Solar influences on climate during the last and penultimate glacial
Final Report Abstract
Northern Hemisphere climate during the last two glacial cycles is characterized by a series of abrupt warming events during the transitions from stadial to interstadial and glacial to interglacial conditions. While the geographic pattern of these changes is relatively well-known, knowledge about their atmospheric and oceanic propagation, as well as the impact of regional feedbacks is limited. Main reason for these limitations are the usually centennial chronological uncertainties between individual paleoclimate archives and an insufficient temporal resolution of the connected records inhibiting to resolve the cascade of processes, possible feedbacks and their timing. One way to overcome this limitation is the synchronization of far afield environmental records like mid-latitude sediment and polar ice core archives. The external forced and globally common production rate of cosmogenic radionuclides like 10Be provides a tool for such synchronizations. Therefore, we first measured 10Be records from Black Sea sediments covering three time-slices: (i) a period of distinct GI climate variability 60000-46000 a BP, (ii) the Last Glacial Maximum (LGM) and (iii) the transition from the Saalian to the Eemian. 10Be/9Be ratios, regression analysis with environmental proxy records from the same sediment cores and high-pass filtering were used to determine the depositional mechanisms and reduce non-production variability in the 10Be timeseries from Black Sea sediments. Comparisons with 10Be time-series from Greenland ice cores, paleointensity time-series from Black Sea sediments and spectral analysis, indicate a good preservation and more or less instantaneous deposition of down to decadal changes in the 10Be production signal in the records covering 60000-46000 a BP and the LGM. Lake level changes and the reconnection to the global ocean during the Saalian-Eemian transition likely introduced biases to the 10Be record for Termination II that are currently under investigation. The preserved 10Be production signal allowed the synchronization of the 60000-46000 a BP and LGM records from Black Sea sediments to 10Be time-series from Greenland ice cores and investigate climate responses in the Black Sea region to onsets of GIs, with minimized chronological uncertainties. Corroborated by Earth System Model simulations, our results reveal a bi-partite climate response to the onset of GIs in the Black Sea region characterized by a simultaneous reduction in winter severity, followed by shift in the hydrological cycle during summer on average 80 years (min. 15/ max. 170 years) later. In addition, winter severity during the preceding stadials seems to modulate the duration of the hydrological lags, which tend to be longer when the preceding winters were more severe. Hypothesized trigger for the lags is a time-transgressive adjustment of the regional oceanic thermal interior, i.e. the mid-latitude North Atlantic, to interstadial conditions. In conclusion, the project outcome underlines the very high potential of Black Sea sediments for recording the solar and geomagnetic modulated 10Be production signal, down to decadal resolution. Our investigations on synchronized paleoclimate records from Black Sea sediments and Greenland ice cores provide novel results about the role of seasonality and oceanic feedbacks for shaping a unique regional response to last glacial abrupt warming events and, thereby, might provide a template for future climate change. In addition, existing Black Sea sediment cores covering the complete penultimate glacial hold the potential for extending these type of studies into the more distant past.
Publications
-
Lagged atmospheric circulation response in the Black Sea region to Greenland Interstadial 10. Proceedings of the National Academy of Sciences, 117(46), 28649-28654.
Czymzik, Markus; Nowaczyk, Norbert R.; Dellwig, Olaf; Wegwerth, Antje; Muscheler, Raimund; Christl, Marcus & Arz, Helge W.
-
Mid-Holocene reinforcement of North Atlantic atmospheric circulation variability from a western Baltic lake sediment record. Climate of the Past, 19(1), 233-248.
Czymzik, Markus; Tjallingii, Rik; Plessen, Birgit; Feldens, Peter; Theuerkauf, Martin; Moros, Matthias; Schwab, Markus J.; Nantke, Carla K. M.; Pinkerneil, Silvia; Brauer, Achim & Arz, Helge W.
-
Tendency of soil erosion dynamics by coupling radioisotopes and RUSLE model on the Southeastern Tibetan Plateau in response to climate warming and human activity. CATENA, 223, 106954.
Chen, Peng; Czymzik, Markus; Yu, Zhongbo; Aldahan, Ala; Wang, Jinguo; Yi, Peng; Hou, Xiaolin; Guo, Shouyan & Zheng, Minjie
-
Synchronizing the Western Gotland Basin (Baltic Sea) and Lake Kälksjön (central Sweden) sediment records using common cosmogenic radionuclide production variations. The Holocene, 34(8), 1128-1137.
Czymzik, Markus; Christl, Marcus; Dellwig, Olaf; Muscheler, Raimund; Müller, Daniela; Kaiser, Jérôme; Schwab, Markus J.; Nantke, Carla KM; Brauer, Achim & Arz, Helge W.
