[RegCNET] tmax and tmin

[BI XUNQIANG]

Dear Bill, Lara, and Gao:

In the next public released RegCM3 version, we will add Tmax, Tmin
and vertital velocity (for pressure level) as the standard output.

We will calculated Tmax and Tmin as the way Bill suggested (for
every land surface step, and reset at 00 UTC).

Any other fields are also necessary to be included ?

Thanks and best regards,

On Tue, 15 Nov 2005, Wm. J. Gutowski wrote:

> Dear Lara:
> 	I am not the expert on this, but I am pretty sure that observed Tmin 
> and Tmax are obtained primarily from min/max thermometers, which record the 
> highest and lowest temperature attained since the last time they were reset. 
> They are almost always reset every 24 hours, though they don't all get reset 
> at the same time.  That is, different stations, even in the same country (or 
> in the US, the same state) may reset their thermometers at different times of 
> the day.  This can induce a small bias in one station's climatological 
> averages compared to what it would get if it reset at another time.  This is 
> documented in the literature somewhere, though I don't have the reference 
> myself.
> 	Using the 3-hourly output will tend to reduce the diurnal temperature 
> range you get because that is probably not sampling the extremes of the day, 
> though I have not seen this reduction tabulated by anyone, and it probably 
> depends on location and season.  Including a computation of the true daily 
> min/max temperature would be just a few lines of code, and some of us 
> RegCNETers have undoubtedly done it for their version of the code - we really 
> should have it as part of the standard model, I think.  There would still be 
> the question of what time of day to "reset the thermometer", but in model 
> intercomparisons I've been part of, we typically agree to go from 00 UTC - 00 
> UTC.
>
> Bill
>
> At 11:32 AM -0800 05.11.14, Lara Kueppers wrote:
>> Hi-
>> Awhile back I asked how Tmin and Tmax in the SRF output file were 
>> calculated. Here is Nellie's recent reply, in case anyone else is 
>> interested.:
>> 
>> "Hi Lara,
>> 
>> I just verified this with Bi...Tmin and Tmax are calculated from the BATS 
>> output, so if you have the model output to the SRF file every 3 hours, then 
>> that is what the min and max are calculated from.  Bi thinks this is a 
>> better way to do it since min and max temp observations are generally taken 
>> from 3 or 6 hourly obs.  You can increase the frequency of the srf output 
>> variables (in the regcm.in file) to see how much of difference it would 
>> make in the diurnal temp range. "
>> 
>> --
>> ~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*
>> Lara M. Kueppers, PhD
>> Postgraduate Researcher
>> Department of Earth Sciences
>> University of California, Santa Cruz
>> 1156 High Street
>> Santa Cruz, CA  95064
>> USA
>> 
>> 831.459.3504 ph
>> 831.459.3074 fax
>> kueppers at pmc.ucsc.edu
>> 
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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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~  Dr. Xunqiang Bi         email:bixq at ictp.it  ~ 
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