Questions about the length scale in MYJ PBL scheme

[skateboy366]

Hi,

I want to calculate the dissipation of turbulence kinetic energy(TKE) in MYJ scheme, which is equal to ((TKE^1.5)/(B1 * l). Here B1 and l are the model constant and length scale respectively. The question is how to determine l.

From the output files in WRF model, I find the variable EL_PBL, which is illustrated in the fllowing forms.

float EL_PBL ( Time, bottom_top_stag, south_north, west_east )
FieldType : 104
MemoryOrder : XYZ
description : Length scale from PBL
units : m
stagger : Z
coordinates : XLONG XLAT XTIME

But this value looks smaller the traditional length scale changed with height. Except the EL_PBL in the WRF output files, are there any other variables about the legnth scale ?

Thank you,
Zihan, Zhao

 

[Ming Chen]

Zhihan,

EL_PBL is the length scale for MYJ PBL scheme. Note that EL_PBL could vary from small values for dissipative eddies to large values for transporting eddies. It depends on the case you are studying.