Projections of an Ice-Diminished Arctic Ocean
- Retrospection and Future Projection

   Jinlun Zhang, D. Andrew Rothrock, and Michael Steele

  Polar Science Center, Applied Physics Laboratory, University of Washington
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Funded by The National Science Foundation Office of Polar Programs

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Future Projections of an Ice-Diminished Arctic Ocean

The approach for future projections is to conduct a series of multi-decade model runs using POIM driven by 'future-based' atmospheric forcing. The future-based forcing consists of a suite of composite forcing for projections of plausible scenarios that are likely to lead to a significantly reduced ice cover. This part of the research focuses on GOAL 2. To achieve this goal we will explore two possible scenarios that are likely to lead to a diminished arctic ice cover:

Scenario 1: Using reanalysis forcing from high NAO/AO years
     This scenario is based on the assumption that the recent dominating positive NAO/AO phase stays at this level for a sufficient period of time. This means that the NAO/AO develops a cyclonicity bias without either reversal or amplification. Correspondingly the arctic surface air temperature is anomalously high (Rigor et al., 2000). This scenario may be linked to natural climate variability that is somehow "locked" in the positive phase, or may be linked to moderate greenhouse gas-induced warming. Composite forcing for this scenario consists of reanalysis data corresponding to a number of years of high NAO/AO indices.

Scenario 2: Adding GCM greenhouse warming
     This idealized warming scenario is based on Arctic Climate Impact Assessment (ACIA, 2004) results. The composite forcing for this scenario consists of NCEP/NCAR reanalysis data randomly selected from the period 1948–2005, except that the surface air temperature, the cloud cover, and the downwelling longwave radiative flux were gradually increased over 2005 to include possible greenhouse warming effects. This increase is based on the average change calculated by the five ACIA climate models using the B2 emissions scenario specified by the IPCC (International Panel on Climate Change) Special Report on Emissions Scenarios (2000). Under this scenario, by the end of this century, annual average temperatures are projected to raise 7oC over the Arctic Ocean. Such an increase is superposed on the reanalysis data evenly throughout the Arctic Ocean. The results from this projection are  archived here.

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[ Home ] [ Introduction ] [ Model ] [ Retrospection ] [ Future Projection ] [ Data ] [Source Code] [ Publications ] [ Links ]