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Antarctic Airborne Measurements Tom Lachlan-Cope (Alexandra Weiss, Russ Ladkin) British Antarctic Survey Instruments • • • • • • • • • Temperature + Humidity Radiation Turbulence (wind) Fast Temperature, Humidity and CO2 Cloud probe Aerosol Camera Laser Altimeter Surface temperature Human activity responsible for Larsen Ice Shelf collapse • There is a significant recent trend in the Southern Hemisphere Mode (SAM) towards its positive phase in summer: result is 20% stronger circumpolar westerly winds. • This reduces the blocking effect of the Peninsula, resulting in greater frequency of advection of relatively warm maritime air across the northern Peninsula from west to east (Fig. 1). • A combination of a climatological temperature gradient across the barrier and the formation of a föhn wind (warm and dry) on the lee side causes a summer temperature sensitivity to the SAM that is three times greater east of the Peninsula than to the west. Figure 1. Difference between positive and negative summer SAM 10-m wind field Peninsula Flight track Ascent Descent Sea Ice Formation • Air/sea/ice interaction • Boundary layer modification • Formation of deep ocean currents IRT (surface Temp) Air Temperature CONVECTIVE HEAT TRANSFER OVER THIN-ICE COVERED COASTAL POLYNYAS E. K. Fiedler, T. A. Lachlan-Cope, I. A. Renfrew, and J. C. King JGR Oceans - inpress Clouds Increase in Cloud Condensation Nuclei • Increased CCN mean more smaller cloud drops – not more cloud. • More smaller drops mean increased albedo (clouds are whiter). • More smaller drops mean less precipitation • Less precipitation mean clouds last longer • So in the end more clouds – perhaps. What do we want to know • Are Antarctic clouds similar to mid-latitude clouds? • How can we represent Antarctic Clouds within climate models? This Season • ICEBELL – Aircraft measurements of sea ice coincident with ship measurements – Scanning laser altimeter fitted • Offcap – Measurements of cross Peninsular flow – Aircraft and ground based measurements • Cloud measurements Future work • Arctic studies – Combined ground based and aircraft measurements of aerosols and clouds. – Using BAS Twin Otter and NERC BA 146 • Aerosol inlet fitted to Twin Otter.
