Spatiotemporal dynamic of environmental indices of watershed sustainability in connection with land-use change

Exploring spatial and temporal land-use changes is valuable for local governments to address issues of sustainability and planning policy where urbanization and industrialization are taking place. Besides anthropogenic effects, natural driving forces like climate change may also affect sustainability. However, such relationships have not been studied minutely. Hence, this study first investigates the land-use changes and their relationship with land surface temperature (LST) for the Shazand Watershed, Iran, in 1986, 1998, 2008, and 2016 coincided with supplementary industrialization stages. Furthermore, the relations among LST and other biophysical parameters, including Normalized Difference Vegetation Index (NDVI), Normalized Difference Buildup Index (NDBI), and Normalized Difference Water Index (NDWI), were analyzed, and corresponding variations were explored. The results indicated that the mean LST of the study watershed has an increasing trend from 1986 to 2008 due to land-use change and drought intensification. Later, LST decreased in 2016. Lower LST was associated with irrigation farming and orchard, and higher LST was related to sparse oak forest areas. There was also a negative correlation between LST and NDVI. As a result, it was inferred that greenery declined LST. Conversely, a positive correlation was found between LST and NDBI resulting from the built-up areas. Since LST could influence biological, physical, chemical processes, it can therefore be supported as an effective index for environmental sustainability assessment.

探究土地利用的时空变化，对于正在经历城镇化与工业化的地区而言，有助于地方政府应对可持续发展与规划政策相关议题。除人为活动影响外，气候变化等自然驱动力同样会对可持续性产生影响，但目前学界尚未对这类关联开展精细化研究。据此，本研究首先针对伊朗沙赞德流域（Shazand Watershed）1986年、1998年、2008年及2016年的土地利用变化及其与地表温度（Land Surface Temperature, LST）的关联展开分析，研究时段覆盖该流域工业化推进的关键阶段。此外，本研究还分析了地表温度与其他生物物理参数之间的关联，涵盖归一化植被指数（Normalized Difference Vegetation Index, NDVI）、归一化建筑指数（Normalized Difference Buildup Index, NDBI）以及归一化水体指数（Normalized Difference Water Index, NDWI），并探究了各参数的变化特征。研究结果显示，受土地利用变化与干旱加剧的共同影响，研究流域的平均地表温度在1986年至2008年间呈上升趋势，而2016年的地表温度有所回落。地表温度较低的区域多对应灌溉农田与果园，而地表温度较高的区域则集中于稀疏栎林地带。地表温度与归一化植被指数呈显著负相关，由此可推知植被覆盖可有效降低地表温度。反之，地表温度与由建成区衍生的归一化建筑指数呈显著正相关。鉴于地表温度可影响生物、物理及化学过程，因此其可作为环境可持续性评估的有效指标。