BayCEER Workshop 2017

Formation of Thermal Microfronts in Gentle Terrain

P 4.2 in BayCEERversity: Across scales, compartments & communities

In the nocturnal boundary layer spatio-temporal temperature and wind speed variability is mainly determined by cloudiness, static stability and wind regime. The Shallow Cold Pool Experiment in the great plains of northeast Colorado, USA, was conducted from October until December of 2012 with the expectation of only small influence of the local microtopography on spatio-temporal temperature variability (https://www.eol.ucar.edu/field_projects/scp). The site was also chosen as most of the Earth's surface is characterized by gentle, less organized terrain of small spatial scale. However, during most nights thermal microfront were generated by the local topography. The thermal microfronts caused horizontal temperature differences of 3 K on average within 30 m distance and occured mainly during clear skies for wind speeds between 2.5 m s^-1 and 4.5 m s^-1. The origin is not fully understood, but possible formations of the thermal microfronts are discussed.

 

Keywords: thermal microfront, nocturnal boundary layer, microtopography