Spatial and temporal patterns of solar absorption by clouds in Australia as revealed by exploratory factor analysis

The first model is able to fit into the radiation observations well especially those in the tropical region in which the seasonal variation is clear. The FA for establishing the second model determines seven dominant factors (with the eighth unimportant one ignored). These seven factors have distinct geographic distributions in each of which a unique factor is the dominant component. Examination of the seasonal cycle and interannual variation of estimated cloud absorption based on this model indicates three major regional groups in term of the estimated annual cloud cover. The southeast region forms a group with the largest cloud cover percentage, the group consisting of central east, northeast and central west Australia has medium percentage, and that with central, central north and northwest Australia as members has the lowest percentage. These three geographic groups have distinct distribution compared with the climate regimes in Australia, and the relationship with the origins of cloud systems is analyzed. The implications of these statistical models to the short- and long-term estimation of solar energy availability based on ground observations and their utilities are discussed.