{"id":16472,"date":"2011-08-12T11:28:44","date_gmt":"2011-08-12T17:28:44","guid":{"rendered":"http:\/\/rankexploits.com\/musings\/?p=16472"},"modified":"2011-08-12T15:22:40","modified_gmt":"2011-08-12T21:22:40","slug":"weighted-prediction-of-ice-melt","status":"publish","type":"post","link":"https:\/\/rankexploits.com\/musings\/2011\/weighted-prediction-of-ice-melt\/","title":{"rendered":"Weighted Prediction of Ice Melt"},"content":{"rendered":"

Wednesday, I posted an update on the probability of a new record for the minimum 7-day average JAXA ice extent and also discussed the possibility of developing a prediction based on weighting a number of candidate predictive models using their corrected Akaike criterion (AICc). Today, I’m going to explain how I weight predictions from a range of candidate models. I think the discussion will also allow readers to see that choice of model can affect the estimated value for ice minimums. <\/p>\n

For those who want the short story though: Today, my estimate that we will break the 7-day average JAXA sea ice extent minimum is 11%. If we were betting on the minimum today, I would enter 4.63 million km^2.
\n<\/p>\n

Recall that in the previous post<\/a> I had decided to attempt to come up with the best predictor of the minimum 7-day average JAXA ice extent using time series for ice extent and ice area and no other information. In that post, I had said I was limiting my method to single<\/I> regressions. Oddly enough, the main reason for that limitation was that, on Wednesday, none of the multiple regressions achieved statistical significance for all parameters. I thought I could simplify blog discussion by ignoring multiple regressions.<\/p>\n

But, yesterday that changed. So, today, I will be including a multiple regression in my list of candidate models. The candidate models, which meet the criteria of being based on time series for Ice Extent or Ice Area only and having all fitting parameters other than the constant shift statistically significant are:<\/p>\n

    \n
  1. Min. 7-day JAXA ice extent v Current 7-day JAXA ice extent.<\/li>\n
  2. Min. 7-day JAXA ice extent v Current 7-day CT area.<\/li>\n
  3. Remaining melt v Current “Vulnerable ice” area (i.e. difference between Current 7-day JAXA ice extent and Current 7-day CT area ).<\/li>\n
  4. Min. 7-day JAXA ice extent v Current 7-day CT area and<\/i> Current “Vulnerable ice” area.<\/li>\n<\/ol>\n

    My method of selecting candidates and determining the best estimate for the minimum 7-day average sea ice extent was to:<\/p>\n