Meteorological and glaciological evidence for different climatic variations on the east and west sides of the Lambert Glacier basin, Antarctica

Abstract

Surface mass-balance studies and climatic records from firn cores show remarkable differences between the east and west sides of the Lambert Glacier basin (LGB). The spatial distribution of the surface accumulation is influenced by the atmospheric moisture flux, and by the surface wind field, which is largely determined by topography. Atmospheric water-vapor budget data for the ice-sheet sector covering the basin (45–90˚ E) show that on the east side of the LGB the moisture flux is poleward, averaging 18 kgm–1 s–1 in 1988, while for the west side it is Equatorward, averaging 5 kgm–1 s–1. A similar pattern, but with much lower transport of vapor flux, is seen across 70˚ S. Two firn cores from the east side of the basin and two from the west side were analyzed to determine accumulation-rate and temperature-proxy variations for the past 50 years. The trends were opposite on the different sides of the basin. Similar opposing trends are seen in meteorological records from Davis and Mawson coastal stations, situated on the east and west sides of the LGB respectively. There is a good correlation between the accumulation/18O record in ice cores from the eastern LGB and the sea-level pressure (obtained from the US National Centers for Environmental Prediction/US National Center for Atmospheric Research (NCEP/NCAR) re-analyses) of a Southern Indian Ocean low (SIOL), but not between the SIOL and the records from the western LGB. This study reveals that variations in local circulation could alter at least the annual to decadal time-scale climate records, and may result in completely different climate histories between adjacent areas.

250 years of accumulation, oxygen isotope and chemical records in a firn core from Princess Elizabeth Land, East Antarctica

“…The accumulation in DT001 core displays an increasing trend before 1820, while after 1820, the trend of the accumulation is not obvious. The accumulation in this core shows an increasing trend between 1940(Xiao et al, 2004, which is consistent with the results of the firn core from Wilks Land (Goodwin, 1991), but conflicts with the results from Dronning Maud Land, Mizuho Plateau and Kamp Land (Isaksson et al, 1996;Oerter et al, 1999;Satow and Watanable, 1990). Therefore, accumulation time series from a single site, such as in this case, should be viewed cautiously and large-scale (e.g.…”

“…However, an δ 18 O decline trend is observed from 1860 to the present. The δ 18 O record and the instrumental surface air temperature record at Davis meteorological station display the same variations (Xiao et al, 2004), which shows the variation of the δ 18 O in the DT001 firn core may represent the temperature change in the region. 27 In order to further study the overall decreasing trend of δ 18 O during the period AD 1860-1996, the comparison between DT001 oxygen isotope record and hemispheric and global temperature averages by year for the period 1856-1998, relative to 1961(Jones et al, 1999 was made (Figure 4).…”

Snow surface height variations on the Antarctic ice sheet in Princess Elizabeth Land, Antarctica: 1 year of data from an automatic weather station

“…LGB69 is located inland of the transition zone (300–500km from the coast (Fig. 1b): Van den Broeke and others, 1999; Xiao and others, 2004), and receives both precipitation and drift snow. Although the monthly transport ( Q T ) and sublimation ( Q E ) of snow could be calculated by the methods developed by Pomeroy and Jones (1996), the lack of data on one parameter, monthly snowfall, would make these values imprecise.…”

“…The Antarctic circumpolar trough is at its deepest and most southerly location during the equinoxes, but, for the sole year of record that we present here, the accumulation episodes are all on the summer side of the equinoxes. However, Xiao and others (2004) use ice-core records to show that a Southern Indian Ocean low located over the north of the Prydz Bay region governs interannual variability of the accumulation and decadal climate change in Princess Elizabeth Land. Longer records are required to establish any links between accumulation seasonality, storminess and the propagation and strength of the circumpolar trough.…”