Our warmest year on record

The Bureau of Meteorology recently released its Annual Climate Statement for 2013. Here are its key points: 

Data collected and analysed by the Bureau of Meteorology show that 2013 was Australia’s warmest year on record while rainfall was slightly below average nationally.

  • Summer 2012–13 was the warmest on record nationally, spring was also the warmest on record and winter the third warmest
  • Overall, 2013 was Australia’s warmest year on record: annual national mean temperature was +1.20 °C above average
  • All States and the Northern Territory ranked in the four warmest years on record
  • Nationally-averaged rainfall was slightly below average for the year, with 428 mm (1961–1990 average 465 mm)
  • Rainfall was mostly below average for the inland east and centre, and above average for the east coast, northern Tasmania and parts of Western Australia.*

Overview

  • 2013 was Australia’s warmest year since records began in 1910. Mean temperatures across Australia have generally been well above average since September 2012. Long periods of warmer-than-average days have been common, with a distinct lack of cold weather. Nights have also been warmer than average, but less so than days.
  • The Australian area-averaged mean temperature for 2013 was +1.20 °C above the 1961–1990 average. Maximum temperatures were +1.45 °C above average, and minimum temperatures +0.94 °C above average. Temperatures were above average across nearly all of Australia for maximum, mean and minimum temperatures, with large areas of inland and southern Australia experiencing the highest on record for each.
  • Australia has experienced just one cooler-than-average year (2011) in the last decade.

* Most of the above-average rainfall on the east coast was due to just one extreme event, cyclone Oswald in late January, as per Special Climate Statement 44 – extreme rainfall and flooding in coastal Queensland and New South Wales (pdf).

The BoM also releases annual statements covering weather at state level in more detail. Key points of the Queensland report: 

Queensland in 2013: Record heat, dry in the west

Queensland’s mean maximum temperature was highest on record in 2013. The year started with some exceptionally hot weather, with high temperature records broken. Locally, there was very heavy rain, especially in January, but it was generally a dry year west of the Great Dividing Range. Mt Isa and Tambo had their lowest annual rainfall on record.

  • Mean maximum temperature highest on record
  • Record hot start to the year
  • Record rain in the east in January from ex-tropical cyclone Oswald
  • Four tropical cyclones
  • Severe thunderstorms in November and December
  • Dry west of the Great Dividing Range
  • Record low rainfall in the west and southern interior

None of the above is necessarily due to global warming but it is all entirely consistent with global warming, and we can expect that weather like this will become normal as global warming progresses. Bearing in mind that this year represents, as the BoM says, temperatures [only] 1.2 C above the baseline and medium-term predictions are in the range of  2 – 6 C above the baseline, I think we should be more worried than most of us are; but I will deal with those issues on their own in another post as soon as I can find time.

Lightning (and other stuff) for geeks

We have been thinking about thunderstorms pretty often in the last week or so, with the severe storms around Brisbane affecting so many people and smaller storms  threatening us although not quite making it all the way to Townsville. (We watch them on the BoM radar and we see clouds building up behind Mt Stuart and then they just …. go away.) (So far.)

Anyway, here on YouTube is a wonderful super-high-speed movie of a bolt of lightning. Captured at over 7000 frames per second, it lets you see the development of the strike. We found it via xkcd, one of our favourite online cartoonists. He has a weekly “What If?” column “Answering your hypothetical questions with physics,” which is somewhat in the style of Mythbusters in that the science is good, the presentation is informal and no question is too wacky to tackle. His page on lightning explains what we are seeing on the video and answers some more-or-less sensible questions about how lightning bolts behave.

While we are thinking about physics/maths, here are two more web pages:

A mathematically generated butterfly created by Ken Perlin of NYU Computer Science. He has lots more “toys from the blog” on his home page but they didn’t work for me when I tried a few – “inactive plug-in” error. If you fancy your luck, here’s his page.

Jason Kottke’s blog isn’t as heavy on maths/IT as xkcd  (he says, “The editorial direction … clusters around a pair of hand-wavy ideas: the liberal arts 2.0, and people are awesome”) but does have a substantial proportion of maths posts. Start here for the maths stuff, or just go to the main page.