TY  - JOUR
A1  - Trauth, Martin H.
A1  - Foerster, Verena
A1  - Junginger, Annett
A1  - Asrat, Asfawossen
A1  - Lamb, Henry F.
A1  - Schäbitz, Frank
T1  - Abrupt or gradual?
BT  - Change point analysis of the late Pleistocene-Holocene climate record from Chew Bahir, southern Ethiopia
JF  - Quaternary research : an interdisciplinary journal
N2  - We used a change point analysis on a late Pleistocene-Holocene lake-sediment record from the Chew Bahir basin in the southern Ethiopian Rift to determine the amplitude and duration of past climate transitions. The most dramatic changes occurred over 240 yr (from similar to 15,700 to 15,460 yr) during the onset of the African Humid Period (AHP), and over 990 yr (from similar to 4875 to 3885 yr) during its protracted termination. The AHP was interrupted by a distinct dry period coinciding with the high-latitude Younger Dryas stadial, which had an abrupt onset (less than similar to 100 yr) at similar to 13,260 yr and lasted until similar to 11,730 yr. Wet-dry-wet transitions prior to the AHP may reflect the high-latitude Dansgaard-Oeschger cycles, as indicated by cross-correlation of the potassium record with the NorthGRIP ice core record between similar to 45-20 ka. These findings may contribute to the debates regarding the amplitude, and duration and mechanisms of past climate transitions, and their possible influence on the development of early modern human cultures.
KW  - Late Pleistocene
KW  - Holocene
KW  - Change point analysis
KW  - Principal component analysis
KW  - Paleoclimatology
KW  - Southern Ethiopian Rift
KW  - African Humid Period
KW  - Younger Dryas
KW  - Dansgaard-Oeschger cycles
Y1  - 2018
U6  - https://doi.org/10.1017/qua.2018.30
SN  - 0033-5894
SN  - 1096-0287
VL  - 90
IS  - 2
SP  - 321
EP  - 330
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - JOUR
A1  - Trauth, Martin H.
A1  - Asrat, Asfawossen
A1  - Düsing, Walter
A1  - Foerster, Verena
A1  - Krämer, K. Hauke
A1  - Marwan, Norbert
A1  - Maslin, Mark A.
A1  - Schäbitz, Frank
T1  - Classifying past climate change in the Chew Bahir basin, southern Ethiopia, using recurrence quantification analysis
JF  - Climate dynamics : observational, theoretical and computational research on the climate system
N2  - The Chew Bahir Drilling Project (CBDP) aims to test possible linkages between climate and evolution in Africa through the analysis of sediment cores that have recorded environmental changes in the Chew Bahir basin. In this statistical project we consider the Chew Bahir palaeolake to be a dynamical system consisting of interactions between its different components, such as the waterbody, the sediment beneath lake, and the organisms living within and around the lake. Recurrence is a common feature of such dynamical systems, with recurring patterns in the state of the system reflecting typical influences. Identifying and defining these influences contributes significantly to our understanding of the dynamics of the system. Different recurring changes in precipitation, evaporation, and wind speed in the Chew Bahir basin could result in similar (but not identical) conditions in the lake (e.g., depth and area of the lake, alkalinity and salinity of the lake water, species assemblages in the water body, and diagenesis in the sediments). Recurrence plots (RPs) are graphic displays of such recurring states within a system. Measures of complexity were subsequently introduced to complement the visual inspection of recurrence plots, and provide quantitative descriptions for use in recurrence quantification analysis (RQA). We present and discuss herein results from an RQA on the environmental record from six short (< 17 m) sediment cores collected during the CBDP, spanning the last 45 kyrs. The different types of variability and transitions in these records were classified to improve our understanding of the response of the biosphere to climate change, and especially the response of humans in the area.
KW  - Paleoclimate dynamics
KW  - Eastern Africa
KW  - Pleistocene
KW  - Holocene
KW  - Time-series analysis
KW  - Recurrence plot
Y1  - 2019
U6  - https://doi.org/10.1007/s00382-019-04641-3
SN  - 0930-7575
SN  - 1432-0894
VL  - 53
IS  - 5-6
SP  - 2557
EP  - 2572
PB  - Springer
CY  - New York
ER  -