Saturday, 14 September 2013

Australia: a country so big that its rainfall can affect global sea level

Australia is a big place. So big, in fact, that the Climate Sciences Research Highlights in Nature a couple of week's ago reported that Australia’s record rains lowered sea level [Nature 500:504 (2013) doi:10.1038/500504a]

Australia soaked up so much rain between early 2010 and late 2011 that global sea levels temporarily dropped.

— or, as Nature World News put it: Sea Level Rise Temporarily Halted as a Result of Australia Hogging all the Rain. (The “hogging” is a bit of an exaggeration, methinks, especially given all the other countries that also had floods in 2010 and 2011!)

A long-term trend of rising sea levels was brought to a screeching halt between 2010 and 2011 when atmospheric patterns came together in such a way that much of the precipitation they carried was driven over Australia, which the continent thirstily soaked up.

“No other continent has this combination of atmospheric set-up and topography,” NCAR [National Center for Atmospheric Research] scientist John Fasullo, the lead author of the study, said in a statement. “Only in Australia could the atmosphere carry such heavy tropical rains to such a large area, only to have those rains fail to make their way to the ocean.”

As the map (from ProProfs Geography Quiz Assignment 3 created by rebeccafr) below shows, most of Australia’s precipitation does drain into the surrounding seas but there is a large catchement area - including a good chunk of Queensland - that drains into Lake Eyre.

I’m not sure how much this contributed to the “soakage” versus empty aquifers elsewhere but, either way, it’s an impressive indication of how large Australia really is.

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