Polar signal characterization

PANDA enables the support measurements essential to the interpretation of data from glacial archives to be carried out. Depending on the case :

  • The dating of ice cores and the synchronization of signals
  • The identification of tracers of origin of air masses or biospheric emissions
  • Concentration data and isotope measurements
  • The reconstruction of temperatures

Thus, PANDA integrates and serves several major research themes :

  • Temperature reconstruction : by combining the information provided by water isotopes and air isotopes.
  • Reconstruction of past climates and characterization of glacial/interglacial transitions and rapid variability : to understand the mechanisms involved, it is essential to be able to place on a common time scale the signals obtained from the gas phase (e.g., past atmospheric greenhouse gas composition) and the signals extracted from the ice phase (e.g., temperature proxies). High-resolution measurements of the liquid and gas phases are necessary for a good characterization of the relationships between the different parameters.
  • Past reconstruction of volcanism : on the basis of sulphur isotope analysis, it is now possible to characterise the nature of an unknown eruption and to classify it as having had a climatic impact or not. This has a multitude of consequences, of course, on the high-frequency variations in global temperature, but also on the possible links between the development/collapse of ancient societies and the climate, on the vulnerability of modern societies to volcanic risk. These themes, which can be approached using ice cores, can only be conceived on the basis of a fine, high-resolution analysis of sulphate concentration profiles (Gautier et al. 2016).
  • Reconstruction of past fire regimes : biomass fires and climate are linked by a set of complex feedbacks, which it is important to characterize. The past frequency and importance of fires can be determined by combining gas (carbon monoxide) and liquid (ammonium, formate) phase measurements.
  • Anthropisation and recent history : the deposition histories and atmospheric concentrations of many aerosols and pollutants of anthropogenic origin (e.g., sulphate, black carbon), and ultimately their temporal and regional emission scenarios, can be reconstructed from glacial records (Lim et al., 2016).
  • Albedo and radiation balance : Black carbon deposited on the snow surface alters the surface albedo and generates increased ablation. By reconstructing its temporal evolution, this parameter can be related to the ice mass balance (Ginot et al., 2014).
  • Reconstruction of the oxidizing capacity via CO and its D17O : the link between climate and atmospheric chemistry is still not established. This could be revealed by studying the isotopic composition of CO but requires ice free of any contamination that only high-resolution CO measurement allows.
  • Stratigraphy : it is recognized that ice core bottom records are regularly disrupted by ice flows over bedrock to the point of generating layer mixing that can lead to time inversions. However, it is at the bottom of the cores that the oldest and most compressed information is hidden. Only high-resolution methods have the capacity to resolve these layers, data that will be central to the Beyond Epica-Oldest Ice project, which aims to drill 1.5Ma old ice to study the Mid-Pleistocene transition (periodicity of climatic cycles increasing from 40 to 100 ka).

Updated on 25 février 2021