Here comes the rain again … or not

In southern Australia, it has been raining less in autumn and winter. This drop in rainfall has been attributed to a 50-year decrease in the average intensity of storms in the region – a trend which is forecast to continue for another 50 years.

CSIRO climate scientist, Dr Jorgen Frederiksen, said these changes are due to weakening of the mid-latitude jet stream and changes in atmospheric temperatures. The jet stream comprises fast moving westerly winds in the upper atmosphere.

“The drop in winter and autumn rainfall observed across southern Australia is due to a large downturn in the intensity of storm formations over at least the last three decades,” Dr Frederiksen said.

“We expect a continuation of these trends as atmospheric temperatures rise based on projections from climate models forced by increasing carbon dioxide concentrations.”

Read more at CSIRO