UNDERSTANDING MASS AND ENERGY LINKAGES ACROSS THE GROUND/ATMOSPHERE INTERFACE IN HYDROTHERMAL DISCHARGE AREAS

Mass and energy exchange between the atmosphere and the shallow subsurface sets the upper boundary condition for models of hydrothermal systems. Vapor fluxes between soil and the atmosphere are an important factor for climate modeling and have a significant impact on ecosystem functions. Unfortunately, there are few analytical frameworks for modeling energy and mass linkage between the atmosphere and thermal land surface. Here, we develop a 1D steady-state analytical model of heat and mass (vapor and groundwater) flux in a hydrothermal discharge area across the land surface boundary; the model includes the effects of convective heat transfer, conduction and advection in the porous medium, and latent heat transfer from evaporation. We use the model to examine the significance of the various heat transfer modes and explore the potential for evaporative cooling to depress near-surface temperatures below those that would be expected in a high heat flux hydrothermal discharge zone. We apply the model to a hydrothermal discharge area in the Alvord Basin, southeast Oregon, present and compare to empirical observations, discuss the factors influencing the dominant heat transfer mechanisms, and the near-surface thermal environment that is predicted by the model