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The global energy balance from a surface perspective

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In the framework of the global energy balance, the radiative energy exchanges between Sun, Earth and space are now accurately quantified from new satellite missions. Much less is known about the magnitude of the energy flows within the climate system and at the Earth surface, which cannot be directly measured by satellites. In addition to satellite observations, here we make extensive use of the growing number of surface observations to constrain the global energy balance not only from space,but also from the surface. We combine these observations with the latest modeling efforts performed for the 5th IPCC assessment report to infer best estimates for the global mean surface radiative components. Our analyses favor global mean downward surface solar and thermal radiation values near 185 and 342 Wm-2, respectively, which are most compatible with surface observations. Combined with an estimated surface absorbed solar radiation and thermal emission of 161 and 397 Wm-2, respectively, this leaves 106 Wm-2 of surface net radiation available globally for distribution amongst the non-radiative surface energy balance components. The climate models overestimate the downward solar and underestimate the downward thermal radiation, thereby simulating nevertheless an adequate global mean surface net radiation by error compensation. This also suggests that, globally, the simulated surface sensible and latent heat fluxes, around 20 and 85 Wm-2 on average, state realistic values. The findings of this study are compiled into a new global energy balance diagram, which may be able to reconcile currently disputed inconsistenciesbetween energy and water cycle estimates.
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... The height of the tropopause is about 9 km at the poles and 17 km at the Equator, so we used the lower value for the Arctic and a middle value of 14 km for the global average. The globally averaged insolation, the atmospheric solar reflection, and the average surface albedo are all obtained from Wild et al. (2013). For the Arctic, the insolation is the annual average for the region north of 70 • N, (2007). ...
... Calibration of the other model parameters was done in two steps. First, the absorption coefficients, k S , k C , k W , and k Cl , the decay for sensible and latent heat transport, b, and the drag coefficient, C D (which is a multiplicative factor of both B 2 and B 3 ), were calibrated using global average energy fluxes obtained from Wild et al. (2013). In addition, this calibration attempted to match estimates from Schmidt et al. (2010), indicating that 25 % of absorption is due to carbon dioxide, 25 % due to clouds, and 50 % due to water vapour. ...
... L. Kypke et al.: Climate bifurcations in a Schwarzschild model of the Arctic atmosphere Table B3. Global average energy fluxes (W m −2 ) from Wild et al. (2013) and contribution fractions for absorption from Schmidt et al. (2010). rences between the model and the data in Table B4 was minimized by allowing the parameters z c , B , L φT , L φB , and L ψ to vary. ...
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... The average geothermal heat flux at the Earth surface is B0.09 W/m 2 ; by comparison, solar radiation reaches the Earth at an average rate of B160 W/m 2 (Wild et al., 2013). Unlike geothermal energy, solar energy is intermittent and dependent on climatic conditions. ...
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