The Earth System and its Many Scales: A View from Biosphere up to Atmosphere and Back Down Again

The space and time scale over which a process operates, say the harvesting of light by a leaf on a tree or the evolution of a synoptic weather system, may seem like a relatively mundane property. For the Earth as a single system, these scales range 13 orders of magnitude in space (from nanometers to 10,000 km) and 25 orders in time (from nanoseconds to billions of years). Though the large range is impressive, the real interesting and challenging scientific problems come about from understand how processes at one scale interact with another. Further, when it comes to biosphere-atmosphere interactions, the scale dependencies work mainly in opposite directions. This presentation shares a journey of how building a scale-aware science allowed my team and collaborators to tackle a vexing problem around quantifying the surface energy balance, a key link of the Earth to the atmosphere and driver of many weather and climate processes. Over the past decades, my lab has made careful measurements of this quantity, but like everyone else, found themselves at a loss to explain persistent biases. Our solutions, emboldened by a major field experiment in Wisconsin called CHEESEHEAD, led us to a journey across many scales and back again. Most importantly, it may have landed one of the first real resolutions to this micrometeorological mystery.