Running 3dvar; not enough memory

hey everyone,
I am trying to assimilate 2 wrfout files the parent and the nested one

  1. when I assimilate the outer domain (Parent) that has 25mb everything
    seems to be ok and it’s producing the output files as well, but when I am
    trying to assimilate the the inner (nested) domain (107mb) is where the problem
    starts … as it gives me the following error

0: ALLOCATE: 15795584 bytes requested; not enough memory

and if i use unlimit option here is what I get

DYNAMICS OPTION: Eulerian Mass Coordinate
-------------- FATAL CALLED ---------------
frame/module_domain.f: Failed to allocate


My model settings are:
bigger domain 142112 res. 30km file size 25mb (this works fine)
Nested domain 283
238 res. 10km file size 107mb ( problems above mentioned)
PC - FC 9 Linux
Intel Duo core 8Gb memory
Compilers PGI (pgf90)

Any Idea on how to solve this will be appreciated.

Thank you in Advance