The Soil Moisture-Atmosphere Coupling Experiment (SMACEX) was conducted in the Walnut Creek Watershed near Ames, Iowa over the period from June 15-July 13, 2002. The study area is representative of a much larger agricultural region in the upper Midwest involved primarily in corn and soybean production. This field campaign was conducted in concert with the Soil Moisture Experiment 2002 (SMEX02) where the primary objective was to investigate the utility of microwave remote sensing for estimating soil moisture under rapidly changing crop biomass in support of the NASA Aqua satellite mission. SMACEX is an interdisciplinary investigation involving a diverse set of field measurements and modeling activities funded by the NASA Land Surface/Terrestrial Hydrology Program. Measurements of the coupled exchange of water, carbon and energy between the soil, vegetation and atmosphere included: tower and aircraft-based water, energy and carbon fluxes, atmospheric radiosoundings and acoustic sodar soundings, ground-based Lidar observations of atmospheric boundary layer water vapor densities and heights, and cloud cover, vegetation biomass and cover, remote sensing in the visible, near-IR, thermal and microwave wavelengths from aircraft and satellite platforms. The complementary scale inherent in these measurements will provide the necessary range to investigate local to regional scale impacts of landscape heterogeneity on water, carbon and energy exchanges. The data and modeling work will address several key issues in global water and energy recycle research.

This paper will provide a description of the hydrometeorological conditions that existed during the field campaign, an overview of the measurements and some preliminary measurement and modeling results, which provide a synopsis of the range in soil moisture, vegetation cover and atmospheric states observed during the study.