The main objective of this task is to port some GSI observation operators into the UFO abstract implementation. This will be done in steps, by first refactoring the observation operators in place inside the GSI. The initial phase is the implementation of Fortran 2003 polymorphic observation operators. Preliminary work has already been done, it will be merged in the GSI trunk before work continues to bring more methods into the polymorphic structure. As work progresses, all inputs and outputs of the observation operators will be identified and passed by argument (as opposed to global variables) through newly defined classes.
This will be done first for radiances and depending on resources for other observation types. It is important to note that this refactored code will be kept usable by GSI, by using the refactored interfaces in the GSI.