Permafrost Distribution along the Qinghai-Tibet Engineering Corridor, China Using High-Resolution Statistical Mapping and Modeling Integrated with Remote Sensing and GIS

Fujun Niu,Guoan Yin,Zhanju Lin,Minghao Liu,Jing Luo

doi:10.3390/rs10020215

Abstract

Permafrost distribution in the Qinghai-Tibet Engineering Corridor (QTEC) is of growing interest due to the increase in infrastructure development in this remote area. Empirical models of mountain permafrost distribution have been established based on field sampled data, as a tool for regional-scale assessments of its distribution. This kind of model approach has never been applied for a large portion of this engineering corridor. In the present study, this methodology is applied to map permafrost distribution throughout the QTEC. After spatial modelling of the mean annual air temperature distribution from MODIS-LST and DEM, using high-resolution satellite image to interpret land surface type, a permafrost probability index was obtained. The evaluation results indicate that the model has an acceptable performance. Conditions highly favorable to permafrost presence (≥70%) are predicted for 60.3% of the study area, declaring a discontinuous permafrost distribution in the QTEC. This map is useful for the infrastructure development along the QTEC. In the future, local ground-truth observations will be required to confirm permafrost presence in favorable areas and to monitor permafrost evolution under the influence of climate change.

Highlights

The IPCC Fifth Assessment Report [1] indicates that most permafrost has been degrading since the last little ice age and the rate has increased recently, as evidenced by permafrost temperature increasing and a positive trend of the active layer thickness
The thawing of ice-rich permafrost has an impact on the stability of the slopes and the thermokarst [13,14,15], which could lead to the intability of the Qinghai-Tibet Railway (QTR) [16]
We investigated the surface characteristics and permafrost conditions along the Qinghai-Tibet Engineering Corridor (QTEC) based on the permafrost survey position and boreholes that were carried out when the QTR and Qinghai-Tibet highway (QTH) were built

Summary

Introduction

The IPCC Fifth Assessment Report [1] indicates that most permafrost has been degrading since the last little ice age and the rate has increased recently, as evidenced by permafrost temperature increasing and a positive trend of the active layer thickness. Permafrost degradation has an impact on surface and subsurface hydrologic conditions, soil strength properties, and ecosystems [2]. Changes in the active layer thickness and permafrost temperature due to climate warming and surface disturbances have major ecological and engineering implications [8,9,10,11,12]. The thawing of ice-rich permafrost has an impact on the stability of the slopes and the thermokarst [13,14,15], which could lead to the intability of the Qinghai-Tibet Railway (QTR) [16]. Climatic change and its associated effects on ground surface evolution, landscape dynamics, and natural hazards make it important to map permafrost distribution on the QTP. Improved methods for mapping permafrost distribution are essential to designing road and pipelines and to understanding the dynamics of alpine ecosystems

Methods

Results

Discussion

Conclusion