Variation of air temperature in a gully in Eastern Kansas during nocturnal periods

Air temperature patterns in shallow valleys during nocturnal periods are an important component of energy exchanges. As part of CASES-99 experiment a shallow prairie valley (gully) in eastern Kansas was instrumented with air temperature sensors placed at 50 cm above the surface. Thermocouples were spaced every 100 m along the length (N-S) of the gully and every 20 m across in a perpendicular transect (E-W). Air temperatures were recorded at 1 Hz and averaged to1 minute values. The upper end of the gully was instrumented with net radiometers and 3-d sonic anemometers to measure the changes in energy balance throughout the night. Results show distinct temperature regimes developing quickly in the gully after sunset as a function of elevation These data are being evaluated to quantify the changes in air temperature patterns during evening transition periods as well as morning. Implications of micro-temperature structures to air flow movement will be discussed.