El Niño Southern Oscillation signal in a new East Antarctic ice core, Mount Brown South

• Other Authors: CROCKART, CAMILLA KATE (hasPrincipalInvestigator), CROCKART, CAMILLA KATE (processor), Australian Antarctic Data Centre (publisher)
• Format: Dataset
• Language: unknown
• Published: Australian Antarctic Data Centre
• Subjects: climatologyMeteorologyAtmosphere; SNOW/ICE CHEMISTRY; EARTH SCIENCE; TERRESTRIAL HYDROSPHERE; SNOW/ICE; SNOW DEPTH; CRYOSPHERE; OXYGEN ISOTOPES; CLIMATE INDICATORS; PALEOCLIMATE INDICATORS; ICE CORE RECORDS; ISOTOPES; IONS; PALEOCLIMATE; EARTH SCIENCE > PALEOCLIMATE > ICE CORE RECORDS > SODIUM; HANS TAUSEN DRILL; VG ISOGAS SIRA MASS SPECTROMETER; KOVACS DRILL; THERMO-FISHER/DIONEX ICS3000 ION CHROMATOGRAPH; MASS SPECTROMETERS; ION CHROMATOGRAPHS; FIELD SURVEYS; GEOGRAPHIC REGION > POLAR; CONTINENT > ANTARCTICA > MOUNT BROWN SOUTH; OCEAN > SOUTHERN OCEAN; LAW DOME; DOME SUMMIT SOUTH; Antarctic; East Antarctica; Law Dome; Mount Brown; Poynter; Rasmussen; Sira; Southern Ocean; Vance; Antarc*; Antarctica; ice core; Sea ice
• Online Access: https://researchdata.edu.au/el-nio-southern-brown-south/1597740; https://doi.org/10.4225/15/58eedf6812621; https://data.aad.gov.au/metadata/records/AAS_4414_MountBrownSouth_LawDome_icecores_seasalt_accumulation_2020; http://nla.gov.au/nla.party-617536

Data used in Crockart et al. (submitted 2020, 'El Niño Southern Oscillation signal in a new East Antarctic ice core, Mount Brown South') for three ice cores collected from Mount Brown South (MBS, 69.111° S, 86.312° E) in East Antarctica (MBS1718-Main, MBS1718-Alpha, MBS1718-Charlie) in summer 2017/2018, and two successive ice cores collected from Law Dome (LD, Dome Summit South site, 66.461° S, 112.841° E) in East Antarctica (DSS1617 drilled in 2016/2017, and DSS97 presented in Vance et al. 2013) over the period 1975-2015/6. The data includes the annual log-transformed sea salt concentrations (chloride and sodium), and the annual ice equivalent (IE) snowfall accumulation (in m yr-1 IE) for the MBS and LD ice cores. Isotope and ion chemistry analyses The oxygen isotopes and ion chemistry in the MBS and LD ice cores were analysed according to established methods (see Curran and Palmer 2001; Curran et al. 2003; Palmer et al. 2001; Plummer et al. 2012). Discrete samples for water stable isotope (1.5 cm) and trace chemistry (3 cm) samples were cut under trace clean conditions. Isotopic values are expressed as per mil (‰) relative to the Vienna Standard Mean Oceanic Water (VSMOW) standard. The standard deviations of δ18O for repeated measurements of laboratory reference water samples were less than 0.07 ‰ (for the LD ice core) and 0.5 ‰ (for the MBS ice cores). The Thermo-Fisher/Dionex ICS3000 ion chromatograph was used to determine the sea salt concentrations (chloride (Cl-) and sodium (Na+)) and sulphate (SO42−). Non sea salt sulphate (nssSO42−) was calculated according to the methods in Plummer et al. (2012) Dating Annual depth layers were assigned to the MBS and LD ice cores using seasonally varying species, principally δ18O, nssSO42-,Na+ and the ratio of SO42-/Cl- (see Plummer et al. 2012 for more details). Volcanic ash layers (indicated by nssSO42− peaks) linked to the Pinatubo volcanic eruption in the Philippines in mid-1991 were used as a reference depth horizon to cross-check the annual depth layer chronology. Each ice core was dated individually and independently, without reference to other site records to ensure independence of the method. Accumulation The annual depth layers were used in combination with an empirical density model (see equation 1) to determine the annual ice equivalent snowfall accumulation rates (see Robert et al. 2015 for more details). Empirical Density = [ρ] – [883.5356 * exp(-0.011078644) * d] + [436.8285] – [1.887488 200 * d] Eq. (1) Sea salts Sea salt concentrations were log-transformed to create a normally distributed record, as the raw concentrations are skewed toward infrequent high concentration events. The sea salt concentration for the year 1987 in the MBS Charlie ice core was excluded. Curran, M. A. J. and Palmer, A. S.: Suppressed ion chromatography methods for the routine determination of ultra low level anions and cations in ice cores, J. Chromatogr., 919, 107–113, doi:10.1016/S0021-9673(01)00790-7, 2001. Curran, M. A. J., van Ommen, T. D., Morgan, V. I., Phillips, K. L., Palmer, A. S.: Ice core evidence for Antarctic sea ice decline since the 1950s, Science, 302, 1203–1206, doi:10.1126/science.1087888, 2003. Palmer, A. S., van Ommen T. D., Curran, M. A. J., Morgan, V. , Souney, J. M. and Mayewski, P.A.: High precision dating of volcanic events (AD 1301-1995) using ice cores from Law Dome, Antarctica, J. Geophys. Res., 106, 28089-28095, doi:10.1029/2001JD000330, 2001. Plummer, C. T., Curran, M. A. J., van Ommen, T. D., Rasmussen, S. O., Moy, A. D., Vance, T. R., Clausen, H. B., Vinther, B. M., Mayewski, P. A.: An independently dated 200- yr volcanic record from Law Dome, East Antarctica, including a new perspective on the dating of the c. 1450s eruption of Kuwae, Vanuatu, Climate Past 795 Discuss., 8, 1567–1590, doi:10.5194/cpd-8-1567-2012, 2012. Roberts, J., Plummer, C., Vance, T., van Ommen, T., Moy, A., Poynter, S., Treverrow, A., Curran, M., George, S.: A 2000-year annual record of snow accumulation rates for Law Dome, East Antarctica, Clim. Past, 11, 697–707, doi:10.5194/cp-11-697-2015, 2015. Vance, T. R., van Ommen, T. D., Curran, M. A. J., Plummer, C. T., Moy, A. D.: A Millennial Proxy Record of ENSO and Eastern Australian Rainfall from the Law Dome Ice Core, East Antarctica, J. Clim., 26, 710–725, doi:10.1175/JCLI-D-12-00003.1, 2013.