Elevation-Dependent Changes to Plant Phenology in Canada’s Arctic Detected Using Long-Term Satellite Observations

Wenjun Chen,Rasim Latifovic,Sylvain G Leblanc,Lori White,Ian Olthof

doi:10.3390/atmos12091133

Abstract

Arctic temperatures have increased at almost twice the global average rate since the industrial revolution. Some studies also reported a further amplified rate of climate warming at high elevations; namely, the elevation dependency of climate change. This elevation-dependent climate change could have important implications for the fate of glaciers and ecosystems at high elevations under climate change. However, the lack of long-term climate data at high elevations, especially in the Arctic, has hindered the investigation of this question. Because of the linkage between climate warming and plant phenology changes and remote sensing’s ability to detect the latter, remote sensing provides an alternative way for investigating the elevation dependency of climate change over Arctic mountains. This study investigated the elevation-dependent changes to plant phenology using AVHRR (Advanced Very High Resolution Radiometer) time series from 1985 to 2013 over five study areas in Canada’s Arctic. We found that the start of the growing season (SOS) became earlier faster with an increasing elevation over mountainous study areas (i.e., Sirmilik, the Torngat Mountains, and Ivvavik National Parks). Similarly, the changes rates in the end of growing season (EOS) and the growing season length (GSL) were also higher at high elevations. One exception was SOS in the Ivvavik National Park: “no warming trend” with the May-June temperature at a nearby climate station decreased slightly during 1985–2013, and so no elevation-dependent amplification.

Highlights

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Summary

Introduction

Air temperatures in the Arctic have increased at almost twice the global average rate [1,2]. On top of the warming trend, some studies showed the dependence of surface warming on elevation, with greater warming rates at higher altitudes, namely, the elevation dependency of climate change [3,4,5,6] This elevation-dependent climate change could have important implications for the fate of glaciers and ecosystems at high elevations under climate change. The freshwater from glaciers forms some rare “polar oases” in the high Arctic, such as the wetlands of Bylot Island, Nunavut, Canada. These wetlands have exceptional productivity for an Arctic ecosystem and attract and sustain a wide variety of breeding migratory bird species, including herbivores such as the cackling goose, the rock ptarmigan, and the greater snow goose (http://www.cen.ulaval.ca/bylot/en/ bylotstudysite.php/, accessed on 20 August 2021). The melting of glaciers can feedback positively to climate warming due to the reduction of albedo [7], and dramatically changes the climate system because of the ocean current alternations such as the collapse of the Atlantic Meridional Overturning Circulation [8]

Objectives

Methods

Results