Arctic 1400 Year Multiproxy Summer Temperature Reconstruction Shi, F.; Yang, B.; Ljungqvist, F.C.; Yang, F. Shi, F. Yang, B. Ljungqvist, F.C. Yang, F. Air Temperature Reconstruction Arctic temperature earth science/paleoclimate/climate reconstructions (surface temperature,multiple proxies,null,degree Celsius,Jun-Aug,climate reconstructions,anomalized|smoothed,composite plus regression|regression analysis,N,reference period: 1961-1990 A.D.; smooth: 50 year loess; calibration data set: MLOST v3b; calibration period: 1880-2000 A.D.) earth science/paleoclimate/climate reconstructions (surface temperature,multiple proxies,two standard deviations upper bound,degree Celsius,Jun-Aug,climate reconstructions,anomalized,composite plus regression|regression analysis,N,reference period: 1961-1990 A.D.; calibration data set: MLOST v3b; calibration period: 1880-2000 A.D.) earth science/paleoclimate/instrumental (surface temperature,null,null,degree Celsius,Jun-Aug,instrumental,anomalized,null,N,reference period: 1961-1990 A.D.) earth science/paleoclimate/climate reconstructions (surface temperature,multiple proxies,null,degree Celsius,Jun-Aug,climate reconstructions,anomalized,composite plus regression|regression analysis,N,reference period: 1961-1990 A.D.; calibration data set: MLOST v3b; calibration period: 1880-2000 A.D.) earth science/paleoclimate/climate reconstructions (age,null,null,year Common Era,null,climate reconstructions,null,null,N,null) earth science/paleoclimate/climate reconstructions (surface temperature,multiple proxies,two standard deviations lower bound,degree Celsius,Jun-Aug,climate reconstructions,anomalized,composite plus regression|regression analysis,N,reference period: 1961-1990 A.D.; calibration data set: MLOST v3b; calibration period: 1880-2000 A.D.) earth science/paleoclimate/reconstructions (Arctic>LATITUDE >LONGITUDE ) A new multi-proxy summer (June to August) temperature reconstruction for the Arctic region (60 to 90°N) with annual resolution over the past 1400 yr is presented. The reconstruction is performed using a novel ensemble method, Ensemble-LOC, designed to preserve low-frequency variability and minimize the influence of the "spurious correlation" between the proxy and instrumental data. The reconstruction is based on a set of 22 proxy records with annual resolution. We find clear evidences for a cold anomaly AD ~630 to 770 related to the Dark Age Cold Period, a warm anomaly ~950 to 1050 related to the Medieval Climate Anomaly, and a cold anomaly ~1200 to 1900 related to the Little Ice Age. The strong 20th century warming is also evident. There are 3 different and distinct warm periods occurring during the Little Ice Age: 1470-1510, 1550-1570, and 1750--1770. However, about half of the total input proxies are not used in the large majority of the reconstructions. We still need additional proxy records from the Arctic region with annual resolution and a strong response to local temperature to further verify the results of this study and in order to investigate possible spatial patterns of past Arctic temperature variability. STUDY NOTES: Summer temperature reconstruction based on 22 multi-proxy records with annual resolution, from 60°N to 90°N, over the past 1400 years. Table 1. Information on the 22 proxy records used. exact latitude (Lat.) and longitude (Lon.), type of proxy, seasonality of temperature signal, dating error, period covered (year AD) by each record, and reference to original publication. Season: season in which the proxy has been shown to be most sensitive to temperature. Delta: dating uncertainty in yr. MXD = tree-ring maximum latewood density; TRW = tree-ring width; IC = ice-core d18O; V = varved lake sediments; HI = tree-ring height-increment chronology; ND: not described No. Site Latitude Longitude ProxyType Season Delta Period Source 1 Torneträsk 68°21’-68°31’N 19°45’-19°80’E MXD April to August ±0 600-2004 Grudd (2008) 2 Polar Urals 66°52’N 65°38°E MXD May to September ±0 778-1990 Esper et al. (2002) 3 Gulf of Alaska 55°-62°N 153-131°W MXD January to September ±0 724-2000 D'Arrigo et al. (2006) 4 Jämtland 63°10’N 12°25’-13°35’E TRW June to August ±0 600-887,909-2002 Linderholm & Gunnarson (2005) 5 Lapland 69.00°N 25°00’E TRW June to August ±0 600-2005 Helama et al. (2010) 6 Yamal 67°30’N 70°00’E TRW June to July ±0 600-1996 Briffa et al. (2008) 7 Avam-Taimyr 72°00’N 101°00’E TRW July ±0 600-2003 Briffa et al. (2008) 8 Indigirka 72°53’N 148°15’E TRW June to August ±0 600-1993 Moberg et al. (2005) 9 Laanila 68°28’-68°31’N 27°16’-27°24’E HI June to August ±0 668-2000 Lindholm et al. (2011) 10 GISP2 72°6’N 38°5’W IC Annual ND 818-1987 Grootes & Stuiver (1997) 11 GRIP 72°58’N 37°64’W IC May to October ±0 600-1979 Vinther et al. (2010) 12 Dye-3 65°18’N 43°83’W IC May to October ±0 600-1978 Vinther et al. (2010) 13 Crete 71°12’N 37°32’W IC May to October ±0 600-1973 Vinther et al. (2010) 14 NGRIP 75°10’N 42°32’W IC Annual ND 600-1995 Vinther et al. (2006) 15 Renland 71°27’N 26°73’W IC Annual ±2-20 800-1986 Vinther et al. (2008) 16 Agassiz 82°42’N 73°50’W IC Annual ±0 600-1972 Vinther et al. (2008) 17 Lower Murray Lake 81°21’N 69°32’W V July ±16 600-1969,1990-2000 Cook et al. (2009) 18 Big Round Lake 69°52’N 68°5’W V July to September ±1-20 971-2003 Thomas & Briner (2009) 19 Iceberg Lake 60°47’N 142°57’W V May to June ±32 600-1998 Loso (2009) 20 Donard Lake 66°4’N 61°21’W V June to August ±1-20 752-1992 Moore et al. (2001) 21 Blue Lake 68°09’N 150°47’W V June to August ±12 600-2005 Bird et al. (2009) 22 Lake C2 82°08’N 77°09’W V June to August ±57 600-1987 Lamoureux & Bradley (1996) NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Shi, F. Investigator : Yang, B. Investigator : Ljungqvist, F.C. Investigator : Yang, F. 2012-09-27 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/13358 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/shi2012/shi2012arctic.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/shi2012/shi2012arctic.xls https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/shi2012/shi2012arctic.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/shi2012/shi2012arctic.xls English https://www.ncdc.noaa.gov/paleo/study/13358 https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/shi2012/shi2012arctic.txt https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/shi2012/shi2012arctic.xls Shi, F., B. Yang, F.C. Ljungqvist, and F. Yang. 2012. Multi-proxy reconstruction of Arctic summer temperatures over the past 1400 years. Climate Research, Vol. 54 (2), pp. 113-128. doi: 10.3354/cr01112 START YEAR: 600 cal yr BP * END YEAR: 2000 cal yr BP -180 60 180 90