Active-layer thermal monitoring on the Fildes Peninsula, King George Island, maritime Antarctica

M R Francelino,C E G R Schaefer,G B Lyra,R F M Michel,F M B Simas,E I Fernandes-Filho,J G Bockheim

doi:10.5194/se-5-1361-2014

Abstract

Abstract. International attention to climate change phenomena has grown in the last decade; the active layer and permafrost are of great importance in understanding processes and future trends due to their role in energy flux regulation. The objective of this paper is to present active-layer temperature data for one Circumpolar Active Layer Monitoring South hemisphere (CALM-S) site located on the Fildes Peninsula, King George Island, maritime Antarctica over an 57-month period (2008–2012). The monitoring site was installed during the summer of 2008 and consists of thermistors (accuracy of ±0.2 °C), arranged vertically with probes at different depths, recording data at hourly intervals in a high-capacity data logger. A series of statistical analyses was performed to describe the soil temperature time series, including a linear fit in order to identify global trends, and a series of autoregressive integrated moving average (ARIMA) models was tested in order to define the best fit for the data. The affects of weather on the thermal regime of the active layer have been identified, providing insights into the influence of climate change on permafrost. The active-layer thermal regime in the studied period was typical of periglacial environments, with extreme variation in surface during the summer resulting in frequent freeze and thaw cycles. The active-layer thickness (ALT) over the studied period shows a degree of variability related to different annual weather conditions, reaching a maximum of 117.5 cm in 2009. The ARIMA model could describe the data adequately and is an important tool for more conclusive analysis and predictions when longer data sets are available. Despite the variability when comparing temperature readings and ACT over the studied period, no trend can be identified.

Highlights

International attention to climate change phenomena has grown in the last decade, and intense modeling of climate scenarios was carried out by scientific investigations researching the sources and trends of these changes (Mora et al, 2013; IPCC, 2012; Moss et al, 2010)
The objective of this paper is to present active-layer temperature data for one Circumpolar Active Layer Monitoring South hemisphere (CALM-S) site located on the Fildes Peninsula, King George Island, maritime Antarctica over a 57-month period (2008–2012)
King George Island is the largest in the archipelago and Fildes Peninsula is at its southwestern end (Fig. 1)

Summary

Introduction

International attention to climate change phenomena has grown in the last decade, and intense modeling of climate scenarios was carried out by scientific investigations researching the sources and trends of these changes (Mora et al, 2013; IPCC, 2012; Moss et al, 2010). The cryosphere and its energy flux became the focus of many investigations, being recognized as a key component of climate for the understanding of actual (climate variability) and future trends (Ledley, 1985; Flanner et al, 2011; van den Broeke et al, 2008). Compared to other regions of the globe, our understanding of Antarctic permafrost is poor, especially in relation to its thermal state and evolution, physical properties, links to pedogenesis, hydrology, geomorphic dynamics, response to atmosphere and, thusly, to the variability and global climate change (Bockheim, 1995, Bockheim et al, 2008). An understanding of the distribution and properties of Antarctic permafrost is essential for the cryospheric sciences and for the life sciences, since it will be a major effect ecosystem modification following climate-induced changes and variability (Vieira et al, 2010)

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