If global warming was largely man induced, then we would not see a summer/winter effect. Basically, temperatures would rise throughout the day and night at a constant rate irrespective of the time of the year.
However if the sun was one of the major causes of global warming, then we would see no or little summer/winter effect overnight (as we previously showed), but would find that summer would be increasing in temperature at a greater rate than winter at 6pm and 9pm.
This is because during summer, the sun is still heating up the surface, whilst in winter, it is long set.
So what do we find? Firstly we find a significant increase in temperature for summer minus winter at 6pm (t = 2.85, p < 0.01). Likewise we also find a significant increase in summer minus winter temperatures at 9pm (t = 3.98, p < 0.001).
Both these two results give more evidence of sun induced global warming as opposed to man made global warming.
In fact both 6pm and 9pm showed significant increase in temperatures during summer (6pm: t = 2.24, p < 0.05; 9pm: t = 4.3, p < 0.001), whilst in winter, both 6pm and 9pm showed no significant increase or decrease in temperature (6pm: t = -1.88, p = 0.067; 9pm: t = -0.98, p = 0.33). Statisticians will note that the above figures actually indicate a decrease in temperature at 6pm and 9pm during winter, however insignificant.
So what we are seeing is that throughout the year, we we seeing no significant increase or decrease in temperature when the sun is not risen, however when the sun is in the air and influencing the earth, it is only then that we are seeing an increase in temperature in the last 50 years.
This points towards very strong proof that global warming is largely caused by the sun and not by man.
8 comments:
If days are warming and nights aren't then increased cooling must be occuring at night because the extra heat is being lost.
I'm not sure whether increased daytime temperatures alone would result in more nighttime cooling or whether a factor that affects cooling (eg cloud cover) needs to change in order to facilitate increased cooling.
i do have data on cloud cover at 3 hour intervals, but i believe (though only from just looking at the data, not analysing) that there is no trend. Will have to do analysis on it.
Not sure how reliable the cloud cover data is....
I'd think cloud cover has a big affect on maximum temperatures (especially in the summer). There has been a lot of cloud in the interior West the last couple of days and as result really big negative temperature anomalies. As much as -12C in some places.
oh yes for sure, but when looking at long trends we have to determine if there is an increase or decrease in cloud cover over many years, not just a few days.
Jonathan, I just found this graph of total Australian cloud cover. Looks like a decline of 3% since 1975.
The BoM calls this 'slight'. Bet they don't refer to the 0.5C temperature increase over the same period as 'slight'.
http://www.bom.gov.au/lam
/climate/levelthree/
climch/clichv5.htm
great work Phil,
interestingly, the year with the maximum cloud cover 1974 also recorded the most amount of rain Australia has ever had in it's recordings,
but more importantly, that same year was the coldest maximum temperature year Australia has had since 1917.
Interestingly, 1973, which had almost the same amount of cloud cover, recorded the second highest minimum temperature on record
got some great data on clouds tho to phil which could well be very very very interesting indeed...
There is quite a lot of talk over at Climate Audit about a shift this year in the PDO. It looks like we are seeing it in increased cloudiness and precip, especially in the West. I'm willing to bet December in WA will be the coldest and wettest in at least 25 years.
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