Abstract
Abstract. Observations of clouds over the Antarctic Peninsula during summer 2010 and 2011 are presented here. The peninsula is up to 2500 m high and acts as a barrier to weather systems approaching from the Pacific sector of the Southern Ocean. Observations of the number of ice and liquid particles as well as the ice water content and liquid water content in the clouds from both sides of the peninsula and from both years were compared. In 2011 there were significantly more water drops and ice crystals, particularly in the east, where there were approximately twice the number of drops and ice crystals in 2011.Ice crystals observations as compared to ice nuclei parameterizations suggest that secondary ice multiplication at temperatures around −5 °C is important for ice crystal formation on both sides of the peninsula below 2000 m. Also, back trajectories have shown that in 2011 the air masses over the peninsula were more likely to have passed close to the surface over the sea ice in the Weddell Sea. This suggests that the sea-ice-covered Weddell Sea can act as a source of both cloud condensation nuclei and ice-nucleating particles.
Highlights
There have been very few in situ measurements of cloud microphysical properties over the Antarctic continent (Bromwich et al, 2012; Lachlan-Cope, 2010)
At each longitude bin the average from each individual flight is shown as a point – the small number of points at each longitude means that it is not reasonable to calculate the standard deviation, but the spread of the points gives some idea of the data variability
The average number of droplets varies from around 60 to over 200 cm−3 (Fig. 6), which is typical of concentrations found over the open ocean away from possible sources of cloud condensation nuclei (CCN) from continental land masses
Summary
There have been very few in situ measurements of cloud microphysical properties over the Antarctic continent (Bromwich et al, 2012; Lachlan-Cope, 2010). During the austral summer in 2010 and 2011 measurements of basic meteorological parameters, turbulence and cloud microphysical properties were taken using the British Antarctic Survey’s (BAS) instrumented Twin Otter aircraft, and it is these measurements that are considered here. Some of these data from four flights in 2010 have already been published (Grosvenor et al, 2012), but that work concentrated on the ice crystals present, while here we consider both the liquid and ice present in the clouds on 24 flights during the two campaigns.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
