## 5 Conclusions  
The spatial-temporal trends and sustainability characteristics of land NPP change in the Han River Basin from 2001 to 2019 were investigated based on the MOD17A3 NPP dataset obtained from GEE. The main drivers of land NPP change and their spatial differences were quantified as well. The results are presented below.  
1. The multi-year average of land NPP was 486 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\) in the Han River Basin from 2001 to 2019, with the highest in 2015 and the lowest in 2001. The interannual variation of land NPP exhibited a fluctuating upward trend, with a more pronounced growth rate from 2001 to 2010 than from 2011 to 2019. The growth rate of land NPP in the upper reaches was faster than the basin-wide average, while the growth rates in the middle and lower reaches were slower than the basin-wide average.
2. The spatial heterogeneity of land NPP was evident, with high values in the west and low values in the east. Of the basin area, with NPP values between 400 and 600 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\), 66.15% was concentrated in the middle and upper reaches of the basin. Land NPP was highest in the watershed above Danjiangkou, followed by the mainstream watershed below Danjiangkou, and lowest in the Tangbai River Watershed. The Theil-Sen slope of land NPP in the Han River Basin from 2001 to 2019 ranged from \(-\)33 to 20 g C\(\cdot\)m\({}^{-2}\cdot\)a\({}^{-1}\). Of the basin area, 57.82% presented a significant increase in land NPP, 0.96% showed a significant decrease, and 41.23% exhibited no significant change. In general, series with continuously significant increases in sustainability pattern of land NPP change were far more than those with continuously significant decreases. Land NPP in the Han River Basin will present sustained growth in the future.
3. It was broadly consistent in the estimation of DEGRADATION between the Trends. Earth method and the sustainability pattern method. However, there were some differences in the assessment of IMPROVEMENT and STABLE, because certain land defined as IMPROVEMENT by Trends.Earth was classified as STABLE by the sustainability pattern method.
4. The MGWR model outperformed the global OLS and GWR models in fitting the drivers of land NPP change in the Han River Basin. There are regional differences in the main factors influencing land NPP change. Precipitation and population count were the dominant factors in most regions, and the population count shows a significant inhibitory effect on the growth of land NPP. In practice, a zoning approach should be adopted to develop differentiated vegetation restoration and conservation programs for specific regions.  
The assessment approach proposed in this study can provide a methodological framework and examples of regional practice that can enable track progress of LDN and the socio-ecological sustainable development of the basin.  
Conceptualization, Y.H. and C.W.; methodology, Y.H.; software, Y.H.; validation, Y.H., C.W. and X.Y.; formal analysis, Y.H.; investigation, X.Y.; resources, Y.H.; data curation, C.W.; writing--original draft preparation, Y.H.; writing--review and editing, [PERSON] and S.Y.; visualization, [PERSON]; supervision, [PERSON]; project administration, C.W.; funding acquisition, C.W. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number 41704013. C.W. was supported by funding from the Sino-German Scientist Cooperation and Exchange Program (42061134010) and the Special Project on Strategic Pioneering Science and Technology of the Chinese Academy of Sciences (XDA15017700, XDB23030100).  
The data that support the findings of this paper are available from the corresponding author upon justifiable request.  
The authors declare no conflict of interest.