RAPID: Characterizing the Chemical and Physical Signature of the 2015-16 El Nino in the Quelccaya Ice Cap Snow and Ice to Calibrate Past ENSO Reconstructions

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This award uses funds, under the auspices of the Rapid Response Research (RAPID) concept, to dig three new snow pits and collect two new ten-meter long cores from the Quelccaya ice cap (QIC) in southern Peru. Samples from these pits and cores will be physically and chemically analyzed to address the hypotheses that post-depositional features (e.g., melt features) and elevated concentrations of dry deposited trace species (e.g., black carbon, dust, ammonium) provide new and reliable markers of past El Niño-Southern Oscillation (ENSO) events and also help facilitate the quantification of the event's intensity. These new markers will be also applied to other ice cores from the southern Andes that exist from extended tropical ice core archives collected over the last forty years.The chemical and physical fingerprints of past El Niño events are preserved in ice cores from Andean glaciers, particularly the QIC, and offer the potential to quantify past regional ENSO variability. Previous isotopic (delta 18-Oxygen) records from the QIC provided a long annually resolved history (1,800 years) of Pacific sea surface temperature (SST) variations. However, delta 18-O on the QIC is also influenced by other internally varying climate system processes (e.g., South American Monsoon, ITCZ position). Consequently, additional El Niño proxies are needed to reduce the uncertainties inherent in past El Niño reconstructions and to help facilitate more accurate projections of intensity and frequency.The new data that could result from the research is aimed at testing two hypotheses: 1) the snow melt and percolation induced by El Niño is identifiable in the prior year's snow layer and can be calibrated to the El Niño's strength in terms of temperature and radiative forcing; and 2) the concentration and co-association of biogenic and evaporitic species will be enhanced and detectable deeper in the ice and thereby reveal past El Niño frequency.The potential broader impacts include capturing the chemical and physical signatures of a modern El Niño event in real time that could help evaluate past ENSO variability preserved in ice cores as well as assessing the role of solar forcing in climate. The research will help support an early career female scientist and the research results will be disseminated in short video segments appropriate for the public.