Standing between farmers and a simpler and more efficient method for managing the water needs of crops is what hydrologist Marc. B. Parlange and some of his colleagues call "the turbulence problem." How exactly does the atmosphere directly above agricultural fields, as well as other environments, interact with the surface of the planet? The answer to this question -- one of many that deals with the physical phenomenon of turbulence -- would greatly help farmers predict and regulate their use of water, according to Parlange, an assistant professor of land, air and water resources at UC Davis. Unfortunately, a clear understanding of turbulence has eluded scientists so far. Parlange and other researchers have chosen another way to explore air-surface interactions and water evaporation from agricultural fields under various atmospheric conditions. Using weather balloons and small weather stations to study evaporation, he is helping develop a model through "dimensional analysis" that he believes could eventually help farmers use water more efficiently. The growers would take a few atmospheric measurements at their fields, plug the numbers into a computer model and act on the information provided. Currently, many growers rely on information from a series of monitoring stations around the state. But they must use charts and calculation tables to apply the information to their specific locations.