function rotate_array,inarray,inlon,outlon=outlon
; rotate the assmilation array 180.
; strip off last element before shift
s=size(inarray)
outlon=shift(inlon(0:s(1)-2),(s(1)-1)/2)
outarray=inarray(0:s(1)-2,*)
outarray=shift(outarray,(s(1)-1)/2,0)

return,outarray
end