Wednesday, August 08, 2007

East Victoria still warmer only when the sun is shining

Using data from Omeo Comparison, Gabo Island Lighthouse and East Sale Airport, we have some good data on Eastern Victoria with the exception with temperatures at midnight.

But first things first, maximum temperatures show no significant increase in temperature since 1910, but it must be noted that the last 10 years have been average 0.5 degrees above the norm. Since the second world war, maximum temperatures have been drastically increasing. Minimum temperatures however do not show any major sign of trend, and statistical analysis suggests insignificance.

With midnight having limited data, other night time temperatures at 3am and 6am show no significant increase or decrease over time. Even 9am shows no significant trend, although it is actually approaching close to a significant decrease.

And whilst we are seeing some temperature dimming at night, when the sun makes its appearance, we see a completely different story. Temperatures at Noon, 3pm, 6pm and 9pm all show significant increases in temperature. The trend at 3pm and 6pm is most obvious. The temperature increase at 9pm is different to previous areas. In general we have seen increases at 9am and a steady temperature at 9pm, whilst here we see stable temperatures at 9am and increases at 9pm. Seems like the trend over the years has meant it is slow to heat up in the morning and slow to cool down after the sun sets.

With minimum temperatures not significantly increasing, it is no surprise that differences in temperature between 3am and 6am and the minimum show no major trend.

Similarly, temperature anomaly trends between 6am and 9am showed no significant difference (although very close to a significant decrease), but temperatures anomalies at Noon were significantly increasing compared to 9am and temperature anomalies at 3pm were significantly increasing with respect to Noon.

Also temperature anomalies at 9pm were significantly decreasing when compared to 6pm despite earlier proving an increasing temperature trend at 9pm. The trend in the above link is strong, obvious and highly significant.

Once again, temperature anomalies are increasing more rapidly over the years when we get to the heat of the day, and decreasing over the years when going away from 3pm.

Is there anything else that can provide this apart from the sun? What else influences temperature with increasing trend to 3pm and decreasing after that, whilst not playing a part at night?


IanP said...

Jonathan - I assume that there is consistancy (over time) in the location, equipment used and site layout for each of the temperature recording stations you have used. I doubt if the thermometer at the start of the period is the same as the temperature recorder used today. I would be interested to see if any of your trends can be matched to these differences.

Jonathan Lowe said...

hi ianp, no doubt technology has changed over time. You can view this website to see some of the effects of this Whats up with that

Australia's temperature stations are probably the best in the world, although the effects of similar things mentioned on the above webpage as well as changes in technology and situation can lter this.

But then again, statistical analysis by the BOM is done on these figures irrespective of such change, and that's what I do as well.