## 3 Results and Analysis
### Consistency of Latitude Changes in Vegetation Phenology
#### 3.3.2 Consistency of Phenological Trends of Different Vegetation Types by Latitude  
Determining changes in vegetation phenology according to latitude is important for analysing trend differences using different methods. To analyse the various vegetation phenology trends above 30\({}^{\circ}\)N, the region between 30\({}^{\circ}\)N and 90\({}^{\circ}\)N is divided into latitude zones of 5\({}^{\circ}\) units. The phenological trends in different vegetation types in the pixels where the land cover types have not changed are then calculated (Figure 6). By analysing the SOS trend changes, we found that the advancing trend mostly dominated in different vegetation types according to latitude zone, with an advanced trend range of 0 to 0.86 days/year. Figure 6: \(Cont.\)However, there are still some differences in the SOS under the various methods. For ENF, Methods 1 (Figure 6A), 3 (Figure 6C) and 5 (Figure 6E) show a significant advancing trend between 55\({}^{\circ}\)N and 70\({}^{\circ}\)N, while Methods 2 (Figure 6B) and 4 (Figure 6D) show no obvious trend. For DBF, the SOS shows a different delay trend under different methods at 40\({}^{\circ}\)-45\({}^{\circ}\)N. For MF, the variation law of different methods is the same in the latitude zone, showing an advancing trend at 50\({}^{\circ}\)-75\({}^{\circ}\)N that is most significant at 65\({}^{\circ}\)-70\({}^{\circ}\)N. The maximum advancing trend can reach 1.02 days/year. For other vegetation types, the SOS trend varies by latitude. For the EOS under the five tested methods, the ENF change is consistent, showing a delaying trend between 45\({}^{\circ}\)N and 65\({}^{\circ}\)N. Specifically, Methods 1 (Figure 6F), 2 (Figure 6G), 3 (Figure 6H) and 4 (Figure 6I) all show maximum delaying trends of 0.92, 1.17, 1.09, and 1.26 days/year, respectively, between 55\({}^{\circ}\)N and 60\({}^{\circ}\)N. For DBF and MF, the delaying trend under Methods 1 and 2 is smaller than Methods 3 and 4 in the corresponding latitude zones. For OS, the EOS trends are advanced in the corresponding latitudes for Methods 1 to 4, between 70\({}^{\circ}\)N and 75\({}^{\circ}\)N. For C, the EOS trends for all five methods are lagged at 35\({}^{\circ}\)-55\({}^{\circ}\)N, and the maximum delay appears at 50\({}^{\circ}\)-55\({}^{\circ}\)N. For Methods 1-5, the delay trends are 1.06, 1.21, 1.25, 1.59, and 0.65 days/year, respectively. According to the analysis of phenological trends of different vegetation types under the five chosen extraction methods (Figure 7A), the SOS trends of other vegetation are all consistent (except for C) and show an advancing trend, among which MF and ENF are more advanced than other vegetations. However, there are significant differences (\(p<0.05\)) between MF and ENF under the different extraction methods (Table 3). By comparing the SOS trend average of the five extraction methods (Figure 7B), we found that Method 4 was the most suitable for SOS extraction of C and S, and Method 5 was the most suitable for SOS extraction of WS and MF. Additionally, Method 1 is the most suitable for SOS extraction of OS and DBF. Except for Method 5, all methods are suitable for SOS extraction of ENF. For the EOS trends of different vegetation types (Figure 7C), the trends of G, S and OS are mainly advancing under the different extraction methods, while those of other vegetation are mainly delaying. By comparing the EOS trend average of the five extraction methods (Figure 7D), we found that, for C and MF, Method 5 was the best method for EOS extraction, but it was the worst for G, S, WS, and OS. Moreover, for G and DBF, Method 4 is the best approach for EOS extraction, and Method 1 is the best for EOS extraction of S and OS. Figure 6: Phenological trends in different vegetation types above 30\({}^{\circ}\)N. The values are the trend averages of the total pixels for different vegetation types in the corresponding latitudes. (**A**–**E**) represent the SOS trend and (**F**–**J**) represent the EOS trend. The NaN indicates that there are missing values in this area.