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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

NIMBUS 7 Earth Radiation Budget (ERB) Matrix User's Guide. Volume 2: Tape Specifications

The ERB MATRIX tape is generated by an IBM 3081 computer program and is a 9 track, 1600 BPI tape. The gross format of the tape given on Page 1, shows an initial standard header file followed by data files. The standard header file contains two standard header records. A trailing documentation file (TDF) is the last file on the tape. Pages 9 through 17 describe, in detail, the standard header file and the TDF. The data files contain data for 37 different ERB parameters. Each file has data based on either a daily, 6 day cyclic, or monthly time interval. There are three types of physical records in the data files; namely, the world grid physical record, the documentation mercator/polar map projection physical record, and the monthly calibration physical record. The manner in which the data for the 37 ERB parameters are stored in the physical records comprising the data files, is given in the gross format section.

Ray, S. N.↗
NASA NTRS1984

New in-flight calibration adjustment of the Nimbus 6 and 7 earth radiation budget wide field of view radiometers

In-flight calibration adjustments are developed to process data obtained from the wide-field-of-view channels of Nimbus-6 and Nimbus-7 after the failure of the Nimbus-7 longwave scanner on June 22, 1980. The sensor characteristics are investigated; the satellite environment is examined in detail; and algorithms are constructed to correct for long-term sensor-response changes, on/off-cycle thermal transients, and filter-dome absorption of longwave radiation. Data and results are presented in graphs and tables, including comparisons of the old and new algorithms.

Kyle, H. L.↗
NASA NTRS1984

The Earth Radiation Budget Experiment (ERBE)

The three-satellite ERBE will be flown in the mid-1980s and will provide upgraded data on changes in the input and outflow of energy which drives climatic phenomena. The spacecraft will carry radiometers, self-calibration equipment, and be programmed with inversion and averaging algorithms. Radiation will be scanned at 0.2-5 and 5-50 microns. The ACRIM detector, similar to that on the SMM spacecraft, will measure the incoming solar radiation at the 600 km sun-synchronous orbit travelled by the three ERBE spacecraft. Data transmitted to the NASA-Langley Center will be analyzed with algorithms which extract radiant flux data from the measured radiances.

Barkstrom, B. R.↗
NASA NTRS1985

Reflection and emission models for clouds derived from Nimbus 7 earth radiation budget scanner measurements

Statistical results from 2.8 million pairs of broadband shortwave and longwave radiance measurements were used to develop reflectance and emittance models for low, middle, and high water clouds and high ice clouds. The reflectance model was a function of the sum and product of the cosine of solar and viewing zenith angles, and the emittance model was related by a power law of the cosine of the viewing zenith angle.

Staylor, W. F.↗
NASA NTRS1986

A preliminary comparison of scanning vs nonscanning radiometer data from Earth Radiation Budget Satellite (ERBS)

A cross validation technique is used to simulate the radiation flux detected by the nonscanning wide FOV (WFOV) and medium FOV (MFOV) radiometers on the ERBS by integrating the top of atmosphere spectral radiance recorded with narrow FOV (NFOV) sensors. Consideration is given to both bidirectional and isotropic radiance contributions, including all shortwave and longwave components. A weighting procedure is defined to adjust for missing or inaccurate data records and a coordinate transformation is devised to account for angular discrepancies among the views of the WFOV, MFOV and NFOV sensors. Student t-test values were calculated for values generated for whole orbit average, morning, noon, evening and night subsatellite views.

Wu, X.↗
NASA NTRS1986

Oceanic cloud feedbacks on earth radiation budget parameters

Oceanic cloud variability and sensitivity to sea surface temperature (SST) were examined using radiometer data gathered with instrumentation on the Nimbus-7 satellite. The study area was a region of the Pacific Ocean north of Hawaii. SST and albedo data for the period 1978-1983 were compared and similar trends were found for minimal values of the albedo and SST.

Chertock, B.↗
NASA NTRS1986

The six year Nimbus-7 Earth Radiation Budget data set

Correlative statistics gathered during the first 6 yr of operation of the Nimbus-7 ERB instrumentation are presented and discussed. The numerical model employed for calculating the net radiation from data collected by wide and narrow field of view scanners is reviewed, along with the scanning patterns and specific data collection scenarios encountered with the remote sensing system. Seasonal and regional discrepancies between the ERB and polar-orbiting NOAA satellite data for average differences between zonal temperatures are noted.

Kyle, H. L.↗
NASA NTRS1986

Defining the minimum temporal and spatial scales available from a new 72-month Nimbus-7 Earth Radiation Budget climate data set

Scale factors and assumptions which were applied in calculations of global radiation budget parameters based on ERB data are discussed. The study was performed to examine the relationship between the composite global ERB map that can be generated every six days using all available data and the actual average global ERB. The wide field of view ERB instrument functioned for the first 19 months of the Nimbus-7 life, and furnished sufficient data for calculating actual ERB averages. The composite was most accurate in regions with the least variation in radiation budget.

Randel, D. L.↗
NASA NTRS1986

Intercomparison of preliminary Earth Radiation Budget Satellite (ERBS) flux estimates and geostationary satellite multi-spectral 'VAS' radiance measurements

Results are reported from a preliminary study to evaluate the level of correlation and, if possible, establish relationships between the spectral radiances sensed by the GOES 6 satellite VISSR Atmospheric Sounder (VAS) and the ERBS longwave sensor. A data set for February 7, 1985 was selected which was scanned with both sensors flying over the region of the Gulf of Mexico. Techniques applied to enhance the equivalence of the data are delineated. Regression equations were applied to assess the levels of correlations for each subsatellite point compared.

Herman, L. D.↗
NASA NTRS1987

Development of response models for the Earth Radiation Budget Experiment (ERBE) sensors. Part 4: Preliminary nonscanner models and count conversion algorithms

Two count conversion algorithms and the associated dynamic sensor model for the M/WFOV nonscanner radiometers are defined. The sensor model provides and updates the constants necessary for the conversion algorithms, though the frequency with which these updates were needed was uncertain. This analysis therefore develops mathematical models for the conversion of irradiance at the sensor field of view (FOV) limiter into data counts, derives from this model two algorithms for the conversion of data counts to irradiance at the sensor FOV aperture and develops measurement models which account for a specific target source together with a sensor. The resulting algorithms are of the gain/offset and Kalman filter types. The gain/offset algorithm was chosen since it provided sufficient accuracy using simpler computations.

Halyo, Nesim↗
NASA NTRS1987

Development of response models for the Earth Radiation Budget Experiment (ERBE) sensors. Part 3: ERBE scanner measurement accuracy analysis due to reduced housekeeping data

The accuracy of scanner measurements was evaluated when the sampling frequency of sensor housekeeping (HK) data was reduced from once every scan to once every eight scans. The resulting increase in uncertainty was greatest for sources with rapid or extreme temperature changes. This analysis focused on the mirror attenuator mosaic (MAM) baffle and plate and scanner radiometer baffle due to their relatively high temperature changes during solar calibrations. Since only solar simulator data were available, the solar temperatures were approximated on these components and the radiative and thermal gradients in the MAM baffle due to reflected sunlight. Of the two cases considered for the MAM plate and baffle temperatures, one uses temperatures obtained from the ground calibration. The other attempt uses temperatures computed from the MAM baffle model. This analysis shows that the heat input variations due largely to the solar radiance and irradiance during a scan cycle are small. It also demonstrates that reasonable intervals longer than the current HK data acquisition interval should not significantly affect the estimation of a radiation field in the sensor field-of-view.

Choi, Sang H.↗
NASA NTRS1990

Use of earth-radiation budget measurements for understanding climate change

Setting the baseline for the greenhouse effect, quantification of the water-vapor feedback, validation of longwave radiation models, determination of the trend in the clear sky albedo of the ocean, and determination of the role of clouds in climate are considered. A summary of cloud radiative forcing estimates is presented, and it is noted that the longwave cloud forcing is essentially the greenhouse effect of the clouds, and that the CO2 concentration in the atmosphere has to be increased by a factor of 250 to equal the cloud greenhouse effect. It is pointed out that the short-wave cloud forcing is due to the enhancement of the albedo of the planet by clouds. The decrease in the solar absorption of 48.4 W/sq m by clouds is found to be larger than its greenhouse effect by about 50 pct.

Ramanathan, V.↗
NASA NTRS1990

Atmospheric energetics and earth radiation budget

Processed ERBE data are used in several studies in which NMC global analyses and forecasts are examined and evaluated. In the first study, ERBE net radiation values for four months are averaged and integrated to provide global net energy transport. Energy transport by atmospheric circulations is obtained using NMC analyses and results provide a measure of reasonableness of the analyses. In the second and third experiments, ERBE values of outgoing longwave radiation are used as 'top-side truth' to examine both the spin-up problem and the radiation algorithms of the global forecasts.

Kann, Deirdre M.↗
NASA NTRS1990

Validation of Earth Radiation Budget Experiment scanning radiometer data inversion procedures

Validation techniques were implemented in the inversion of scanner radiometer data to assess the accuracy of the top of atmosphere radiant fluxes. An evaluation of SW radiant flux standard deviations for the same scene type shows that they contribute about 6.0 W/sq m for viewing zenith angles less than 55 deg and can reach values of up to 17.6 W/sq m for larger zenith angles in the backward scanning position. Three-channel intercomparison results, presented as color graphic displays and histograms, effectively validate the radiance measurements and the spectral factors. Along-track data were used to validate limb-darkening models and showed good agreement with current ERBE models. These validation techniques were found to be very effective in assessing the quality of the radiant fluxes generated by the ERBE inversion algorithm.

Manalo, Natividad D.↗
NASA NTRS1991

Shortwave wide-field-of-view results from the Earth Radiation Budget Experiment

The deconvolution (DCN) and numerical filter (NF) techniques of analyzing nonscanning radiometer measurements are evaluated by comparison with scanning radiometer results for monthly mean maps of albedo and absorbed solar radiation. Both techniques successfully enhance the resolution of the monthly mean product. The numerical filter albedo adheres closer to the scanning radiometer in the zonal average than does the DCN albedo. Zonal rms's, however, show that the DCN albedo is about 1 percent better than the NF in the Southern Hemisphere, but in the Northern Hemisphere the NF is better by up to 2 percent.

Rutan, David↗