The CERES/ARM/GEWEX Experiment (CAGEX) for the Retrieval of Radiative Fluxes with Satellite Data

Charlock, Thomas P.; Alberta, Timothy L.

doi:10.1175/1520-0477(1996)077<2673:tceftr>2.0.co;2

Cited by 87 publications

(57 citation statements)

References 29 publications

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“…These measurements offer much less information for understanding the separate effects of clouds on the atmospheric (ATM) and the surface (SFC) radiation budgets and it will be stressed how these influences are critical aspects of the cloud feedback problem. Much of what we know about the effects of clouds on the surface and atmospheric radiation budget is gleaned from model simulations directly or models constrained by certain types of data (e.g., Pinker and Corio 1984;Zhang et al 1995;Charlock and Alberta 1996;and others). It will also be demonstrated how available TOA observations of clouds and TOA radiative fluxes cannot constrain critical assumptions about the relation between cloud physical and radiative processes-relationships of central relevance to the cloud feedback problem.…”

Section: Effects Of Clouds On the Radiation Budgetmentioning

confidence: 99%

Cloud Feedbacks in the Climate System: A Critical Review

2005

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This paper offers a critical review of the topic of cloud-climate feedbacks and exposes some of the underlying reasons for the inherent lack of understanding of these feedbacks and why progress might be expected on this important climate problem in the coming decade. Although many processes and related parameters come under the influence of clouds, it is argued that atmospheric processes fundamentally govern the cloud feedbacks via the relationship between the atmospheric circulations, cloudiness, and the radiative and latent heating of the atmosphere. It is also shown how perturbations to the atmospheric radiation budget that are induced by cloud changes in response to climate forcing dictate the eventual response of the global-mean hydrological cycle of the climate model to climate forcing. This suggests that cloud feedbacks are likely to control the bulk precipitation efficiency and associated responses of the planet's hydrological cycle to climate radiative forcings.The paper provides a brief overview of the effects of clouds on the radiation budget of the earthatmosphere system and a review of cloud feedbacks as they have been defined in simple systems, one being a system in radiative-convective equilibrium (RCE) and others relating to simple feedback ideas that regulate tropical SSTs. The systems perspective is reviewed as it has served as the basis for most feedback analyses. What emerges is the importance of being clear about the definition of the system. It is shown how different assumptions about the system produce very different conclusions about the magnitude and sign of feedbacks. Much more diligence is called for in terms of defining the system and justifying assumptions. In principle, there is also neither any theoretical basis to justify the system that defines feedbacks in terms of global-time-mean changes in surface temperature nor is there any compelling empirical evidence to do so. The lack of maturity of feedback analysis methods also suggests that progress in understanding climate feedback will require development of alternative methods of analysis.It has been argued that, in view of the complex nature of the climate system, and the cumbersome problems encountered in diagnosing feedbacks, understanding cloud feedback will be gleaned neither from observations nor proved from simple theoretical argument alone. The blueprint for progress must follow a more arduous path that requires a carefully orchestrated and systematic combination of model and observations. Models provide the tool for diagnosing processes and quantifying feedbacks while observations provide the essential test of the model's credibility in representing these processes. While GCM climate and NWP models represent the most complete description of all the interactions between the processes that presumably establish the main cloud feedbacks, the weak link in the use of these models lies in the cloud parameterization imbedded in them. Aspects of these parameterizations remain worrisome, containing levels of empiricism and ...

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Section: Effects Of Clouds On the Radiation Budgetmentioning

confidence: 99%

Cloud Feedbacks in the Climate System: A Critical Review

2005

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“…2016, 8,90 3/19 analysis across the global land surface. As the southern Great Plains and south-central Africa are located in special and vital geographical locations, they were chosen as hot spots for a detailed analysis of the relationship between the variations in surface Rn and their driving factors.…”

Section: In Situ Observation Datamentioning

confidence: 99%

“…2016, 8,90 7/19 correlation analysis, and principal components analysis, showing its strength when the independent variables are interrelated and when there are fewer data samples available [53].…”

Section: Daily Scalementioning

confidence: 99%

“…2016, 8,90 albedo does not provide more information than NDVI owing to the collinearity with NDVI. Tm showed a positive correlation with Rn; it is widely accepted that Tm determines the ULW but is affected by the shortwave radiation.…”

Section: South-central Africamentioning

confidence: 99%

“…Charlock et al [8] conducted the CERES/ARM/GEWEX Experiment (CAGEX) before the launch of satellites, in order to validate the Fu-Liou radiative transfer model [9]. They found that the modeled longwave radiation agrees well with the in situ observations, while the shortwave radiation exhibits a large difference between the modeled and in situ data.…”

Section: Introductionmentioning

confidence: 99%

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Validation and Spatiotemporal Analysis of CERES Surface Net Radiation Product

et al. 2016

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Abstract:The Clouds and the Earth's Radiant Energy System (CERES) generates one of the few global satellite radiation products. The CERES ARM Validation Experiment (CAVE) has been providing long-term in situ observations for the validation of the CERES products. However, the number of these sites is low and their distribution is globally sparse, and particularly the surface net radiation product has not been rigorously validated yet. Therefore, additional validation efforts are highly required to determine the accuracy of the CERES radiation products. In this study, global land surface measurements were comprehensively collected for use in the validation of the CERES net radiation (R n ) product on a daily (340 sites) and a monthly (260 sites) basis, respectively. The validation results demonstrated that the CERES R n product was, overall, highly accurate. The daily validations had a Mean Bias Error (MBE) of 3.43 W¨m´2, Root Mean Square Error (RMSE) of 33.56 W¨m´2, and R 2 of 0.79, and the monthly validations had an MBE of 3.40 W¨m´2, RMSE of 25.57 W¨m´2, and R 2 of 0.84. The accuracy was slightly lower for the high latitudes. Following the validation, the monthly CERES R n product, from March 2000 to July 2014, was used for a further analysis. The global spatiotemporal variation of the R n , which occurred during the measurement period, was analyzed. In addition, two hot spot regions, the southern Great Plains and south-central Africa, were then selected for use in determining the driving factors or attribution of the R n variation. We determined that R n over the southern Great Plains decreased by´0.33 W¨m´2 per year, which was mainly driven by changes in surface green vegetation and precipitation. In south-central Africa, R n decreased at a rate of´0.63 W¨m´2 per year, the major driving factor of which was surface green vegetation.

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A clear‐sky radiation closure study using a one‐dimensional radiative transfer model and collocated satellite‐surface‐reanalysis data sets

Dolinar

Dong

et al. 2016

JGR Atmospheres

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Earth's climate is largely determined by the planet's energy budget, i.e., the balance of incoming and outgoing radiation at the surface and top of atmosphere (TOA). Studies have shown that computing clear‐sky radiative fluxes are strongly dependent on atmospheric state variables, such as temperature and water vapor profiles, while the all‐sky fluxes are greatly influenced by the presence of clouds. NASA‐modeled vertical profiles of temperature and water vapor are used to derive the surface radiation budget from Clouds and Earth Radiant Energy System (CERES), which is regarded as one of the primary sources for evaluating climate change in climate models. In this study, we evaluate the Modern‐Era Retrospective Analysis for Research and Applications version 2 (MERRA‐2) reanalyzed clear‐sky temperature and water vapor profiles with newly generated atmospheric profiles from Department of Energy Atmospheric Radiation Measurement (ARM)‐merged soundings and Aura Microwave Limb Sounder retrievals at three ARM sites. The temperature profiles are well replicated in MERRA‐2 at all three sites, whereas tropospheric water vapor is slightly dry below ~700 hPa. These profiles are then used to calculate clear‐sky surface and TOA radiative fluxes from the Langley‐modified Fu‐Liou radiative transfer model (RTM). In order to achieve radiative closure at both the surface and TOA, the ARM‐measured surface albedos and aerosol optical depths are adjusted to account for surface inhomogeneity. In general, most of the averaged RTM‐calculated surface downward and TOA upward shortwave and longwave fluxes agree within ~5 W/m2 of the observations, which is within the uncertainties of the ARM and CERES measurements. Yet still, further efforts are required to reduce the bias in calculated fluxes in coastal regions.

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The CERES/ARM/GEWEX Experiment (CAGEX) for the Retrieval of Radiative Fluxes with Satellite Data

Cited by 87 publications

References 29 publications

Cloud Feedbacks in the Climate System: A Critical Review

Cloud Feedbacks in the Climate System: A Critical Review

Validation and Spatiotemporal Analysis of CERES Surface Net Radiation Product

A clear‐sky radiation closure study using a one‐dimensional radiative transfer model and collocated satellite‐surface‐reanalysis data sets

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