The energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models

Wild, Martin; Folini, Doris; Hakuba, Maria Z.; Schär, Christoph; Seneviratne, Sonia I.; Kato, Seiji; Rutan, David A.; Ammann, Christof; Wood, Eric F.; König-Langlo, Gert

doi:10.1007/s00382-014-2430-z

Cited by 280 publications

(354 citation statements)

References 70 publications

(133 reference statements)

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“…Although these low biases have generally decreased over time, increases in observed time series as suggested above may imply that the underestimation of DLR continues to be a serious issue even in the latest generation of climate models used in the IPCC Fifth Assessment Report (Wild et al, 2015). In the context of the quantification of the global energy balance, estimates making use of the information contained in the surface observations (Ohmura and Gilgen, 1993;Wild et al, 1998Wild et al, , 2015 over many years have suggested a higher global mean DLR than typically advocated in various published global energy balance estimates such as those given in the IPCC assessments up to the Fourth Assessment Report. An increase in observed DLR time series may further support such higher DLR estimates within the global energy balance.…”

Section: Bsrn Archives: Application Of Possible New Wsg and Wisg Refementioning

confidence: 99%

Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

et al. 2017

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Abstract. A large number of radiometers are traceable to the World Standard Group (WSG) for shortwave radiation and the interim World Infrared Standard Group (WISG) for longwave radiation, hosted by the PhysikalischMeteorologisches Observatorium Davos/World Radiation Centre (PMOD/WRC, Davos, Switzerland). The WSG and WISG have recently been found to over-and underestimate radiation values, respectively (Fehlmann et al., 2012; Gröb-ner et al., 2014), although research is still ongoing. In view of a possible revision of the reference scales of both standard groups, this study discusses the methods involved and the implications on existing archives of radiation time series, such as the Baseline Surface Radiation Network (BSRN). Based on PMOD/WRC calibration archives and BSRN data archives, the downward longwave radiation (DLR) time series over the 2006-2015 period were analysed at four stations (polar and mid-latitude locations). DLR was found to increase by up to 3.5 and 5.4 W m −2 for all-sky and clearsky conditions, respectively, after applying a WISG reference scale correction and a minor correction for the dependence of pyrgeometer sensitivity on atmospheric integrated water vapour content. Similar increases in DLR may be expected at other BSRN stations. Based on our analysis, a number of recommendations are made for future studies.

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Section: Bsrn Archives: Application Of Possible New Wsg and Wisg Refementioning

confidence: 99%

Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

et al. 2017

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“…Valdivieso et al [2015] showed that most reanalysis products feature a bias during the period 1993-2009 in the global-mean net surface flux in the order of 1-2 W/m 2 which is larger than the energy gain derived from estimates of the top of atmosphere (TOA) imbalance of about 0.50 (±0.43) W/m 2 [Loeb et al, 2012]. For comparison, the current generation of climate models of the Coupled Model Intercomparison Project Phase 5 (CMIP5) exhibits an uncertainty in the net surface and TOA fluxes in the order of 10 W/m 2 and 5 W/m 2 , respectively [Wild et al, 2015]. However, the extent to which these uncertainties in simulated air-sea fluxes impact the ocean circulation and ocean heat uptake (OHU) in climate models is not fully understood.…”

Section: Introductionmentioning

confidence: 99%

Drivers of uncertainty in simulated ocean circulation and heat uptake

Huber

Zanna

2017

Geophysical Research Letters

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The impact of uncertainties in air‐sea fluxes and ocean model parameters on the ocean circulation and ocean heat uptake (OHU) is assessed in a novel modeling framework. We use an ocean‐only model forced with the simulated sea surface fields of the CMIP5 climate models. The simulations are performed using control and 1% CO2 warming scenarios. The ocean‐only ensemble adequately reproduces the mean Atlantic Meridional Overturning Circulation (AMOC) and the zonally integrated OHU. The ensemble spread in AMOC strength, its weakening, and Atlantic OHU due to different air‐sea fluxes is twice as large as the uncertainty range related to vertical and mesocale eddy diffusivities. The sensitivity of OHU to uncertainties in air‐sea fluxes and model parameters differs vastly across basins, with the Southern Ocean exhibiting strong sensitivity to air‐sea fluxes and model parameters. This study clearly demonstrates that model biases in air‐sea fluxes are one of the key sources of uncertainty in climate simulations.

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“…The global mean annual volume of evaporation has been intensively debated in recent years (see, e.g., Wang and Dickinson, 2012), with the range of reported global averages in current Coupled Model Intercomparison Project Phase 5 (CMIP5) models being large (Wild et al, 2014) and observational benchmark data sets also differing significantly . In this section, we aim to give some context to the global magnitude of evaporation that results from the WACMOS-ET analyses by contrasting the results with alternative evaporation data sets and existing literature.…”

Section: Global Magnitude Of Terrestrial Evaporationmentioning

confidence: 99%

The WACMOS-ET project – Part 2: Evaluation of global terrestrial evaporation data sets

Miralles

Jiménez²,

Jung

et al. 2016

Hydrol. Earth Syst. Sci.

290

214

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Abstract. The WAter Cycle Multi-mission Observation Strategy -EvapoTranspiration (WACMOS-ET) project aims to advance the development of land evaporation estimates on global and regional scales. Its main objective is the derivation, validation, and intercomparison of a group of existing evaporation retrieval algorithms driven by a common forcing data set. Three commonly used process-based evaporation methodologies are evaluated: the PenmanMonteith algorithm behind the official Moderate Resolution Imaging Spectroradiometer (MODIS) evaporation product (PM-MOD), the Global Land Evaporation Amsterdam Model (GLEAM), and the Priestley-Taylor Jet Propulsion Laboratory model (PT-JPL). The resulting global spatiotemporal variability of evaporation, the closure of regional water budgets, and the discrete estimation of land evaporation components or sources (i.e. transpiration, interception loss, and direct soil evaporation) are investigated using river discharge data, independent global evaporation data sets and results from previous studies. In a companion article (Part 1), Michel et al. (2016) inspect the performance of these three models at local scales using measurements from eddy-covariance towers and include in the assessment the Surface Energy Balance System (SEBS) model. In agreement with Part 1, our results indicate that the Priestley and Taylor products (PT-JPL and GLEAM) perform best overall for most ecosystems and climate regimes. While all three evaporation products adequately represent the expected average geographical patterns and seasonality, there is a tendency in PM-MOD to underestimate the flux in the tropics and subtropics. Overall, results from GLEAM and PT-JPL appear more realistic when compared to surface water balances from 837 globally distributed catchments and to separate evaporation estimates from ERAInterim and the model tree ensemble (MTE). Nonetheless, all products show large dissimilarities during conditions of water stress and drought and deficiencies in the way evaporation is partitioned into its different components. This observed inter-product variability, even when common forcing is used, suggests that caution is necessary in applying a single data set for large-scale studies in isolation. A general finding that different models perform better under different conditions highlights the potential for considering biome-or climatespecific composites of models. Nevertheless, the generation of a multi-product ensemble, with weighting based on validation analyses and uncertainty assessments, is proposed as the Published by Copernicus Publications on behalf of the European Geosciences Union. D. G. Miralles et al.: The WACMOS-ET project -Part 2best way forward in our long-term goal to develop a robust observational benchmark data set of continental evaporation.

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The energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models

Cited by 280 publications

References 70 publications

Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

Revising shortwave and longwave radiation archives in view of possible revisions of the WSG and WISG reference scales: methods and implications

Drivers of uncertainty in simulated ocean circulation and heat uptake

The WACMOS-ET project – Part 2: Evaluation of global terrestrial evaporation data sets

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