Consistent fluctuations in intermediate water temperature off the coast of Greenland and Norway during Dansgaard-Oeschger events

Dansgaard-Oeschger events: tipping points in the climate system

The largest variability in temperature over the last sixty thousand years is connected with Dansgaard-Oeschger events. Various prototype models have been proposed to explain these rapid climate fluctuations, but until now no observational constraint has been forwarded to choose between different theories. We assess the bimodality of the system reconstructing the topology of the multi-dimensiona...

North Atlantic warming during Dansgaard-Oeschger events synchronous with Antarctic warming and out-of-phase with Greenland climate

The precise reason for the differences and out-of-phase relationship between the abrupt Dansgaard-Oeschger warmings in the Nordic seas and Greenland ice cores and the gradual warmings in the south-central Atlantic and Antarctic ice cores is poorly understood. Termed the bipolar seesaw, the differences are apparently linked to perturbations in the ocean circulation pattern. Here we show that sur...

Limitations of red noise in analysing Dansgaard-Oeschger events

During the last glacial period, climate records from the North Atlantic region exhibit a pronounced spectral component corresponding to a period of about 1470 years, which has attracted much attention. This spectral peak is closely related to the recurrence pattern of DansgaardOeschger (DO) events. In previous studies a red noise random process, more precisely a first-order autoregressive (AR1)...

A two‐parameter stochastic process for Dansgaard‐Oeschger events

[1] Various climatic processes are thought to evolve as rapid, shift‐like events, which points at the presence of nonlinear dynamics. Time series analysis of nonlinear processes, however, is not trivial, for example, because of the difficulty in coming up with a realistic random process as a viable null hypothesis. In this methodology paper we construct a basic two‐parameter process of shift‐li...

Quantifying the periodicity of Heinrich and Dansgaard–Oeschger events during Marine Oxygen Isotope Stage 3