## 3 Results
### Descriptive Statistics  
Since SOS dates for many observations occurred before 23 February 2000, when the MCD43A4 data first became available, we removed this year from further analyses of SOS and LOS. In addition, since the descriptive statistics placed the EOS dates for many observations after the last year (2011) of data, further analysis for both EOS and LOS did not include 2011. For each year, we sampled 48,942 exurban and 128,539 urban points, although the number of samples used for any given year varied due to no data values. The maximum number of no data values for all three base pair selection methods for the SOS was between 30,489 and 33,005 for the entire exurban area in and 91,482 and 116,354 for the urban areas. The normalized data of the informal selection show an earlier SOS for urban areas by a factor of 2.21 to 6.73 days on average, depending on the class. The more developed classes had the biggest difference in SOS and the least developed classes along with all of the classes together had the smallest difference. Although the developed areas as a whole and individual classes both show a later EOS for the urban areas, the number of days between the mean EOS for the urban and the exurban area had a lower range that was from 0.04 to 0.71 days. Lastly, the difference in the average length of season was longer in urban areas and ranges from being 2.84 days for all developed areas up to 6.8 days longer for the most developed areas, with the difference increasing for each class with percent imperviousness (Figure 6a). Standard deviations for the years were generally largest for the LOS parameter (Table 4). The normalized data of the 95% statistical selection threshold show an earlier SOS for urban areas by a factor of 1.05 to 3.56 days on average. Although the developed areas as a whole and the two classes of developed open space and developed medium intensity show a later EOS for the urban areas up to 1.25 days, the other two classes show a later EOS for the exurban area of 0.35 and 0.79 days. Again, the difference in the average length of season was longer in urban areas and ranges from being 0.78 days up to 4.32 days longer. The difference for each class does not consistently increase with percent imperviousness (Figure 6b). The normalized data of the 90% statistical selection threshold on STARFM version 1.2.1 also show an earlier SOS for all urban areas ranging from 0.28 to 3.55 days. All developed areas as a whole and all four classes show a later EOS for the urban areas ranging from 2.84 to 5.15 days. Again, the difference \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & **All** & **Open** & **Low** & **Medium** & **High** \\  & & **Developed** & **Space** & **Intensity** & **Intensity** & **Intensity** \\ \hline \multirow{8}{*}{**Informal Base Pair Selection**} & **SOS Urban** & 18.4 & 16.6 & 16.3 & 17.7 & 21.7 \\  & **SOS Exurban** & 17.7 & 16.0 & 16.4 & 17.6 & 22.9 \\  & **EOS Urban** & 17.6 & 17.9 & 16.1 & 16.5 & 22.0 \\  & **EOS Exurban** & 19.7 & 19.3 & 18.6 & 20.2 & 25.3 \\  & **LOS Urban** & 24.5 & 24.9 & 22.3 & 23.3 & 29.9 \\  & **LOS Exurban** & 26.2 & 25.8 & 24.5 & 25.9 & 35.1 \\ \hline \multirow{8}{*}{**95\% Clear Base Pair Selection**} & **SOS Urban** & 19.0 & 16.4 & 16.8 & 18.6 & 26.0 \\  & **SOS Exurban** & 19.2 & 17.5 & 18.4 & 19.8 & 22.3 \\  & **EOS Urban** & 19.1 & 20.1 & 17.6 & 17.9 & 23.7 \\  & **EOS Exurban** & 21.7 & 21.7 & 20.8 & 22.4 & 24.1 \\  & **LOS Urban** & 26.1 & 25.7 & 23.7 & 25.2 & 34.0 \\  & **LOS Exurban** & 29.4 & 29.5 & 28.5 & 29.9 & 31.9 \\ \hline \multirow{8}{*}{**90\% Clear Base Pair Selection**} & **SOS Urban** & 28.3 & 22.7 & 27.3 & 28.8 & 35.5 \\  & **SOS Exurban** & 24.6 & 22.0 & 24.3 & 26.1 & 29.4 \\ \cline{1-1}  & **EOS Urban** & 24.4 & 26.3 & 23.8 & 22.9 & 30.4 \\ \cline{1-1}  & **EOS Exurban** & 27.3 & 27.3 & 26.3 & 28.4 & 31.9 \\ \cline{1-1}  & **LOS Urban** & 36.8 & 36.6 & 35.9 & 36.5 & 47.3 \\ \cline{1-1}  & **LOS Exurban** & 36.9 & 36.5 & 35.8 & 38.6 & 42.8 \\ \hline \hline \end{tabular}
\end{table}