4DVar NCOM in RELO and COAMPS5

Long term goals To improve the accuracy of the ocean data assimilation and forecast by implementing the four-dimensional variational 4DVAR technique with the Navy coastal ocean model NCOM. Objectives This project will implement a 4DVar capability into the relocatable regional NCOM system and the COAMPS5 system as well as merge the NCODA and NAVDAS-AR frameworks. The tangent linear and adjoint for NCOM will be for the latest version using the generalized vertical coordinate system. All code will be added to the appropriate subversion repositories. The code will be tested on the operational computer systems prior to a validation test report. The results will be validated in one area to be determined in coordination with the operational POC. The area extent of the validation area will be balanced against available computational resources in conjunction with the operational POC. A validation test report for the area relative to available in situ data will be written. The evaluations will be for temperature structure, salinity structure and acoustic proxy parameters relative to in situ profile data. In addition, evaluations will be constructed for velocity comparisons to in situ drifter data. All evaluations will be constructed with the new 4DVar system relative to the existing operational 3DVar system. The code will be available to all Navy operational centers to OPTEST.