about masking a field with differnt dimensionality

[Xiuhua Zhu <xiuhua@xxxxxxx>]

Dear all.

i have a question to mask a 4-d field using one 2-d mask file

i have 2 files:

>>>>>>>>>>>>>    1> ./mld_gt200_mask.cdf
name     title                             I         J         K         L
MLD_MASK IF MEAN_MLD GT 200  THEN 1       1:96      1:48      1:1       ...

  2> rho2000db.nc  (default) name     title                           
I         J         K         L
                 RHO                         insitu 
density                   1:96      1:48      1:40      1:600
>>>>>>>>>>>>>


i did  the following to mask the rho field:


>>>>>>>>>>>>>>
def grid/like=rho/z=rho[d=2]/t=rho[d=2]  mkgrid
let masked_rho=rho[d=2]*mld_mask[d=1,gz=mkgrid]
shade/k=1/l=1 masked_rho
>>>>>>>>>>>>>

1.      the figure window shows    'no valid data',       though the 
mld_mask contains correct information.

2.     when i simply multiply the two fields together by using    ' 
mld_mask*[rho[d=2]]'          the new variable only contains information 
at the first z level.(xy*1*t)

does anybody have any idea?

thanks in advance

Xh.