Merged Observatory Data Files (MODFs) for the Year of Polar Prediction: Turning Observations from Multiple Platforms into a Single Modeller-Ready Product

The Year of Polar Prediction (YOPP) supersite Model Intercomparison Project (MIP), aka YOPPsiteMIP, is designed to facilitate process-based validation of numerical weather prediction (NWP) models at several polar locations during a few Special Observing Periods (SOPs). One key component of YOPPsiteMIP is the set of Merged Observatory Data Files (MODFs) that is being created for about a dozen well-instrumented locations in the Arctic. MODFs are being designed and refined in collaboration with interested scientists at NWP centers. They will contain, to the extent possible, high-resolution vetted observations of the same geophysical variables provided in the model output data files for those same locations from participating NWP centers. There is a strong emphasis on using standardized variable names and including rich useful metadata in the MODFs. The first MODFs to be created use data from Utqiaġvik (formerly Barrow), Alaska. The process has involved observationalists, computer programmers, and data scientists as well as the NWP specialists. The process has also been an exercise in tradeoffs between our dreams and the practical realities associated with both observational data and standardized structures for sharing and describing them. A "recipe book" is in preparation, which will allow other YOPP scientists to create MODFs for some of the sites, and work is underway to develop an MODF template that can be used for observations and modelling associated with the upcoming MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition. This presentation will outline the initial desires and plans, then delve into the issues we have confronted as we sought to make those dreams a reality. An update on the status of the MODFs and the "recipe book", as well as thoughts about how this concept might be ported to other situations, will also be discussed.