%AMaillard, Julia%ARavetta, François%ARaut, Jean-Christophe%AFochesatto, Gilberto%ALaw, Kathy%BJournal Name: Boundary-Layer Meteorology; Journal Volume: 185; Journal Issue: 3; Related Information: CHORUS Timestamp: 2022-10-14 02:18:53 %D2022%ISpringer Science + Business Media %JJournal Name: Boundary-Layer Meteorology; Journal Volume: 185; Journal Issue: 3; Related Information: CHORUS Timestamp: 2022-10-14 02:18:53 %K %MOSTI ID: 10370136 %PMedium: X %TModulation of Boundary-Layer Stability and the Surface Energy Budget by a Local Flow in Central Alaska %XAbstract

The pre-ALPACA (Alaskan Layered Pollution And Chemical Analysis) 2019 winter campaign took place in Fairbanks, Alaska, in November–December 2019. One objective of the campaign was to study the life-cycle of surface-based temperature inversions and the associated surface energy budget changes. Several instruments, including a 4-component radiometer and sonic anemometer were deployed in the open, snow-covered University of Alaska Fairbanks (UAF) Campus Agricultural Field. A local flow from a connecting valley occurs at this site. This flow is characterized by locally elevated wind speeds (greater than 3 m s$$^{-1}$$-1) under clear-sky conditions and a north-westerly direction. It is notably different to the wind observed at the airport more than 3.5 km to the south-west. The surface energy budget at the UAF Field site exhibits two preferential modes. In the first mode, turbulent sensible heat and net longwave fluxes are close to 0 W m$$^{-2}$$-2, linked to the presence of clouds and generally low winds. In the second, the net longwave flux is around − 50 W m$$^{-2}$$-2and the turbulent sensible heat flux is around 15 W m$$^{-2}$$-2, linked to clear skies and elevated wind speeds. The development of surface-based temperature inversions at the field is hindered compared to the airport because the local flow sustains vertical mixing. In this second mode the residual of the surface energy budget is large, possibly due to horizontal temperature advection.

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