scholarly journals Angular Distribution Models for Top-of-Atmosphere Radiative Flux Estimation from the Clouds and the Earth’s Radiant Energy System Instrument on the Terra Satellite. Part I: Methodology

2005 ◽  
Vol 22 (4) ◽  
pp. 338-351 ◽  
Author(s):  
Norman G. Loeb ◽  
Seiji Kato ◽  
Konstantin Loukachine ◽  
Natividad Manalo-Smith
Keyword(s):  
Angular Distribution ◽  
Radiant Energy ◽  
Tropical Rainfall Measuring Mission ◽  
Energy System ◽  
Distribution Models ◽  
Radiative Fluxes ◽  
Earth Observing System ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Terra Satellite

Abstract The Clouds and Earth’s Radiant Energy System (CERES) provides coincident global cloud and aerosol properties together with reflected solar, emitted terrestrial longwave, and infrared window radiative fluxes. These data are needed to improve the understanding and modeling of the interaction between clouds, aerosols, and radiation at the top of the atmosphere, surface, and within the atmosphere. This paper describes the approach used to estimate top-of-atmosphere (TOA) radiative fluxes from instantaneous CERES radiance measurements on the Terra satellite. A key component involves the development of empirical angular distribution models (ADMs) that account for the angular dependence of the earth’s radiation field at the TOA. The CERES Terra ADMs are developed using 24 months of CERES radiances, coincident cloud and aerosol retrievals from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from the Global Modeling and Assimilation Office (GMAO)’s Goddard Earth Observing System (GEOS) Data Assimilation System (DAS) V4.0.3 product. Scene information for the ADMs is from MODIS retrievals and GEOS DAS V4.0.3 properties over the ocean, land, desert, and snow for both clear and cloudy conditions. Because the CERES Terra ADMs are global, and far more CERES data are available on Terra than were available from CERES on the Tropical Rainfall Measuring Mission (TRMM), the methodology used to define CERES Terra ADMs is different in many respects from that used to develop CERES TRMM ADMs, particularly over snow/sea ice, under cloudy conditions, and for clear scenes over land and desert.

scholarly journals Top-of-Atmosphere Direct Radiative Effect of Aerosols over Global Oceans from Merged CERES and MODIS Observations

2005 ◽  
Vol 18 (17) ◽  
pp. 3506-3526 ◽  
Author(s):  
Norman G. Loeb ◽  
Natividad Manalo-Smith
Keyword(s):  
Information Service ◽  
Radiant Energy ◽  
Energy System ◽  
Surface Fluxes ◽  
Radiative Effect ◽  
Distribution Models ◽  
Radiative Fluxes ◽  
Clear Sky ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Global Oceans

Abstract The direct radiative effect of aerosols (DREA) is defined as the difference between radiative fluxes in the absence and presence of aerosols. In this study, the direct radiative effect of aerosols is estimated for 46 months (March 2000–December 2003) of merged Clouds and the Earth’s Radiant Energy System (CERES) and Moderate Resolution Imaging Spectroradiometer (MODIS) Terra global measurements over ocean. This analysis includes the contribution from clear regions in both clear and partly cloudy CERES footprints. MODIS–CERES narrow-to-broadband regressions are developed to convert clear-sky MODIS narrowband radiances to broadband shortwave (SW) radiances, and CERES clear-sky angular distribution models (ADMs) are used to estimate the corresponding top-of-atmosphere (TOA) radiative fluxes that are needed to determine the DREA. Clear-sky MODIS pixels are identified using two independent cloud masks: (i) the NOAA/National Environmental Satellite, Data, and Information Service (NESDIS) algorithm that is used for inferring aerosol properties from MODIS on the CERES Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) product (NOAA SSF); and (ii) the standard algorithm that is used by the MODIS aerosol group to produce the MODIS aerosol product (MOD04). Over global oceans, direct radiative cooling by aerosols for clear scenes that are identified from MOD04 is estimated to be 40% larger than for clear scenes from NOAA SSF (5.5 compared to 3.8 W m−2). Regionally, differences are largest in areas that are affected by dust aerosol, such as oceanic regions that are adjacent to the Sahara and Saudi Arabian deserts, and in northern Pacific Ocean regions that are influenced by dust transported from Asia. The net total-sky (clear and cloudy) DREA is negative (cooling) and is estimated to be −2.0 W m−2 from MOD04, and −1.6 W m−2 from NOAA SSF. The DREA is shown to have pronounced seasonal cycles in the Northern Hemisphere and large year-to-year fluctuations near deserts. However, no systematic trend in deseasonalized anomalies of the DREA is observed over the 46-month time series that is considered.

scholarly journals Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from the CERES instruments: validation

2015 ◽  
Vol 8 (5) ◽  
pp. 4489-4536 ◽  
Author(s):  
W. Su ◽  
J. Corbett ◽  
Z. Eitzen ◽  
L. Liang
Keyword(s):  
Angular Distribution ◽  
Radiant Energy ◽  
Energy System ◽  
Direct Integration ◽  
Distribution Models ◽  
Radiative Fluxes ◽  
Rms Error ◽  
Sky Conditions ◽  
Along Track ◽  
Scene Identification

Abstract. Radiative fluxes at the top of the atmosphere (TOA) from the Clouds and the Earth's Radiant Energy System (CERES) instrument are fundamental variables for understanding the Earth's energy balance and how it changes with time. TOA radiative fluxes are derived from the CERES radiance measurements using empirical angular distribution models (ADMs). This paper evaluates the accuracy of CERES TOA fluxes using direct integration and flux consistency tests. Direct integration tests show that the overall bias in regional monthly mean TOA shortwave (SW) flux is less than 0.2 W m−2 and the RMS error is less than 1.1 W m−2. The bias and RMS error are very similar between Terra and Aqua. The bias in regional monthly mean TOA LW fluxes is less than 0.5 W m−2 and the RMS error is less than 0.8 W m−2 for both Terra and Aqua. The accuracy of the TOA instantaneous flux is assessed by performing tests using fluxes inverted from nadir- and oblique-viewing angles using CERES along-track observations and temporally- and spatially-matched MODIS observations, and using fluxes inverted from multi-angle MISR observations. The TOA instantaneous SW flux uncertainties are about 2.3% (1.9 W m−2) over clear ocean, 1.6% (4.5 W m−2) over clear land, and 2.0% (6.0 W m−2) over clear snow/ice; and are about 3.3% (9.0 W m−2), 2.7% (8.4 W m−2), and 3.7% (9.9 W m−2) over ocean, land, and snow/ice under all-sky conditions. The TOA SW flux uncertainties are generally larger for thin broken clouds than for moderate and thick overcast clouds. The TOA instantaneous daytime LW flux uncertainties are 0.5% (1.5 W m−2), 0.8% (2.4 W m−2), and 0.7 % (1.3 W m−2) over clear ocean, land, and snow/ice; and are about 1.5% (3.5 W m−2), 1.0% (2.9 W m−2), and 1.1 % (2.1 W m−2) over ocean, land, and snow/ice under all-sky conditions. The TOA instantaneous nighttime LW flux uncertainties are about 0.5–1% (< 2.0 W m−2) for all surface types. Flux uncertainties caused by errors in scene identification are also assessed by using the collocated CALIPSO, CloudSat, CERES and MODIS data product. Errors in scene identification tend to underestimate TOA SW flux by about 0.6 W m−2 and overestimate TOA daytime (nighttime) LW flux by 0.4 (0.2) W m−2 when all CERES viewing angles are considered.

scholarly journals Angular Distribution Models for Top-of-Atmosphere Radiative Flux Estimation from the Clouds and the Earth’s Radiant Energy System Instrument on the Terra Satellite. Part II: Validation

2007 ◽  
Vol 24 (4) ◽  
pp. 564-584 ◽  
Author(s):  
Norman G. Loeb ◽  
Seiji Kato ◽  
Konstantin Loukachine ◽  
Natividad Manalo-Smith ◽  
David R. Doelling
Keyword(s):  
Angular Distribution ◽  
Zenith Angle ◽  
Radiant Energy ◽  
Energy System ◽  
Radiation Budget ◽  
Bias Error ◽  
Polar Regions ◽  
Distribution Models ◽  
Latitudinal Dependence ◽  
Terra Satellite

Abstract Errors in top-of-atmosphere (TOA) radiative fluxes from the Clouds and the Earth’s Radiant Energy System (CERES) instrument due to uncertainties in radiance-to-flux conversion from CERES Terra angular distribution models (ADMs) are evaluated through a series of consistency tests. These tests show that the overall bias in regional monthly mean shortwave (SW) TOA flux is less than 0.2 W m−2 and the regional RMS error ranges from 0.70 to 1.4 W m−2. In contrast, SW TOA fluxes inferred using theoretical ADMs that assume clouds are plane parallel are overestimated by 3–4 W m−2 and exhibit a strong latitudinal dependence. In the longwave (LW), the bias error ranges from 0.2 to 0.4 W m−2 and regional RMS errors remain smaller than 0.7 W m−2. Global mean albedos derived from ADMs developed during the Earth Radiation Budget Experiment (ERBE) and applied to CERES measurements show a systematic increase with viewing zenith angle of 4%–8%, while albedos from the CERES Terra ADMs show a smaller increase of 1%–2%. The LW fluxes from the ERBE ADMs show a systematic decrease with viewing zenith angle of 2%–2.4%, whereas fluxes from the CERES Terra ADMs remain within 0.7%–0.8% at all angles. Based on several months of multiangle CERES along-track data, the SW TOA flux consistency between nadir- and oblique-viewing zenith angles is generally 5% (&lt;17 W m−2) over land and ocean and 9% (26 W m−2) in polar regions, and LW TOA flux consistency is approximate 3% (7 W m−2) over all surfaces. Based on these results and a theoretically derived conversion between TOA flux consistency and TOA flux error, the best estimate of the error in CERES TOA flux due to the radiance-to-flux conversion is 3% (10 W m−2) in the SW and 1.8% (3–5 W m−2) in the LW. Monthly mean TOA fluxes based on ERBE ADMs are larger than monthly mean TOA fluxes based on CERES Terra ADMs by 1.8 and 1.3 W m−2 in the SW and LW, respectively.

scholarly journals Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from CERES instruments: validation

2015 ◽  
Vol 8 (8) ◽  
pp. 3297-3313 ◽  
Author(s):  
W. Su ◽  
J. Corbett ◽  
Z. Eitzen ◽  
L. Liang
Keyword(s):  
Angular Distribution ◽  
Energy Balance ◽  
Radiant Energy ◽  
Energy System ◽  
Direct Integration ◽  
Distribution Models ◽  
Radiative Fluxes ◽  
Sky Conditions ◽  
Along Track ◽  
Scene Identification

Abstract. Radiative fluxes at the top of the atmosphere (TOA) from the Clouds and the Earth's Radiant Energy System (CERES) instrument are fundamental variables for understanding the Earth's energy balance and how it changes with time. TOA radiative fluxes are derived from the CERES radiance measurements using empirical angular distribution models (ADMs). This paper evaluates the accuracy of CERES TOA fluxes using direct integration and flux consistency tests. Direct integration tests show that the overall bias in regional monthly mean TOA shortwave (SW) flux is less than 0.2 Wm−2 and the RMSE is less than 1.1 Wm−2. The bias and RMSE are very similar between Terra and Aqua. The bias in regional monthly mean TOA LW fluxes is less than 0.5 Wm−2 and the RMSE is less than 0.8 Wm−2 for both Terra and Aqua. The accuracy of the TOA instantaneous flux is assessed by performing tests using fluxes inverted from nadir- and oblique-viewing angles using CERES along-track observations and temporally and spatially matched MODIS observations, and using fluxes inverted from multi-angle MISR observations. The averaged TOA instantaneous SW flux uncertainties from these two tests are about 2.3 % (1.9 Wm−2) over clear ocean, 1.6 % (4.5 Wm−2) over clear land, and 2.0 % (6.0 Wm−2) over clear snow/ice; and are about 3.3 % (9.0 Wm−2), 2.7 % (8.4 Wm−2), and 3.7 % (9.9 Wm−2) over ocean, land, and snow/ice under all-sky conditions. The TOA SW flux uncertainties are generally larger for thin broken clouds than for moderate and thick overcast clouds. The TOA instantaneous daytime LW flux uncertainties derived from the CERES-MODIS test are 0.5 % (1.5 Wm−2), 0.8 % (2.4 Wm−2), and 0.7 % (1.3 Wm−2) over clear ocean, land, and snow/ice; and are about 1.5 % (3.5 Wm−2), 1.0 % (2.9 Wm−2), and 1.1 % (2.1 Wm−2) over ocean, land, and snow/ice under all-sky conditions. The TOA instantaneous nighttime LW flux uncertainties are about 0.5–1 % (< 2.0 Wm−2) for all surface types. Flux uncertainties caused by errors in scene identification are also assessed by using the collocated CALIPSO, CloudSat, CERES and MODIS data product. Errors in scene identification tend to underestimate TOA SW flux by about 0.6 Wm−2 and overestimate TOA daytime (nighttime) LW flux by 0.4 (0.2) Wm−2 when all CERES viewing angles are considered.

scholarly journals Evaluation of Five Satellite Top-of-Atmosphere Albedo Products over Land

2019 ◽  
Vol 11 (24) ◽  
pp. 2919
Author(s):  
Chuan Zhan ◽  
Richard P. Allan ◽  
Shunlin Liang ◽  
Dongdong Wang ◽  
Zhen Song
Keyword(s):  
High Latitude ◽  
Radiant Energy ◽  
Energy System ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Regional Product ◽  
Changes Over Time ◽  
Year 2000 ◽  
Energy Pathways

Five satellite top-of-atmosphere (TOA) albedo products over land were evaluated in this study including global products from the Advanced Very High Resolution Radiometer (AVHRR) (TAL-AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS) (TAL-MODIS), and Clouds and the Earth’s Radiant Energy System (CERES); one regional product from the Climate Monitoring Satellite Application Facility (CM SAF); and one harmonized product termed Diagnosing Earth’s Energy Pathways in the Climate system (DEEP-C). Results showed that overall, there is good consistency among these five products, particularly after the year 2000. The differences among these products in the high-latitude regions were relatively larger. The percentage differences among TAL-AVHRR, TAL-MODIS, and CERES were generally less than 20%, while the differences between TAL-AVHRR and DEEP-C before 2000 were much larger. Except for the obvious decrease in the differences after 2000, the differences did not show significant changes over time, but varied among different regions. The differences between TAL-AVHRR and the other products were relatively large in the high-latitude regions of North America, Asia, and the Maritime Continent, while the differences between DEEP-C and CM SAF in Europe and Africa were smaller. Interannual variability was consistent between products after 2000, before which the differences among the three products were much larger.

scholarly journals Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from CERES instruments: methodology

2015 ◽  
Vol 8 (2) ◽  
pp. 611-632 ◽  
Author(s):  
W. Su ◽  
J. Corbett ◽  
Z. Eitzen ◽  
L. Liang
Keyword(s):  
Angular Distribution ◽  
Sea Ice ◽  
Regional Scale ◽  
Radiant Energy ◽  
Energy System ◽  
Continuous Functions ◽  
Climate Feedback ◽  
Radiative Energy ◽  
Next Generation ◽  
Distribution Models

Abstract. The top-of-atmosphere (TOA) radiative fluxes are critical components to advancing our understanding of the Earth's radiative energy balance, radiative effects of clouds and aerosols, and climate feedback. The Clouds and the Earth's Radiant Energy System (CERES) instruments provide broadband shortwave and longwave radiance measurements. These radiances are converted to fluxes by using scene-type-dependent angular distribution models (ADMs). This paper describes the next-generation ADMs that are developed for Terra and Aqua using all available CERES rotating azimuth plane radiance measurements. Coincident cloud and aerosol retrievals, and radiance measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from Goddard Earth Observing System (GEOS) data assimilation version 5.4.1 are used to define scene type. CERES radiance measurements are stratified by scene type and by other parameters that are important for determining the anisotropy of the given scene type. Anisotropic factors are then defined either for discrete intervals of relevant parameters or as a continuous functions of combined parameters, depending on the scene type. Significant differences between the ADMs described in this paper and the existing ADMs are over clear-sky scene types and polar scene types. Over clear ocean, we developed a set of shortwave (SW) ADMs that explicitly account for aerosols. Over clear land, the SW ADMs are developed for every 1° latitude × 1° longitude region for every calendar month using a kernel-based bidirectional reflectance model. Over clear Antarctic scenes, SW ADMs are developed by accounting the effects of sastrugi on anisotropy. Over sea ice, a sea-ice brightness index is used to classify the scene type. Under cloudy conditions over all surface types, the longwave (LW) and window (WN) ADMs are developed by combining surface and cloud-top temperature, surface and cloud emissivity, cloud fraction, and precipitable water. Compared to the existing ADMs, the new ADMs change the monthly mean instantaneous fluxes by up to 5 W m−2 on a regional scale of 1° latitude × 1° longitude, but the flux changes are less than 0.5 W m−2 on a global scale.

scholarly journals CERES Synoptic Product: Methodology and Validation of Surface Radiant Flux

2015 ◽  
Vol 32 (6) ◽  
pp. 1121-1143 ◽  
Author(s):  
David A. Rutan ◽  
Seiji Kato ◽  
David R. Doelling ◽  
Fred G. Rose ◽  
Le Trang Nguyen ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Diurnal Cycle ◽  
Radiant Energy ◽  
Energy System ◽  
Surface Fluxes ◽  
Radiant Flux ◽  
Earth Observing System ◽  
Cloud Properties ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Surface Observations

AbstractThe Clouds and the Earth’s Radiant Energy System Synoptic (SYN1deg), edition 3, product provides climate-quality global 3-hourly 1° × 1°gridded top of atmosphere, in-atmosphere, and surface radiant fluxes. The in-atmosphere surface fluxes are computed hourly using a radiative transfer code based upon inputs from Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS), 3-hourly geostationary (GEO) data, and meteorological assimilation data from the Goddard Earth Observing System. The GEO visible and infrared imager calibration is tied to MODIS to ensure uniform MODIS-like cloud properties across all satellite cloud datasets. Computed surface radiant fluxes are compared to surface observations at 85 globally distributed land (37) and ocean buoy (48) sites as well as several other publicly available global surface radiant flux data products. Computed monthly mean downward fluxes from SYN1deg have a bias (standard deviation) of 3.0 W m−2 (5.7%) for shortwave and −4.0 W m−2 (2.9%) for longwave compared to surface observations. The standard deviation between surface downward shortwave flux calculations and observations at the 3-hourly time scale is reduced when the diurnal cycle of cloud changes is explicitly accounted for. The improvement is smaller for surface downward longwave flux owing to an additional sensitivity to boundary layer temperature/humidity, which has a weaker diurnal cycle compared to clouds.

scholarly journals A Supplementary Clear-Sky Snow and Ice Recognition Technique for CERES Level 2 Products

2013 ◽  
Vol 30 (3) ◽  
pp. 557-568 ◽  
Author(s):  
Alexander Radkevich ◽  
Konstantin Khlopenkov ◽  
David Rutan ◽  
Seiji Kato
Keyword(s):  
Confidence Intervals ◽  
Radiant Energy ◽  
Energy System ◽  
Radiation Budget ◽  
Data Series ◽  
Clear Sky ◽  
Multiple Thresholds ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Snow And Ice

Abstract Identification of clear-sky snow and ice is an important step in the production of cryosphere radiation budget products, which are used in the derivation of long-term data series for climate research. In this paper, a new method of clear-sky snow/ice identification for Moderate Resolution Imaging Spectroradiometer (MODIS) is presented. The algorithm’s goal is to enhance the identification of snow and ice within the Clouds and the Earth’s Radiant Energy System (CERES) data after application of the standard CERES scene identification scheme. The input of the algorithm uses spectral radiances from five MODIS bands and surface skin temperature available in the CERES Single Scanner Footprint (SSF) product. The algorithm produces a cryosphere rating from an aggregated test: a higher rating corresponds to a more certain identification of the clear-sky snow/ice-covered scene. Empirical analysis of regions of interest representing distinctive targets such as snow, ice, ice and water clouds, open waters, and snow-free land selected from a number of MODIS images shows that the cryosphere rating of snow/ice targets falls into 95% confidence intervals lying above the same confidence intervals of all other targets. This enables recognition of clear-sky cryosphere by using a single threshold applied to the rating, which makes this technique different from traditional branching techniques based on multiple thresholds. Limited tests show that the established threshold clearly separates the cryosphere rating values computed for the cryosphere from those computed for noncryosphere scenes, whereas individual tests applied consequently cannot reliably identify the cryosphere for complex scenes.

Sign in / Sign up

Export Citation Format

Share Document