Accordingly, the time is ripe to begin an intensified exchange between the two scientific communities of computer vision and ice core science. Another important issue is the evaluation of post-depositional layer changes, for which the chemical images provide rich information. One critical task is to assess the paleoclimate significance of single line profiles along the main core axis, which we show is a scale-dependent problem for which advanced image analysis methods are critical. To illustrate this new inter-disciplinary frontier, we describe a selected set of key questions.
However, the quantitative study of record preservation in chemical images raises new questions that call for the expertise of the computer vision community. For this, state-of-the-art imaging by laser-ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) has the potential to be revolutionary due to its combination of micron-scale 2D chemical information with visual features. A pressing issue is the analysis of the oldest, highly thinned ice core sections, where the identification of paleoclimate signals is particularly challenging. Polar ice cores play a central role in studies of the earth’s climate system through natural archives. The study highlights that, if to be used as a centennial-millennial scale proxy, ice wedges should be sampled near the surface where δ¹⁸O records would be less affected by in situ freezing and plugging, and veinlets should be dated directly and smoothed to remove the local random variance.
#OID THE TALOS PRINCIPLE IMAGE CRACK#
The higher variability in the wedge is attributed to the timing of meltwater infiltrating the wedge crack over the growth period, which from the onset to termination of snowmelt, is in the order of 3–6‰. Finally, the composite δ¹⁸O time-series of ice wedges and δ¹⁸O records of the Agassiz Ice Cap showed a similar Holocene cooling trend, however the wedges δ¹⁸O records had a higher degree of variability throughout the Holocene (∼4 ‰ versus ∼2 ‰ in the Agassiz records). Additionally, ice wedge mean δ¹⁸O records showed a decreasing trend with depth, likely due Rayleigh fractionation during freezing of residual water in the crack. Covariance analysis showed that two δ¹⁸O profiles collected at the same depth had high noise (c. Radiocarbon ages of dissolved organic carbon in ice wedges showed that cracking occurs mostly near the center of the wedge, but age reversals were observed. Then, based on the high resolution analysis of ice wedges from the Eureka Sound Lowland (Ellesmere and Axel Heiberg Islands), we evaluate the effect of sampling depth and edge effects on the δ¹⁸O records and compare a composite δ¹⁸O time-series of ice wedges to the Holocene 25-yr annual and 20-yr winter δ¹⁸O records of the nearby Agassiz Ice Cap. This study first reviews the development of ice wedges and the potential isotopic fractionation that takes place from snow deposition to formation of ice veinlets. Over the past few decades, the δ¹⁸O records of ice wedges have been used to estimate late Quaternary winter air temperatures. either to employ LA-ICP-MS to study the impurity-microstructure interplay or to investigate highly thinned climate proxy signals in deep polar ice.
With this, it is demonstrated how instrumental settings can be adapted specifically fit-for-purpose, i.e. Scale-dependent image analysis shows that the spatial significance of a single line profile along the main core axis increases systematically as the imprint of grain boundaries weakens. The localization of impurities with both marine and terrestrial sources is discussed, revealing generally a strong connection with the network of grain boundaries but also distinct differences among climatic periods.
Here first results are presented from applying LA-ICP-MS elemental imaging to selected glacial and interglacial samples of the Talos Dome and EPICA Dome C ice cores from central Antarctica. This new method has great potential in its application for investigating the localization of impurities on the ice sample, crucial to avoid misinterpretation of ultra-fine resolution signals. Recent adaptions of the LA-ICP-MS technique have achieved fast washout times as the basis for introducing state-of-the-art 2D imaging to ice core analysis. Due to its micron-scale resolution and micro-destructiveness, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is especially suited for exploring closely spaced layers in the oldest and highly thinned sections of polar ice cores.
0 kommentar(er)
