The Parallel Ocean Program (POP) was developed at LANL under the sponsorship of the Department of Energy's CHAMMP program, which brought massively parallel computers to the realm of climate modeling. POP is a descendent of the Bryan-Cox-Semtner class of ocean models first developed by Kirk Bryan and Michael Cox [Bryan69] at the NOAA Geophysical Fluid Dynamics Laboratory in Princeton, NJ in the late 1960s. POP had its origins in a version of the model developed by Semtner and Chervin [Semtner86] [ChervinSemtner88]. The complete ''family tree'' of the BCS models is displayed in the figure below (courtesy of Bert Semtner, Naval Postgraduate School).
Under the CHAMMP program, the Semtner-Chervin version was rewritten in CM Fortran for the Connection Machine CM-2 and CM-5 massively parallel computers. Experience with the resulting model led to a number of changes resulting in what is now known as the Parallel Ocean Program (POP). Although originally motivated by the adaptation of POP for massively parallel computers, many of these changes improved not only its computational performance but the fidelity of the model's physical representation of the real ocean. The most significant of these improvements are summarized below. Details can be found in articles by Smith, [Smith et al 93], Dukowicz et al., [Dukowicz et al 93], and Dukowicz and Smith [Dukowicz and Smith94]. The model has continued to develop to adapt to new machines, incorporate new numerical algorithms and introduce new physical parameterizations.