Development of Methods for Detection and Monitoring of Fire Disturbance in the Alaskan Tundra Using a Two-Decade Long Record of Synthetic Aperture Radar Satellite Images

Liza Jenkins,Laura Bourgeau-Chavez,Nancy French,Tatiana Loboda,Brian Thelen

doi:10.3390/rs6076347

Abstract

Using the extensive archive of historical ERS-1 and -2 synthetic aperture radar (SAR) images, this analysis demonstrates that fire disturbance can be effectively detected and monitored in high northern latitudes using radar technology. A total of 392 SAR images from May to August spanning 1992–2010 were analyzed from three study fires in the Alaskan tundra. The investigated fires included the 2007 Anaktuvuk River Fire and the 1993 DCKN178 Fire on the North Slope of Alaska and the 1999 Uvgoon Creek Fire in the Noatak National Preserve. A 3 dB difference was found between burned and unburned tundra, with the best time for burned area detection being as late in the growing season as possible before frozen ground conditions develop. This corresponds to mid-August for the study fires. In contrast to electro-optical studies from the same region, measures of landscape recovery as detected by the SAR were on the order of four to five years instead of one.

Highlights

The Arctic is changing at unprecedented rates
Tundra fire records are not maintained to the level they have been in boreal regions [4]
A constellation of Radarsat-2 satellites is planned and could provide additional data options. This manuscript describes the use of microwave radar data to detect and monitor fire disturbance in tundra regions

Summary

Introduction

The Arctic is changing at unprecedented rates. The changes in the seasonal timing and decreased duration of frozen conditions combined with increased air temperatures has already manifested itself in visible changes in the Arctic landscape including increased plant productivity [1], thermokarst, and drying of lakes [2]. Changes in wildfire frequency and severity are suspected but undocumented in the tundra. In boreal ecosystems wildfire has already been documented as increasing in frequency and severity over the last 50 years [3]. The baseline fire regime in the tundra is not well quantified due primarily to the relatively low level of human habitation in Arctic regions, and limited fire management and suppression efforts. Tundra fire records are not maintained to the level they have been in boreal regions [4]. Contributing to the lack of tundra fire data records is that the optical satellite data record over the Arctic has limitations due to persistent cloud cover, lack of algorithms suitable to detection of burns in tundra, and quick green up of tundra vegetation within one year of fire [5]. The physical and ecological effects of fire disturbance on the tundra are poorly understood due to the logistical challenges of obtaining field measurements, and especially repeat measurements, in remote locations

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Discussion

Conclusion