Fix interpolation error of obsop

[cd10kfsu]

The obsop break down when handling AVHRR obs at the location

rlon = 73.812500000000000
rlat = 79.854179382324219

The error trace back to

At line 188 of file common_obs_mom6.f90
Fortran runtime error: Index '37' of dimension 2 of array 'lat2d' above upper bound of 36

This error is caused by the grid interpolation subroutine phys2ijk

Ocean-LETKF/src/obs/obsop_sst.f90

Lines 262 to 265 in 9e5bc65

	!---------------------------------------------------------------------------
	! Convert the physical coordinate to model grid coordinate (note: real, not integer)
	!---------------------------------------------------------------------------
	CALL phys2ijk(elem(n),rlon(n),rlat(n),rlev(n),ri,rj,rk) !(OCEAN)

It is probably due to the grid search in the tripolar coordinates.