The Cooperative Atmosphere-Surface Exchange Study—1999 (CASES-99) refers to a field experiment carried out in southeast Kansas during October 1999 and the subsequent program of investigation. Comprehensive data, primarily taken during the nighttime but typically including the evening and morning transition, supports data analyses, theoretical studies, and state-of-the-art numerical modeling in a concerted effort by participants to investigate four areas of scientific interest. The choice of these scientific topics is motivated by both the need to delineate physical processes that characterize the stable boundary layer, which are as yet not clearly understood, and the specific scientific goals of the investigators. Each of the scientific goals should be largely achievable with the measurements taken, as is shown with preliminary analysis within the scope of three of the four scientific goals. Underlying this effort is the fundamental motivation to eliminate deficiencies in surface layer and turbulent diffusion parameterizations in atmospheric models, particularly where the Richardson number exceeds 0.25. This extensive nocturnal boundary layer (NBL) dataset is available to the scientific community at large, and the CASES-99 participants encourage all interested parties to utilize it.Carmen Nappo acknowledges the support of the U.S. Army Research Laboratory under Grant MIPROB-NOAA007. JS and SB acknowledge the support of Army Research Office Grant DAAD 1999- 1-0320, National Science Foundation Grant ATM-9906637.
JC and ET acknowledge the Spanish Commission for Science and Technology through Projects CLI97-0343 and CLI99-1326- E
