Figure 4

The linkage of summer precipitation to topographical height (below 1600 m) in the BTH region for 2008–2018. The line represents summer precipitation variations with topographical height (binned at an interval of 100 m), and the error bars are also shown (±0.5 standard deviation). The vertical blue dotted line in the map represents the boundary line between the plain and mountainous areas, and the column chart shows the number of samples in the corresponding set.