Laminated sediments in the Bering Sea reveal atmospheric teleconnections to Greenland climate on millennial to decadal timescales during the last deglaciation
Summary: Annually laminated sediments from the NE Bering Sea reveal a decadal-scale correlation to Greenland ice core records during termination I, suggesting an atmospheric teleconnection. Lamination occurrence is tightly coupled to Bølling-Allerød and Preboreal warm phases. Increases in export production, closely coupled to SST and sea ice changes, are hypothesized to be a main cause of deglacial anoxia, rather than changes in overturning/ventilation rates of mid-depth waters entering the Bering Sea.
Enhanced 20th-century heat transfer to the Arctic simulated in the context of climate variations over the last millennium
Summary: Temperature reconstructions for the Atlantic Water layer in Fram Strait have previously revealed a dramatic warming during the 20th century that is unprecedented in the last 2000 years. Our study presents results from climate model simulations over the last millennium that are able to reproduce such changes and relate them to increased oceanic heat transports to the Arctic and to a re-organization of the North Atlantic ocean circulation caused by global warming.
Investigating uncertainties in global gridded datasets of climate extremes
Summary: Observational data sets contain uncertainties, e.g. from the instrument accuracy, as well as from the fact that usually only a single method is used in processing. We have performed an assessment of the size of the uncertainties associated with choices in the method used. The largest effects come from changes which affect the station network or the gridding method used. However, for the temperature indices in places with many stations, these changes have little effect on the long-term behaviour.
Climate history of the Southern Hemisphere Westerlies belt during the last glacial–interglacial transition revealed from lake water oxygen isotope reconstruction of Laguna Potrok Aike (52° S, Argentina)
Evidence for a three-phase sequence during Heinrich Stadial 4 using a multiproxy approach based on Greenland ice core records
M. Guillevic, L. Bazin, A. Landais, C. Stowasser, V. Masson-Delmotte, T. Blunier, F. Eynaud, S. Falourd, E. Michel, B. Minster, T. Popp, F. Prié, and B. M. Vinther Clim. Past, 10, 2115-2133, 2014 AbstractFinal Revised Paper (PDF, 858 KB)Supplement (16 KB)Discussion Paper (CPD)
02 Dec 2014
Annual proxy data from Lago Grande di Monticchio (southern Italy) between 76 and 112 ka: new chronological constraints and insights on abrupt climatic oscillations
Sensitivity of East African savannah vegetation to historical moisture-balance variation
Summary: Using fossil pollen assemblages to trace vegetation response to relatively modest historical climate fluctuations is difficult. In this study, pollen data from a lake-sediment record in Queen Elizabeth National Park (Uganda) show that its landscape has been an open wooded savannah throughout the past 200 years, with known historical moisture-balance variation exerting modest effects on local tree cover (mostly Acacia and Ficus) and the occurrence of damp soil areas (promoting Phoenix palms).
The global monsoon across timescales: coherent variability of regional monsoons
Summary: All regional monsoons belong to a cohesive global monsoon circulation system, albeit thateach regional subsystem has its own indigenous features. A comprehensive review of global monsoon variability reveals that regional monsoons can vary coherently across a range of timescales, from interannual up to orbital and tectonic. Study of monsoon variability from both global and regional perspectives is imperative and advantageous for integrated understanding of the modern and paleo-monsoon dynamics.
HadISDH land surface multi-variable humidity and temperature record for climate monitoring
Summary: We have developed HadISDH, a new gridded global land monthly mean climate montitoring product for humidity and temperature from 1973 to then end of 2013 (updated annually) based entirely on in situ observations. Uncertainty estimates are provided. Over the period of record significant warming and increases in water vapour have taken place. The specific humidity trends have slowed since a peak in 1998 concurrent with decreasing relative humidity from 2000 onwards.
Hydroclimate variability of the northwestern Amazon Basin near the Andean foothills of Peru related to the South American Monsoon System during the last 1600 years
Summary: In this paper we explore a speleothem δ18O record from Palestina cave, northwestern Peru, on the eastern side of the Andes cordillera, in the upper Amazon Basin. The δ18O record is interpreted as a proxy for South American Summer Monsoon (SASM) intensity and allows the reconstruction of its variability during the last 1600 years. Replicating regional climate signals from different sites and using different proxies is essential for a comprehensive understanding of past changes in SASM activity.
J. Apaéstegui, F. W. Cruz, A. Sifeddine, M. Vuille, J. C. Espinoza, J. L. Guyot, M. Khodri, N. Strikis, R. V. Santos, H. Cheng, L. Edwards, E. Carvalho, and W. Santini Clim. Past, 10, 1967-1981, 2014 AbstractFinal Revised Paper (PDF, 7946 KB)Supplement (1495 KB)Discussion Paper (CPD)
19 Nov 2014
Links between CO2, glaciation and water flow: reconciling the Cenozoic history of the Antarctic Circumpolar Current
Fire in ice: two millennia of boreal forest fire history from the Greenland NEEM ice core
P. Zennaro, N. Kehrwald, J. R. McConnell, S. Schüpbach, O. J. Maselli, J. Marlon, P. Vallelonga, D. Leuenberger, R. Zangrando, A. Spolaor, M. Borrotti, E. Barbaro, A. Gambaro, and C. Barbante Clim. Past, 10, 1905-1924, 2014 AbstractFinal Revised Paper (PDF, 1307 KB)Supplement (5732 KB)Discussion Paper (CPD)
29 Oct 2014
The role of the northward-directed (sub)surface limb of the Atlantic Meridional Overturning Circulation during the 8.2 ka event