Description: 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 Wm**-2 and 397 Wm**-2, respectively, this leaves 106 Wm**-2 of surface net radiation available 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 inconsistencies between energy and water cycle estimates.

Description: The Global Energy Balance Archive (GEBA) is a database for the central storage of the worldwide measured energy fluxes at the Earth's surface, maintained at ETH Zurich (Switzerland). This paper documents the status of the GEBA version 2017 dataset, presents the new web interface and user access, and reviews the scientific impact that GEBA data had in various applications. GEBA has continuously been expanded and updated and contains in its 2017 version around 500.000 monthly mean entries of various surface energy balance components measured at 2500 locations. The database contains observations from 15 surface energy flux components, with the most widely measured quantity available in GEBA being the shortwave radiation incident at the Earth's surface (global radiation). Many of the historic records extend over several decades. GEBA contains monthly data from a variety of sources, namely from the World Radiation Data Centre (WRDC) in St. Petersburg, from national weather services, from different research networks (BSRN, ARM, SURFRAD), from peer-reviewed publications, project and data reports, and from personal communications. Quality checks are applied to test for gross errors in the dataset. GEBA has played a key role in various research applications, such as in the quantification of the global energy balance, in the discussion of the anomalous atmospheric shortwave absorption, and in the detection of multi-decadal variations in global radiation, known as "global dimming" and "brightening". GEBA is further extensively used for the evaluation of climate models and satellite-derived surface flux products. On a more applied level, GEBA provides the basis for engineering applications in the context of solar power generation, water management, agricultural production and tourism. GEBA is publicly accessible through the internet via http://www.geba.ethz.ch.

Description: The energy budgets over land and oceans are still afflicted with considerable uncertainties, despite their key importance for terrestrial and maritime climates. We evaluate these budgets as represented in 43 CMIP5 climate models with direct observations from both surface and space and identify substantial biases, particularly in the surface fluxes of downward solar and thermal radiation. These flux biases in the various models are then linearly related to their respective land and ocean means to infer best estimates for present day downward solar and thermal radiation over land and oceans. Over land, where most direct observations are available to constrain the surface fluxes, we obtain 184 and 306 Wm−2 for solar and thermal downward radiation, respectively. Over oceans, with weaker observational constraints, corresponding estimates are around 185 and 356 Wm−2. Considering additionally surface albedo and emissivity, we infer a surface absorbed solar and net thermal radiation of 136 and −66 Wm−2 over land, and 170 and −53 Wm−2 over oceans, respectively. The surface net radiation is thus estimated at 70 Wm−2 over land and 117 Wm−2 over oceans, which may impose additional constraints on the poorly known sensible/latent heat flux magnitudes, estimated here near 32/38 Wm−2 over land, and 16/100 Wm−2 over oceans. Estimated uncertainties are on the order of 10 and 5 Wm−2 for most surface and TOA fluxes, respectively. By combining these surface budgets with satellite-determined TOA budgets we quantify the atmospheric energy budgets as residuals (including ocean to land transports), and revisit the global mean energy balance.

Description: The energy budgets over land and oceans are still afflicted with considerable uncertainties, despite their key importance for terrestrial and maritime climates. We evaluate these budgets as represented in 43 CMIP5 climate models with direct observations from both surface and space and identify substantial biases, particularly in the surface fluxes of downward solar and thermal radiation. These flux biases in the various models are then linearly related to their respective land and ocean means to infer best estimates for present day downward solar and thermal radiation over land and oceans. Over land, where most direct observations are available to constrain the surface fluxes, we obtain 184 and 306 Wm-2 for solar and thermal downward radiation, respectively. Over oceans, with weaker observational constraints, corresponding estimates are around 185 and 356 Wm-2. Considering additionally surface albedo and emissivity, we infer a surface absorbed solar and net thermal radiation of 136 and -66 Wm-2 over land, and 170 and -53 Wm-2 over oceans, respectively. The surface net radiation is thus estimated at 70 Wm-2 over land and 117 Wm-2 over oceans, which may impose additional constraints on the poorly known sensible/latent heat flux magnitudes, estimated here near 32/38 Wm-2 over land, and 16/100 Wm-2 over oceans. Estimated uncertainties are on the order of 10 and 5 Wm-2 for most surface and TOA fluxes, respectively. By combining these surface budgets with satellite-determined TOA budgets we quantify the atmospheric energy budgets as residuals (including ocean to land transports), and revisit the global mean energy balance. This study has recently been published online in Climate Dynamics.

Description: Here we provide a new assessment of the global mean energy fluxes from a surface perspective and present an associated diagram of the global mean energy balance, adapted from the study by Wild et al. (2013) [1] with two slight modifications as outlined in this paper. The radiative energy exchanges between Sun, Earth and space are now accurately quantified from new satellite missions. Much less has been 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, 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 Wm-2 and 398 Wm-2, respectively, this leaves 105 Wm-2 of surface net radiation available for distribution amongst the non-radiative surface energy balance components. Considering an imbalance of 0.6 Wm-2, the global mean sensible and latent heat fluxes are estimated at 20 and 84 Wm-2, respectively, to close the surface energy balance. The global mean surface radiative fluxes derived here in combination with a latent heat flux of 84 Wm-2 may be able to reconcile currently disputed inconsistencies between energy and water cycle estimates. The findings of this study are compiled into a new global energy balance diagram.

Description: The genesis and evolution of Earth’s climate is largely regulated by the global energy balance. Despite the central importance of the global energy balance for the climate system and climate change, substantial uncertainties still exist in the quantification of its different components, and its representation in climate models. While the net radiative energy flow in and out of the climate system at the top of atmosphere is known with considerable accuracy from new satellite programs such as CERES, much less is known about the energy distribution within the climate system and at the Earth surface. Accordingly, the quantification of the global energy balance has been controversially disputed in the past. Here we review this discussion and make an attempt to put additional constraints on the components with largest uncertainties. In addition to satellite observations, we thereby 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 (CMIP5) 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. These estimates are lower and higher, respectively, than in many previous assessments, including those presented in previous IPCC reports. It is encouraging that our estimates, which make full use of the information contained in the surface networks, coincide within 2 Wm-2 with the latest satellite-derived estimates (Stephens et al. 2012, Kato et al. submitted to J. Climate), which are completely independently determined. Combining our above estimates with an estimated global mean surface absorbed solar radiation and thermal emission of 161 Wm-2 and 397 Wm-2, respectively, results in 106 Wm-2 of surface net radiation globally available for distribution amongst the non-radiative surface energy balance components. The 23 CMIP5 models investigated in this study overestimate the downward solar and underestimate the downward thermal radiation, both by 5-10 Wm-2 on average. Thus, the CMIP5 models nevertheless simulate an adequate global mean surface net radiation, by error compensation in their downward solar and thermal components. 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, and may be able to reconcile currently disputed inconsistencies between global mean energy and water cycle estimates. The study is published online in Climate Dynamics. Wild, M., Folini, D., Schär, C., Loeb, N., Dutton, E.G., and König-Langlo, G., 2013: The global energy balance from a surface perspective, Clim. Dyn., published online. Doi:10.1007/s00382-012-1569-8.