scholarly journals Seemingly divergent sea surface temperature proxy records in the central Mediterranean during the last deglaciation

2013 ◽  
Vol 9 (3) ◽  
pp. 1375-1383 ◽  
Author(s):  
M.-A. Sicre ◽  
G. Siani ◽  
D. Genty ◽  
N. Kallel ◽  
L. Essallami
Keyword(s):  
Adriatic Sea ◽  
Planktonic Foraminifera ◽  
Sea Surface ◽  
Last Deglaciation ◽  
Central Mediterranean ◽  
Proxy Record ◽  
Proxy Records ◽  
The Last Deglaciation ◽  
Temperature Proxy ◽  
Two Temperature

Abstract. Sea surface temperatures (SSTs) were reconstructed over the last 25 000 yr using alkenone paleothermometry and planktonic foraminifera assemblages from two cores of the central Mediterranean Sea: the MD04-2797 core (Siculo–Tunisian channel) and the MD90-917 core (South Adriatic Sea). Comparison of the centennial scale structure of the two temperature signals during the last deglaciation period reveals significant differences in timing and amplitude. We suggest that seasonal changes likely account for seemingly proxy record divergences during abrupt transitions from glacial to interglacial climates and for the apparent short duration of the Younger Dryas (YD) depicted by the alkenone time series, a feature that has already been stressed in earlier studies on the Mediterranean deglaciation.

scholarly journals Seemingly divergent sea surface temperature proxy records in the central Mediterranean during the last deglacial

2013 ◽  
Vol 9 (1) ◽  
pp. 683-701 ◽  
Author(s):  
M.-A. Sicre ◽  
G. Siani ◽  
D. Genty ◽  
N. Kallel ◽  
L. Essallami
Keyword(s):  
Adriatic Sea ◽  
Planktonic Foraminifera ◽  
Younger Dryas ◽  
Sea Surface ◽  
Central Mediterranean ◽  
Proxy Record ◽  
Proxy Records ◽  
Temperature Proxy ◽  
Two Temperature ◽  
Last Deglacial

Abstract. Sea surface temperatures (SSTs) were reconstructed over the last 25 000 yr using alkenone paleothermometry and planktonic foraminifera assemblages from two cores of the central Mediterranean Sea: the MD04-2797 core (Siculo–Tunisian channel) and the MD90-917 core (South Adriatic Sea). Comparison of the centennial scale structure of the two temperature signals during the last deglacial period reveals significant differences in timing and amplitude. We suggest seasonal changes likely account for seeming proxy record divergences during abrupt transitions from glacial to interglacial climates and for the apparent short duration of the Younger Dryas (YD) depicted by the alkenone time-series, a feature that has already been stressed in earlier studies on the Mediterranean deglaciation.

Towards model-data comparison of the deglacial temperature evolution in space and time

2021 ◽  
Author(s):  
Nils Weitzel ◽  
Heather Andres ◽  
Jean-Philippe Baudouin ◽  
Oliver Bothe ◽  
Andrew Dolman ◽  
...  
Keyword(s):  
Earth System ◽  
Sources Of Information ◽  
Last Deglaciation ◽  
Model Data ◽  
Glacial Cycle ◽  
Data Comparison ◽  
Space And Time ◽  
Proxy Records ◽  
Scale Temperature ◽  
The Last Deglaciation

<div> <p>The increasing number of Earth system model simulations that try to simulate the climate during the last deglaciation (ca 20 to 10 thousand years ago) creates a demand for benchmarking against environmental proxy records synthesized for the same time period. Comparing these two data sources over a period with changing background conditions requires new methods for model-data comparison that incorporate multiple types and sources of uncertainty.</p> <p>Natural archives of past reality are distributed sparsely and non-uniformly in space and time. Signals that can be obtained are in addition perturbed by uncertainties related to dating, the relationship between the proxy sensor and environmental fields, the archive build-up, and measurement. On the other hand, paleoclimate simulations are four-dimensional, complete, and physically consistent representations of the climate. However, they are subject to errors due to model inadequacies and sensitivity to the forcing protocol, and will not reproduce any particular history of unforced variability. </p> </div><div> <p>We present a method for probabilistic, multivariate quantification of the deviation between paleo-data and paleoclimate simulations that draws on the strengths of both sources of information and accounts for the aforementioned uncertainties. We compare the shape and magnitude of orbital- and millennial-scale temperature fluctuations during the last deglaciation and compute metrics of regional and global model-data mismatches. We test our algorithm with an ensemble of published simulations of the deglaciation and simulations from the ongoing PalMod project, which aims at the simulation of the last glacial cycle with comprehensive Earth system models. These are evaluated against a compilation of temperature reconstructions from multiple archives. Our work aims for a standardized model-data comparison workflow that will be used in PalMod. This workflow can be extended subsequently with additional proxy data, new simulations, and improved representations of proxy uncertainties. </p> </div>

scholarly journals Northern and southern hemisphere controls on seasonal sea surface temperatures in the Indian Ocean during the last deglaciation

2013 ◽  
Vol 28 (4) ◽  
pp. 619-632 ◽  
Author(s):  
Yiming V. Wang ◽  
Guillaume Leduc ◽  
Marcus Regenberg ◽  
Nils Andersen ◽  
Thomas Larsen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Last Deglaciation ◽  
Surface Temperatures ◽  
The Indian Ocean ◽  
The Last Deglaciation

scholarly journals Antarctic temperature and CO<sub>2</sub>: near-synchrony yet variable phasing during the last deglaciation

2018 ◽  
Author(s):  
Jai Chowdhry Beeman ◽  
Léa Gest ◽  
Frédéric Parrenin ◽  
Dominique Raynaud ◽  
Tyler J. Fudge ◽  
...  
Keyword(s):  
Phase Relationship ◽  
Ice Cores ◽  
Complex Nature ◽  
Temperature Phase ◽  
Last Deglaciation ◽  
The Holocene ◽  
Uncertainty Range ◽  
Major Transition ◽  
The Last Deglaciation ◽  
Temperature Proxy

Abstract. The last deglaciation, which occurred from 18,000 to 11,000 years ago, is the most recent large natural climatic variation of global extent. With accurately dated paleoclimate records, we can investigate the timings of related variables in the climate system during this major transition. Here, we use an accurate relative chronology to compare regional temperature proxy data and global atmospheric CO2 as recorded in Antarctic ice cores. We build a stack of temperature variations by averaging the records from five ice cores distributed across Antarctica, and develop a volcanic synchronization to compare it with the high-resolution, robustly dated WAIS Divide CO2 record. We assess the CO2/Antarctic temperature phase relationship using a stochastic method to accurately identify the probable timings of abrupt changes in their trends. During the large, millenial-scale changes at the onset of the last deglaciation at 18 ka and the onset of the Holocene at 11.5 ka, Antarctic temperature most likely led CO2 by several centuries. A marked event in both series around 16 ka began with a rapid rise in CO2, which stabilized synchronously with temperature. CO2 and Antarctic temperature peaked nearly synchronously at 14.4 ka, the onset of the Antarctic Cold Reversal (ACR) period. And CO2 likely led Antarctic temperature by around 250 years at the end of the ACR. The five major changes identified for both series are coherent, and synchrony is within the 2 σ uncertainty range for all of the changes except the Holocene onset. But the often-multimodal timings, centennial-scale substructures, and likely-variable phasings we identify testify to the complex nature of the two series, and of the mechanisms driving the carbon cycle and Antarctic temperature during the deglaciation.

scholarly journals Sea surface temperatures of the western Arabian Sea during the last deglaciation

2007 ◽  
Vol 22 (2) ◽  
Author(s):  
M. H. Saher ◽  
S. J. A. Jung ◽  
H. Elderfield ◽  
M. J. Greaves ◽  
D. Kroon
Keyword(s):  
Arabian Sea ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Last Deglaciation ◽  
Surface Temperatures ◽  
The Last Deglaciation
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