Trends in climate extremes in Southeast Asia, the South Pacific, and Australasia

Several studies have been conducted to ascertain how climate extremes have been changing over Australia and the surrounding region. The results of these studies will be described.

The first study is a collaborative effort with scientists from 15 countries in Southeast Asia, the South Pacific, and Australasia. A common data period was selected, common quality control software used on all the data, and common methods of analysis were employed. The result is time-series of eight indices of climate extremes that can be compared across the region, and with other climate extremes trends in other parts of the globe.

The second study examines how decisions of such apparently trivial matters as whether to only use days with rainfall (rather than all days) in calculating trends in rainfall extremes can substantially affect the results. Several different ways of defining intense rainfalls have been compared, using a high-quality daily rainfall data set for Australia. The results indicate that care is needed in selecting the appropriate index of extreme rainfall, depending on the question to be examined.

Finally, a study of how best to determine whether the entire distribution, and especially the "extreme" ends of the distribution, is changing has been carried out. Suggestions as to how to improve monitoring of trends and changes in climate extremes will be presented.