[ferret_users] regrding on time dimension

Hi all,

I have two files. In first file there is only one time step and in second 12. I want to creat mask on temp variable on second file using land variable in 1st(see below). I did following:

let lmsk=if land[d=1] gt 0 then 1
let ta_msk= ta*lmsk
shade ta_msk[l=1] ! this works ok
*** NOTE: Ambiguous coordinates on T axis: TA*LMSK
! but it doesn't work for other time step
shade ta_msk[l=2]
**ERROR: illegal limits: LMSK is not in the range L=2
          Axis extremes are L=1

I tried by inserting time dimension in variable land
DEFINE GRID/LIKE=TA[d=2] gmask
let land_rg=land[d=1,gt=gmask]
let TA_MSK_RG = TA*LAND_RG
shade ta_msk_rg[l=1]
--but resulting plot display No valid data

I think i can get around the problem if time dimension on variable land can be removed some how. How can I solve it?

Regards
Jagadish
===
use HEAD_BAT.NC
sh d
     currently SET data sets:
    1> ./HEAD_BAT.NC (default)
name     title                             I         J         K         L

LAND     Land Mask             1:118     1:109     ...       1:1

sh grid land
    GRID GCH1
name       axis            & nbsp; # pts   start                end
LON       LONGITUDE     118mi   52.372E(52.373)      108.09E(108.09)
LAT       LATITUDE         109 i   2.378S               44.79N
normal    Z
TIME      TIME                 1 r   01-DEC-2000 00:00    01-DEC-2000 00:00

use SRF2000AVG.nc
sh d
2> ./SRF2000AVG.nc (default)
name     title                             I         J         K         L
TA       Anemom Temp       1:118     1:109     ...       1:12

sh grid ta
    GRID GMASK
name       axis              # pts   start                end
LON       LONGITUDE      118mi   52.372E(52.373)      108.09E(108.09)
LAT       LATITUDE           109 i   2.378S               44.79N
normal    Z
TIME1     TIME                12 i   15-JAN-2000 00:00    15-DEC-2000 00:00