Radiative forcing by well‐mixed greenhouse gases: Estimates from climate models in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4)

摘要: The radiative effects from increased concentrations of well-mixed greenhouse gases (WMGHGs) represent the most significant and best understood anthropogenic forcing climate system. comprehensive tools for simulating past future climates influenced by WMGHGs are fully coupled atmosphere-ocean general circulation models (AOGCMs). Because importance as agents it is essential that AOGCMs compute these accurately possible. We present results a transfer model intercomparison between forcings computed parameterizations benchmark line-by-line (LBL) codes. comparison focused on CO2, CH4, N2O, CFC-11, CFC-12, H2O expected in warmer climates. included include several LBL codes global submitted to Intergovernmental Panel Climate Change (IPCC) Fourth Assessment Report (AR4). In general, excellent agreement with each other. However, many cases, there substantial discrepancies among some cases this because neglect particular absorbers, near-infrared CH4 while others due methods modeling processes. biases AOGCM generally largest at surface level. quantify differences discuss implications interpreting variations response across multimodel ensemble simulations assembled IPCC AR4.