Tuesday, May 01, 2007

South East South Australia

The south eastern section of south Australia comprises of a couple of weather stations that have reliable data. These being at Cape Northumberland and Mount Gambier airport.

Maximum and minimum data go back to the end of the second world war, whilst time based data, with the exception of midnight (which only starts in 1994), goes back to the mid 1950s.

Analysis of maximum temperatures show a significant increase in temperature since 1943 (t=7.4, p<0.01). The graph linked above is quite dramatic. Similarly, a significant increase was found for minimum temperatures as well (t=6.6,p<0.01).

In both cases the increase was clearly evident. For the minimum case, we saw a large number of negative anomalies between 1943 and 1958 and since about 1980 it shows only greater than normal minimum temperatures.

Given the dramatic increase, one would expect to see increases in temperature at almost all times. However this is not the case.

There was no significant increases in temperature at 3am (t=1.5,p=0.12), 6am (t=0.02, p=0.98), 9am (t=-0.2, p=0.85) and at Noon (t=0.8,p=0.4). Just looking at the above mentioned graphs one can clearly not see any trend pattern.

However we did find significant increases in temperature at 3pm (t=4.5,p<0.01), 6pm (t=3.8,p<0.01) and 9pm (t=2.5,p<0.05). Incidentally, rainfall showed no significant change (t=-0.6,p=0.56).

So how can the minimum temperature increase so dramatically, yet temperatures from 3am through to Noon show no significant increase? These are times when the minimum would occur. The minimum generally occurs at the end of the night, shortly before the sun makes its appearance and warms us up.

It makes perfect sense that if maximum temperatures are increasing, so does the temperature at and around 3pm, which is what we found. We even found that temperature anomalies at 3pm were significantly higher than at Noon (p<0.01) and that temperature anomalies at 9pm were significantly lower than at 6pm (p<0.01). This indicates, that the temperature around south east southern Australia is heating up during the day, but more importantly is heating up at a greater rate when the sun is at it's hottest. Does this not clearly indicate an increase in solar heating?

But the results found on minimum temperatures are quite bizzare. The strength of the increase in minimum temperatures is very strong and very significant. Even if we only analyse minimum temperatures from 1955 (the same time as the beginning of time based temperature), we still find a highly significant increase (t=4.2,p<0.01).

So how is it that minimum temperatures can dramatically increase yet we see no signs of increased warming including and in between 3am and Noon? The answer will lie in the next few "weatheranalysis" posts.

7 comments:

Anonymous said...

great stuff there JLo (ha!)
interesting about the differences in temp between noon and 3pm and 6pm and 9pm. Obviously indicates solar radiation which would also include less cloud cover (not sure if you have data on this??).

I'm interested to see your analysis on minimum temperatures despite no time based increased. wierd indeed, but it sounds like you have an answer.

If you do, you really need to peer-review publish these things.

Phil_B said...

Jonathan, as I pointed out earlier, minimum temperatures typically occur after dawn, not before as you and most others assume.

The minimum temperature (on most days) will occur at the point heating from the (rising) sun exceeds radiant cooling of the earth's surface.

The time this occurs varies by location, latitude, time of year, and other factors like level of atmospheric particles, and could be as much as an hour after dawn at higher latitudes,

Jonathan Lowe said...

yes of course Phil, but the general public don't understand this. this will of course be discussed very soon.

Jonathan Lowe said...

thanks also for the link on timblair phil. All links and spreading the word is very much appreciated indeed. my traffic has skyrocketed of late, largely due to junkscience.

But interesting, phil, is that you quoted me as being an amature. I guess, by dictionary definition I am. But it worries me, that as an amature, I still have given the most comprehensive analysis of temperature data to date. Now that scares me.

Phil_B said...

I also linked to you at

http://backseatdriving.blogspot.com/2007/04/climate-skeptics-guest-post-why-david.html

The conclusions of a prominent AGW believer turned sceptic meshes nicely with your data.

I wouldn't worry too much about being labelled an amateur. Almost all the great scientific discoverers prior to the early-20th century were amateurs.

The word we used to bandy around in the dotcom boom was 'disintermediation', meaning the internet removes the need for separate professional classes to interpret for the masses.

One prediction I have made is the emergence of citizen scientists motivated by love of the subject rather than a salary.

Think of yourself as an early adopter of the disintermediation the internet allows

J. Hansford said...

You are worried about being called an amature Johnathan? I wouldn't worry to much about that. Amature astronomers find comets and discover Nova events.....

Jonathan Lowe said...

no i wasn't worried about being called an amature, just found it amusing!