Temporal-spatial variability of modern climate in the Altai Mountains during 1970-2015

different elevations of the Altai Mountains (Fig 8A). Their increased rates were 0.37˚C/decade in high elevation, 0.44˚C/decade in middle elevation and 0.39˚C/decade in low elevation, respectively. Being consistent with the synchronously increasing trend of MAT in different elevations, the MAP in different elevations was also increasing in the studied period (Fig 8B) and their rates were 7.27 mm/decade in high elevation, 0.86 mm/decade in middle elevation and 7.49 mm/decade in low elevation, respectively. All trends of MAP were insignificant (P>0.05). Overall, we found that the variations of MAP were complex than that of MAT in different sub- regions and different elevations of the Altai Mountains, being similar with their changes in the Tianshan Mountains [9]. It should be noted that the the fastest warming rightly corresponds to the smallest increased precipitation in sub-region 2 and in middle elevations. Discussions Analysis of divergent trends of climate change and elevations It is very important to reveal the relationship between temperature and elevation for under- standing regional climate response to global warming. Two proposals about relationships between temperature trend and elevation were existed. Firstly, the warming rate in higher ele- vations was much larger than that in lower elevations [4–7, 43–45]. Secondly, the divergent magnitude of temperature trend was not associated with elevation [9, 46]. The relationships between the magnitude of MAT and seasonal temperature trend and elevation in the Altai

Mountains were showed in Fig 9. The slight positive correlations between MAT trend magni- tude and elevation were found in annual, summer and autumn, the relationship was only sig- nificant in summer. The negative relationship occurred in spring and winter, and they were not significant. Overall, the magnitude of temperature trend was negatively correlated with Fig 9. Relationships between annual and seasonal air temperature trend magnitude and elevation in the Altai Mountains. https://doi.org/10.1371/journal.pone.0230196.g009 PLOS ONE Modern climate characters in the Altai Mountains PLOS ONE | https://doi.org/10.1371/journal.pone.0230196 March 17, 2020 9 / 15