Earth Radiation Budget Experiment Data Research Articles

On the determination of climate feedbacks from ERBE data

Climate feedbacks are estimated from fluctuations in the outgoing radiation budget from the latest version of Earth Radiation Budget Experiment (ERBE) nonscanner data. It appears, for the entire tropics, the observed outgoing radiation fluxes increase with the increase in sea surface temperatures (SSTs). The observed behavior of radiation fluxes implies negative feedback processes associated with relatively low climate sensitivity. This is the opposite of the behavior of 11 atmospheric models forced by the same SSTs. Therefore, the models display much higher climate sensitivity than is inferred from ERBE, though it is difficult to pin down such high sensitivities with any precision. Results also show, the feedback in ERBE is mostly from shortwave radiation while the feedback in the models is mostly from longwave radiation. Although such a test does not distinguish the mechanisms, this is important since the inconsistency of climate feedbacks constitutes a very fundamental problem in climate prediction.

The Total Meridional Heat Flux and Its Oceanic and Atmospheric Partition

Abstract Atmospheric meridional heat transport is inferred as a residual from the Earth Radiation Budget Experiment (ERBE) data and in situ oceanic estimates. Reversing the conventional approach of computing the ocean as an atmospheric model residual is done to permit calculation of a preliminary uncertainty estimate for the atmospheric flux. The structure of the ERBE errors is itself an important uncertainty. Total energy transport is almost indistinguishable from a hemispherically antisymmetric analytic function, despite the great asymmetry of the oceanic heat fluxes. ERBE data appear sufficiently noisy so that a considerable range of atmospheric transports remains possible: the maximum atmospheric value lies between 3 and 5 PW in the Northern Hemisphere, at one standard deviation, although the values are sensitive to the noise assumptions made here. The Northern Hemisphere ocean and atmosphere carry comparable poleward heat fluxes to about 28°N where the oceanic flux drops rapidly, but does not actually vanish until the oceanic surface area goes to zero. Within the estimated error bars, there is a remarkable antisymmetry about the equator of the combined ocean and atmospheric transports, despite the marked oceanic transport asymmetry.

Testing the impact of clouds on the radiation budgets of 19 atmospheric general circulation models

We compare cloud‐radiative forcing (CRF) at the top‐of‐the atmosphere from 19 atmospheric general circulation models, employing simulations with prescribed sea‐surface temperatures, to observations from the Earth Radiation Budget Experiment (ERBE). With respect to 60°N to 60°S means, a surprising result is that many of the 19 models produce unusually large biases in Net CRF that are all of the same sign (negative), meaning that many of the models significantly overestimate cloud radiative cooling. The primary focus of this study, however, is to demonstrate a diagnostic procedure, using ERBE data, to test if a model might produce, for a given region, reasonable CRF as a consequence of compensating errors caused either by unrealistic cloud vertical structure, cloud optical depth or cloud fraction. For this purpose we have chosen two regions, one in the western tropical Pacific characterized by high clouds spanning the range from thin cirrus to deep convective clouds, and the other in the southeastern Pacific characterized by trade cumulus. For a subset of eight models, it is found that most typically produce more realistic regionally‐averaged CRF (and its longwave and shortwave components) for the southeastern region as opposed to the western region. However, when the diagnostic procedure for investigating cloud vertical structure and cloud optical depth is imposed, this somewhat better agreement in the southeastern region is found to be the result of compensating errors in either cloud vertical structure, cloud optical depth or cloud fraction. The comparison with ERBE data also shows large errors in clear‐sky fluxes for many of the models.

Seasonal Change of the Atmospheric Heat Budget over the Southern Ocean from ECMWF and ERBE Data

The seasonal variation of the zonally averaged atmospheric energy budget between 60° and 70°S was estimated. This region is predominantly within the seasonal sea ice zone of the Southern Ocean, including some parts of the Antarctic continent. In the Southern Ocean, seasonal sea ice extent exhibits large amplitudes and affects the surface heat exchange considerably. Seasonal variation of the energy budget and its relationship to the surface condition should be clarified as the basic variation. In spite of its importance, the data to estimate energy budgets are extremely sparse in this sea ice zone. Hence, the global objective analyses with forecasting models are mainly used as data for the present study. The surface energy flux is obtained as a remainder term in the energy budget of the total atmosphere, with the energy divergence and changes to the energy content of the atmospheric column derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) objective analyses, and with the radiation budget at the top of the atmosphere estimated from the Earth Radiation Budget Experiment (ERBE) data. The derived values of the surface flux are not seasonally symmetric. This differs from other latitude bands (e.g., 50°–60°S) where the variation is symmetric and is driven by shortwave radiation change. The monthly mean surface energy flux shows an immediate increase to the maximum of 116 W m−2 in May (heating of the atmosphere), and then gradually decreases to the minimum of −108 W m−2 in December (cooling of the atmosphere). It is suggested that the asymmetry at 60°–70°S is due to the effect of seasonal sea ice extent changes on the surface energy exchanges. A comparison of the derived values of the surface flux with the latent heat required for the change in sea ice extent provides some support for this suggestion. The rate of sea ice expansion shows a peak in May when the surface energy flux becomes maximum. The turbulent heat component of the surface energy flux is compared with other estimates of turbulent heat exchange over the Southern Ocean. Suppression of the turbulent heat exchange in late winter derived in the present study, in comparison with those values over open water area, suggests the effect of extended sea ice cover.

Comments on “Tropical Convection and the Energy Balance at the Top of the Atmosphere”

Analyses of the Earth Radiation Budget Experiment (ERBE) data show that the effects of clouds on the solar and thermal infrared radiation in the tropical deep convective regions have a similar magnitude but opposite signs. This small difference in the effects of clouds on radiation led Hartmann et al. (2001) to conclude that the contrast in the net radiation at the top of the atmosphere between the convective and non-convective regions must also be small. However, we have found that the ERBE data do not generally show a small contrast in the radiation between the convective and non-convective regions, and the model used by Hartmann et al., therefore, seems unlikely to represent the real physical processes involving convection, radiation, and climate in an appropriate way.

Comparison of different earth radiation budget experiment data sets over tropical oceans

AbstractWe compare radiation budgets derived from different Earth Radiation Budget Experiment (ERBE) archives over the tropical oceans (30S and 30N) from 1985 to 1989. Two ERBE data sets are used. One is taken from the Earth Radiation Budget Satellite (ERBS), and the other from the combined ERBS, National Oceanic and Atmospheric Administration (NOAA) 9, and NOAA 10 satellites. The domain‐mean all‐sky outgoing longwave radiation (OLR) derived from the combined data set shows a notable change in early 1987 when NOAA 10 replaced NOAA 9. This change is also found in longwave (LW) cloud radiative forcing (CRF), all‐sky shortwave (SW) radiation, and SWCRF. The ERBS, however, does not show such changes.We also examine the sensitivity of cloud–radiation interaction to the sea surface temperature (SST) of the tropical oceans. In general, each component of radiative feedbacks derived from the two ERBE data have the same sign, although they show a certain degree of discrepancy in the magnitude. The discrepancy is more notable for averaged quantities over the entire tropical oceans, particularly over the subtropics where convective activities are relatively weak. The combined data show a larger sensitivity of LWCRF and SWCRF to SST than those of the ERBS, consistent with the above results. The response of clouds to an increase in SST has a net cooling effect when using the combined data but has a net heating effect when using the ERBS data (−0.80 W m−2 K−1 versus 0.48 W m−2 K−1). Most of the discrepancies of the net CRF between the two ERBE data sets can be accounted for by the difference in the sensitivity of all‐sky OLR (4.52 W m−2 K−1 versus 1.73 W m−2 K−1). Copyright © 2002 Royal Meteorological Society.

Radiative Forcing of Saharan Dust: GOCART Model Simulations Compared with ERBE Data

Abstract This study uses information on Saharan aerosol from a dust transport model to calculate radiative forcing values. The transport model is driven by assimilated meteorological fields from the Goddard Earth Observing System Data Assimilation System. The model produces global three-dimensional dust spatial information for four different mineral aerosol sizes. These dust fields are input to an offline radiative transfer calculation to obtain the direct radiative forcing due to the dust fields. These estimates of the shortwave reduction of radiation at the top of the atmosphere (TOA) compare reasonably well with the TOA reductions derived from Earth Radiation Budget Experiment (ERBE) and Total Ozone Mapping Spectrometer (TOMS) satellite data. The longwave radiation also agrees with the observations; however, potential errors in the assimilated temperatures complicate the comparison. Depending on the assumptions used in the calculation and the dust loading, the summertime forcing ranges from 0 to −18 W ...

Radiative Effects of Various Cloud Types as Classified by the Split Window Technique over the Eastern Sub-tropical Pacific Derived from Collocated ERBE and AVHRR Data.

The radiative effects of several cloud types as classified by the split window (11 and 12 μm) technique were studied using coincident and collocated Earth Radiation Budget Experiment (ERBE) S-8 data and Advanced Very High Resolution Radiometer (AVHRR) data from NOAA-9. The parameter investigated was cloud radiative forcing (CRF), the difference between clear and cloudy shortwave flux (SW) and longwave flux (OLR) at the top of the atmosphere. In computing the CRF, the accuracy of clear SW and OLR is essential. Clear scene IDs in the ERBE dataset were evaluated using coincident and collocated AVHRR image data. The mean visible reflectance and SW for clear footprints defined by the ERBE are reasonably small and are 3.2% and 89.0 Wm-2, respectively. However, the values computed using our technique are smaller, 2.7% and 83.9 Wm-2, respectively. The use of collocated AVHRR image data improves clear footprint definition and implies that care should be taken when computing CRF from ERBE data alone. The CRF from several cloud types classified by the split window were compared. Cumulonimbus clouds show the largest impact on top of the atmosphere radiation for both SW and OLR. Cirrus and lowlevel cumulus clouds have similar effects on OLR, but large differences between them are seen for SW. The impact of low-level cumulus clouds on SW is much larger than that of cirrus clouds. Some optically thin cirrus clouds show positive cloud radiative forcing (warming effect). The relationships between OLR and cloud types (including cloud-free) as classified by the split window technique were investigated. By using brightness temperature differences between the split window channels, OLR estimation is improved for cloud-free and low-level cumulus clouds when compared with OLR estimated by the National Oceanic and Atmospheric Administration (NOAA) operational algorithm.

Combining ERBE and ISCCP data to assess clouds in the Hadley Centre, ECMWF and LMD atmospheric climate models

This study compares radiative fluxes and cloudiness fields from three general circulation models (the HadAM4 version of the Hadley Centre Unified model, cycle 16r2 of the ECMWF model and version LMDZ 2.0 of the LMD GCM), using a combination of satellite observations from the Earth Radiation Budget Experiment (ERBE) and the International Satellite Cloud Climatology Project (ISCCP). To facilitate a meaningful comparison with the ISCCP C1 data, values of column cloud optical thickness and cloud top pressure are diagnosed from the models in a manner consistent with the satellite view from space. Decomposing the cloud radiative effect into contributions from low-medium- and high-level clouds reveals a tendency for the models' low-level clouds to compensate for underestimates in the shortwave cloud radiative effect caused by a lack of high-level or mid-level clouds. The low clouds fail to compensate for the associated errors in the longwave. Consequently, disproportionate errors in the longwave and shortwave cloud radiative effect in models may be taken as an indication that compensating errors are likely to be present. Mid-level cloud errors in the mid-latitudes appear to depend as much on the choice of the convection scheme as on the cloud scheme. Convective and boundary layer mixing schemes require as much consideration as cloud and precipitation schemes when it comes to assessing the simulation of clouds by models. Two distinct types of cloud feedback are discussed. While there is reason to doubt that current models are able to simulate potential `cloud regime' type feedbacks with skill, there is hope that a model capable of simulating potential `cloud amount' type feedbacks will be achievable once the reasons for the remaining differences between the models are understood.

Longwave radiation budget of the southern hemisphere using ISCCP C2 climatological data

The longwave radiation budget at the top of the atmosphere (TOA) and at the surface of the Southern Hemisphere was estimated for 10° latitudinal zones, using a radiative transfer model and long‐term mean monthly climatological data from the International Satellite Cloud Climatology Project (ISCCP) from 1983 to 1990. The model radiative fluxes at TOA were validated against Earth Radiation Budget Experiment (ERBE) scanner S4 satellite data (1984–1989) while at the surface they have been compared with other model results and available surface measurements. Large discrepancies were found between model and ERBE TOA fluxes over Antarctica that were resolved by increasing the winter polar cloudiness significantly. Generally, our model TOA fluxes agree within the standard deviation of the ERBE data. Important differences from previous works are also found in the polar regions, in terms of magnitudes, and seasonal/latitudinal trends in surface fluxes. The mean annual and hemispherical outgoing longwave radiation at TOA, upward longwave radiation, downwelling, and net upward longwave radiation at the surface, are computed to be 236, 387, 341, and 46 W m−2, respectively.

The Amazon Energy Budget Using the ABLE-2B and FluAmazon Data

Abstract Radiosonde and satellite data collected from the Atmosphere Boundary Layer Experiment—Wet Season and Amazon Water Vapor Flux Experiment are used to investigate the energy budget. The relationship between the cloud cover variability and the different terms of the energy budget equations was examined. The radiosonde data were used to compute the energy divergence flux for each triangle composed by three radiosonde stations. Earth Radiation Budget Experiment data were used to compute the radiative flux in the top of the atmosphere. The cloud cover variability were computed from the International Satellite Cloud Climatology Project data. When the atmosphere undergoes a change from the mean state to the convective state, it stores energy mainly in the middle layers, while the maximum energy storage was found around 650 hPa mainly due to the perturbation of the latent energy. Conversely, when the atmosphere undergoes a change from a mean state to a nearly clear sky situation, the atmosphere column lose...

Is there a cosmic ray signal in recent variations in global cloudiness and cloud radiative forcing?

In order to evaluate a recent hypothesis of a coupling between galactic cosmic rays, clouds, and climate we have investigated temporal variations in global cloudiness and radiative fluxes at the top of the atmosphere. For this purpose we have used the best available global data sets, i.e., those of the International Satellite Cloud Climatology Project (ISCCP) and the Earth Radiation Budget Experiment (ERBE), respectively. Both globally and over midlatitude oceans only, we find a decrease in total cloud coverage between 1986 and 1990 of 2%, while between 1990 and 1993 there is a slightly smaller decrease. When the results are related to temporal variations in cosmic ray activity, we do not find support for a coupling between cosmic rays, total cloudiness, and radiative forcing of climate. A possible exception is low marine clouds at midlatitudes, characterized by few cloud condensation nuclei and a large net cooling effect, but no physical mechanism is known which might explain a connection between cosmic rays and low clouds. The net radiative effect of clouds during the period 1985–1989 shows an enhanced cooling effect despite a reduction in both total and low cloud cover. This contradicts the simple relationship between cloud cover and radiation assumed in the cosmic‐ray‐cloud‐climate hypothesis. The interpretation of the results is rendered difficult by the short time series of ISCCP and ERBE data and by uncertainties concerning instrument calibrations and changes of satellites. When a 43‐year time series of synoptic observations over sea is related to cosmic rays over the same period, a weak, negative correlation is found.

Net Cloud Radiative Forcing at the Top of the Atmosphere in the Asian Monsoon Region

Based on the data from Earth Radiation Budget Experiment (ERBE), many investigators have concluded that the net cloud radiative forcing at the top of the atmosphere is small in the deep convective region of the Tropics. This conclusion has been shown to be invalid for the Asian monsoon region during the period June–September. The ERBE data have been used to show that in the Asian monsoon region the net cloud radiative forcing at the top of the atmosphere is negative and its magnitude exceeds $30 W m^{-2}$ in 25% of the grids in this region. The large negative net cloud radiative forcing in the Asian monsoon region during June–September has been shown to be on account of the presence of large amount of high clouds and the large optical depth of these clouds. This combination of high cloud amount and high optical depth occurs in the Asian monsoon region only. In the other deep convective regions of the Tropics, high clouds with large optical depths are present, but they do not cover a large area.

The net radiation budget of the northern hemisphere

A radiative transfer model was used together with mean monthly long‐term climatological data to infer the net radiation budget of the Northern Hemisphere for latitudinal zones of 10° width. Most of the data were taken from the International Satellite Cloud Climatology Project and supplemented by data from the collaboration between National Centers for Environmental Prediction and National Center for Atmospheric Research, for the vertical profiles of water vapor and temperature. Seasonal and latitudinal variations of net shortwave, longwave, and all‐wave radiative fluxes and cloud radiative forcings were estimated at the top of the atmosphere (TOA) and at the Earth's surface, and also radiative cooling/heating rates, together with their mean annual and mean hemispherical variations. The validation of the net TOA all‐wave fluxes is based on a comparison with 5 years mean Earth Radiation Budget Experiment data for the shortwave and longwave fluxes in two of our previous studies. The net all‐wave fluxes were found to be mainly determined by the net shortwave fluxes. Near radiative equilibrium was found on a mean annual basis for net all‐wave radiation at TOA, while at the surface a gain of 99 W m−2 was found for the hemisphere. The estimated net all‐wave forcings generally decrease from equator to pole, with local maxima in middle to high latitudes, and from summer to winter. The net shortwave cloud forcings were found to dominate the net longwave ones, by a factor of about 2. Mean annual hemispherical cloud forcings equal to 25 W m−2 and 13 W m−2 were computed at TOA and at the surface, respectively. A net all‐wave atmospheric radiative cooling was computed, which decreases from equator to pole, with a local maximum in the subtropics, and from winter to summer, having a mean annual hemispherical value of 97 W m−2. For all fluxes, forcings, and cooling/heating rates, detailed comparisons with the work of other authors were performed, and the main discrepancies are discussed.

A model for the longwave radiation budget of the northern hemisphere: Comparison with Earth Radiation Budget Experiment data

A deterministic model for atmospheric longwave radiation transfer was used with climatological data to predict the mean monthly zonal (10° latitudinal zones) longwave radiation budget at the Earth's surface and at the top of the atmosphere for the Northern Hemisphere. The climatological data were obtained from the International Satellite Cloud Climatology Project (1983–1990), and from the National Centers for Environmental Prediction/National Center for Atmospheric Research Reanalysis Project. The model's outgoing fluxes agree within 4 W m−2, on average, with the corresponding values determined from the Earth Radiation Budget Experiment (1985–1989) satellite data. The validation of the model for the top‐of‐atmosphere radiation budget allows one to obtain a better understanding of the important processes that govern the transfer of the longwave radiation for each season and zone. At the surface, validation of the predicted downwelling radiation is difficult owing to the lack of extensive ground‐based measurements. However, we have made intercomparisons with other model predictions and with ground‐based measurements that were available. The predictions of the model for the surface longwave radiation budget provide a measure against which simpler algorithms, derived from ground‐based measurements, can be compared and used to convert satellite climatologies to a globally distributed surface longwave radiation budget for climatic studies.

Mapping global land surface albedo from NOAA AVHRR

A set of algorithms is combined for a simple derivation of land surface albedo from measurements of reflected visible and near‐infrared radiation made by the advanced very high resolution radiometer (AVHRR) onboard the National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites. The system consists of a narrowband‐to‐broadband conversion and bidirectional correction at the top of the atmosphere and an atmospheric correction. We demonstrate the results with 1 month worth of data from the NOAA National Environmental Satellite, Data, and Information Service (NESDIS) global vegetation index (GVI) weekly data set and the NOAA/NASA Pathfinder Atmosphere (PATMOS) project daily data. Error analysis of the methodology indicates that the surface albedo can be retrieved with 10–15% relative accuracy. Monthly albedo maps derived from September 1989 GVI and PATMOS data agree well except for small discrepancies attributed mainly to different preprocessing and residual atmospheric effects. A 5‐year mean September map derived from the GVI multiannual time series is consistent with that derived from low‐resolution Earth Radiation Budget Experiment data as well as with a September map compiled from ground observations and used in many numerical weather and climate models. Instantaneous GVI‐derived albedos were found to be consistent with surface albedo measurements over various surface types. The discrepancies found can be attributed to differences in areal coverage and representativeness of the satellite and ground data. The present pilot study is a prototype for a routine real‐time production of high‐resolution global surface albedo maps from NOAA AVHRR Global Area Coverage (GAC) data.

Determination of the Shortwave Anisotropic Function for Clear-Sky Desert Scenes from ScaRaB Data: Comparison with Models Issued from Other Satellite Data

Abstract Determination of directional albedo and bidirectional anisotropic function are necessary to the radiance-to-flux conversion. The most recent model, used for the Earth Radiation Budget Experiment data, is based on data from the sun-synchronous Nimbus-7 mission that is observed close to local noon. Because the desert zones are restricted in latitude (20°–35° in each hemisphere), only a small range of solar zenith angles was sampled. Here, the author considers for clear-sky desert regions the improvements that can be made using non-sun-synchronous satellite data, precessing in local time. This study made from ScaRaB data (Scanner for Radiation Budget, on board the Meteor-3-07 satellite) concerns the clear-sky deserts. The four great deserts on the earth (the Sahara, Arabian Desert, Namib-Kalahari, and Australian Desert) have been considered with 1.25° latitude × 1.25° longitude study areas. A normalization method, explained here, makes it possible to combine the values of bidirectionel anisotropic r...

Global surface ultraviolet radiation climatology from TOMS and ERBE data

A global climatology of biologically active solar ultraviolet radiation (UVR) at the Earth's surface is derived using NASA total ozone mapping spectrometer (TOMS) measurements of column ozone abundance and NASA Earth Radiation Budget Experiment (ERBE) measurements of solar reflectance from the Earth‐atmosphere system. These two sources of satellite data are used as input to a delta‐Eddington radiative transfer model to estimate climatological cloud opacity and thereby demonstrate how surface UVR varies with geography and season. The surface UVR fluxes are spectrally resolved to enable weighted integration with any biological action spectrum. Solar elevation is shown to be more important than total column ozone abundance in governing the variability of surface UVR over large geographic areas, although some regions with pronounced local minima in ozone (30 Dobson units or more) will cause noticeable enhancements of integrated UV‐B (280–315 nm) flux relative to UV‐A (315–400 nm). The greatest variability in surface UVR within a given climate zone is induced by cloud cover. During summer, regions that show lower surface UVR fluxes relative to their surrounding regions include the eastern United States (versus the western United States), India, China (in the vicinity of the Yangtze River), and Japan (relative to the surrounding oceans). Cloud cover over tropical rainforest areas reduces the surface UVR flux relative to ocean areas at the same latitudes. The UVR cloud transmission derived from the TOMS and ERBE data correlates with an independent climatology of global cloud coverage. The UVR mapping method, based on the TOMS and ERBE data, allows a direct investigation of diurnal variability and a rigorous calculation of the biologically relevant integrated daily dose of UVR. However, it is shown that a UVR mapping method based on TOMS data alone, which is limited to only local noon satellite measurements, can make defensible estimates of the integrated daily UVR dose and the instantaneous local noon UVR surface flux.

The 1985 Biomass Burning Season in South America: Satellite Remote Sensing of Fires, Smoke, and Regional Radiative Energy Budgets

Using satellite imagery, more than five million square kilometers of the forest and cerrado regions over South America are extensively studied to monitor fires and smoke during the 1985 biomass burning season. The results are characterized for four major ecosystems, namely, 1) tropical rain forest, 2) tropical broadleaf seasonal, 3) savanna/grass and seasonal woods (SGW), and 4) mild/warm/hot grass/shrub (MGS). The spatial and temporal distribution of fires are examined from two different methods using the multispectral Advanced Very High Resolution Radiometer Local Area Coverage data. Using collocated measurements from the instantaneous scanner Earth Radiation Budget Experiment data, the direct regional radiative forcing of biomass burning aerosols is computed. The results show that more than 70% of the fires occur in the MGS and SGW ecosystems due to agricultural practices. The smoke generated from biomass burning has negative instantaneous net radiative forcing values for all four major ecosystems within South America. The smoke found directly over the fires has mean net radiative forcing values ranging from 225.6 to 233.9 W m22. These results confirm that the regional net radiative impact of biomass burning is one of cooling. The spectral and broadband properties for clear-sky and smoke regions are also presented that could be used as input and/or validation for other studies attempting to model the impact of aerosols on the earth‐atmosphere system. These results have important applications for future instruments from the Earth Observing System (EOS) program. Specifically, the combination of the Visible Infrared Scanner and Clouds and the Earth’s Radiant Energy System (CERES) instruments from the Tropical Rainfall Measuring Mission and the combination of Moderate Resolution Imaging Spectrometer and CERES instruments from the EOS morning crossing mission could provide reliable estimates of the direct radiative forcing of aerosols on a global scale, thereby reducing the uncertainties in current global aerosol radiative forcing values.

Clouds and the Earth's Radiant Energy System (CERES): algorithm overview

The Clouds and the Earth's Radiant Energy System (CERES) is part of NASA's Earth Observing System (EOS), CERES objectives include the following. (1) For climate change analysis, provide a continuation of the Earth Radiation Budget Experiment (ERBE) record of radiative fluxes at the top-of-the-atmosphere (TOA), analyzed using the same techniques as the existing ERBE data. (2) Double the accuracy of estimates of radiative fluxes at TOA and the Earth's surface. (3) Provide the first long-term global estimates of the radiative fluxes within the Earth's atmosphere. (4) Provide cloud property estimates collocated in space and time that are consistent with the radiative fluxes from surface to TOA. In order to accomplish these goals, CERES uses data from a combination of spaceborne instruments: CERES scanners, which are an improved version of the ERBE broadband radiometers, and collocated cloud spectral imager data on the same spacecraft. The CERES cloud and radiative flux data products should prove extremely useful in advancing the understanding of cloud-radiation interactions, particularly cloud feedback effects on the Earth's radiation balance. For this reason, the CERES data should be fundamental to the ability to understand, detect, and predict global climate change. CERES results should also be very useful for studying regional climate changes associated with deforestation, desertification, anthropogenic aerosols, and ENSO events. This overview summarizes the Release 3 version of the planned CERES data products and data analysis algorithms. These algorithms are a prototype for the system that will produce the scientific data required for studying the role of clouds and radiation in the Earth's climate system.