Spatial variability of climate and past atmospheric circulation patterns from central West Antarctic glaciochemistry

Abstract

changes over distances of 50-100 km and sea-salt concentrations drop by 50% between the middle two sites. One likely contributor to the high variability seen at this spatial scale is variability in synoptic-and finer-scale meteorology. Empirical orthogonal function (EOF) analysis shows that 80% or more of the variance in site chemistry can be attributed to two types of air masses: winter season air (50-70% of site variance) with a strong marine signature (heavy loading of sea-salt species) and summer season air (21% of the variance), marked by marine biogenic non-sea-salt SO 4 plus NO3. This pattern of winter and summer regimes appears at other West Antarctic sites suggesting it may apply to the entire region. We show that a general picture of the patterns of variability in West Antarctica can best be drawn by using an analysis technique that fully exploits high resolution, multiparameter, multisite data sets.

Interlaboratory comparison of 10Be concentrations in two ice cores from Central West Antarctica

“…The drill locations are at 82°22 0 01 00 S, 119°16 0 59 00 W (920 masl) and at 82°05 0 38 00 S, 115°13 0 41 00 W (1315 masl). In the literature the cores are also known as Central West Antarctica A, CWA-A and CWA-B [10]. The two drill sites are within a few hundred km of the WAIS Divide site and show average annual snow accumulation rates (over the past 40 yr) of 13.9 cm weq yr À1 at BSH-2 and 22.5 cm weq yr À1 at BSH-5, similar to the snow accumulation rate of $20 cm weq yr À1 at WAIS Divide.…”

“…For radionuclide analysis we used core pieces of 20-30 cm length, corresponding to age intervals of $1.5 yr for BSH-2 and $0.8 yr for BSH-5. Each laboratory cut their own cores into four sections, so there is a slight offset (<6 cm) between the individual samples, but the four samples of each core combined should yield the same 10 The typical sample size is $1 kg, ranging from 0.7-1.3 kg for individual samples.…”

“…We have now put in place a second line at Purdue University, identical to the one in Berkeley. This second line not only affords us the opportunity to increase our sample throughput but it also allows us to perform inter-laboratory comparisons for 10 Be concentrations in ice samples. In this study each lab separated 10 Be from 23 nearly identical samples from two ice cores that were previously drilled in Central West Antarctica.…”

Southern hemisphere atmospheric circulation: impacts on Antarctic climate and reconstructions from Antarctic ice core data

“…Given that this variability has an approximately 21 year period, the authors speculate that it is linked with the 22 year solar Hale cycle. Reusch et al (1999) have analysed and interpreted a series of 4 short (approximately 40 years of accumulation) ice cores from near Byrd station, west Antarctica, that were separated by only 200km in total. Whilst this multisite technique represents an interesting methodological advance, the circulation reconstruction presented in this work was basic: they identified two EOFs of note -marine sea-salt influenced winter air masses and biogenically and stratospherically influenced summer air masses.…”

A 2680-year record of sea ice extent in the Ross Sea and the associated atmospheric circulation derived from the DT401 East Antarctic ice core

“…Considerable efforts have been made to reconstruct the historical SIE variations and atmospheric circulation during past decades to centuries through the Antarctic ice core records (Abram et al, 2013;Goodwin et al, 2004;Kreutz and Mayewski, 1999;Mayewski et al, 2004;Meyerson et al, 2002;Peel and Mulvaney, 1992;Reusch et al, 1999;Russell and McGregor, 2009;Souney, 2002;Vance et al, 2013;Xiao et al, 2013Xiao et al, , 2004Yan et al, 2005). The findings revealed that sea salt ions (mainly Na + and Cl  ), methanesulphonic acid (MSA) and non-sea salt sulfate (nss-SO 4 2 ) were good indicators of the SIE (Abram et al, 2013;Meyerson et al, 2002;Xiao et al, 2013) and associated atmospheric circulation patterns, such as the Southern Oscillation Index (SOI) (Xiao et al, 2004), Southern Annular Mode (SAM) (Xiao et al, 2013), ENSO (Abram et al, 2013;Vance et al, 2013), and Pacific Decadal Oscillation (PDO) (Vance et al, 2013).…”