Relating observations to processes: How to avoid flying blind

How do we know that measurements are related to a particular process? Over the last decade it has become clear that meso-scale processes play a central role in the transport of energy and momentum in the Magnetosphere-Ionosphere (M-I) system. Thus, to advance our understanding of M-I coupling we must obtain the relevant observations related to these processes which however present a difficult observational challenge. An example is ionospheric north-south structures has a scale size on the order of a few hundreds of km and lifetimes of maybe 10 min. This clearly shows that standard assumptions such as static over the time it takes to traverse the structure and infinite current sheets are invalid and using them will lead to incorrect conclusions. Imaging has proven to be a powerful tool for organizing observations but also services such as SuperMAG and AMPERE can provide a reference frame. The latter services, however, are coarser in time and space and thus are limited to processes with ionospheric scale-sizes greater than a few hundreds of km. Without a reference frame satellite measurements are effectively made blindly and relating them to particular processes is difficult. We discuss examples of this fundamental observational challenge and show how we can overcome it.