British Antarctic Survey

• Main Authors: J. C. King, T. A. Lachlan-cope, R. S. Ladkin, A. Weiss, High Cross, Madingley Rd
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2007
• Subjects: Airborne measurements; Antarctic; Orographic flows; Stable boundary layer; 3; Larsen Ice Shelf; Antarc*; Antarctica; British Antarctic Survey; Ice Shelf
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.555.4429; http://nora.nerc.ac.uk/3218/1/Flight_19_paper_PDFA.pdf

We present aircraft measurements of boundary layer structure and surface fluxes from a flight over the Larsen Ice Shelf, Antarctica. Warm advection, associated with föhn flow, led to the formation of a stable boundary layer over the ice shelf, with a very sharp low-level jet at the top of the surface inversion. The strong shear associated with the jet kept the gradient Richardson number small and maintained a turbulent boundary layer over a depth of at least 600 m. The net energy balance at the surface was 52 W m-2, equivalent to a melt rate of 13 mm water per day. Net radiation (48 W m-2) made the largest contribution to melt. The contribution from the sensible heat flux (13 W m-2) was largely balanced by an upwards flux of latent heat (–9 W m-2). These measurements provide insight into the processes that control surface melt rates in an area that has experienced recent rapid warming and deglaciation.