  Ocean science is a discipline that employs ocean models as an essential
research asset. Such scientific modeling provides mathematical abstractions of
real-world systems, e.g., the oceans. These models are then coded as
implementations of the mathematical abstractions. The developed software
systems are called models of the real-world system.
  To advance the state in engineering such ocean models, we intend to better
understand how ocean models are developed and maintained in ocean science. In
this paper, we present the results of semi-structured interviews and the
Thematic Analysis~(TA) of the interview results to analyze the domain of ocean
modeling. Thereby, we identified developer requirements and impediments to
model development and evolution, and related themes. This analysis can help to
understand where methods from software engineering should be introduced and
which challenges need to be addressed.
  We suggest that other researchers extend and repeat our TA with model
developers and research software engineers working in related domains to
further advance our knowledge and skills in scientific modeling.
