NOAA/WDS Paleoclimatology - Lake Braya Sø, Greenland 7,000 Year Temperature Reconstructions

High-resolution paleoclimate reconstructions are often restricted by the difficulties of sampling geologic archives in great detail and the analytical costs of processing large numbers of samples. Using sediments from Lake Braya Sø, Greenland, we introduce a new method that provides a quantitative high-resolution paleoclimate record by combining measurements of the alkenone unsaturation index (UK37) with non-destructive scanning reflectance spectroscopic measurements in the visible range (VIS-RS). The proxy-to-proxy (PTP) method exploits two distinct calibrations: the in situ calibration of UK37 to lake water temperature and the calibration of scanning VIS-RS data to down core UK37 data. Using this approach, we produced a quantitative temperature record that is longer and has 5 times higher sampling resolution than the original UK37 time series, thereby allowing detection of temperature variability in frequency bands characteristic of the AMO over the past 7,000 years.