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Magnitude-frequency analysis by the Gumbel method of temperature records at 166 Australian stations produced data for maps of extreme temperatures at recurrence intervals of 1.58, 2.33, five, ten, twenty-five, fifty, and 100 years on the annual series, plus a generalized map of actual values for the 100-year interval. Whereas the extremes for recurrence intervals up to about twenty-five years conform well to the Theory of Extreme Values, those for greater recurrence intervals produce convex-upward graphs, suggesting a similarity to Gumbel's Type III probability. In sonic parts of the continent ranges between the 1.58-year and the 100-year extremes are small. Graphs for some very exposed coastal stations flatten abruptly in their upper ranges. Sample occurrences of absolute extremes at selected stations involved unusual transport of cTW air from the interior at low levels across the coastlands in association with patterns of cyclonicity and anticyclonicity that for the most part contrast with most frequent patterns. [ABSTRACT FROM AUTHOR]

An air mass frequency model is constructed to facilitate the formulation of a genetic classification of climate. The model uses Venn diagrams to distinguish three basic climatic regimes, each determined by the relative dominance of air masses: the dominant regimes, where a single air mass dominates all year; the seasonal regimes, determined by seasonally dominant air masses; and the compound regimes, with no dominant air mass. Different climates within each regime are distinguished by actual air mass types. Monthly air mass dominance is determined from actual station surface data for application of the model to world climates. This is completed by analysis of monthly data plotted on modified climographs and by the construction of a monthly air mass identification chart. The proposed system is illustrated by Australian data. [ABSTRACT FROM AUTHOR]