Spatio-Temporal Characteristics and Differences in Snow Density between the Tibet Plateau and the Arctic

The Tibet Plateau (TP) and the Arctic are typically cold regions with abundant snow cover, which plays a key role in land surface processes. Knowledge of variations in snow density is essential for understanding hydrology, ecology, and snow cover feedback. Here, we utilized extensive measurements recorded by 697 ground-based snow sites during 1950-2019 to identify the spatio-temporal characteristics of snow density in these two regions. We examined the spatial heterogeneity of snow density for different snow classes, which are from a global seasonal snow cover classification system, with each class determined from air temperature, precipitation, and wind speed climatologies. We also investigated possible mechanisms driving observed snow density differences. The long-term mean snow density in the Arctic was 1.6 times that of the TP. Slight differences were noted in the monthly TP snow densities, with values ranging from 122 +/- 29 to 158 +/- 52 kg/m(3). In the Arctic, however, a clear increasing trend was shown from October to June, particularly with a rate of 30.3 kg/m(3) per month from March to June. For the same snow class, the average snow density in the Arctic was higher than that in the TP. The Arctic was characterized mainly by a longer snowfall duration and deeper snow cover, with some areas showing perennial snow cover. In contrast, the TP was dominated by seasonal snow cover that was shallower and warmer, with less (more) snowfall in winter (spring). The results will be helpful for future simulations of snow cover changes and land interactions at high latitudes and altitudes.

Automated summary

Through analyzing data from the past 70 years, we found significant differences in snow density between the Tibet Plateau and the Arctic. The average snow density in the Arctic is 1.6 times higher than that in the Tibet Plateau, and it increases gradually over time. The snow cover in the two regions also differs, with the Arctic having a longer and deeper snow cover, while the Tibet Plateau has mainly seasonal snow cover with a shallower snow layer.