LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir model v2.0.4

Abstract

The LOSCAR model is designed to efficiently compute the partitioningof carbon between ocean, atmosphere, and sediments on time scalesranging from centuries to millions of years. While a varietyof computationally inexpensive carbon cycle models are alreadyavailable, many are missing a critical sediment component,which is indispensable for long-term integrations. One of LOSCAR'sstrengths is the coupling of ocean-atmosphere routines to a computationallyefficient sediment module. This allows, for instance, adequate computationof CaCO 3 dissolution, calcite compensation, and long-term carbon cyclefluxes, including weathering of carbonate and silicate rocks.The ocean component includes various biogeochemical tracers such astotal carbon, alkalinity, phosphate, oxygen, and stable carbonisotopes. LOSCAR's configuration of ocean geometry is flexible andallows for easy switching between modern and paleo-versions.We have previously published applications of the modeltackling future projections of ocean chemistry and weathering, pCO 2 sensitivityto carbon cycle perturbations throughout the Cenozoic, andcarbon/calcium cycling during the Paleocene-Eocene Thermal Maximum.The focus of the present contribution is the detailed descriptionof the model including numerical architecture, processes andparameterizations, tuning, and examples of input and output.Typical CPU integration times of LOSCAR are of order secondsfor several thousand model years on current standarddesktop machines. The LOSCAR source code in C can be obtainedfrom the author by sending a request toloscar.model@gmail.com. © Author(s) 2012.