ADS Physics/Geophysics Abstract Service

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Title:
Spatial autocorrelation of radiation measured by the Earth Radiation Budget Experiment: Scene inhomogeneity and reciprocity violation
Authors:
DAVIES, ROGER
Affiliation:
AAMcGill Univ., Montreal, Quebec, Canada
Journal:
Journal of Geophysical Research (ISSN 0148-0227), vol. 99, no. D10, p. 20,879-20,887
Publication Date:
10/1994
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
AUTOCORRELATION, CLOUDS (METEOROLOGY), EARTH RADIATION BUDGET, SCENE ANALYSIS, SPATIAL DISTRIBUTION, CLIMATOLOGY, EARTH RADIATION BUDGET EXPERIMENT, LONG WAVE RADIATION, RADIATIVE TRANSFER, SHORT WAVE RADIATION
Bibliographic Code:
1994JGR....9920879D

Abstract

The spatial autocorrelation functions of broad-band longwave and shortwave radiances measured by the Earth Radiation Budget Experiment (ERBE) are analyzed as a function of view angle in an investigation of the general effects of scene inhomogeneity on radiation. For nadir views, the correlation distance of the autocorrelation function is about 900 km for longwave radiance and about 500 km for shortwave radiance, consistent with higher degrees of freedom in shortwave reflection. Both functions rise monotonically with view angle, but there is a substantial difference in the relative angular dependence of the shortwave and longwave functions, especially for view angles less than 50 deg. In this range, the increase with angle of the longwave functions is found to depend only on the expansion of pixel area with angle, whereas the shortwave functions show an additional dependence on angle that is attributed to the occlusion of inhomogeneities by cloud height variations. Beyond a view angle of about 50 deg, both longwave and shortwave functions appear to be affected by cloud sides. The shortwave autocorrelation functions do not satisfy the principle of directional reciprocity, thereby proving that the average scene is horizontally inhomogeneous over the scale of an ERBE pixel (1500 sq km). Coarse stratification of the measurements by cloud amount, however, indicates that the average cloud-free scene does satisfy directional reciprocity on this scale.

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Title:
Limb-darkening models from along-track operation of the ERBE scanning radiometer
Authors:
SMITH, G. LOUIS; MANALO-SMITH, NATIVIDAD; AVIS, LEE M.
Affiliation:
AANASA. Langley Research Center, Hampton, VA, US ABLockheed Engineering and Sciences Co., Hampton, VA, US ACNASA. Langley Research Center, Hampton, VA, US
Journal:
Journal of Applied Meteorology (ISSN 0894-8763), vol. 33, no. 1, p. 74-84
Publication Date:
01/1994
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC MODELS, EARTH RADIATION BUDGET EXPERIMENT, LIMB DARKENING, RADIANCE, RADIOMETERS, ALGORITHMS, CLOUD COVER, NOAA SATELLITES, SATELLITE OBSERVATION, SCENE ANALYSIS
Bibliographic Code:
1994JApMe..33...74S

Abstract

During January and August 1985, the scanning radiometers of the Earth Radiation Budget Experiment(ERBE) aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 satellite were operated in along-track scanning modes. Along-track scanning permits the study of many measurement problems. It provides the data for developing a limb-darkening model for a single site over a short period of time and also permits the indentification of the scene from data taken at smaller nadir angles. The earth-emitted radiation measured by the scanners has been analyzed to produce limb-darkening models for a variety of scene types. Limb-darkening models relate the radiance in any given direction to the radiant flux. The scene types were computed using measurements within 10 deg of zenith. The models have values near zenith of 1.02-1.09. The typical zenith values of the model are 1.06 for both day and night for ERBS, and for NOAA-9, 1.06 for day and 1.05 for night. Mean models are formed for the ERBS and NOAA-9 results and are found to differ less than 1%, the ERBS results being the higher. The models vary about 1% with latitude near zenith and agree with earlier models that were used to analyze ERBE data typically to 2%.

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Title:
A statistical cloud scheme for use in an AGCM
Authors:
RICARD, J. L.; ROYER, J. F.
Affiliation:
AACentre National de Recherches Meteorologiques, Toulouse, France ABCentre National de Recherches Meteorologiques, Toulouse, France
Journal:
Annales Geophysicae (ISSN 0992-7689), vol. 11, no. 11/12, p. 1095-1115
Publication Date:
12/1993
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC GENERAL CIRCULATION MODELS, ATMOSPHERIC MOISTURE, ATMOSPHERIC TURBULENCE, CLOUD COVER, COMPUTATIONAL GRIDS, PARAMETERIZATION, STATISTICAL ANALYSIS, WATER VAPOR
Bibliographic Code:
1993AnGeo..11.1095R

Abstract

We have designed a diagnostic subgrid scale cloud scheme that brings some coherence to the various representations of clouds within the general circulation models (GCM). It takes into account interactions between cloud fraction coverage, liquid water content and turbulence (for stratiform clouds). The scheme has been developed on the basis of a statistical cloud scheme and a level 2 subgrid scale turbulence scheme (Yamada and Mellor) in which we introduce the effects of water vapor and liquid water. The scheme has been implemented in the T42-20 level version of the French spectral GCM used for climate studies. Simultaneously, large-scale precipitation has been modified according to Smith's scheme (with different parameterizations for liquid and ice water). The GCM has been run with and without the new parameterizations. We have studied the impact of the implementation of two new parameterizations on the results of the French Emeraude GCM in January. The model simulations are validated with satellite data from the earth radiation budget (ERB) experiment (total cloudiness field) and from the Earth Radiation Budget Experiment (ERBE) experiment (visible and IR radiation fields at the top of the atmosphere).

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Title:
THE SPATIAL-SCALE DEPENDENCE OF THE OBSERVED ANISOTROPY OF REFLECTED AND EMITTED RADIATION.
Authors:
YE, QIAN
Affiliation:
OREGON STATE UNIVERSITY.
Journal:
Thesis (PH.D.)--OREGON STATE UNIVERSITY, 1993.Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6256.
Publication Date:
00/1993
Category:
Physics: Atmospheric Science
Origin:
UMI
Abstract Copyright:
(c) 1993: UMI Company
Bibliographic Code:
1993PhDT........60Y

Abstract

The Earth Radiation Budget Experiment (ERBE) uses Angular Dependence Models (ADMs) to convert satellite observed radiances to radiative fluxes at the top of the atmosphere. Owing to errors in scene identification and to the relationship between the spatial scales of cloud systems and the spatial resolution of the ERBE scanner, the anisotropy of the radiation fields determined from ERBE observations was suspected of exhibiting a field of view size dependence. In order to remove effects due to the spatial scale of cloud fields, ERBE scanner observations from the Earth Radiation Budget Satellite (ERBS) were averaged to construct observations having a constant size field of view for all scan angles. Comparing the anisotropy for constant size fields of view with that obtained using unaltered full-resolution scanner observations, it was found that there were significant and systematic differences of the order of 5-10% for all scene types. The frequencies of occurrence for clear, partly cloudy, mostly cloudy and overcast cloud categories identified by the ERBE scene identification algorithm were calculated for the constant size field of view observations. It was found that the ERBE scene identification method failed to correctly identify scene types. A bispectral threshold method was developed for scene identification. In the determination of the thresholds, the ERBE scene identification method was assumed to be correct for nadir observations. The thresholds were then determined so that the population of scene types remained constant from nadir to limb for the constant size field of view observations. ADMs were developed using the threshold scene identification method. Results showed that the spatial-scale dependence of the ADMs was significantly reduced. The threshold ADMs satisfied the principle of reciprocity more closely than did the ERBE ADMs for all cloud categories. Using the threshold scene identification, the view zenith angle dependence of the global average albedo and the longwave flux were significantly reduced compared with those obtained using the ERBE scene identification. The estimated global average albedo increases from 0.282 for the ERBE algorithm to 0.299 for the threshold algorithm. There was no significant change for the value of the estimated longwave flux.

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Title:
The spatial-scale dependence of the observed anisotropy of reflected and emitted radiation
Authors:
YE, QIAN
Affiliation:
Oregon State Univ., Corvallis, OR.
Journal:
Ph.D. Thesis Oregon State Univ., Corvallis, OR.
Publication Date:
00/1993
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ANISOTROPY, CLOUD COVER, EARTH RADIATION BUDGET EXPERIMENT, EMITTANCE, RADIATION DISTRIBUTION, REFLECTED WAVES, SPATIAL DISTRIBUTION, ALBEDO, EARTH RADIATION BUDGET, FIELD OF VIEW, RADIANCE, SCENE ANALYSIS
Bibliographic Code:
1993PhDT.........3Y

Abstract

The Earth Radiation Budget Experiment (ERBE) uses angular dependence models (ADM's) to convert satellite observed radiances to radiative fluxes at the top of the atmosphere. Owing to errors in scene identification and to the relationship between the spatial scales of cloud systems and the spatial resolution of the ERBE scanner, the anisotropy of the radiation fields determined from ERBE observations was suspected of exhibiting a field of view size dependence. In order to remove effects due to the spatial scale of cloud fields, ERBE scanner observations from the Earth Radiation Budget Satellite (ERBS) were averaged to construct observations having a constant size field of view for all scan angles. Comparing the anisotropy for constant size fields of view with that obtained using unaltered full-resolution scanner observations, it was found that there were significant and systematic differences of the order of 5-10 percent for all scene types. The frequencies of occurrence for clear, partly cloudy, mostly cloudy, and overcast cloud categories identified by the ERBE scene identification algorithm were calculated for the constant size field of view observations. It was found that the ERBE scene identification method failed to correctly identify scene types. A bispectral threshold method was developed for scene identification. In the determination of the thresholds, the ERBE scene identification method was assumed to be correct for nadir observations. The thresholds were then determined so that the population of scene types remained constant from nadir to limb for the constant size field of view observations. ADM's were developed using the threshold scene identification method. Results showed that the spatial-scale dependence of the ADM's was significantly reduced. The threshold ADM's satisfied the principle of reciprocity more closely than did the ERBE ADM's for all cloud categories. Using the threshold scene identification, the view zenith angle dependence of the global average albedo and the longwave flux were significantly reduced compared with those obtained using the ERBE scene identification. The estimated global average albedo increases from 0.282 for the ERBE algorithm to 0.299 for the threshold algorithm. There was no significant change for the value of the estimated longwave flux.

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Title:
A model for the energy budget of the atmosphere - Comparison with data from the Earth Radiation Budget Experiment
Authors:
MINSCHWANER, KENNETH; MCELROY, MICHAEL B.
Affiliation:
AB(Harvard Univ., Cambridge, MA)
Journal:
Planetary and Space Science (ISSN 0032-0633), vol. 40, no. 9, p. 1237-1250.
Publication Date:
09/1992
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC MODELS, EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, ALBEDO, FINITE DIFFERENCE THEORY, GREENHOUSE EFFECT, HUMIDITY, INFRARED RADIATION, PARAMETERIZATION, RADIANT COOLING, RADIATIVE HEAT TRANSFER, SEA SURFACE TEMPERATURE, SURFACE TEMPERATURE
Bibliographic Code:
1992P&SS...40.1237M

Abstract

A radiative-convective model is developed and used to examine the sensitivity of clear-sky fluxes of IR radiation to changes in sea-surface temperature, atmospheric lapse rates, and relative humidity. The radiative model uses the correlated-k method and includes an improved treatment of the finite-difference approximation in the evaluation of the vertical flux integral. Absorption coefficients are calculated directly from spectroscopic data. Model results for radiative cooling rates agree with benchmark line-by-line calculations to better than 5 percent. Comparison with Earth Radiation Budget Experiment (ERBE) measurements indicates that a 6.5 K/km lapse-rate model would be inconsistent with fluxes observed at the top of the atmosphere. Agreement is improved significantly using a parameterization in which the static stability is specified empirically as a function of surface temperature. Comparison with measurements for higher temperatures suggests that significant increases in middle and upper tropospheric humidity may be associated with warmer sea surface temperatures.

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Title:
Top-of-atmosphere radiative fluxes - Validation of ERBE scanner inversion algorithm using Nimbus-7 ERB data
Authors:
SUTTLES, JOHN T.; WIELICKI, BRUCE A.; VEMURY, SASTRI
Affiliation:
AB(NASA, Langley Research Center, Hampton, VA) AC(Scientific Management and Applied Research Technologies, Inc., Silver Spring, MD)
Journal:
Journal of Applied Meteorology (ISSN 0894-8763), vol. 31, no. 7, July 1992, p. 784-796.
Publication Date:
07/1992
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, SATELLITE OBSERVATION, ALBEDO, CLOUD COVER, CLOUD PHYSICS, LONG WAVE RADIATION, NIMBUS 7 SATELLITE, RADIATIVE TRANSFER
Bibliographic Code:
1992JApMe..31..784S

Abstract

The ERBE algorithm is applied to the Nimbus-7 earth radiation budget (ERB) scanner data for June 1979 to analyze the performance of an inversion method in deriving top-of-atmosphere albedos and longwave radiative fluxes. The performance is assessed by comparing ERBE algorithm results with appropriate results derived using the sorting-by-angular-bins (SAB) method, the ERB MATRIX algorithm, and the 'new-cloud ERB' (NCLE) algorithm. Comparisons are made for top-of-atmosphere albedos, longwave fluxes, viewing zenith-angle dependence of derived albedos and longwave fluxes, and cloud fractional coverage. Using the SAB method as a reference, the rms accuracy of monthly average ERBE-derived results are estimated to be 0.0165 (5.6 W/sq m) for albedos (shortwave fluxes) and 3.0 W/sq m for longwave fluxes. The ERBE-derived results were found to depend systematically on the viewing zenith angle, varying from near nadir to near the limb by about 10 percent for albedos and by 6-7 percent for longwave fluxes. Analyses indicated that the ERBE angular models are the most likely source of the systematic angular dependences. Comparison of the ERBE-derived cloud fractions, based on a maximum-likelihood estimation method, with results from the NCLE showed agreement within about 10 percent.

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Title:
The Earth radiation budget experiment: Overview of data-processing and error sources
Authors:
FEIJT, ARNOUT J.
Affiliation:
Royal Netherlands Meteorological Inst., De Bilt.
Journal:
The Earth radiation budget experiment: Overview of data-processing and error sources
Publication Date:
00/1992
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
DATA PROCESSING, EARTH RADIATION BUDGET EXPERIMENT, ERROR ANALYSIS, ERRORS, RADIOMETERS, EARTH RADIATION BUDGET, INSTRUMENT ERRORS, LATITUDE, STANDARD DEVIATION, TERRESTRIAL RADIATION
Bibliographic Code:
1992erbe.rept.....F

Abstract

The data processing and error sources of the Earth Radiation Budget Experiment (ERBE), which provides global information on the radiation properties of the Earth's atmosphere and surface, are addressed. The data processing scheme, which is used to convert raw radiometer counts into values for radiant exitance at the top of the atmosphere, is described and error sources are evaluated. When possible, the magnitude of the errors is estimated. This is proven difficult, because the errors depend on surface characteristics, atmospheric conditions, latitude, solar zenith angle, and the viewing geometry. Most scanner measurements were processed and validated. When using monthly mean scanner values one should be aware that specific regions may show considerable biased values of the radiant existance. The standard deviation in the regional monthly mean values is of the order of 5 W/sq m. Instantaneous scanner values should be used with caution, because errors in the radiant existance values for shortwave radiation in the order of 45 W/sq m are no exception. The error is highly dependent on viewing geometry, atmospheric conditions, and latitude. Nonscanner data are not fully validated yet. Probably the errors will exceed those of the scanner.

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Title:
A study of the thermal and optical characteristics of radiometric channels for Earth radiation budget applications
Authors:
MAHAN, J. R.; TIRA, NOUR E.
Affiliation:
Virginia Polytechnic Inst. and State Univ., Blacksburg.
Journal:
Final Report Virginia Polytechnic Inst. and State Univ., Blacksburg. Dept. of Mechanical Engineering.
Publication Date:
12/1991
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC RADIATION, DYNAMIC MODELS, EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, OPTICAL PROPERTIES, RADIOMETERS, TRANSFER FUNCTIONS, CALIBRATING, CAVITIES, ENERGY BUDGETS, FREQUENCY DISTRIBUTION, IN-FLIGHT MONITORING, RADIANT FLUX DENSITY, SCATTERING, THERMAL NOISE
Bibliographic Code:
1991vpi..rept.....M

Abstract

An improved dynamic electrothermal model for the Earth Radiation Budget Experiment (ERBE) total, nonscanning channels is formulated. This model is then used to accurately simulate two types of dynamic solar observation: the solar calibration and the so-called pitchover maneuver. Using a second model, the nonscanner active cavity radiometer (ACR) thermal noise is studied. This study reveals that radiative emission and scattering by the surrounding parts of the nonscanner cavity are acceptably small. The dynamic electrothermal model is also used to compute ACR instrument transfer function. Accurate in-flight measurement of this transfer function is shown to depend on the energy distribution over the frequency spectrum of the radiation input function. A new array-type field of view limiter, whose geometry controls the input function, is proposed for in-flight calibration of an ACR and other types of radiometers. The point spread function (PSF) of the ERBE and the Clouds and Earth's Radiant Energy System (CERES) scanning radiometers is computed. The PSF is useful in characterizing the channel optics. It also has potential for recovering the distribution of the radiative flux from Earth by deconvolution.

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Title:
The effect of clouds on the earth's radiation budget
Authors:
ZISKIN, DANIEL; STROBEL, DARRELL F.
Affiliation:
Johns Hopkins Univ., Baltimore, MD.
Journal:
Progress Report Johns Hopkins Univ., Baltimore, MD. Dept. of Earth and Planetary Sciences.
Publication Date:
09/1991
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC RADIATION, CLIMATOLOGY, CLOUD PHYSICS, CLOUDS (METEOROLOGY), EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, OPTICAL THICKNESS, COEFFICIENTS, CORRELATION, INDONESIA, MATHEMATICAL MODELS, PARAMETERIZATION, SATELLITE OBSERVATION
Bibliographic Code:
1991jhu..rept.....Z

Abstract

The radiative fluxes from the Earth Radiation Budget Experiment (ERBE) and the cloud properties from the International Satellite Cloud Climatology Project (ISCCP) over Indonesia for the months of June and July of 1985 and 1986 were analyzed to determine the cloud sensitivity coefficients. The method involved a linear least squares regression between co-incident flux and cloud coverage measurements. The calculated slope is identified as the cloud sensitivity. It was found that the correlations between the total cloud fraction and radiation parameters were modest. However, correlations between cloud fraction and IR flux were improved by separating clouds by height. Likewise, correlations between the visible flux and cloud fractions were improved by distinguishing clouds based on optical depth. Calculating correlations between the net fluxes and either height or optical depth segregated cloud fractions were somewhat improved. When clouds were classified in terms of their height and optical depth, correlations among all the radiation components were improved. Mean cloud sensitivities based on the regression of radiative fluxes against height and optical depth separated cloud types are presented. Results are compared to a one-dimensional radiation model with a simple cloud parameterization scheme.

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Title:
RETRIEVAL OF RADIATION BUDGETS IN THE ARCTIC FROM SATELLITE MEASUREMENTS.
Authors:
LI, ZHANQING
Affiliation:
MCGILL UNIVERSITY (CANADA).
Journal:
Thesis (PH.D.)--MCGILL UNIVERSITY (CANADA), 1991.Source: Dissertation Abstracts International, Volume: 53-12, Section: B, page: 6353.
Publication Date:
00/1991
Category:
Physics: Atmospheric Science; Geophysics
Origin:
UMI
Abstract Copyright:
(c) 1991: UMI Company
Bibliographic Code:
1991PhDT.......258L

Abstract

This study addresses the problems associated with each step of the process of retrieving radiation budgets at the top of atmosphere (TOA) and at the surface from satellite measurements in the Arctic. The data used are from the Earth Radiation Budget Experiment (ERBE) radiometer and Advanced Very High Resolution Radiometer (AVHRR), together with radiative transfer calculations. The limitations of the ERBE scene identification algorithm when applied to observations in the Arctic are investigated by comparing the scenes identified by ERBE with simultaneous and colocated AVHRR-based scenes. Considerable discrepancies are found, especially the misidentification by the ERBE scene identification method of clear fractional ice as being partly cloudy skies over open water. More accurate TOA fluxes and cloud forcing in the Arctic are derived by taking advantage of the broadband radiance measurements made by the ERBE radiometer and the more reliable scene identification deduced from narrowband multispectral measurements made by the AVHRR. Comparisons of the cloud forcing determined from the two scene identification methods show differences as large as 50 W m^ {-2} in some regions of the Arctic. The validity of the ERBE angular dependence models (ADMs) is also evaluated in the Arctic. It is found that the ADM for clear ice/snow is not reliable when applied in the Arctic during summer. The ADM for overcast skies contains systematic errors when applied to overcast conditions over ice/snow surfaces. The systematic error is removed by modifying the ADM. To estimate the surface absorbed flux from reflected flux at the TOA, a simple parameterized model is developed based on comprehensive radiative simulations. The model is independent of cloud optical thickness, surface type, and has only a moderate dependence on the presence or absence of cloud, cloud type and water vapour, but a strong dependence on solar zenith angle (SZA). Surface absorbed fluxes determined by radiative transfer calculations may generally be estimated to within 10 W m^{-2} by the simple model from TOA reflected fluxes with knowledge of the SZA and precipitable water. Finally, narrowband-to-broadband reflectance conversion is carried out with careful attention paid to a particular statistical problem, namely, regression analysis with spatially autocorrelated satellite measurements. Both scene-dependent and scene-independent regressional models are developed to estimate broadband reflectance from the narrowband reflectances in channels 1 and 2 of AVHRR. The RMS errors in the percentage reflectances from the scene-dependent models are 1.0, 1.8, 2.0 and 3.1 for the ocean, land, ice/snow and cloud, respectively. Except for land, the scene-independent model does virtually as good a job as the scene-dependent models.

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Title:
A study of the Earth Radiation Budget Experiment: Shortwave measurements and bidirectional reflectance models for the ocean surface
Authors:
DLHOPOLSKY, ROSE MARIE
Affiliation:
State Univ. of New York, Stony Brook.
Journal:
Ph.D. Thesis State Univ. of New York, Stony Brook.
Publication Date:
00/1991
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC RADIATION, BIDIRECTIONAL REFLECTANCE, EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, RADIATION MEASUREMENT, SHORT WAVE RADIATION, NIMBUS 7 SATELLITE, OCEAN SURFACE, RADIANCE, SPECULAR REFLECTION
Bibliographic Code:
1991PhDT........15D

Abstract

Shortwave radiances from the Earth Radiation Budget Experiment (ERBE) satellites are converted to fluxes using bidirectional reflectance models created from Nimbus 7 data. These models describe the dependence of a shortwave measurement on the angle at which a scene is being observed and the position of the sun relative to that scene and the satellite. In this study, reflectances are derived from Earth Radiation Budget Satellite (ERBS) shortwave radiances and sorted according to the range of angles at which they were measured. This range is called the angular bin size. The Nimbus 7 Bidirectional Reflectance Models were created using this same procedure. In this study, the size of the angular bins is made smaller than the sizes in the Nimbus 7 Bidirectional Reflectance Models in order to more accurately describe the angular dependence of the shortwave reflection. Results indicate that the size of the Nimbus 7 angular bins causes the ERBE shortwave fluxes to be overestimated when the satellite views specular reflection from the ocean surface. This is especially severe for solar zenith angles less than 25 degrees. Clear sky shortwave radiances measured under specular geometries are very large and are therefore not included in the processing. However, these radiances are sometimes identified as clouds and included in the data set. This occurs because shortwave radiances reflected from clouds do not exhibit as strong a dependence on viewing geometry as the clear sky ocean surface. Therefore, a large shortwave radiance is identified as a cloud. Examples are given where this affects the regional data.

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Title:
A comparison of ERBE and AVHRR longwave flux estimates
Authors:
GRUBER, ARNOLD; ARDANUY, PHILIP; WEISS, MITCHELL; YANG, S. K.; ELLINGSON, ROBERT G.; OH, SUNG NAM
Affiliation:
AF(Maryland Univ., College Park.)
Journal:
A comparison of ERBE and AVHRR longwave flux estimates
Publication Date:
11/1990
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ADVANCED VERY HIGH RESOLUTION RADIOMETER, ATMOSPHERIC RADIATION, COMPARISON, EARTH RADIATION BUDGET EXPERIMENT, ESTIMATES, LONG WAVE RADIATION, RADIANT FLUX DENSITY, BROADBAND, NARROWBAND, NOAA SATELLITES, SATELLITE OBSERVATION, TIROS SATELLITES
Bibliographic Code:
1990erbe.rept.....G

Abstract

Comparisons were made between estimates of the outgoing longwave radiation at the top of the atmosphere derived from narrowband advanced very high resolution radiometer (AVHRR) and broadband earth radiation budget experiment (ERBE) scanning instruments. Four months of measurements are considered: April, July, and October, 1985 and January 1986. Two types of comparisons are considered: instantaneous and monthly averaged. In the former, regional, zonal, and global analyses are performed using collocated and coincident outgoing longwave radiation (OLR) estimates on a 2.5 degree latitude/longitude scale. In general, the two data sets are found to be in reasonable good agreement, with the mean state and fundamental variability in time and space captured by the two sets of measurements. However, systematic biases are observed between the two data sets, particularly over the subtropical oceans, the daytime deserts, and over snow-covered surfaces at the high latitudes. The monthly global bias between the two data sets (ERBE minus AVHRR) is between -1 and 2 W/sq m during daytime and between 4 to 7 w/sq m during nighttime, while the RMS differences range between 12(June) and 15(January) W/sq m. In the comparison of the monthly averaged fields, very good agreement is found in the large-scale patterns, while certain different characteristics are revealed. In general, ERBE overestimates AVHRR by about 4 W/sp m with an RMS difference of 5 W/sq m to 8 W/sq m. The relationship between the two data sets appears to be dependent on the surface geography and season. Possible reasons for the differences are discussed.

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Title:
Earth radiation budget measurements from space
Authors:
KANDEL, ROBERT
Affiliation:
Laboratoire de Meteorologie Dynamique du CNRS, Palaiseau (France).
Journal:
In ESA, Remote Sensing and the Earth's Environment p 35-42 (SEE N90-25398 19-43)
Publication Date:
03/1990
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ANISOTROPY, DIURNAL VARIATIONS, EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, CYCLES, DATA PROCESSING, SAMPLING, TERRESTRIAL RADIATION
Bibliographic Code:
1990rsee.rept...35K

Abstract

Ways in which data processing must take into account the sampling characteristics of the satellite-orbit/instrument combination are discussed. Incorporation into these studies of the anisotropy and diurnal variation of the radiation reflected and emitted by the Earth/atmosphere system is considered. The role of the ongoing Earth Radiation Budget Experiment (ERBE) in resolving some of these questions is discussed. The usefulness of integrating basic observations made by several polar orbiting platforms so as to obtain complete diurnal coverage is considered.

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Title:
Earth Radiation Budget Experiment - Preliminary seasonal results
Authors:
BARKSTROM, BRUCE R.; HARRISON, EDWIN F.; LEE, ROBERT B., III
Affiliation:
AC(NASA, Langley Research Center, Hampton, VA)
Journal:
EOS (ISSN 0096-3941), vol. 71, Feb. 27, 1990, p. 297, 304.
Publication Date:
02/1990
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
EARTH RADIATION BUDGET EXPERIMENT, NOAA 10 SATELLITE, NOAA 9 SATELLITE, SATELLITE-BORNE INSTRUMENTS, DATA ACQUISITION, DATA PROCESSING, SOLAR RADIATION
Bibliographic Code:
1990EOS....71..297B

Abstract

Data from the Earth Radiation Budget Satellite (ERBS) and from the operational NOAA-9 satellite being placed in the archive of the earth Radiation Budget Experiment (ERBE) are discussed. The results of the ERBE data validation effort are reviewed along with ERBE solar constant observations and earth-viewing results. The latter include monthly average results for July 1985, annual average clear-sky fluxes, and annual average, zonal, and global results.

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Title:
Spatial sampling error of a scanning radiation budget radiometer
Authors:
UDELHOFEN, PETRO MARIA
Affiliation:
Cologne Univ. (Germany, F.R.).
Journal:
Ph.D. Thesis Cologne Univ. (Germany, F.R.). Inst. fuer Geophysik und Meteorologie.
Publication Date:
00/1990
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
EARTH RADIATION BUDGET EXPERIMENT, ERROR ANALYSIS, RADIOMETERS, SAMPLING, DIGITAL SIMULATION, ESTIMATES, RADIOMETRIC RESOLUTION
Bibliographic Code:
1990PhDT.........2U

Abstract

Simulations of ERBE (Earth Radiation Budget Experiment) scanner measurements were performed to investigate the spatial sampling error of regional averaged radiation fluxes. Meteosat data with a spatial resolution of 0.04 deg were used for the description of the true radiation field. Regional means were calculated by weighting and arithmetically averaging the simulating ERBE scanner measurements. The optimal estimate can be derived by taking a phase shifted spatial filter as a weighting function. The phase shift of the distribution of weights varies with scan angle of the region and is related to the phase shift of the point spread function. Analyses of sampling error of the arithmetic estimates for different scene types show in most cases overestimations of short wave and underestimations of long wave fluxes. The total error of the arithmetic estimate varies between 5 and 31 W/sq m in the short wave region, and between 2 and 20 W/sq m in the long wave region.

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Title:
Earth Radiation Budget Experiment (ERBE) validation
Authors:
BARKSTROM, BRUCE R.; HARRISON, EDWIN F.; SMITH, G. LOUIS; GREEN, RICHARD N.; KIBLER, JAMES F.; CESS, ROBERT D.
Affiliation:
AF(State Univ. of New York, Stony Brook.)
Journal:
Earth Radiation Budget Experiment (ERBE) validation
Publication Date:
00/1990
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ACCURACY, EARTH RADIATION BUDGET EXPERIMENT, PROVING, ALGORITHMS, ATMOSPHERIC RADIATION, DATA PROCESSING, ENERGY BUDGETS, LIMB DARKENING
Bibliographic Code:
1990erbe.rept.....B

Abstract

During the past 4 years, data from the Earth Radiation Budget Experiment (ERBE) have been undergoing detailed examination. There is no direct source of groundtruth for the radiation budget. Thus, this validation effort has had to rely heavily upon intercomparisons between different types of measurements. The ERBE SCIENCE Team chose 10 measures of agreement as validation criteria. Late in August 1988, the Team agreed that the data met these conditions. As a result, the final, monthly averaged data products are being archived. These products, their validation, and some results for January 1986 are described. Information is provided on obtaining the data from the archive.

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Title:
First estimates of the diurnal variation of longwave radiation from the multiple-satellite Earth Radiation Budget Experiment (ERBE)
Authors:
HARRISON, EDWIN F.; BROOKS, DAVID R.; MINNIS, PATRICK; WIELICKI, BRUCE A.; STAYLOR, W. FRANK
Affiliation:
AE(NASA, Langley Research Center, Hampton, VA)
Journal:
American Meteorological Society, Bulletin (ISSN 0003-0007), vol. 69, Oct. 1988, p. 1144-1151.
Publication Date:
10/1988
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
DIURNAL VARIATIONS, EARTH RADIATION BUDGET EXPERIMENT, LONG WAVE RADIATION, SATELLITE OBSERVATION, AMAZON REGION (SOUTH AMERICA), DESERTS, GOES SATELLITES, OCEANS
Bibliographic Code:
1988AMSBu..69.1144H

Abstract

First results for diurnal cycles derived from the Earth Radiation Budget Experiment are presented for the combined Earth Radiation Budget Satellite and NOAA-9 spacecraft for April 1985. Regional scale longwave radiation data are analyzed to determine diurnal variations for the total scene (including clouds) and for clear-sky conditions. The longwave diurnal range was found to be greatest for clear desert regions (up to about 70 W/sq m) and smallest for clear oceans (less than 5 W/sq m). Local time of maximum longwave radiation occurs at a wide range of times throughout the day and night over oceans, but generally occurs from noon to early afternoon over land and desert regions.

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Title:
Development of algorithms for understanding the temporal and spatial variability of the earth's radiation balance
Authors:
BROOKS, D. R.; HARRISON, E. F.; MINNIS, P.; SUTTLES, J. T.; KANDEL, R. S.
Affiliation:
AE(Ecole Polytechnique, Palaiseau, France) AD(NASA, Langley Research Center, Hampton, VA)
Journal:
Reviews of Geophysics (ISSN 8755-1209), vol. 24, May 1986, p. 422-438.
Publication Date:
05/1986
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
EARTH RADIATION BUDGET EXPERIMENT, RADIATION DISTRIBUTION, SPATIAL DISTRIBUTION, TEMPORAL DISTRIBUTION, TERRESTRIAL RADIATION, ANNUAL VARIATIONS, DATA PROCESSING, DIURNAL VARIATIONS, EARTH RADIATION BUDGET, ENVIRONMENT SIMULATION, QUALITY CONTROL, SHORT WAVE RADIATION
Bibliographic Code:
1986RvGeo..24..422B

Abstract

A brief description is given of how temporal and spatial variability in the earth's radiative behavior influences the goals of satellite radiation monitoring systems and how some previous systems have addressed the existing problems. Then, results of some simulations of radiation budget monitoring missions are presented. These studies led to the design of the Earth Radiation Budget Experiment (ERBE). A description is given of the temporal and spatial averaging algorithms developed for the ERBE data analysis. These algorithms are intended primarily to produce monthly averages of the net radiant exitance on regional, zonal, and global scales and to provide insight into the regional diurnal variability of radiative parameters such as albedo and long-wave radiant exitance. The algorithms are applied to scanner and nonscanner data for up to three satellites. Modeling of dialy shortwave albedo and radiant exitance with satellite samling that is insufficient to fully account for changing meteorology is discussed in detail. Studies performed during the ERBE mission and software design are reviewed. These studies provide quantitative estimates of the effects of temporally sparse and biased sampling on inferred diurnal and regional radiative parameters. Other topics covered include long-wave diurnal modeling, extraction of a regional monthly net clear-sky radiation budget, the statistical significance of observed diurnal variability, quality control of the analysis, and proposals for validating the results of ERBE time and space averaging.

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Title:
Inversion methods for satellite studies of the Earth Radiation Budget - Development of algorithms for the ERBE mission
Authors:
SMITH, G. L.; GREEN, R. N.; AVIS, L. M.; SUTTLES, J. T.; WIELICKI, B. A.; RASCHKE, E.; DAVIES, R.
Affiliation:
AE(NASA, Langley Research Center, Hampton, VA) AF(Koeln, Universitaet, Cologne, West Germany) AG(Purdue University, West Lafayette, IN)
Journal:
Reviews of Geophysics (ISSN 8755-1209), vol. 24, May 1986, p. 407-421.
Publication Date:
05/1986
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
DATA PROCESSING, DATA REDUCTION, EARTH RADIATION BUDGET, EARTH RADIATION BUDGET EXPERIMENT, RADIATION MEASUREMENT, TERRESTRIAL RADIATION, CLOUD COVER, ENERGY DISTRIBUTION, INVERSIONS, NIMBUS SATELLITES, RADIANCE, REFLECTANCE, SCANNERS, SCENE ANALYSIS
Bibliographic Code:
1986RvGeo..24..407S

Abstract

The Earth Radiation Budget Experiment carries a three-channel scanning radiometer and a set of nadir-looking wide and medium field-of-view instruments for measuring the radiation emitted from earth and the solar radiation reflected from earth. This paper describes the algorithms which are used to compute the radiant exitances at a reference level ('top of the atmosphere') from these measurements. Methods used to analyze data from previous radiation budget experiments are reviewed, and the rationale for the present algorithms is developed. The scanner data are converted to radiances by use of spectral factors, which account for imperfect spectral response of the optics. These radiances are converted to radiant exitances at the reference level by use of directional models, which account for anisotropy of the radiation as it leaves the earth. The spectral factors and directional models are selected on the basis of the scene, which is identified on the basis of the location and the long-wave and shortwave radiances. These individual results are averaged over 2.5 x 2.5 deg regions. Data from the wide and medium field-of-view instruments are analyzed by use of the traditional shape factor method and also by use of a numerical filter, which permits resolution enhancement along the orbit track.

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Title:
Comparison of ERBE inferred and model computed clear-sky albedos
Authors:
BRIEGLEB, B. P.; RAMANATHAN, V.
Affiliation:
AB(National Center for Atmospheric Research, Boulder, CO)
Journal:
IN: Conference on Atmospheric Radiation, 6th, Williamsburg, VA, May 13-16, 1986, Extended Abstracts (A87-15076 04-47). Boston, MA, American Meteorological Society, 1986, p. J32, J33.
Publication Date:
00/1986
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
ATMOSPHERIC MODELS, DATA PROCESSING, EARTH ALBEDO, EARTH RADIATION BUDGET, AIR WATER INTERACTIONS, ATMOSPHERIC ATTENUATION, CLIMATOLOGY, OCEAN SURFACE, SPACEBORNE EXPERIMENTS
Bibliographic Code:
1986atra.conf...32B

Abstract

Over-ocean clear-sky albedos measured with instruments on the Earth Radiation Budget Satellite (ERBS) are compared with albedos simulated using a radiative transfer model (RTM). The comparison covers the monthly mean albedos for November 1984. The ERBS albedo was calculated with a scene identification algorithm. Techniques used to suppress cloud cover uncertainties are discussed. The plane-parallel delta-Eddington RTM accounted for O3, O2, CO2 and H2O gaseous absorption and background aerosol absorption.