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Study of cave climates is a neglected aspect of microclimatology. An understanding of the processes that control cave climate is required in the study of cave flora and fauna, thermodynamic conditions for karst processes underground, hydrogeologic features of speleothems as well as human use of caves for recreational and commercial purposes. An understanding of cave airflow is of central importance as the climate of a cave is a function of air exchange with the outside environment. The study site is the Glowworm Cave of New Zealand and is of particular interest because of its heavy visitor use and the presence of climate sensitive cave fauna on which the value of the cave as a tourist attraction depends.The study examines airflow using conventional methods together with experimental procedures using SF, and CC12Fz tracer gases. The results show that the rate and direction of airflow are a direct response to a thermally induced disequilibrium in air density between the cave and outside air. Both diurnal and seasonal patterns in the direction of airflow were identified. Reversal of airflow occurs when the cave to outside air density gradient is zero rather than when thermal conditions of the cave and external air are the same. Major and minor airflow routes through the cave were identified. The results of the gas tracer experiments allowed estimation of rates of air change in different parts of the cave and confirm the marked difference in ventilation that occurs within the cave. Information of this type is important because of the relationship between natural ventilation and C02 buildup. There is also the effect of ventilation on differences in climate within the cave as the thermal and moisture effects of outside air will not be as pronounced in parts of the cave where air change is limited.

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Between 1982 and 1989, biweekly whole air samples were collected at the German Antarctic station “Georg von Neumayer”. In addition, a smaller number of samples were taken in 1988 and 1989 at Scott Base, the New Zealand Antarctic station. These samples were analyzed for several light hydrocarbons and halocarbons. For the light alkanes and acetylene, the average results from the two stations which are located at opposite coasts of Antarctica agree. The annual mean values for ethane, propane, n‐butane, i‐pentane and acetylene are 380 ± 8 ppt, 84 ± 4 ppt, 50 ± 4 ppt, 15 ± 2 ppt, and 17 ± 1 ppt, respectively. The mixing ratios of ethane, propane, and i‐pentane show a seasonal cycle with a peak in August, a minimum in February and an average maximum to minimum variation of 40%‐50%. Acetylene also shows a maximum around August, but its seasonal variation is higher by a factor of three. For ethane, propane and acetylene, the measurements indicate that during the last few years, the average mixing ratios in austral winter have slightly increased. A possible explanation of this secular trend is the increase of biomass burning in the Southern Hemisphere. This is also consistent with the assumption that part of the seasonal variation found for ethane, propane and acetylene reflects the seasonal dependence of biomass burning.