Rapid Warming Over East Antarctica Since the 1940s Caused by Increasing Influence of El Niño Southern Oscillation and Southern Annular Mode

Ejaz, Tariq; Rahaman, Waliur; Laluraj, C. M.; Mahalinganathan, K.; Thamban, Meloth

doi:10.3389/feart.2022.799613

Cited by 4 publications

(4 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This phenomenon also can be observed in the temperature change during the period 1979-2019 from ERA5, although the warming of West Antarctica and the Antarctic Peninsula also exists in the meantime [25]. Ice core records of oxygen isotopes from coastal Dronning Maud Land also found warming of 0.45 • C per decade during the period 1942-2019, which coincides with the increase in ENSO events and its strong antiphase relation with SAM [33]. Moreover, there is a strong connection between autumn climate change in western East Antarctica and ENSO [34].…”

Section: Discussionmentioning

confidence: 57%

Assessment of Antarctic Amplification Based on a Reconstruction of Near-Surface Air Temperature

et al. 2023

View full text Add to dashboard Cite

Polar amplification has been a research focus in climate research in recent decades. However, little attention has been paid to Antarctic amplification (AnA). We have examined the variations in annual and seasonal temperature over the Antarctic Ice Sheet and its amplification based on reconstruction covering the period 2002–2018. The results show the occurrence of annual and seasonal AnA, with an AnA index greater than 1.39 with seasonal differences, and that AnA is strong in the austral winter and spring. Moreover, AnA displays regional differences, with the greatest amplification occurring in East Antarctica, with an AnA index greater than 1.51, followed by West Antarctica. AnA is always absent in the Antarctic Peninsula. In addition, amplification in East Antarctica is most conspicuous in spring, which corresponds to the obvious warming in this season; and the spring amplification signal is weakest for West Antarctica. When considering the influence of the ocean, the AnA becomes obvious, compared to when only the land is considered. Southern Annular Mode (SAM), surface pressure and westerlies work together to affect the temperature change over Antarctica and AnA; and SAM and surface pressure are highly correlated with the temperature change over East Antarctica. The picture reflects the accelerated changes in Antarctic temperature.

show abstract

Section: Discussionmentioning

confidence: 57%

Assessment of Antarctic Amplification Based on a Reconstruction of Near-Surface Air Temperature

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Our results illustrate the relationship between SHA and the SOI/SAM over periods of 12/18 months respectively, but responses in SST and sea ice to the SOI and SAM can show periodicity of up to 15 years (Ejaz et al, 2022). There are other interannual tendencies in SHA that are not simply explained by the two major climate modes.…”

Section: Other Mechanismsmentioning

confidence: 55%

“…Further, SHA captures changes happening in the sub-surface water column, and can provide greater insight into the changes' driving factors than studies that consider only surface signals such as SST or sea ice (e.g. Stammerjohn et al, 2008;Holland and Kwok, 2012;Ejaz et al, 2022;Kwok and Comiso, 2002). The coverage of our results also sheds light on lesser-studied areas, for instance, the Southern Indian and Co-operation seas, which also exhibit a distinct response to climate variability and likely contribute to the broader picture of circumpolar changes across the Southern Ocean.…”

Section: Novelty and Comparison Against Other Studiesmentioning

confidence: 99%

Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height

Cocks,

Silvano,

Marzocchi

et al. 2023

Preprint

View full text Add to dashboard Cite

Abstract. The Southern Ocean plays a central role in regulating the global overturing circulation, ventilating the deep ocean, and driving sea level rise by delivering heat to Antarctic ice shelves. Understanding heat and freshwater content in this region is key to monitoring these global processes and identifying multiyear changes; however, in-situ observations are limited, and often do not offer the spatial or temporal consistency needed to study long-term variability. Perturbations in steric height can reveal changes in oceanic heat and freshwater content inasmuch as they impact the density of the water column. Here, we show for the first time that the monthly steric height anomaly of the Southern Ocean south of 50° S can be assessed using altimetry and GRACE gravimetry data from 2002 to 2018. Steric height anomalies are validated against in-situ Argo float and CTD data from tagged elephant seals. We find good agreement in the ice-free ocean and parts of the seasonal ice zone, but that the uncertainty of steric height increases on the Antarctic continental shelf and within the permanent ice zone due to leakage error and anti-aliasing in GRACE. The open-ocean steric height anomalies exhibit spatio-temporally coherent patterns that: (i) capture the expected seasonal cycle of low (high) steric height in winter (summer); and (ii) reflect interannual anomalies in surface heat and freshwater content and wind forcing associated with positive and negative phases of the two major modes of Southern Hemisphere climate variability (the El Niño – Southern Oscillation and Southern Annular Mode).

show abstract

“…The mean δ 18 O value of IC12 (−18.47 ± 0.05 ‰) is significantly higher than the means of FK17 and TIR18 (−19.12 ± 0.02 ‰ and −19.46 ± 0.02 ‰, respectively), implying higher temperature at DIR than at LIR and HIR, although it has been shown that several other factors might influence the δ 18 O records, such as conditions at the source, transport, precipitation, sea ice extent, and post-depositional processes such as diffusion (Naik et al, 2010;Ejaz et al, 2021;Sinclair et al, 2012). Our records could thus be used to produce a past temperature reconstruction as done by Ejaz et al (2022), using the δ 18 O record from an ice core and ERA5 surface air temperature and then investigating the potential role of the climate modes such as El Niño-Southern Oscillation, the Interdecadal Pacific Oscillation, and the Southern Annular Mode in the temperature variability. Deuterium excess (d-excess), which is derived from δ 18 O and δD, is a tracer of precipitation origin and a proxy of the temperature and relative humidity at the evaporation site (Stenni et al, 2010).…”

Section: Long-term Trends and Spatial Variability In The Paleo-proxy ...mentioning

confidence: 94%

Spatial and temporal variability of environmental proxies from the top 120 m of two ice cores in Dronning Maud Land (East Antarctica)

Wauthy,

Tison,

Inoue

et al. 2024

Earth Syst. Sci. Data

View full text Add to dashboard Cite

Abstract. The Antarctic ice sheet's future contribution to sea level rise is difficult to predict, mostly because of the uncertainty and variability of the surface mass balance (SMB). Ice cores are used to locally (kilometer scale) reconstruct SMB with a very good temporal resolution (up to sub-annual), especially in coastal areas where accumulation rates are high. The number of ice core records has been increasing in recent years, revealing an important spatial variability and different trends of SMB, highlighting the crucial need for greater spatial and temporal representativeness. We present records of density, water stable isotopes (δ18O, δD, and deuterium excess), major ions concentrations (Na+, K+, Mg2+, Ca2+, MSA, Cl−, SO42-, and NO3-), and continuous electrical conductivity measurement (ECM), as well as age models and resulting surface mass balance from the top 120 m of two ice cores (FK17 and TIR18) drilled on two adjacent ice rises located in coastal Dronning Maud Land and dating back to the end of the 18th century. Both environmental proxies and SMB show contrasting behaviors, suggesting strong spatial and temporal variability at the regional scale. In terms of precipitation proxies, both ice cores show a long-term decrease in deuterium excess (d-excess) and a long-term increase in δ18O, although less pronounced. In terms of chemical proxies, the non-sea-salt sulfate (nssSO42-) concentrations of FK17 are twice those of TIR18 and display an increasing trend on the long-term, whereas there is only a small increase after 1950 in TIR18. The SO42-/Na+ ratios show a similar contrast between FK17 and TIR18 and are consistently higher than the seawater ratio, indicating a dominant impact of the nssSO42- on the SO42- signature. The mean long-term SMB is similar for FK17 and TIR18 (0.57 ± 0.05 and 0.56 ± 0.05 mi.e.yr-1, respectively), but the annual records are very different: since the 1950s, TIR18 shows a continuous decrease while FK17 has shown an increasing trend until 1995 followed by a recent decrease. The datasets presented here offer numerous development possibilities for the interpretation of the different paleo-profiles and for addressing the mechanisms behind the spatial and temporal variability observed at the regional scale (tens of kilometers) in East Antarctica. The “Mass2Ant IceCores” datasets are available on Zenodo (https://doi.org/10.5281/zenodo.7848435; Wauthy et al., 2023).

show abstract

Rapid Warming Over East Antarctica Since the 1940s Caused by Increasing Influence of El Niño Southern Oscillation and Southern Annular Mode

Cited by 4 publications

References 71 publications

Assessment of Antarctic Amplification Based on a Reconstruction of Near-Surface Air Temperature

Assessment of Antarctic Amplification Based on a Reconstruction of Near-Surface Air Temperature

Assessing heat and freshwater changes in the Southern Ocean using satellite-derived steric height

Spatial and temporal variability of environmental proxies from the top 120 m of two ice cores in Dronning Maud Land (East Antarctica)

Contact Info

Product

Resources

About