensor variability,
sea surface temperature readings are affected by water turbulence
determined by prevailing wind, tide, current and cloud cover and also
turbidity.
Occasionally I have observed daily variations of up to 2C sea surface
temperature at the same location when using the same calibrated sensor.
But I could not speculate the consequences of a permanent 2C deg rise of
sea temperature on sea birds however it is well known and expected that
sea surface temperatures will rise in various parts of the world's
oceans during La Nina weather patterns. See
http://www.globalweathercycles.com/elninoforecastgwo.html
Regards
Ian May
St Helens, Tasmania
currently at Price, SA.
0428337956
Laurie Knight wrote:
If we can park the issue of scientific credibility, I would like the
tread to return to the original point. What is the impact of a rapid
increase in the temperature of ocean currents, such as the East
Australian Current on the distribution of pelagic birds? I know that
Paul Walbridge measured the sea temperature on each trip out of
Southport that I went on, so I presume that the subject of sea
temperature is of potential interest to pelagic birders ...
Regards, Laurie.
On 01/02/2012, at 8:02 AM, Nikolas Haass wrote:
Dear Birding-Aus,
Not sure if everyone here knows the difference between a scientific
article such as the one by Wu et al. in Nature Climate Change and
someones personal blog.
I am not a climatologist but I am a scientist, too. Manuscripts
submitted to any journal of the Nature Publishing Group (NPG) and to
their serious competitors (e.g. Science and many others) undergo a
thorough peer-review - usually by experts in the field. The main
journal of the group, Nature, has a rejection rate of more than 90%,
which shows how hard it is to get an article published in such a
journal. But yes, it happens once in a while that a story gets
published and later turns out to be wrong. Then other serious
scientists - not some dubious bloggers - have the chance to correct
the error in a professional peer-reviewed paper.
M. complains about the lack of "REAL data" and calls the Wu et al.
paper "flawed". O.K., maybe or maybe not? Where are the "REAL data"
then that prove the Wu et al. paper wrong, M.? Finally, M.'s lack of
understanding of the topic climate change is documented by his
comment regarding "tiny differences in ocean temperatures".
Why am I writing this? In doubt, it makes more sense to incorporate
a professionally published article into public knowledge than
someone's un-peer-reviewed blog that reflects the opinion of the
writer rather than real science!
Cheers,
Nikolas
P.S. Maybe the webmaster should take this whole counterproductive
debate off the web?
---------------- Nikolas Haass Sydney, NSW
From: Jeremy O'Wheel <>
To: Laurie Knight <>
Cc: Birding Aus <>
Sent: Tuesday, January 31, 2012 10:42 PM
Subject: Re: [Birding-Aus] Impact of climate change on pelagic birding
Anthony Watts has no climatology qualifications, and his blog is
devoid of
any meaningful science. He has continually been debunked by actual
scientists and is only a source of misinformation. Two degrees is a
massive change for average temperatures. It's important to remember
that
the average global temp during the last ice age was *only* five degrees
lower than now, and most of Europe, North America, and Tasmania were
covered in ice. Averages are not the same as single day temperatures.
Jeremy O'Wheel
On 31/01/2012 9:01 PM, "Laurie Knight" <>
wrote:
Why do you say that a 1.5 to 2C change over 100 years is tiny,
Martin? I
would have thought a temperature change of that magnitude is quite
significant.
Anyhow, the article in question is available at http://www.nature.com/**
nclimate/journal/vaop/**ncurrent/full/nclimate1353.**html<http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1353.html
>
The abstract is as follows:
"Enhanced warming over the global subtropical western boundary currents
. Lixin Wu, . Wenju Cai, . Liping Zhang, . Hisashi
Nakamura, . Axel Timmermann, . Terry Joyce,. Michael J.
McPhaden,
. Michael Alexander, . Bo Qiu, . Martin Visbeck, . Ping
Chang . & Benjamin Giese
Nature Climate Change (2012) doi:10.1038/**nclimate1353Received 06
May 2011
Accepted 30 November 2011 Published online 29 January 2012
Subtropical western boundary currents are warm, fast-flowing
currents that
form on the western side of ocean basins. They carry warm tropical
water to
the mid-latitudes and vent large amounts of heat and moisture to the
atmosphere along their paths, affecting atmospheric jet streams and
mid-latitude storms, as well as ocean carbon uptake1, 2, 3, 4. The
possibility that these highly energetic currents might change under
greenhouse-gas forcing has raised significant concerns5, 6, 7, but
detecting such changes is challenging owing to limited observations.
Here,
using reconstructed sea surface temperature datasets and century-
long ocean
and atmosphere reanalysis products, we find that the post-1900 surface
ocean warming rate over the path of these currents is two to three
times
faster than the global mean surface ocean warming rate. The accelerated
warming is associated with a synchronous poleward shift and/or
intensification of global subtropical western boundary currents in
conjunction with a systematic change in winds over both hemispheres.
This
enhanced warming may reduce the ability of the oceans to absorb
anthropogenic carbon dioxide over these regions. However,
uncertainties in
detection and attribution of these warming trends remain, pointing to a
need for a long-term monitoring network of the global western boundary
currents and their extensions."
The point remains that a lot of pelagic birding occurs along the East
Australian Current and a 2C warming may have a significant impact on
marine
activity off SE Australia.
Regards, Laurie.
On 31/01/2012, at 8:52 PM, Martin Wigginton wrote:
> Yes, I agree with Laurie that we should welcome any study that
seeks to
> obtain REAL data. With such tiny differences in ocean
temperatures, it
> might be difficult to detect impacts on bird distributions.
Nevertheless,
> real data is the stuff that counts.
>
> But flawed studies such as Wenju Cai's ocean 'hot-spots' give the
game
> away when they state:
>
> "Detecting these changes has been hindered by limited observations
but
> with a combination of multi-national ocean watch systems and computer
> simulations we have been able to reconstruct an ocean history..."
>
> We should view with considerable scepticism studies such as these
which
> rely so heavily on computer modelling to reach what is clearly a
> pre-determined conclusion.
>
> See also http://wattsupwiththat.com/**2012/01/30/oh-noes-wind-**
>
driven-global-warming-hot-**spots/<http://wattsupwiththat.com/2012/01/30/oh-noes-wind-driven-global-warming-hot-spots/
>
>
> ------------
> Martin
> *All outgoing mails scanned by Norton Anti-Virus 2011
>
>
> -----Original Message----- From: Laurie Knight
> Sent: Tuesday, January 31, 2012 7:58 AM
> To: Birding Aus
> Subject: [Birding-Aus] Impact of climate change on pelagic birding
>
>
> >
> > There are some interesting articles reporting rapidly rising
> > temperatures in key ocean curren...
>
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