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Description:
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Currently , global warming is a focus of attention . In order to scientifically evaluate evidence about global warming , and prove the existence of global warming , this research analyzes almost 100 years’ daily temperature records in a local weather station (Period : 1 /1 /1914 -12 /31 /2006 , Station : Lubbock International Airport , TX 79403 , CoopID : 415411 ) .
Since mean and variance are very important in evaluating that the temperature records are inconsistent with an unchanging climate , this research create effective approaches to test the inequality of the variance and the mean of daily temperature in each year , and find their trend over the time . First , it provides the approach to test the normality of daily temperature because a lot of statistical tests are sensitive to normality assumption . Then , based on the results of invalid normality , it gives the detail procedures to test the equality of variances and means using some statistical tests which are robust to departure from normality . In testing the equality of variances , Brown and Forsythe’s test is used . In testing the equality of variances , Kruskal -Wallis nonparametric test and Z -test are used . In addition , “Loess” Smoother technique is used to find the trend of the variance and the mean of daily temperature over time . The results show that the equality of variances and means are both invalid , and their trends are increasing over time . These results suggest global warming really exists in the local place , and they also provides evidences that support global warming
Furthermore , the probability of maximum temperature is found to be a Weibull distribution by applying Extreme Value Theory . Based on fitting data to the distribution , some useful predictions are made , such as estimation of 100 -year return level which predicts what the annual maximum temperature will be on average every 100 years .
Overall , this research scientifically estimates the local effect of global warming . It gives a good reference for the study of global warming , climate change , weather prediction , or time series data . |