Short-Term Meteorological and Environmental Signals Recorded in a Firn Core from a High-Accumulation Site on Plateau Laclavere, Antarctic Peninsula

Kirstin Hoffmann-Abdi,Thomas Opel,Christoph Schneider,Francisco Fernandoy,Hanno Meyer,Johannes Freitag,Joseph Mcconnell

doi:10.3390/geosciences11100428

Abstract

High-accumulation sites are crucial for understanding the patterns and mechanisms of climate and environmental change in Antarctica since they allow gaining high-resolution proxy records from firn and ice. Here, we present new glacio- and isotope-geochemical data at sub-annual resolution from a firn core retrieved from an ice cap on Plateau Laclavere (LCL), northern Antarctic Peninsula, covering the period 2012–2015. The signals of two volcanic eruptions and two forest fire events in South America could be identified in the non-sea-salt sulphur and black carbon records, respectively. Mean annual snow accumulation on LCL amounts to 2500 kg m−2 a−1 and exhibits low inter-annual variability. Time series of δ18O, δD and d excess show no seasonal cyclicity, which may result from (1) a reduced annual temperature amplitude due to the maritime climate and (2) post-depositional processes. The firn core stratigraphy indicates strong surface melt on LCL during austral summers 2013 and 2015, likely related to large-scale warm-air advection from lower latitudes and temporal variations in sea ice extent in the Bellingshausen-Amundsen Sea. The LCL ice cap is a highly valuable natural archive since it captures regional meteorological and environmental signals as well as their connection to the South American continent.

Highlights

The Antarctic Peninsula (AP) has long been considered as one of the “hot spots” of global climate warming since near-surface air temperatures on the AP have increased by more than 3 ◦ C since the 1950s [1,2,3]
Due to the generally high snow accumulation on LCL, the H2 O2 record is well preserved in the O’Higgins station (OH)-12 firn core, showing clear seasonal cycles in the upper 16 m, albeit a pronounced double peak structure (Figure 2)
Surface melt can lead to the redistribution of H2 O2 in the snowpack causing a staircase shape of the peaks, which is not the case in OH-12 above 16 m depth

Summary

Introduction

The Antarctic Peninsula (AP) has long been considered as one of the “hot spots” of global climate warming since near-surface air temperatures on the AP have increased by more than 3 ◦ C since the 1950s [1,2,3]. Since the mid-1970s, the SAM has shifted towards its positive phase, especially in austral summer and autumn [15,18]. This has been associated with a strengthening of the circumpolar vortex and, an intensification (15–20%) and poleward migration of the westerlies over the Southern Ocean [14,15,19,20]

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Conclusion