Modelling and mapping climate change impacts on permafrost at high spatial resolution for an Arctic region with complex terrain

Y Zhang,D Mclennan,I Olthof,R Fraser,X Wang,S Ponomarenko,W Chen,W Wu

doi:10.5194/tc-7-1121-2013

Y Zhang, D Mclennan + Show 6 more

Open Access

https://doi.org/10.5194/tc-7-1121-2013

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Abstract

Abstract. Most spatial modelling of climate change impacts on permafrost has been conducted at half-degree latitude/longitude or coarser spatial resolution. At such coarse resolution, topographic effects on insolation cannot be considered accurately and the results are not suitable for land-use planning and ecological assessment. Here we mapped climate change impacts on permafrost from 1968 to 2100 at 10 m resolution using a process-based model for Ivvavik National Park, an Arctic region with complex terrain in northern Yukon, Canada. Soil and drainage conditions were defined based on ecosystem types, which were mapped using SPOT imagery. Leaf area indices were mapped using Landsat imagery and the ecosystem map. Climate distribution was estimated based on elevation and station observations, and the effects of topography on insolation were calculated based on slope, aspect and viewshed. To reduce computation time, we clustered climate distribution and topographic effects on insolation into discrete types. The modelled active-layer thickness and permafrost distribution were comparable with field observations and other studies. The map portrayed large variations in active-layer thickness, with ecosystem types being the most important controlling variable, followed by climate, including topographic effects on insolation. The results show deepening in active-layer thickness and progressive degradation of permafrost, although permafrost will persist in most of the park during the 21st century. This study also shows that ground conditions and climate scenarios are the major sources of uncertainty for high-resolution permafrost mapping.

Highlights

Climate warming at high latitudes was about twice the global average during the 20th century (ACIA, 2005)
30-m resolution modelling studies (Duchesne et al, 2008; Zhang et al, 2012), the 2 km-resolution study (Jafarov et al, 2012), or the half-degree latitude/longitude or even coarser resolution modelling studies (Zhang et al, 2006, 2008). In this high-resolution study, satellite remote sensing data were used more effectively; topographic effects on solar radiation can be calculated more accurately; the plot size of field observations is comparable to the grid size, they can be used directly for model calibration and validation; and the results reveal more spatial details, and are more suitable for land-use planning and ecological monitoring and assessment
Soil and ground conditions were estimated based on ecosystem types and field observations

Summary

Introduction

Climate warming at high latitudes was about twice the global average during the 20th century (ACIA, 2005). Most climate models project that climate warming in northern high latitudes will continue at a rate higher than the global average during the 21st century (ACIA, 2005), which will further induce permafrost degradation. Most transient permafrost modelling and mapping studies have been conducted using half-degree latitude/longitude or coarser spatial resolution (e.g., Anisimov and Reneva, 2006; Marchenko et al, 2008; Zhang et al, 2006, 2008). These coarse resolution studies cannot accurately consider topographic effects on insolation since topographic conditions usually vary over shorter distances.

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