Water stable isotopes in snow along a traverse of the West Antarctic Ice Sheet: insights into moisture origins, air-masses distillation history, and climatic value

Marcher, Andressa; Bernardo, Ronaldo; Simões, Jefferson Cárdia; Auger, Jeffrey D.

doi:10.1590/0001-3765202220210353

Cited by 2 publications

(6 citation statements)

References 57 publications

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“…The prevailing wind direction is from the south (180°) and the annual average wind speed is 11.9 m/s, which indicates that the Criosfera 1 site is commonly affected by strong wind events (SWE). Due to the extreme wind regime, the presence of sastrugi and low-scale dunes fields of 20-40 cm high in wide extension is well marked around the study area (Marcher et al, 2022).…”

Section: Study Areamentioning

confidence: 94%

“…In summer, the temperature reaches a maximum of ⁓ -5°C, and in the winter, it reaches a minimum of ⁓ -55°C. The site experiences dry and cold air masses associated with strong katabatic winds from the Antarctic Plateau (Pinto, 2017;Marcher et al, 2022), as a result of the configuration of the terrain in the Ronne Embayment region (Parish & Bromwich 2007).…”

Section: Study Areamentioning

confidence: 99%

“…BR-WAIS traverse was carried out in the 2014-2015 austral summer (between January 4 th and 21 st ) during the 32 nd Brazilian Antarctic Operation and was attended by a research group from the CPC/UFRGS. See Marcher et al (2022) for more details about this traverse. A Mark III auger (Kovacs Enterprises, Inc., USA) coupled with an electrical drill drive powered by a generator was used to collect the TT01 core.…”

Section: Firn/ice Cores Collectionmentioning

confidence: 99%

“…Challenges in interpreting both isotopic and accumulation records are amplified by the shortage of these records in various Antarctica sectors. Because of this and given the importance of these proxies for climatic reconstructions, shallow core studies are encouraged to know which and how much climate information can potentially be extracted from isotopic and accumulation records on a basin-scale in each Antarctica sector (Masson-Delmotte et al, 2008;Thomas et al, 2017;Goursaud et al, 2019;Marcher et al, 2022). Here, we investigate the stable isotopic content (δ 18 O, δD, and d-excess) and the snow accumulation variability from the two high-resolution shallow firn cores drilled on the upper reaches of the Möller Ice Stream basin, Weddell Sea Sector, in the transition between West Antarctica Ice Sheet (WAIS) and East Antarctica Ice Sheet (EAIS).…”

Section: Introductionmentioning

confidence: 99%

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The stable water isotopes and snow accumulation from Weddell Sea sector imprint the large-scale atmospheric circulation variability

Marcher

Simões²,

Bernardo³

et al. 2022

Preprint

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Abstract. Stable water isotopes and accumulation data extracted from polar ice/firn cores provide valuable climate information. Here, we present novel isotopic and accumulation time series from an upstream area of the Möller Ice Stream (MIS) basin, Weddell Sea Sector (WSS), Antarctica – a Brazilian research area (84°00’00’’S; 79°29’39’’W; 1276 m a.s.l.). Our purpose was to understand the depositional history and investigate how much the recent climate signal (21st century) is stored in the shallowest ice sheet layers in this area. Therefore, we crossed the isotopic (δ18O, δD, and d-excess) and snow accumulation data of two shallow firn cores (both ⁓9.0 m deep) with glaciological information, local and regional meteorological data (both ERA5 and AWS), indices of large-scale atmospheric modes (as SAM and ENSO) and the Amundsen Sea Low (ASL). The isotopic records cover 16 years (from 1999 to 2015-austral summer) and the accumulation records cover 20 years (from 1999 to 2018). We find that interannual δs variability is strongly explained by changes in the phase of the SAM (r = 0.74; p < 0.05; α = 0.05) and, consequently, also by changes in pressure of both the WSS (r = -0.57; p < 0.05; α = 0.05) and the ASL (r = -0.56; p < 0.05; α = 0.05). The regional temperature in WSS (r = 0.50; p < 0.05; α = 0.05) and Antarctica Peninsula (r = 0.70; p < 0.05; α = 0.05), as well as the sea ice concentration in the Weddell Sea (r = -0.49; p = 0.05; α = 0.05) are other factors that measurably influence the δs in the study area. In the period covered by our study, the rarest and strongest wind events (SWE; > ⁓15 m/s) and extreme precipitation events (EPE) oscillate almost completely out of phase, and this relationship is largely explained by the sub-decadal changes in the SWE-ENSO relationship and by the SAM variability. This oscillatory pattern between SWE and EPE justifies the non-temporally stable correlation between δs and local temperature in the study area. For the period of 2013–2018, we show that the trigger to start accumulating snow on the studied site is the occurrence of a range of EPE in a short time or of the one EPE with higher snowfall rates and that, the low snowfall events are hardly ever preserved. Our snow accumulation composite record shows that the SWE-EPE seesaw governs the snow accumulation in the upstream area of the MIS basin in the 1999–2018 period. When the frequency of SWE increases and EPE decreases, the local snow accumulation increase. In contrast, in the opposite scenario, the accumulation approaches the forecast precipitation data indicating that the influence of blowing snow and wind drift decreases. Because of this relation, incredibly there was a significant decrease in snow accumulation in the study area in the 1999–2018 period due to an increase in EPE in recent years. Probably, in a scenario of future warming, the persistence of SAM positive trend, and the EPE increase due to intensification of wetter and warmer air masses incursions by the WSS such a relationship will change. Our results indicate that both isotopic compositions and snow accumulation are strongly influenced by large-scale modes of climate variability in the MIS basin inland. Furthermore, they also provide valuable information to understand mass balance at the basin scale in the WSS. We recommend more shallow drills and snow pits in this site to construct the best composite record to reconstruct these atmospheric circulation patterns and solve challenges regarding the topographic effect.

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Section: Study Areamentioning

confidence: 94%

Section: Study Areamentioning

confidence: 99%

Section: Firn/ice Cores Collectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The stable water isotopes and snow accumulation from Weddell Sea sector imprint the large-scale atmospheric circulation variability

Marcher

Simões²,

Bernardo³

et al. 2022

Preprint

Self Cite

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show abstract

“…particular, the volume records some of the Brazilian scientific investigations into the West Antarctic ice sheet that only started during the International Polar Year (2007)(2008)(2009). There are seven articles on glaciological topics, of which six address the chemistry of snow and the record of ice cores (e.g., Marcher et al 2022).…”

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confidence: 99%

Forty years of Brazilian Antarctic research: A tribute to Professor Antonio Carlos Rocha-Campos

Simões

Leppe

Sayão

2022

An. Acad. Bras. Ciênc.

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Water stable isotopes in snow along a traverse of the West Antarctic Ice Sheet: insights into moisture origins, air-masses distillation history, and climatic value

Cited by 2 publications

References 57 publications

The stable water isotopes and snow accumulation from Weddell Sea sector imprint the large-scale atmospheric circulation variability

The stable water isotopes and snow accumulation from Weddell Sea sector imprint the large-scale atmospheric circulation variability

Forty years of Brazilian Antarctic research: A tribute to Professor Antonio Carlos Rocha-Campos

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