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Long Piston Coring

Holocene

Holocene PIs Meeting

Tropics

Abrupt Climate Change

Methane

Paleoclimate Workshop

ESH Initiative Review

 

Tropics

In June 2003, 20 scientists met at the University of Southern California for a 3 day workshop to discuss the current state of knowledge concerning (1) tropical climate variability during the last glacial episode and Holocene and, (2) the potential role that the tropical ocean/atmosphere system may have played in causing and/or contributing to the large and abrupt climate changes that have occurred during the past 60 kyr. The discussions lead to a consensus opinion on the part of the participants of the workshop that while good progress has been made in the effort to document major episodes of climatic change within the tropics during the past 50 thousand years, there remains a critical need to better quantify the magnitude of sea surface temperature changes throughout the tropics, particularly in the upwelling centers and to quantify how the transport of latent heat out of the tropics changed during episodes of rapid climate change. To accomplish this will require substantial effort from both marine and terrestrial paleoclimate scientists and specific focus on archives that are capable of providing sufficient temporal resolution to resolve leads and lags between the low and high latitude climates. Information of this kind would substantially improve the ability of computer models to simulate global ocean/atmospheric dynamics at times of large climate transitions and begin to assess whether the tropical ocean/atmosphere has multiple modes of natural variability and whether the tropical ocean/atmospheric variability has been responsible for large and sometimes abrupt global climate changes in the past. The workshop participants agreed there is a need for a concentrated community effort that would test whether large and sometimes abrupt climate change originate in the tropics or the extratropics.

The hypothesis put forward by the group is:

Large, sometimes abrupt changes in ocean/atmospheric dynamics centered in the tropics have caused large climate changes in the extratropics.

Among the priority questions that will need to be answered by the community in order to validate or reject the hypothesis include:

  • In addition to the interannual variability (ENSO), are there other modes of tropical ocean/atmospheric behavior that can be recognized by studies of paleoarchives? If so, how has the behavior of these modes changed over time in relation to changes in the extratropics?
  • Is it possible to determine from proxy records how the tropical ocean/atmosphere system responds to specific changes in forcing including orbital and solar variability?
  • What aspects of the tropical ocean/atmospheric system have changed at times of abrupt climate change in the extratropics? (i.e. LIA, MWP, 4kyr event, 8.2kyr event, YD, B/A)?

Download Draft Tropics Workshop Report (PDF 251 KB)

© 2005 MESH