April 16, 2009

Analysis Disproves Prevalent C.U. 'Weather Machine' Myth

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Sun Weather Columnists Brian Crandall ’10 and John Cintineo ’09 recently analyzed weather data during the Cornell Days of the last several years in order to find out whether there does in fact exist a “weather machine.”

The Cornell Days weather machine is commonplace discussion during the period when accepted high schoolers come back to decide whether they will make Cornell their home. The myth often conjures up thoughts of President David Skorton pulling a lever and making the clouds disappear. But this current of bout of beautiful weather raises the question of whether there is in fact a machine, and what it actually does.
Going over the temperature data, we thought it would be best to compare the actual average to the climatological average. The climatological average is calculated from the roughly 100 years of data of daily Ithaca weather that has been recorded. The actual average was recorded for the Cornell Days of a particular year. Since Cornell Days varies from year to year, the climatological average supplied is the median date. For example, in 1994 Cornell Days ran from April 11 to April 25, the climatological average supplied is for April 18th.
The data for average highs shows no warming trend with Cornell Days. The high figure in 2008 can be attributed to two really warm days that skewed the data. The same goes for the average lows, which show no warming trend either.
Of the nine given “Cornell Days” periods, we had five periods with above normal precipitation and four with below normal precipitation. The average precipitation for the nine periods was about 1.41 inches, which is a bit above the average normal precipitation for these days in April, which is 1.31 inches. However, getting an average of 1.41 inches of rain is only in the 54th percentile (the average normal of 1.31 in. is the 50th percentile), based on our sample size of nine and assuming a normal distribution. So, we can safely say that we don’t always have beautiful weather for Cornell Days, and that lately, Cornell Days have actually been a bit wetter than normal.
The overall average for the highs was about 54.5 degrees, and the average of the lows is 33.2 degrees. These are not significant differences from the climatological means, so there has been no real warming trend. A better explanation would be that it’s mid-April, the weather is warming up and it’s perfectly normal to be colder or warmer than usual from year to year. There’s just no real trend to those changes, whether it be a warming trend or cooling trend.
That being said, this data only went back to 1994. This analysis only shows there hasn’t been a big difference in the past 15 years. Significant climate change with regards to warming temperatures should take at least few decades to show up, and Cornell Days simply doesn’t go back far enough in time.

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