Comparing modeled streamfunction, heat and freshwater content in the Arctic Ocean
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Within the framework of the Arctic Ocean Model Intercomparison Project results from several coupled sea ice-ocean models are compared in order to investigate vertically integrated properties of the Arctic Ocean. Annual means and seasonal ranges of streamfunction, freshwater and heat content are shown. For streamfunction the entire water column is integrated. For heat and freshwater content integration is over the upper 1000 m. The study represents a step toward identifying differences among model approaches and will serve as a base for upcoming studies where all models will be executed with common forcing. In this first stage only readily available outputs are compared, while forcing as well as numerical parameterizations differ. The intercomparison shows streamfunctions differing in pattern and by several Sverdrups in magnitude. Differences occur as well for the seasonal range, where streamfunction is subject to large variability. Annual mean heat content, referenced to 0 degreesC, in the Canada Basin varies from -3.5 to +1.8 GJ m(-2) among the models, representing both colder and warmer solutions compared to the climatology. Seasonal range is highest in regions with seasonal or no ice cover. Corresponding freshwater content, referenced to 34.8 ppt, shows differences most obviously in the Beaufort Sea and Canada Basin where maximum values vary between 6 and 24 m for the individual models. Maxima in the seasonal range are related to river inflow. In the current stage of the project, applied windstress contributes significantly to the differences. However differences due to model resolutions and model parameterizations can already be detected. (C) 2003 Elsevier Ltd. All rights reserved.