Spatial modeling of permafrost distribution and properties on the Qinghai‐Tibet Plateau

Abstract

AbstractAccurate information on the distribution of permafrost and its thermal and hydrological properties is critical for environmental management and engineering development. This study modeled the current state of permafrost on the Qinghai‐Tibet Plateau (QTP), including the spatial distribution of permafrost, active‐layer thickness (ALT), mean annual ground temperature (MAGT), depth of zero annual amplitude (DZAA) and ground‐ice content using an improved Noah land surface model (LSM). The improved model was examined at a typical permafrost site and then applied to the entire QTP using existing gridded meteorological data and newly developed soil data. The simulated permafrost distribution and properties were validated against existing permafrost maps in three representative survey areas and with measurements from 54 boreholes. The results indicate that the Noah LSM with augmented physics and proper soil data support can model permafrost over the QTP. Permafrost was simulated to underlie an area of 1.113 × 106 km2 in 2010, accounting for 43.8% of the entire area of the QTP. The modeled regional average ALT and MAGT were 3.23 m and −1.56°C, respectively. Spatially, MAGT increases and DZAA becomes shallower from north to south. Thermally unstable permafrost (MAGT above −0.5°C) is predominant, accounting for 38.75% of the whole permafrost area on the QTP. Ice‐rich permafrost was mainly simulated around lakes across the north‐central QTP.