Well your first graph looks interesting and it gives a picture of big variation of temperatures. So if you want to present any trend out of the data it needs to be treated with seasonal adjustments.
Series are made up of four components: St: The Seasonal Component Tt: The Trend Component Ct: The Cyclical Component It: The Error, or irregular component. One way of looking at such data is take each daily value and compare that value with the average value for that day One scary thing about the discussions about heat measurements and trends over time is that the researchers have been manipulating the data to fit their interests. 2010/1/7 David Mitchell <[email protected]>: > Yes, the second data set is the minimum high and minimum low temperatures for > yearly intervals. It is an extract from the original data. > > -- > David Mitchell > > On 1/7/2010 13:41, Björn Helgason wrote: >> The Y scale in one graph goes from -20 to +100 and so do the curves >> The Y scale on the other goes from -20 to +20 and the curves therefore >> not the same >> >> >> 2010/1/7 David Mitchell<[email protected]>: >>> It may depend on how one looks at the data: >>> >>> http://www.jsoftware.com/jwiki/Scripts/WeatherPlot?action=AttachFile&do=get&target=rochestermintemp.png >>> >>> ;) >>> >>> -- >>> David Mitchell >>> >>> On 1/7/2010 9:23, Björn Helgason wrote: >>>> Looking at this data it is nothing that says there is any general >>>> warming going on. >>>> >>>> If anything it looks like it is getting cooler. >>>> >>>> >>>> >>>> 2010/1/6 David Mitchell<[email protected]>: >>>>> >>>>> Here is one example of what I find useful with J: >>>>> >>>>> http://www.jsoftware.com/jwiki/Scripts/WeatherPlot >>>>> >>>>> -- >>>>> David Mitchell >>> ---------------------------------------------------------------------- > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm -- Björn Helgason, Verkfræðingur Fornustekkum II 781 Hornafirði Po Box 127,801 Selfoss , t-póst: [email protected] gsm: +3546985532 sími: +3544781286 http://groups.google.com/group/J-Programming Tæknikunnátta höndlar hið flókna, sköpunargáfa er meistari einfaldleikans góður kennari getur stigið á tær án þess að glansinn fari af skónum /|_ .-----------------------------------. ,' .\ / | Með léttri lund verður | ,--' _,' | Dagurinn í dag | / / | Enn betri en gærdagurinn | ( -. | `-----------------------------------' | ) | (\_ _/) (`-. '--.) (='.'=) ♖♘♗♕♔♙ `. )----' (")_(") ☃☠ ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
