Wiles - Coastal Alaska - TSME - AK096, PAGES North America 2k Version D'Arrigo, R.D.; Wiles, G.; Wilson, R.J.S. D'Arrigo, R.D. Wiles, G. Wilson, R.J.S. PAGES 2k Network PAGES NAmerica 2k TSME Tsuga mertensiana (Bong.) Carrière mountain hemlock earth science/paleoclimate/tree-ring (Coastal Alaska>LATITUDE 61.05>LONGITUDE -146.98) Previous tree-ring-based Northern Hemisphere temperature reconstructions portray a varying amplitude range between the "Medieval Warm Period" (MWP), "Little Ice Age" (LIA) and present. We describe a new reconstruction, developed using largely different methodologies and additional new data compared to previous efforts. Unlike earlier studies, we quantify differences between more traditional (STD) and Regional Curve Standardization (RCS) methodologies, concluding that RCS is superior for retention of low-frequency trends. Continental North American versus Eurasian RCS series developed prior to merging to the hemispheric scale cohere surprisingly well, suggesting common forcing, although there are notable deviations (e.g., fifteenth to sixteenth century). Results indicate clear MWP (warm), LIA (cool), and recent (warm) episodes. Direct interpretation of the RCS reconstruction suggests that MWP temperatures were nearly 0.7°C cooler than in the late twentieth century, with an amplitude difference of 1.14°C from the coldest (1600-1609) to warmest (1937-1946) decades. However, we advise caution with this analysis. Although we conclude, as found elsewhere, that recent warming has been substantial relative to natural fluctuations of the past millennium, we also note that owing to the spatially heterogeneous nature of the MWP, and its different timing within different regions, present palaeoclimatic methodologies will likely "flatten out" estimates for this period relative to twentieth century warming, which expresses a more homogenous global "fingerprint." Therefore we stress that presently available paleoclimatic reconstructions are inadequate for making specific inferences, at hemispheric scales, about MWP warmth relative to the present anthropogenic period and that such comparisons can only still be made at the local/regional scale. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : D'Arrigo, R.D. Investigator : Wiles, G. Investigator : Wilson, R.J.S. 2013-04-10 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/14275 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/pages2k/namerica2k/nam-tr_3-ak096-1200-1987.txt https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/pages2k/namerica2k/nam-tr_3-ak096-1200-1987.txt English https://www.ncdc.noaa.gov/paleo/study/14275 https://www1.ncdc.noaa.gov/pub/data/paleo/reconstructions/pages2k/namerica2k/nam-tr_3-ak096-1200-1987.txt D'Arrigo, R., R. Wilson, and G. Jacoby. 2006. On the long-term context for late twentieth century warming. Journal of Geophysical Research, 111, D03103, doi:10.1029/2005JD006352 Wilson, R., Wiles, G., D’Arrigo, R. and Zweck, C. 2007. Cycles and shifts: 1300-years of multidecadal temperature variability in the Gulf of Alaska. Climate Dynamics, 28, 425-440. DOI:10.1007/s00382-006-0194-9 START YEAR: 1200 AD * END YEAR: 1987 AD -146.98 61.05 -146.98 61.05