Preparing for an Operational Environment: Software Development Standards in the Integrated Greenhouse Gas Monitoring System for Germany

Modern scientific projects typically rely on software, e.g., for implementing numerical models, performing data pre- and postprocessing, solving inverse problems, or assimilating observations. Consequently, the reliability and reproducibility of scientific results critically depend on software quality. Scientific results are also intended to be shared or reused, and so is the software that produces them: especially in operational settings, where traceability and maintainability are essential. Therefore, a sustainable software development strategy becomes key to a project's success. Nevertheless, often software standards are treated as a secondary concern. This can lead to difficulties when introducing new features, delays in users' projects, limited reproducibility, strained collaborations, and ultimately lack of suitability for operational use.
 
We present the case of the German Weather Service (DWD) contributions within the Integrated Greenhouse Gas Monitoring System for Germany (ITMS). The primary objective of ITMS is the verification of greenhouse gas emissions, which imposes particularly high requirements on the results' traceability and reproducibility. Accordingly, most if not all software-based components of our system should adhere to software development standards that ensure these requirements. We provide an overview of our software development standards and their application, and discuss lessons learned that are transferable to both legacy and newly developed scientific software projects.