Climate Models as Guidance for the Design of Observing Systems: the Case of Polar Climate and Sea Ice Prediction

Purpose of review. The Arctic and Antarctic are among the regions most exposed to climate change, but ironically, they are also
the ones for which the least observations are available. Climate models have been instrumental in completing the big picture. It is
generally accepted that observations feed the development of climate models: parameterizations are designed based on empirically
observed relationships, climate model predictions are initialized using observational products, and numerical simulations
are evaluated given matching observational datasets.
Recent findings. Recent research suggests that the opposite also holds: climate models can feed the development of polar
observational networks by indicating the type, location, frequency, and timing of measurements that would be most useful for
answering a specific scientific question.
Summary. Here, we review the foundations of this emerging notion with five cases borrowed from the field of polar prediction
with a focus on sea ice (sub-seasonal to centennial time scales). We suggest that climate models, besides their usual purposes, can
be used to objectively prioritize future observational needs – if, of course, the limitations of the realism of these models have been
recognized. This idea, which has been already extensively exploited in the context of Numerical Weather Prediction, reinforces
the notion that observations and models are two sides of the same coin rather than distinct conceptual entities.