Increasing annual and extreme precipitation in permafrost-dominated Siberia during 1959–2018

Abstract

Increased attention to precipitation changes in permafrost-dominated Siberia is promoted by intensified flooding under climate warming. The observed daily precipitation spanning 60 years (1959–2018) from 129 meteorological stations across the Siberian lowlands with elevations less than 500 m (50°N–70°N, 60°E–140°E) captures significant changes in both annual and extreme precipitation. For 1959–2018, the average annual precipitation over the Siberian lowlands was 428 ± 110 mm. The average annual precipitation in non-permafrost zones was approximately 458 ± 114 mm, larger than that in permafrost zones (407 ± 102 mm). Additionally, non-permafrost zones experienced greater intensities and frequencies of precipitation extremes than permafrost zones according to four extreme precipitation indices (i.e., R99p, R95p, R×5d, and R10mm). However, the rate of increase in precipitation and precipitation extremes was greater in permafrost zones than in non-permafrost zones. These results obtained from in situ observations are generally consistent with ERA5 precipitation reanalysis data. Given faster warming in permafrost than in non-permafrost zones, the rate of increase in precipitation and precipitation extremes in permafrost zones also respond more than those in non-permafrost zones. In particular, summer precipitation in permafrost zones accelerates permafrost degradation, and the release of carbon dioxide and methane from permafrost sediments is very likely to have positive feedback effects on regional temperature and precipitation increases. Our results indicate that Siberia will face risks attributable to increased precipitation and precipitation extremes in the context of climate warming, and such risks will be greater in the permafrost zones than in the non-permafrost zones.