Quality Assurance and Error Identification for the Community Earth System Model

Earth system models are valuable tools for furthering our understanding of past, present, and future climate states. Because these models tend to be large and complex as well as in a state of near constant development, quality assurance (and subsequent debugging) are critical pieces in the development cycle. Here, we describe our multi-year effort to better evaluate the quality and "correctness" of the Community Earth System Model (CESM), a widely-used climate model. Our approach depends on an initial coarse-grain ensemble-based consistency test to determine code correctness, which has already proved successful in practice. The additional capability desired is a means of easily tracing a coarse-grain failure to its root cause, and we discuss our strategy and promising efforts to date toward that goal.