Multidecadal variability:





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Finding signature of multidecadal variability (MDV) in the time series of Arctic vorticity (which defines shifts of circulation regimes in the high-latitude climate system) was the impetus for our research on MDV in the Arctic and North Atlantic.
Paleoclimate records also provide evidence of MDV.
The NAO (atmosphere) and North Atlantic sea surface temperature (SST, also expressed as the AMO) display large amplitude multidecadal signal.
The sea-ice edge in the Nordic Seas exhibits strong MDV.
GCMs simulate MDV and suggest a connection at multidecadal time scales between the Arctic and North Atlantic.
Fish catch variations display the multidecadal signal.

Several years have passed since a paper was published which demonstrated the important role of multidecadal fluctuations in shaping high-latitude oceanic, ice, and atmospheric variability [Polyakov and Johnson, 2000]. As the observational record gets longer, climate scientists have a better perspective on how to interpret the record. Consequently, we made substantial progress towards documenting this variability in the Arctic and North Atlantic regions, addressing Arctic/North Atlantic connections, and (to the extent possible) developing hypothesis/models of the underlying mechanisms driving this variability. This web page aims to provide a summary of our current thinking on this topic and will be updated regularly as our ideas become more refined. We present a description of MDV in Arctic atmosphere, ice , and ocean, as well as in the North Atlantic atmosphere and ocean. One of the most important findings of our analyses is striking pattern of coherent long-term variations of the key climate parameters and strong coupling of long-term changes in the Arctic/North Atlantic climate system. The MDV is ubiquitous in all of these time series and elucidating the mechanisms behind this relationship is critical to our understanding of the complex nature of low-frequency variability found in the Arctic and at lower latitudes and its relationship with anthropogenic climate change. Finally we note that this web page is not designed to provide on overview of all existing studies of MDV in the Arctic/North Atlantic climate system, it is merely a review of our contribution to this important climate issue.