Overall negative trends for snow cover extent and duration in global mountain regions over 1982-2020

Notwithstanding the large availability of data and models, a consistent picture of the snow cover extent and duration changes in global mountain areas is lacking for long-term trends. Here, model data and satellite images are combined by using Artificial Neural Networks to generate a consistent time series from 1982 to 2020 over global mountain areas. The analysis of the harmonized time series over 38 years indicates an overall negative trend of - 3.6% +/- 2.7% for yearly snow cover extent and of - 15.1 days +/- 11.6 days for snow cover duration. The most affected season by negative trends is winter with an average reduction in snow cover extent of - 11.5% +/- 6.9%, and the most affected season by positive changes is spring with an average increase of 10% +/- 5.9%, the latter mainly located in High Mountain Asia. The results indicated a shift in the snow regime located between the 80 s and 90 s of the previous century, where the period from 1982 to 1999 is characterized by a higher number of areas with significant changes and a higher rate of changes with respect to the period 2000-2020. This quantification can lead to a more accurate evaluation of the impact on water resources for mountainous communities.

Automated summary

Despite the availability of data and models, there is a lack of consistent understanding of long-term trends in snow cover extent and duration changes in global mountain areas. In this study, model data and satellite images are combined using Artificial Neural Networks to create a consistent time series from 1982 to 2020 for global mountain areas. The analysis of this harmonized time series over 38 years reveals an overall negative trend in yearly snow cover extent and snow cover duration.