Ionic content in an ice core from the West Antarctic Ice Sheet: 1882-2008 A.D.

Abstract

The study of atmospheric aerosols through polar ice cores is one of the most common and robust tools for the investigation of past changes in the circulation and chemistry of the atmosphere. Only a few subannual resolution records are available for the development of paleochemical and environmental interpretations. Here, we report the ionic content record for the period of 1882-2008 A.D. in an ice core recovered at the ice divide of the West Antarctic Ice Sheet. The ion concentrations found in the core were determined by ion chromatography on more than 2,000 samples and the basic statistics were calculated for major inorganic and organic ions. The dating of the core layers was based on the seasonality of SO 4 2-, NO 3 -, and Na + , checked by the identification of the Krakatau (1883), Agung (1963) and Pinatubo/Hudson (1991) volcanic eruption signals. Significant aerosol input events were identified and grouped considering the ions present, their provenance and the season. The ionic balance, together with the decomposition of some origin indicators, showed that 36% of the ionic charge is derived from sea salt aerosols, 13% from mineral dust, and 17% from biogenic marine activity, while 34% are mainly products of chemical reactivity in the atmosphere.Isaías Ullmann Thoen et al. Figure 6. Characterization of the ionic content found in the Mount Johns ice core (central West Antarctica). (A) Detailed ionic balance. (B) Ionic decomposition based on sea salt fractions, standard deviations and medians of time series, and major provenance interpretation. A B 863 Brazilian Journal of Geology, 48(4): 853-865, December 2018Isaías Ullmann Thoen et al.

Marine diatoms in ice cores from the Antarctic Peninsula and Ellsworth Land, Antarctica – species diversity and regional variability

“…For SHIC, SKBL and JUR, an ice core chronology was established based on their hydrogen peroxide (H2O2) annual cycle that is assumed to peak during the austral summer solstice and to exhibit its minimum during the austral winter (Frey et al, 2006;Thomas et al, 2008). Ice core chronologies were resolved using the annual cycle of the non-sea salt component of major ions, such as non-sea salt sulphates (nssSO4 2-) (Piel et al, 2006), that is assumed to peak between November and January in this region (Pasteris et al, 2014;Thoen et al, 2018). This non-sea salt stratigraphy was further corroborated by the presence of volcanic tephra in the 2001 AD ice core layer (Tetzner et al, 2021b).…”

Refractory black carbon (rBC) variability in a 47-year West Antarctic snow and firn core

“…BC has been studied in Antarctic snow since the late 1980s and early 1990s (Chýlek et al, 1987(Chýlek et al, , 1992Warren and Clarke, 1990). These initial studies used filter-based methods, which could under-or overestimate BC concentrations due to some analytical artifacts (Soto-García et al, 2011;Torres et al, 2014;Wang et al, 2012). Studies using the SP2 started appearing more than 2 decades later, aiming at recent snow rBC concentrations (Casey et al, 2017;Khan et al, 2019), near-surface air (Khan et al, 2018), recent-past ice cores (couple centuries - Bisiaux et al, 2012a, b;Pasteris et al, 2014) and the past millennia (Arienzo et al, 2017).…”

Conteúdo iônico em um testemunho de firn do Platô Antártico

“…4) é possível observar que o nitrato não apresenta correlação com os outros íons analisados. Isso porque é um aerossol secundário, que não tem o oceano como fonte e seus processos de formação são complexos, podendo vir de múltiplas fontes (Thoen et al, 2018). Conforme Bertler et al (2005), o nitrato pode ser produzido na estratosfera por oxidação de N 2 O e pelas nuvens polares através do HNO 3 , e na ionosfera por dissociação de N 2 .…”

“…Os perfis iônicos nos permitem identificar os picos de concentrações mais altas e também as suas durações. Conforme afirmam Thoen et al (2018), eles são associados a importantes eventos ocorridos em condições climáticas atípicas. Na Antártica, os eventos vulcânicos são identificados por um relativo aumento na linha de base das concentrações de sulfato (Sneed et al, 2011).…”