sum_grad.f90(61): error #6460: This is not a field name that is defined in the encompassing structure. [TL_T] & OCEAN(ng) % tl_t,
sum_grad.f90(62): error #6460: This is not a field name that is defined in the encompassing structure. [TL_U] & OCEAN(ng) % tl_u,
sum_grad.f90(63): error #6460: This is not a field name that is defined in the encompassing structure. [TL_V] & OCEAN(ng) % tl_v,
sum_grad.f90(64): error #6460: This is not a field name that is defined in the encompassing structure. [TL_ZETA] & OCEAN(ng) % tl_zeta)
--------------------------------------^
compilation aborted for sum_grad.f90 (code 1)
However, The issue will disappear when I turn off the RPCG option. Could anyone give me some help? Thanks in advance.
Hmm, you must be doing something wrong. We always need the RPCG solver for the RBL4DVAR data assimilation algorithm. I don't understand the nature of the error because ROMS 4D-Var algorithms need the nonlinear (NLM), tangent linear (TLM), and adjoint (ADM) kernels, and all those variable are in the OCEAN(ng) structure. This posting doesn't make any sense to me. It seems that you are playing with the CPP options incorrectly. We have been running the dual formulation, RBL4DVAR/RPCG, for years without such problems.