Arctic Biosphere Atmosphere Coupling at Multiple Scales: Hypotheses

The critical issue to be addressed in this proposal is what controls the temporal and spatial variability of water, net C and energy exchange between arctic ecosystems and the atmosphere? We identify the critical unknowns that make this goal compelling, and associate each unknown with a testable hypothesis (H) or linked hypotheses. Six of the unknowns relate to improving understanding of a specific process or issue. The seventh unknown is integrative, and relates to the problem of linking observations across different scales to provide useful regional estimates with quantifiable errors.