## Springfield, Ohio Historical Climate

Wikipedia's OH county maps by Catbar (free to distribute).

**Download the historical National Weather Sevice data for Springfield, OH**compiled by the Weather Warehouse (http://www.weather-warehouse.com/) and organized by me. Open the first tab, January; the column A lists the years with available data, B is the lowest daily temperature recorded,C the highest daily temperature recorded, D the warmest daily minimum temperature, E the coldest daily maximum temperature, F the average daily minimum temperature, G the average daily maximum temperature, H the mean daily temperature, I total daily precipitation in inches, J maximum daily rain in inches.

Your goal is to choose 1 parameter and explore whether their are significant trends through time for any given month. For example, is the coldest maximum temperature increasing or decreasing through time? For your ease, I have created 2 tabs that have monthly data for Average Mean Temperature and Total Precipitation that can be easily used to create graphs, you may select one of these to explore or chose another parameter.

**Assignment**

1) Graph 1 climate parameter through time for six months. For example if you are comparing mean temperature though time you will have a x axis from 1970-2012 with y values reflecting temperature in F. You will then graph all 6 months with mean temperature data (see the Average_Mean worksheet I created with compiled data from all 6 months for example).

2) Run a best-fit linear trendline through each monthly data set (6 pt)

3) Select options and display the R-squared value for each line (6 pt)

4) Determine is the trend significant*** at a 95% probability and report your findings. THis will require a sentence such as January total mean temperatures increased significantly through time, whereas there were no significant trends for total mean temperature for March May, July, September or November. (6 pt)

5) Reflect on your findings with a sentence or two (How might climate change relate to critical zone research questions? Are you surprised at the trends or lack of trends you observed? (3 pt)

*****To determine significance.**

1) Determine the number of samples examined (N, e.g. 42 low temperature values in January)

2) Find the nearest (but higher if you have to chose) value of N on this chart for correlation significance

**http://faculty.fortlewis.edu/CHEW_B/Documents/Table%20of%20critical%20values%20for%20Pearson%20correlation.htm**

In this case choose 45.

In this case choose 45.

3) Look at the top of the chart and find a two-tailed probability of 0.05, this corresponds to a 95% probability of certainty (0.95 of 1).

4) Record the number at the intersection of the 0.05 probability with a N-value of 40, (0.294)

This number is equivalent to a R value with a significant linear correlation.

**Square this number (e.g. 0.294*0.294), this is equivalent to a significant R-squared value**

5) Is the R-squared you graphed significant? (Is it higher than the value you calculated using the table?- if so it is significant, if not there is no trend.