tag:blogger.com,1999:blog-4572286363399496963.post4903490306955587919..comments2024-03-27T04:17:21.221-08:00Comments on Deep Cold: Alaska Weather & Climate: Most Extreme Year Ever for Fairbanks?Rickhttp://www.blogger.com/profile/03946704894714514716noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-4572286363399496963.post-73357959612632695332013-08-08T21:12:22.086-08:002013-08-08T21:12:22.086-08:00Thanks Richard. Unfortunately the number of steps ...Thanks Richard. Unfortunately the number of steps needed to do the analysis is far greater than my ability to automate the process. I would like to replicate this for a more maritime climate like Juneau and an Arctic climate like Barrow as time permits. There seems to be a lot of research on tracking extremes (records) but not so much on annual or seasonal variability. Of course I only spent a few minutes looking it up. Maybe we should come up with a good index of variability and write a paper about it for Alaska. Climatologist49https://www.blogger.com/profile/04560505931210357679noreply@blogger.comtag:blogger.com,1999:blog-4572286363399496963.post-24661369583855338302013-08-08T17:52:58.941-08:002013-08-08T17:52:58.941-08:00Brian,
Thanks for the links and the update. The ...Brian,<br /><br />Thanks for the links and the update. The new calculation matches what I expected, with by far the highest contribution to the score coming from the higher anomaly categories.<br /><br />Very nice work. It would be kind of fun to run through the GHCN and see what the highest annual chi-square value ever recorded is, though admittedly that would be a pretty arcane statistic!<br />Richard Jameshttps://www.blogger.com/profile/08313902028896263276noreply@blogger.comtag:blogger.com,1999:blog-4572286363399496963.post-20516973388877422492013-08-08T10:24:38.144-08:002013-08-08T10:24:38.144-08:00Actually, I did make a mistake in the Chi-squared ...Actually, I did make a mistake in the Chi-squared calculation and will update the graphic during lunch. Darn!<br /><br />As for the methodology, the test is suposed to measure how far away you are from the expected values so the data are not supposed to be normalized. The goal of the test is to see IF the data are normal. Climatologist49https://www.blogger.com/profile/04560505931210357679noreply@blogger.comtag:blogger.com,1999:blog-4572286363399496963.post-58391172044582542182013-08-08T09:52:01.441-08:002013-08-08T09:52:01.441-08:00Brian,
Very nice charts. Both cities have seen n...Brian,<br /><br />Very nice charts. Both cities have seen nearly 50 percent of days outside the +/1 SD range!<br /><br />I'm a little confused about the Chi-squared statistic, because I have always thought it should be normalized by the expected value in each category. Imagine that the "over 3SD" frequency was exactly normal (i.e. move the surplus days into the other categories), then the Chi-squared value ought to drop considerably, but your calculation would show rather little change. Perhaps you can direct me to a reference for the type of statistical test you are doing.<br />Richard Jameshttps://www.blogger.com/profile/08313902028896263276noreply@blogger.com