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Hans Burchard  
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 More options Jan 26, 12:35 am
From: "Hans Burchard" <hans.burch...@io-warnemuende.de>
Date: Thu, 26 Jan 2012 06:35:43 +0100 (CET)
Local: Thurs, Jan 26 2012 12:35 am
Subject: Roughness length zo
Dear Yiannis,

thanks a lot for your mail below regarding the surface roughness length to
which you attached the following paper with observations from the Central
Baltic Sea:

Carlsson, Bj rn, Yiannis Papadimitrakis, Anna Rutgersson, 2010: Evaluation
of a Roughness Length Model and Sea Surface Properties with Data from the
Baltic Sea. J. Phys. Oceanogr., 40, 2007 2024.
doi: http://dx.doi.org/10.1175/2010JPO4340.1

I copy this reply to the GOTM list, because I think that many are
interested in this issue.

All the best,

Hans.

--
Hans Burchard
Leibniz Institute for Baltic Sea Research Warnemuende
Dept. for Physical Oceanography and Instrumentation
Seestrasse 15
D-18119 Rostock-Warnemuende
Germany

Tel.  : +49 - 381 - 5197 -140
Fax   : +49 - 381 - 5197 -114
web   : http://www.io-warnemuende.de/hans-burchard-en.html
E-Mail: hans.burch...@io-warnemuende.de
skype : hans.burchard


 
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Adolf STIPS  
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 More options Jan 26, 3:09 am
From: Adolf STIPS <adolf.st...@jrc.ec.europa.eu>
Date: Thu, 26 Jan 2012 09:09:47 +0100
Local: Thurs, Jan 26 2012 3:09 am
Subject: Re: [gotm-users:1023] Roughness length zo

Dear Yiannis,

thank you for the interesting paper.
(and may be you remember that we met at Ispra?)

Unfortunately we cannot abandon the Charnock relationship for determining z0,
within GOTM, as we cannot apply your proposed parameterizations based on wave age or swell
ratio, as we simply do not have these parameters available in GOTM.
(Wave model or measurements would be needed)

By the way, are you aware of the z0 measurements from Gemmrich&Farmer?
The are specifically addressing the z0 problem under breaking waves in the open sea,
so I wonder that you have not cited them?

In my opinion Hasse a few years ago made a nice remark about the Charnock relation:
"There are only two types of people, they overly optimistic who think "Charnock" explains
everything and the overly pessimistic who think it does not explain anything. None of them is right."

Best regards, Adolf

On Jan 26, 2012, at 6:35 AM, Hans Burchard wrote:


 
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Hans Burchard  
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 More options Jan 26, 3:09 pm
From: "Hans Burchard" <hans.burch...@io-warnemuende.de>
Date: Thu, 26 Jan 2012 21:09:40 +0100 (CET)
Local: Thurs, Jan 26 2012 3:09 pm
Subject: Re: [gotm-users:1023] Roughness length zo
Hello Hans and colleagues:

Happy new & turbulent year!

The z0 debate points at a real research problem. In all those cases
where our quantitative knowledge of processes and parameters  is
dramatically weak, the scatter so large, we can see it as being bad.
But as researchers we have to see it as the contrary - a chance for
real research, our favorite hobby.

A REAL problem! I have already contacted Sandro Carniel with respect
to whether it could make sense to organize a small dedicated team with
only one problem: a better understanding of z0, "the Charnok issue",
and the general sea surface turbulence.

At the sea surface we have mainly three sources of turbulence:
- the "linear" waves and their generic shear, the
- overall current shear in the upper water column, and
- the breaking waves.

These processes control the major scales of mixing and have
consequences for gas and heat exchange, i.e. climate-change issues.

I think there is so many valuable work done already that we
have a good chance today to go (on their shoulders) one step further
and concentrate on the above one and only question.

One basis should be the corrected physical understanding of turbulence
in the sense given in two papers here:
http://export.arxiv.org/api/query?search_query=all:baumert+AND+helmut

We could combine with the works by Papadimitrakis, Banner, Craig, Stips,
W est, Prandke, Farmer, Gemmrich, et al. (please don't crucify me for
not being
mentioned here, it is late today...).

Major question, as always: who is able to write a proposal and to organize
this process? Are there volunteers?

All the best,
Helmut
------------------------------------------------------------------------
Dr. Helmut Z. Baumert
*IAMARIS e.V. - Angewandte Wasserforschung *
Gesch ftsf hrung
Bei den M hren 69 A
20457 Hamburg
Fon 040 3690 5195
Fax 040 3690 5196
http://export.arxiv.org/api/query?search_query=all:baumert+AND+helmut
------------------------------------------------------------------------

--
Hans Burchard
Leibniz Institute for Baltic Sea Research Warnemuende
Dept. for Physical Oceanography and Instrumentation
Seestrasse 15
D-18119 Rostock-Warnemuende
Germany

Tel.  : +49 - 381 - 5197 -140
Fax   : +49 - 381 - 5197 -114
web   : http://www.io-warnemuende.de/hans-burchard-en.html
E-Mail: hans.burch...@io-warnemuende.de
skype : hans.burchard


 
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