How much snow falls in the world’s mountains? A first look at mountain snowfall estimates in A-train observations and reanalyses

Abstract. CloudSat estimates that 1773 cubic km of snow falls, on average, each year over the world’s mountains. This volume of snow amounts to five percent of the volume of snowfall accumulations globally. This study provides a synthesis of mountain snowfall estimates over the four continents containing mountains (Eurasia, North America, South America and Africa), comparing snowfall estimates from new observation-based and four reanalysis datasets. Globally, the fraction of snow that falls in the world’s mountains is very similar between all these independent datasets (4–5 %), providing confidence in this estimate. The fraction of mountain snowfall for the different continents is also very similar between the different datasets. However, the magnitude of snowfall estimates differs substantially. The consensus in fractions and the dissimilarities in magnitude seem to indicate that large-scale forcings are similarly represented in the five datasets: however, at smaller scales (microphysics) there might be large discrepancies.