"To observe the system" means to carefully and attentively watch or study how a particular organization, process, or set of interactions works or functions. Full definition
It is a scientific expert advisory group charged with making recommendations for a sustained global ocean observing system for climate in support of the goals of its sponsors. (wcrp-climate.org)
We simply have not all the tools and observing systems in place to give these numbers with confidence. (realclimate.org)
New approaches should fully integrate global observing systems for environmental and social issues. (dotearth.blogs.nytimes.com)