[RegCNET] spin-up time. How long would you choose it to be

[William J. Gutowski]

Costas:
	If you have the resources, a small amount of experimentation 
would be useful, interesting and perhaps publishable.  It certainly 
could be a good way to do "parallel" computing and getting overall 
faster turnaround.  Ray and I have had discussions with various 
people over the years about spin-up and possibly tacking together 
long sequences of simulations, as you propose, but I'm not sure 
anyone has looked thoroughly at the problem for the time scales you 
are interested in.  It would be interesting to repeat analyses 
similar to those in that Pan et al. paper, but with longer overlap 
and simulation periods and including soil moisture and temperature.
	On the issue of spin-up, John Roads has advocated a 2-year 
spin-up for the Inter-CSE Transferability Experiments (e.g., 
http://rcmlab.agron.iastate.edu/twg/ and links therein).  Jens and/or 
Ole Christensen once published some work on RCM spin-up that proposed 
even longer periods, but I believe the longer periods were primarily 
for slowly evolving and weakly interacting lowest layers of their 
multi-layer soil model.

	These references may also be of interest:

Title: One-way nested regional climate simulations and domain size
Author(s): Vannitsem S, Chome F
Source: JOURNAL OF CLIMATE 18 (1): 229-233 JAN 1 2005

Title: Reinitialized versus continuous simulations for regional 
climate downscaling
Author(s): Qian JH, Seth A, Zebiak S
Source: MONTHLY WEATHER REVIEW 131 (11): 2857-2874 NOV 2003

And possibly these, too, on the issue of re-initialization:

Title: Multi-year simulations and experimental seasonal predictions 
for rainy seasons in China by using a nested regional climate model 
(RegCM_NCC). part I: Sensitivity study
Author(s): Ding YH, Shi XL, Liu YM, Liu Y, Li QQ, Qian FF, Miao QQ, 
Zhai QQ, Gao K
Source: ADVANCES IN ATMOSPHERIC SCIENCES 23 (3): 323-341 MAY 2006

Title: Polar MM5 simulations of the winter climate of the Laurentide 
Ice Sheet at the LGM
Author(s): Bromwich DH, Toracinta ER, Wei HL, Oglesby RJ, Fastook JL, Hughes TJ
Source: JOURNAL OF CLIMATE 17 (17): 3415-3433 SEP 2004

Title: Aspects of the fine-scale climatology over Lake Tanganyika as 
resolved by a mesoscale model
Author(s): Savijarvi H, Jarvenoja S
Source: METEOROLOGY AND ATMOSPHERIC PHYSICS 73 (1-2): 77-88 2000

Cheers,
Bill

At 11:28 AM -0500 7/20/06, Raymond Arritt wrote:
>Hello Costas,
>
>Some members of our group published a paper on this topic a few 
>years ago.  The paper is for North America instead of the 
>Mediterranean so there will be some differences in soil moisture 
>response; nevertheless, the results may be of interest for you.  The 
>citation is:
>
>Pan, Z., E. Takle, W. Gutowski, and R. Turner, 1999: Long simulation of
>regional climate as a sequence of short segments.  Mon. Wea. Rev., 127,
>308-321.
>
>Regards,
>Ray Arritt
>
>
>
>Costas Douvis wrote:
>>Dear colleagues
>>
>>I intend to run a 40-year simulation over the Mediterranean with
>>ERA-40 boundaries. I am facing the dilemma of doing one simulation
>>for the whole 40-year period or doing 3 x 15-year simulations at
>>three PCs thus splitting the 40-year period into three sub-periods
>>with an overlapping of 1-2 years from one sub-period to the other.
>>This will save me time but I am not sure if there will be any
>>problems with the continuity of the simulation by splitting one long
>>simulation into 3 shorter ones. I assume that for the atmospheric
>>part of the model a spin-up time of one month would be fine and so an
>>overlapping of one year from one sub-period to the other could be
>>safe enough but how about the other parts of the model like the land
>>surface? I would be grateful if you could give me your opinion.
>>
>>Best regards Costas Douvis
>>
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-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
William J. Gutowski, Jr.
3021 Agronomy Hall
Dept. of Geological and
      Atmospheric Sciences
Iowa State University
Dept. of Agronomy
Ames, Iowa  50011-1010

gutowski at iastate.edu
Tel:1-515-294-5632
Fax:1-515-294-2619
http://www.ge-at.iastate.edu/
http://rcmlab.agron.iastate.edu/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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