We are going to have a look at the temperature variation within a year by converting dates to the corresponding day of the year in numbers. This number is between 1 and 366, where 1 corresponds to January 1st and 365 (or 366) corresponds to December 31st. Perform the following steps to analyze the intra-year daily average temperature:
Initialize arrays for the range 1-366 with averages initialized to
zeros:rng = np.arange(1, 366) avgs = np.zeros(365) avgs2 = np.zeros(365)
Calculate averages by the day of the year before and after a cutoff point:
for i in rng: indices = np.where(days[:cutoff] == i) avgs[i-1] = temp[indices].mean() indices = np.where(days[cutoff+1:] == i) avgs2[i-1] = temp[indices].mean()
Fit the averages before the cutoff point to a quadratic polynomial (just a first-order approximation):
poly = np.polyfit(rng, avgs, 2) print poly
The following polynomial coefficients in descending power are printed:
[ -4.91329859e-04...