Are We Courting Closure Controversy: Do Biological Processes Drive the Surface Energy Imbalance?

The surface energy balance closure problem has stymied micrometeorologists for decades. Much emphasis has been placed on biases in measurement techniques, and physical processes that are thought not to be resolved. There has been considerably less attention given to the role of unobserved biological sources and sinks of energy. Usually, in the energy balance context, if biological energy storage is considered, it is taken as a constant fraction of net ecosystem carbon dioxide exchange, which represents the energy ultimately stored in the chemical bonds of photosynthates. Yet to achieve “permanent” energy storage in chemical bonds, there are transient energy storage and release in photochemical processes not observed by any conventional monitoring systems. Such unobserved transient dynamics lead to time delay in the observed energy balance. Specifically, this includes generation of the electric and pH gradient across the thylakoid membrane (i.e., the proton motive force, pmf), and photochemical reaction products that provide reducing power (NADPH) and chemical energy (ATP) for the carbon reactions of photosynthesis. These transient processes store and release energy that is not detectable by our measurement systems. This presentation will address the question: Do biological processes explain part of the lack of energy balance closure?