Workshop on hyper-resolution land surface modeling A Challenge to the Modelling Community: Building a Hyper-Resolution Land Surface Model Summary of Princeton Workshop on hyper-resolution land surface modeling NOAH Workshop Austin, TX March 15-17 2010

Premise: Water is important in many ways –for agriculture and energy production, solute transport, land-atmosphere interactions, floods and droughts. For many of the water-related problems facing society, the current spatial scale of our models is insufficient to provide accurate information as well as to better understand the hydrologic cycle. Current computational capabilities have outrun the capabilities, and theoretical underpinnings, of current land surface hydrological models. Much higher spatial resolutions are demonstrably feasible for multi-decadal to century simulations

Societal and scientific needs that could be met through hyper-resolution land surface modelling Improved flood forecasting (spatial distribution; linkages to high resolution hydrodynamic modeling) Modeling and prediction of effects of human activity on the water cycle through accurate representation of water extractions, irrigation, and reservoir management Predict agricultural/crop modeling; drought and famine prediction Climate and land use projections (e.g., analysis of water scarcity and food security issues) Ecoystem, biodiversity, and habitat predictions (earth system modeling context)

Current High Resolution Datasets: HydroSHEDS

The mosaic concept: Has its time come and gone?

CO2 Evasion in the Amazon (8S,72W) (0,72W) (0,54W) (8S,54W) Over 300,000 km2 inundated area, 1800+ samples of CO2 partial pressures, 10 year time series, and an evasion flux model Results: 470 Tg C/yr all Basin; 13 x more C by outgassing than by discharge But what are seasonal and global variations? If extrapolate Amazon case to global wetlands, = 0.9 Gt C/yr, 3x larger than previous global estimates; Tropics are in balance, not a C Sink? Richey, J.E., J.M. Melack, A.K. Aufdenkampe, V.M. Ballester, and L.L. Hess, Outgassing from Amazonian rivers and wetlands as a large tropical source of atmospheric CO2, Nature, 416, 617-620, 2002.

What is the new paradigm? Frankly, we don’t know yet! What is it not? “Flat earth” (needs to know explicitly about topography, and its effect on runoff generation Mosaic land cover Static vegetation Parameterized (and static) stream networks Static landscape (landscape and channel forming processes) Other hydrological simplifications