Macquarie Island Aerobiology and Wind Climate Project: Phase 3

Metadata record for data from ASAC Project 246
See the link below for public details on this project.

From the abstract of the referenced paper:

Analyses of data collected during the summer of 1979-80 from pollen traps and a flag tatter experiment along a transect across Macquarie Island, between Bauer Bay and Sandy Bay, suggest that the most sheltered locations are in the lee of prominent ridges, especially below the eastern coastal cliff tops, but also, paradoxically, on the lower slopes of the windward (west) coast. The presence of feldmark community pollen grains from 'downwind' and higher altitudes in the west coast pollen traps indicates that, during the period here documented, the island formed a topographic barrier such that when there were winds from westerly quarters of sufficient velocity, not only would the predictable lee side rotor circulations have been produced, but also a trapped windward (west coast) rotor that, at low altitudes, would have run counter to the prevailing winds. Flag tatter data from the most exposed sites indicate local wind climates of greater severity than any measured in the same way at comparable maritime latitudes across similar topographic barriers elsewhere. It can be inferred that windward rotors are not uncommon on Macquarie Island.

The effectiveness of Macquarie Island as a barrier to local ocean and atmospheric circulation is a function of balances between tectonic and denudational (including marine) processes and glacial eustasy, and would have varied over time. This, and the resulting effect of local wind circulation on fallout patterns, need to be considered when interpreting pollen diagrams.