Friday, September 28, 2007

Australia: Only hot during the day

We showed earlier that Australian temperatures at Midnight, 3am and 6am have not significantly increased, however as soon as the sun rose, temperatures at 9am and Noon showed significant increases. Whats more, surprisingly maximum and minimum temperatures have increased since the second world war.

So what happens at 3pm, 6pm and 9pm? The results below show is.

Temperature at 3pm showed a significant increase. (t = 3.8, p < 0.01)at a rate of 0.85 degrees Celsius per 100 years. The graph shown below of this, despite a bit of variability is strong, significant and obvious.

However temperatures at 6pm proved not to show a significant increase (t = 0.37, p = 0.7) as shown on the graph below.

The last 5 years have shown above normal temperatures at 6pm, but the overall trend is not significant and not clearly obvious to the eye.

Simiralily at 9pm there as been no significant increase in temperature (t = 1.4, p = 0.15). Although it has to be noted on the graph below, that like 6pm, the last 5 years have all seen greater than normal temperatures at this time.

So we've shown that Australia is only heating up at times when the sun is making an impact, that is from 9am till 3pm. Both 6pm and 9pm temperatures have seen increases, but they are not significant. Overnight temperatures are not moving either way.

So how come therefore we see increases in minimum temperature when overnight temperatures are not increasing? Isn't the minimum temperature meant to be an accurate measure of overnight temperature? We'll show you in the next article, that not only is the minimum a poor measure of overnight temperatures, that there could possibly be some big irregularities with the minimum temperature before the mid 70s and after.


Chris said...

I don't understand. Isn't the whole point of CO2 that it selectivly absorbs outgoing long wave radiation? Why would you have OLR at night?

Philip said...

Why would you have OLR at night?

The Earth' surface emits long wave radiation, aka heat, 24/7. However, during the day sunlight warms the Earth surface at a much greater rate than radiation cools it. If Co2 were warming the Earth by reducing the amount of heat radiated out into space, then the effect should noticeable at night and result in decreased nighttime cooling.

Increased nighttime cooling is directly contrary to the CO2 driven warming theory. Iincreased nighttime cooling not only means that the observed warming is caused by something other than CO2. It also means the effect of CO2 is negligable.

Chris said...

I think you will find the source of OLR is ISR. I see no time dependency in Stephan Boltzmann, you are violating energy conservation here.

braddles said...

Have you alowed for daylight saving changes in your charts?

I note that daylight saving occurred during WWII. I think this would increase readings at 3 pm (slightly), 6pm and midnight, and reduce readings at 6am and 9am, which is exactly the pattern we see in the early 1940s.

Daylight saving was introduced again in late 1971, although it has varied between the states.

Jonathan Lowe said...

hi braddles,
yes day light savings is accounted for. The times based temps given are based on the natural time.