Visit to FRSGC, Yokohama, 4. July 2003 CLIMATE MODEL SIMULATES GLOBAL COLD CLIMATE DURING LATE MAUNDER MINIMUM (1675-1710) Hans von Storch, Fidel González-Ruoco, Ulrich Cubasch, Jürg Luterbacher, Eduardo Zorita, Beate Müller, Stephanie Legutke, and Ulrich Schlese Climate model simulates global cold climate and large-scale North Atlantic sea-ice anomalies during Late Maunder Minimum (1675-1710) Hans von Storch, Fidel J. Gonzalez-Rouco, Ulrich Cubasch, Jürg Luterbacher, Eduardo Zorita, Beate Müller, Stephanie Legutke and Ulrich Schlese With a state-of-the-art climate model, the effect of time varying solar and volcanic-aerosol forcing has been simulated. During the winters 1675-1710 a marked global cooling was simulated. This event mimics, in terms of broad patterns and time mean intensity, the strong cooling “Late Maunder Minimum” (LMM, 1675-1710) in Europe documented in various historical sources and early instrumental time series. The modeled LMM is causally related to the solar and volcanic forcing anomalies in the decades preceding and during the LMM creating an almost global cooling and large-scale circulation and sea ice coverage anomalies consistent with the phenomenon known as “Great Salinity Anomaly”. The results are downscaled with a regional model to the Baltic sea catchment. Visit to FRSGC, Yokohama, 4. July 2003

Simulation with ECHO-G (ECHAM4/HOPE-G) for 500 years (Columbus-run), and - 1000 years (Erik run) forced with - variable solar output - Volcanic aerosol load - GHG concentrations Die Korrelation zwischen den detrended Lean und Crowley Daten ist 0.99. Die Amplituden der aus der Crowleydaten geschaetzen Solarconstat ist allerdings etwas groesser als die Lean Schaetzung. Lean Daten reichen bis 1997. Die Solarkurve ist unsere Ableitung aus den Crowley-Daten, die Nettoeinstarhlung darstellen. Unsere Kurve ist einfach proportional zu der crowley kurve. Deswegen hoeren sie bei 1998. wo die Crowley daten aufhoeren. In diesem jahrhundert varlaufen sie sehr parallel zu den Lean Daten, obwohl sie auch information ueber Be10 enthalten.

SAT, coherence and phase for NH Eduardo Zorita, pers. comm.

HC result, similare result by Ammann, NCAR Tett, pers. comm.

Eduardo Zorita, pers. comm.

Late Maunder Minimum Cold winters and springs, 1675-1710 Analysis of Columbus run, only.

Baltic Sea ice winter index after Koslowski (1998) grey: Index, red: 5 year mean, blue:20 year mean

The Late Maunder Minimum (LMM) is the coldest phase of the so-called ‘Little Ice Age’ with marked climatic variability over wide parts of Europe. 1675-1710 vs. 1550-1800 Reconstruction from historical evidence, from Luterbacher et al. Temperature conditions in Switzerland according to Pfister‘s classification. From Luterbacher, 2001

Late Maunder Minimum 1675-1710 vs. 1550-1800 Reconstruction from historical evidence, from Luterbacher et al. Late Maunder Minimum Model-based reconstuction 1675-1710 vs. 1550-1800

LMM – reference period, winter Beate Müller, pers. comm. Erik Columbus Eduardo Zorita, pers. comm.

Simulated global 1675-1710 temperature anomaly

Ice Cores From Greenland and Antarctica North Greenland Stacked isotope record from five North-Greenland ice cores (Schwager, 2000) Reconstruction of solar variability, deduced from 10Be measurements (Crowley, 2000) Antarctica a) Stacked isotope record from five North-Greenland ice cores (Schwager, 2000) b) Reconstruction of solar variability, deduced from 10Be measurements (Crowley, 2000) c) Stacked isotope record from three ice cores from Dronning Maud Land, Antarctica (Graf et al., in press ) Stacked isotope record from three ice cores from Dronning Maud Land, Antarctica (Graf et al., in press )

Die Eisverhältnisse waren zwar nicht wesentlich stärker als später, es gab aber davor und danach war es deutlich eisärmer (etwa zwischen 1640-1670 und 1710 und 1740). Keinen deutlichen Unterschied kann ich sehen zwischen LMM und 160-1640 und 1740-1840). Aber 1695 war eisextrem wie danach nur nochmal 1893. Astrid Ogilvie hölt die Koch'sche Reihe für fehlerhaft. Daher hat sie mal eine eigene Berechnung gemacht im vergleich zu Koch. den Scan hänge ich mal an. (ist mehr drauf zu erkennen als in den Koch'schen Zeichnungen. Ogilvie: The past climate an sea ice records from Iceland Part 1 Data to A.D. 1780 (Climatic Change 6 - 1984 pp 131-152). nebenbei: es ist meiner Meinung nach nicht so, dass das ein Temperatur-Indiz ist, eher ein Transportphänomen. Viel Eis im Sommer in Island bedeutet in jedem Falle hoher Eisexport durch die Fram-Straße im Winter, da etwa 3-4 Monate Zeitverzögerung (im vergl. Kap Farvel 5 Monate). Die zweite Grafik stammt aus Ogilvie & Johnsson: "Little ice age" research: A perspective from Iceland. (Climatic Change 48: 9-52, 2001)

Corals off Madagaskar The reconstructed 338 year record of variations in sea-surface temperatures as inferred from the 1982-95 annual mean d18O -SST calibration equations using SST observations from NCEP-AOI-SST (Reynolds and Smith, 1994) and GISST 2.3b (Rayner et al., 1996). Observed SST based on GISST 2.3b is shown for comparison. The empirically reconstructed 338 year record of variations in sea-surface temperatures as inferred from the 1982-95 annual mean 18O -SST calibration equations using SST observations from different sources. (From Zinke)

· Galapagos (E-Pacific, 1oS, 90oW, Dunbar et al., 1994): 367 years of coral 18O records from 1587-1953, with annual resolution. The intervals 1660-80, 1710-1800 and 1870-95 were found warmer than “normal”, whereas the intervals 1600-1660, 1680-1700 (LMM) and 1800-25 cooler than on average. 18O increases of about 0.1-0.15‰ heavier during LMM than between 1660-70 and 1705-50 is indicative for a cooling of 0.5-0.75K. ·        New Caledonia (SW-Pacific, 22oS, 166oE, Quinn et al., 1998): 335 years of coral 18O records from 1657-1952, with seasonal resolution. The records describe a brief interval of modest cooling in the late 17th century, with an annual mean SST about 0.2-0.3K cooler between 1680-1740 than between 1660-80 and 1740-50 ·        Great Barrier Reef, Abraham Reef (SW-Pacific, 22oS, 153oE, Druffel and Griffin, 1993): 323 years of coral 18O records from 1635-1957, with bi-annual resolution. More positive 18O values (ca. 0.1‰) during the LMM, are consistent with lower SST’s of about 0.5K Zinke, pers. communication

Indicator for bioproductivity and intensity of upwelling in the ocean off Peru. The indicator is derived from characteristics in the marine sediment. Higher values are associated with stronger upwelling and lower values with reduced upwelling. The black line is a 7-point running mean of the annual (light) curve. deMenocal et al. (2000)

Institut für Küstenforschung I f K Simulated differences of ice coverage, in percent, during the LMM event 1675-1710 and the long term mean 1550-1800.

LMM1 1671-1684 NAO- and Cooling LMM2 1685-1708 NAO+ and Warming Irene Fischer-Bruns, pers. comm.

European annual mean temperature sorted in ascending order. European during pre-industrial times and LMM (Luterbacher) European annual mean temperature sorted in ascending order. (Müller, pers. comm.) Differences of European during pre-industrial times and LMM (Luterbacher-blue, REMO-green)

Conclusions AOGCM ECHO-G has been integrated with natural forcing (estimates) related to solar output and volcanic aerosols and anthropogenic GHG forcing over several hundred years (Columbus: 450 yrs, Erik the Red: 1000 yrs). Both simulations generate a globally cooler Northern winter Earth, 1400-1800, consistent with the concept of LIA. The cooling is considerably larger than described by Mann et al. The 100ß yrs Erik-simulation generates a medieval warm time during northern winter. Both simulations simulate a marked global (north of 20°S) cooling during the Late Maunder Minimum in Northern winter. (Also: Dalton Minimum). The extra cooling amounts to 0.2-0.5K. Model simulations consistent with a number of proxy data, in Europe, and across the globe (corals, ice cores). Model simulates a significant ice anomaly in the Labrador Sea and adjacent seas during the LMM. NAO not uniform during LMM.