Soil freeze depth variability across Eurasia during 1850–2100

Abstract

Soil freeze depth (SFD) is an important indicator of cryospheric and climate change. Changes in SFD have important effects on hydrology, the energy balance, carbon exchange, and ecosystem diversity. However, quantifying and predicting SFD at large scales remains a challenge due to sparse long-term observations. This study employs the Stefan solution combined with 16 of the coupled model inter-comparison project phase 5 (CMIP5) models over the historical period (1850–2005) and three representative concentration pathways (RCP 2.6, 4.5, and 8.5) for 2006–2100, the Climatic Research Unit dataset (1901–2013), and hundreds of soil temperature, air temperature, precipitation, and snow depth sites to analyze the spatiotemporal variability of SFD in Eurasia under historical and projected climate change. During 1850–2005, a statistically significant SFD decrease of 0.49 ± 0.04 cm/decade is observed. Spatially, the biggest decreases are generally in Siberia and on the Tibetan Plateau. There is a projected decrease in 2006–2100 SFD of 4.58 ± 0.26, 1.85 ± 0.21, and 0.45 ± 0.18 cm/decade for RCP 8.5, 4.5, 2.6, respectively. These variations in SFD provide key insights into spatiotemporal changes in climate, and facilitate improved understanding of variation in frozen ground across Eurasia.