Hi,
Perhaps this was an approach trying to improve vertical transfer of moisture in PBL.
When you consider both profiles ( e.g. type plot+x*(1-x)^2 and 0.25*x*(1-x) from 0 to 1 into
http://www.wolframalpha.com/ ) the second profile has smaller d ( ) / dz. If we check Eq. 2 in
Holtslag et al. (1990), this can reduce humidity tendency*.
I stop here, maybe someone with more insight can give better justification.
Cheers,
Ivan
*Maybe the entire equation for humidity tendency could be added in
Chapter 3 of the RegCM ReferenceMan4.1.pdf?
On Fri, Jul 1, 2011 at 11:16 AM, flyyks <flyyks@gmail.com> wrote:
> Hi,
>
> Thanks for your reply.
>
> The modification of this parameterization is used in all versions of RegCM.
> There should be some reason for this modification. Can you give me
> some deeper interpretation? Is this method more reasonable?
>
>
> 2011-07-01
> ________________________________
> flyyks
> ________________________________
> 发件人： Ivan Guettler
> 发送时间： 2011-07-01 15:00:31
> 收件人： flyyks
> 抄送： regcnet
> 主题： Re: [RegCNET] calculation of K in PBL scheme
> Hi,
> Computation of temperature diffusivity profile is documented in
> Holtslag et al., 1990: A High Resolution Air Mass Transformation Model
> for Short-Range Weather Forecasting. Mon. Wea. Rev., 118, 1561-1575.
> It seems the same profile should be applied for moisture also, but it
> was customized latter in model development. If needed, you could
> easily test what is more appropriate for your simulation.
> Cheers,
> Ivan
> On Thu, Jun 30, 2011 at 5:51 PM, flyyks <flyyks@gmail.com> wrote:
>> Hi,
>>
>> In "blhnew.F", the diffusivity of temperature is proportional to (1-z/h)**2;
>> but that of humidity is proportional to 0.25*(1-z/h).
>>
>> can you give me the reference about this parameterization? Thank you!
>>
>>
>>
>> 2011-06-30
>> ________________________________
>> flyyks
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>>