John Turner: Future Priorities for Antarctic Polar Low/Mesocyclone Research: A Personal View

British Antarctic Survey, Cambridge, UK


During the preparation of our book Polar Lows: Mesoscale Weather Systems in the Polar Regions (Rasmussen & Turner, 2003) we reviewed the whole literature of polar lows/mesocyclones in the Arctic and Antarctic. It became clear that while there had been great advances over the last few decades in some areas of research, there were still many gaps in our knowledge, particularly concerning Antarctic mesoscale vortices. In this talk I will give a personal assessment of where future research should be directed and how we can better forecast polar lows/mesocyclones in the Antarctic. I will cover the following areas:

-         Climatological studies. Examining the need for new, manual analyses of satellite imagery and the possible automatic detection of vortices in high resolution imagery. The published climatologies tend to mostly be regional in nature and there is a pressing need for a consistent Antarctic-wide climatological study of vortices. At the moment this would probably have to be carried out via a manual analysis of imagery, since automatic vortex detection schemes are still not very reliable. However, with operational analyses now having horizontal resolutions as high as 50 km, it should soon be possible to use more objective vortex detection schemes using these analyses.

-         Case studies. There are still relatively few detailed case studies of Antarctic polar lows compared to what has been done in the Antarctic. The case studies in the literature are also rather biased towards certain areas, such as the Weddell Sea and the Ross Sea/Ross Ice Shelf. Case studies around the coast of East Antarctic would be of particular value, along with cases for the very interesting area south of New Zealand. More case studies are needed of systems occurring over the Ronne Ice Shelf and over the interior plateau.

-         Modelling of vortices. Within the last decade high resolution, limited area models have started to have success in representing mesoscale lows, but again the number of case studies carried out has been rather limited. It would be very valuable to have case studies carried out for a range of baroclinic and more convective systems occurring over different parts of the continent.

-         Forecasting and nowcasting of polar lows/mesocyclones. It has become clear that mesoscale lows are of great importance to operational activities in some parts of the Antarctic, yet forecasting these lows still presents many difficulties. Operational model output can provide ‘hints’ as to where polar lows may develop, but often don’t have the resolution to explicitly represent them. Regional models offer great potential in this area.

-         Theoretical understanding. Here there has been much less research than with the polar lows of the Northern Hemisphere. Obviously the very convective systems of the north are not found, yet more work is needed on understanding the mechanisms behind the wide range of systems observed around the Antarctic.