**Subject: **Re: a problem of arbitrary initialization of LSM

**From: **Erik Kluzek (*erik@ucar.edu*)

**Date: **Wed Aug 22 2001 - 11:45:38 MDT

**Next message:**Yuqiong LIU: "problems with continuous run of ccm3"**Previous message:**Xuguang Wang: "a problem of arbitrary initialization of LSM"**In reply to:**Xuguang Wang: "a problem of arbitrary initialization of LSM"**Next in thread:**Xuguang Wang: "big difference of snow height between ccm3 and NCEP/NCAR reanalysis"**Reply:**Erik Kluzek: "Re: a problem of arbitrary initialization of LSM"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

On Wed, 22 Aug 2001, Xuguang Wang wrote:

*>
*

*> Unfortunately, the arbitrary initialization of LSM does not give
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*> reasonable initial values as the user's guide says. Take TG, the ground
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*> temperature, as an example, by arbitrary initialization, TG is equal to
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*> 283K all over the globe. This is obviously unreasonable.
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*>
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*> Have any of you tried the arbitrary initialization for LSM? Could any of
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*> you give me some suggestions to solve this problem? Thanks.
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*>
*

Xuguang, "arbitrary initialization" is not meant to give "realistic" values --

just "reasonable ones". 283K over the globe is certainly not realistic -- but

it is a reasonable value that represents a value that TG could be. In other

words 170K or 370K would be unreasonable as TG could never reach those values.

Then intent of "arbitrary initialization" is to give

values that will allow you to run the model. If you run with

"arbitrary initialization" it should be understood that you plan on running

for several years to let the land-model spin-up before you start evaluating

your output. At NCAR we typically we typically let the simulation run for five

years or so before we start analyzing simulation data -- when arbitrary initialization

is used. So if we want to analyze a 5-years of simulation run with

"arbitrary initialization" we'll run for 10 ignore the first five years and

only look at the last 5.

As an alturnative you could create your own programs to create more realistic

values to start up LSM. The CCM3 web-page also has LSM initial condition dataset

for T42 that you could use.

Erik Kluzek, (CGD at NCAR)

National Center for Atmospheric Research

Boulder CO, (off) (303)497-1326 (fax) (303)497-1324

--------- Home page and public PGP key---------------

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