Lake Silvaplana, Switzerland 775 Year Summer Temperature Reconstruction Trachsel, M.; Grosjean, M.; Schnyder, D.; Kamenik, C.; Rein, B. Trachsel, M. Grosjean, M. Schnyder, D. Kamenik, C. Rein, B. Air Temperature Reconstruction earth science/paleoclimate/climate reconstructions|paleolimnology (age,null,null,year Common Era,null,climate reconstructions|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|paleolimnology (surface temperature,null,null,degree Celsius,Jun-Aug,climate reconstructions|paleolimnology,filtered,null,N,9-100 year band pass filtered; based on visible reflectance spectroscopy) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Lake Silvaplana>LATITUDE 46.45>LONGITUDE 9.8) High-resolution (annual to sub-decadal) quantitative reconstructions of climate variables are needed from a variety of paleoclimate archives across the world to place current climate change in the context of long-term natural climate variability. Rapid, high-resolution, non-destructive scanning techniques are required to produce such high-resolution records from lake sediments. In this study we explored the potential of scanning reflectance spectroscopy (VIS-RS; 380-730 nm) to produce quantitative summer temperature reconstructions from minerogenic sediments of proglacial, annually laminated Lake Silvaplana, in the eastern Swiss Alps. The scanning resolution was 2 mm, which corresponded to sediment deposition over 1-2 years. We found correlations up to r = 0.84 (p<0.05) for the calibration period 1864-1950, between six reflectance-dependent variables and summer (JJAS) temperature. These reflectance-dependent variables (e.g. slope of the reflectance 570/630 nm, indicative of illite, biotite and chlorite; minimum reflectance at 690 nm indicative of chlorite) indicate the mineralogical composition of the clastic sediments, which is, in turn, related to climate in the catchment of this particular proglacial lake. We used multiple linear regression (MLR) to establish a calibration model that explains 84% of the variance of summer (JJAS) temperature during the calibration period 1864-1950. We then applied the calibration model downcore to develop a quantitative summer temperature reconstruction extending back to AD 1177. This temperature reconstruction is in good agreement with two independent temperature reconstructions based on documentary data that extend back to AD 1500 and tree ring data that extend back to AD 1177. This study confirms the great potential of in situ scanning reflectance spectroscopy as a novel non-destructive technique to rapidly acquire high-resolution quantitative paleoclimate information from minerogenic lake sediments. STUDY NOTES: 775 year summer (JJA) temperature reconstruction for the Swiss Alps based on visible reflectance spectroscopy from Lake Silvaplana, Switzerland. Lake Silvaplana, Switzerland: 46°27'N, 9°48'E, 1800m NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Trachsel, M. Investigator : Grosjean, M. Investigator : Schnyder, D. Investigator : Kamenik, C. Investigator : Rein, B. 2012-06-13 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/13016 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/silvaplana2010c.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/silvaplana2010c.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/silvaplana2010c.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/silvaplana2010c.txt English https://www.ncdc.noaa.gov/paleo/study/13016 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/silvaplana2010c.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/europe/switzerland/silvaplana2010c.txt Trachsel, M., M. Grosjean, D. Schnyder, C. Kamenik, and B. Rein. 2010. Scanning reflectance spectroscopy (380–730 nm): a novel method for quantitative high-resolution climate reconstructions from minerogenic lake sediments. Journal of Paleolimnology, December 2010, Vol. 44, Issue 4, pp 979-994. DOI: 10.1007/s10933-010-9468-7 START YEAR: 1175 AD * END YEAR: 1949 AD 9.8 46.45 9.8 46.45