McDavitt on what the weather did in 2009
Metservice’s weather ambassador Bob McDavitt has compiled his annual review of weather trends for the previous year.
Click on the presentation below to view in full-screen mode or to download.
[slideshare id=2772724&doc=2009review-091223221454-phpapp02&type=d]
3 Responses to “McDavitt on what the weather did in 2009”
Anyone like to explain to me ( in simple terms ) why the New Zealand Air Temperature Graph suggests this year is well below the mean?. Is the graph a true reflection of the measurements?.
Visually, the past year area below the long term mean appears larger than the area above, suggesting 2009 is significantly colder than the mean. When I cut and weigh ( yes I know I’m a loser with nothing better to do ), the mass of paper representing the area below the LTM is 12.0 mg, and above 6.6 mg.
I assume the process of graphing or averaging may be responsible for graphing errors, but given the contentious nature of the climate claims, perhaps a little more clarification is required?.
Was 2009 colder than the LTM, and what are the year-to-year trends.. If it’s also the hottest decade in NZ, I assume the error bars on the temperature measurements and calculations are relatively small, justifying such a claim. Is there a similar graph anywhere with error bars?.
The following table is compiled from NIWA’sa individual monthly climate summaries for the past year , obtainable from http://www.niwa.co.nz/our-science/climate/publications/all/cs/monthly (dec 2009 is still being computed so I’m using Dec 2008 instead)
Dec
Jan
whoops – tab key was wrong one to use when typing in a table…it stored my reply instead of tabbing.
The following table is compiled from NIWA’sa individual monthly climate summaries for the past year for New Zealand , obtainable from http://www.niwa.co.nz/our-science/climate/publications/all/cs/monthly (Dec 2009 is still being computed so I’m using Dec 2008 instead)
National Average difference from Long Term Mean
Dec 15.8 0.2
Jan 17.6 0.6
Feb 17.5 -0.3
Mar 15.1 -0.6
Apr 13.4 0.1
May 9.0 -1.6
June 7.5 -0.7
July 7.3 -0.4
Aug 10.2 1.7
Sep 10.6 0.3
Oct 10.6 -1.4
Nov 13.6 -0.1
average for year 12.4 -0.2
so the year ending Nov 2009 was on the cool side by -0.2c, slightly lower than the long term mean.
. Better to use the actual numbers rathe than cutting and weighing graphs- there may be some confusion as to the width and smoothing of the lines.
I suppose we can dwelve through the NIWA monthly climate summaries and extend this exercise to compute the variations form the Long term mean for the decade ending November 2009 , or a term of our choice, but for this article I was just interested in looking back at 2009.
bob mcdavitt