PIC: Comprehensive R package for permafrost indices computing with daily weather observations and atmospheric forcing over the Qinghai–Tibet Plateau

Abstract

Abstract. An R package permafrost indices computing (PIC) was developed, which integrates meteorological observations, remote sensing data, and field measurements to compute the factors or indices of permafrost and seasonal frozen soil. At present, 16 temperature/depth-related indices are integrated into the R package PIC to estimate the possible change trends of frozen soil in the Qinghai-Tibet Plateau (QTP). These indices include the mean annual air temperature, mean annual ground 15 surface temperature, mean annual ground temperature, seasonal thawing/freezing n factor (nt/nf), thawing/freezing degreedays of air and ground surface (DDTa/DDTs/DDFa/DDFs), temperature at the top of the permafrost, active layer thickness, and maximum seasonal freeze depth. The PIC package supports two computational modes, namely, the stations and region calculation that enables statistical analysis and intuitive visualization on the time series and spatial simulations. Over 10 statistical methods were adopted to evaluate these indices in stations, and a sequential Mann-Kendall trend test and spatial 20 trend method were adopted. Multiple visual manners display the temporal and spatial variabilities on the stations and region.The data sets of 52 weather stations and a central region of QTP were prepared and simulated to evaluate the temporal-spatial change trends of permafrost with the climate. Simulation results show extensive permafrost degradation in QTP, and the temporal-spatial trends of the permafrost conditions in QTP were consistent with those of previous studies. The PIC package Geosci. Model Dev. Discuss., https://doi

Identifying Soil Freeze/Thaw States Using Scattering and Coherence Time Series of High-Resolution C-Band Synthetic Aperture Radar in the Qinghai-Tibet Plateau

“…40 years [3], [4]. As an important indicator of climate change [5], the total area of permafrost has decreased by approximately 410 000 km 2 [6] while the rate of increase in the thickness of the active layer is the highest up to 7.5 cm per year [7].…”