SEARCH · Search NASA

Results for “reflective solar”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22

All sources NASA NTRS DOE OSTI

NASA NTRS2018

Initial Determination of the NOAA-20 VIIRS Screen Transmittances with Both Yaw Maneuver and Regular on Orbit Data

One of the scientific instruments aboard the NOAA-20 satellite is the Visible Infrared Imaging Radiometer Suite (VIIRS). The VIIRS regularly performs on-orbit radiometric calibration of its reflective solar bands, primarily through observations of an onboard sunlit solar diffuser (SD). The incident sunlight passes through an attenuation screen (the SD screen) and scatters off the SD to provide a radiance source for the calibration. The on-orbit change of the SD bidirectional reflectance distribution function (BRDF), denoted as the H-factor, is determined by an onboard solar diffuser stability monitor (SDSM). The eight SDSM detectors observe the sun through another attenuation screen (the SDSM screen) and the sunlit SD almost at the same time to measures the SD BRDF change. The products of the SD screen transmittance and the BRDF at t=0 and the SDSM screen transmittance were measured prelaunch. Large undulations in the H-factor were seen when using the prelaunch screen transmittances. Fifteen on-orbit yaw maneuvers were performed to validate and to further characterize the screens. Although significantly improved, the H-factor from the yaw maneuver data determined screen transmittance still has undulations as large as about 0.7-0.8%, revealing that the angular step size of the yaw maneuvers is too large. In this paper, we add regular on-orbit data to the yaw maneuver data to further improve the relative products and the relative SDSM screen transmittance. The H-factor time series derived from the newly determined screen transmittance is much smoother than that derived from using only the yaw maneuver data and thus improves considerably the radiometric calibration accuracy.

Lei, Ning↗

NASA NTRS2013

A New Approach for Spectroradiometric Calibration Consistency on the Ground and in Space

A Space-based Calibration Transfer Spectroradiometer (SCATS) is combined with a ground calibration spectral albedo radiometric standard which consists of an opaque quartz glass Mie scattering diffuser (MSD) which has very good Lambertian scattering properties in both reflectance and transmittance modes. This system provides the capability for determining long term changes in the spectral albedo calibrations which operate in the solar reflective wavelength region. The spectral albedo calibration would be traceable to the SIRCUS and STARR NIST calibration facilities. The on-orbit radiometric standard is the Sun. The NIST traceable ground spectral albedo calibration is invariant between the ground and on-orbit over the instrument lifetime due to the use of a field of view defining mechanical baffle to differentiate between radiance and irradiance.

Heath, Donald F.↗

NASA NTRS2021

S-NPP VIIRS Solar Diffuser Degradation at the View Direction of the Rotating Telescope Assembly

S-NPP VIIRS has been on-orbit for more than nine years since it was launched on October28th,2011. The VIIRS reflective solar bands (RSBs) are calibrated on-orbit primarily by an onboard solar diffuser (SD). The SD on-orbit degradation is tracked by an onboard SD stability monitor(SDSM). The VIIRS RSBs view the SD through a rotating telescope assembly (RTA). The RTA views the SD from a direction that is quite different from that of the SDSM. It has been shown that the SD degrades non-uniformly with respect to the incident and outgoing directions, especially at the short wavelengths. Thus, the SDSM calibration cannot provide an accurate SD degradation estimation for the view direction of the RTA, resulting in long-term drifts in the calibration coefficients derived from the SD and SDSM calibration. S-NPP VIIRS has been scheduled to view the Moon approximately monthly since its launch. The lunar observations can provide accurate long-term trends for the RSB calibration coefficients since the lunar surface reflectance is quite stable. By comparing the SD and lunar calibration results, we can obtain the SD degradation differences at the view directions of the SDSM and RTA and derive the SD degradation at the view direction of the RTA. Moreover, we can also derive the SD degradation in the short-wave infrared (SWIR) spectral range, wherein the SDSM cannot track the SD degradation. In this paper, we will derive the SD degradation for the view direction of the RTA from the SD, SDSM, and lunar calibrations from the visible to SWIR spectral range. We will also simulate the SD degradation with analytical models and compare their performances.

SNPP VIIRS↗

NASA NTRS2020

Determination of the NOAA-20 VIIRS screen transmittance functions with both the yaw maneuver and regular on-orbit calibration data

The Visible Infrared Imaging Radiometer Suite (VIIRS) aboard theNOAA-20 satellite regularly performs on-orbit radiometric calibration of its reflective solar bands (RSBs) through observations of an onboard sunlit solar diffuser (SD). The incident sunlight passes through an attenuation screen (the SD screen) and then scatters off the SD to provide a radiance source for the calibration. The on-orbit change of the SD’s bidirectional reflectance distribution function (BRDF), referred to as the H-factor, is determined by an onboard solar diffuser stability monitor (SDSM) whose eight detectors alternately observe the Sun through another attenuation screen (the SDSM screen) and the sunlit SD. The products of the SD screen transmittance and the BRDF at the mission start for both the SDSM and RSBs and the SDSM screen effective transmittance were measured prelaunch. Large unrealistic undulations in the retrieved H-factor were seen when using the prelaunch screen functions. To improve the accuracy of the retrieved H-factor, shortly after the satellite launch, 15 yaw maneuvers were performed to further characterize the screens. Although significantly improved, the H-factor derived using the screen functions determined fromthe yaw maneuver data still has large unrealistic undulations, revealing that the solar azimuth angular step size of the yaw maneuvers is too large. In this paper,we add high-quality regular on-orbitSDcalibration data to the yaw maneuver data to further improve the relative product of the SD screen effective transmittance and the BRDF at the mission start for the SDSM and the SDSM screen relative effective transmittance. The H-factor time series derived from the newly determined screen transmittance functions is much smoother than that derived from using only the yaw maneuver data and thus considerably improves the radiometric calibration accuracy.

Ning Lei↗

NASA NTRSDate not supplied

Jpss-4 VIIRS Polarization Sensitivity Performance Comparison With Heritage VIIRS Sensors

The Joint Polar Satellite System 4 (JPSS-4) is the follow-on for the Suomi-National Polar-orbiting Partnership (S-NPP) and Joint Polar Satellite Systems 1-3 (JPSS-1, -2 and -3) missions. A primary sensor on both JPSS and S-NPP spacecrafts is the Visible-Infrared Imaging Radiometer Suite (VIIRS) that provides valuable weather and climate products to the user community. VIIRS covers the Reflective Solar Band (RSB) and Thermal Emissive Band (TEB) spectral regions and contains a Day Night Band (DNB) that uses Lunar illumination at night. VIIRS provides top-of-atmosphere radiance, reflectance, and brightness temperature within the Sensor Data Records (SDRs) that are used in sea surface temperature, cloud characterization, land surface properties and ocean color/chlorophyll Environmental Data Record (EDR) products. The SDR calibration is performed using unpolarized sources such as a Solar Diffuser (SD) for the RSBs or an On-Board Calibrator BlackBody (OBCBB) for the TEBs. Earth scenes with polarizing properties will create radiometric bias errors within the SDRs based on how sensitive VIIRS is to polarized illumination and must be corrected in some EDR algorithms. This paper will discuss the JPSS-4 VIIRS polarization characterization methodology, polarization sensitivity results and compare its performance to its predecessors S-NPP and JPSS-1 through -3 VIIRS.

David Moyer↗

NASA NTRS2011

A New Radiometric Calibration Paradigm for the OMPS Nadir Total Column and Profile Instruments

A fused silica Mie Scattering Diffuser (MSD) has been developed at Ball Aerospace & Technology Corp. that has measured characteristics which could be used to increase the accuracy of the spectral albedo calibration of the Ozone Mapping and Profiler Suite (OMPS) Nadir ozone total column and profile instrument by almost an order of magnitude. Measurements have been made of the optical characteristics on both natural and synthetic forms of fused silica MSDs. Preliminary measurements suggest that MSDs are useable in the solar reflective wavelength region from 250 nm to 3.7 m. To date synthetic and natural MSDs have been irradiated for 60 hours of UV radiation from a solar simulator, and synthetic MSDs have been irradiated with increasing doses of Co-60 gamma rays at 30, 500 krads up to 1.5 Mrads, and 30 krads of 200 MeV protons. The principal effects have been small loses in transmittance at wavelengths < 350 nm. The high energy particle irradiation measurements were provided by Neal Nickles and Dean Spieth.

Heath, Donald↗

NASA NTRS1995

Removal of the solar component in AVHRR 3.7 micrometer radiances for the retrieval of cirrus cloud parameters

A numerical scheme has been developed to remove the solar component in the Advanced Very High Resolution Radiometer (AVHRR) 3.7- micrometer channel for the retrieval of cirrus parameters during daytime. This method uses a number of prescribed threshold values for AVHRR channels 1 (0.63 micrometer), 2 (0.8 micrometer), 3 (3.7 micrometer), 4 (10.9 micrometer), and 5 (12 micrometer) to separate clear and cloudy pixels. A look-up table relating channels 1 and 3 solar reflectances is subsequently constructed based on the prescribed mean effective ice crystal sizes and satellite geometric parameters. An adding-doubling radiative transfer program has been used to generate numerical values in the construction of the look-up table. Removal of the channel 3 solar component is accomplished by using the look-up table and the measured channel 1 reflectance. The cloud retrieval scheme described in Ou et al. has been modified in connection with the removal program. The authors have applied the removal-retrieval scheme to the AVHRR global area coverage daytime data, collected during the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment cirrus intensive field observation (FIRE IFO) at 2100 UTC 28 October 1986 over the Wisconsin area. Distributions of the retrieved cloud heights and optical depths are comparable to those determined from Geostationary Operational Environmental Satellite (GOES) visible and IR channels data reported by Minnis et al. Moreover, verifications of the retrieved cirrus temperature and height against lidar data have been carried out using results reported from three FIRE IFO stations. The retrieved cloud heights are within 0.5 km of the measured lidar values.

Rao, N. X.↗

NASA NTRS1986

Continued observations of the H Ly alpha emission from Uranus

Observations of Uranus obtained over four years with the IUE Observatory supports the initial identification of a bright H Ly alpha flux which varies independently of the solar H Ly alpha flux, implying a largely self-excited emission. An average brightness of 1400 Rayleighs is derived, and limits for the possible contribution by reflected solar H Ly alpha emission, estimated to be about 200 Rayleighs, suggest that the remaining self-excited emission is produced by an aurora. Based on comparison with solar wind measurements obtained in the vicinity of Uranus by Voyager 2 and Pioneer 11, no evidence for correlation between the solar wind density and the H Ly alpha brightness is found. The upper limit to H2 emission gives a lower limit to the ratio of H Ly alpha/H2 emissions of about 2.4, suggesting that the precipitating particles may be significantly less energetic on Uranus than those responsible for the aurora on Jupiter. The average power in precipitating particles is estimated to be of the order of 10 to the 12th W.

Clarke, J.↗

NASA NTRS2016

MAVEN Observation of an Obliquely Propagating Low-Frequency Wave Upstream of Mars

We report Mars Atmosphere and Volatile EvolutioN (MAVEN) mission observations of a large amplitude low-frequency plasma wave that propagated oblique to the ambient magnetic field upstream of Mars along with a non-solar-wind plasma component that had a flow velocity perpendicular to the magnetic field. We consider nine possibilities for this wave that include various combinations of its propagation direction, polarization in the solar wind frame, and ion source responsible for its generation. Using the observed wave parameters and the measured plasma parameters as constraints, we uniquely identify the wave by systematically discarding these possibilities. We determine that the wave is a right-hand polarized wave that propagated upstream in the solar wind frame. We find two possibilities for the ion source that can be responsible for this wave generation. They are either newly born pickup protons or reflected solar wind protons from the bow shock.We determine that the observed non-solar-wind component is not responsible for the wave generation, and it is likely that the non-solar-wind component was merely perturbed by the passage of the wave.

low frequency wave↗

NASA NTRS2016

JPSS-1 VIIRS Pre-Launch Response Versus Scan Angle Testing and Performance

The Visible Infrared Imaging Radiometer Suite (VIIRS) instruments on-board both the Suomi National Polar-orbiting Partnership (S-NPP) and the first Joint Polar Satellite System (JPSS-1) spacecraft, with launch dates of October 2011 and December 2016 respectively, are cross-track scanners with an angular swath of +/-56.06 deg. A four-mirror Rotating Telescope Assembly (RTA) is used for scanning combined with a Half Angle Mirror (HAM) that directs light exiting from the RTA into the aft-optics. It has 14 Reflective Solar Bands (RSBs), seven Thermal Emissive Bands (TEBs) and a panchromatic Day Night Band (DNB). There are three internal calibration targets, the Solar Diffuser, the BlackBody and the Space View, that have fixed scan angles within the internal cavity of VIIRS. VIIRS has calibration requirements of 2% on RSB reflectance and as tight as 0.4% on TEB radiance that requires the sensor's gain change across the scan or Response Versus Scan angle (RVS) to be well quantified. A flow down of the top level calibration requirements put constraints on the characterization of the RVS to 0.2%-0.3% but there are no specified limitations on the magnitude of response change across scan. The RVS change across scan angle can vary significantly between bands with the RSBs having smaller changes of approximately 2% and some TEBs having approximately 10% variation. Within aband, the RVS has both detector and HAM side dependencies that vary across scan. Errors in the RVS characterization will contribute to image banding and striping artifacts if their magnitudes are above the noise level of the detectors. The RVS was characterized pre-launch for both S-NPP and JPSS-1 VIIRS and a comparison of the RVS curves between these two sensors will be discussed.

Moyer, David↗

DOE OSTI2021

Infrared fluorescent coatings

The present invention provides for a composition comprising a pigment, wherein the composition is suitable for coating a surface that is, or is expected to be, exposed to the sun. The pigment comprises particles that fluoresce in sunlight, thereby remaining cooler in the sun than coatings pigmented with non-fluorescent particles. The particles comprise solids that fluoresce or glow in the visible or near infrared (NIR) spectra, or that fluoresce when doped. Suitable dopants include, but are not limited to, ions of rare earths and transition metals. A coating composition includes: (i) a film-forming resin; (ii) an infrared reflective pigment; and (iii) an infrared fluorescent pigment different from the infrared reflective pigment. When the coating composition is cured to form a coating and exposed to radiation comprising fluorescence-exciting radiation, the coating has a greater effective solar reflectance (ESR) compared to the same coating exposed to the radiation comprising fluorescence-exciting radiation except without the infrared fluorescent pigment. A multi-layer coating including the coating composition, and a substrate at least partially coated with the coating composition is also disclosed. A method of reducing temperature of an article includes applying the coating composition to at least a portion of the article.

Zalich, Michael Andrew↗

DOE OSTI2022

Infrared fluorescent coating compositions

A coating composition includes: (i) a film-forming resin; (ii) an infrared reflective pigment; and (iii) an infrared fluorescent pigment different from the infrared reflective pigment. When the coating composition is cured to form a coating and exposed to radiation comprising fluorescence-exciting radiation, the coating has a greater effective solar reflectance (ESR) compared to the same coating exposed to the radiation comprising fluorescence-exciting radiation except without the infrared fluorescent pigment. A multi-layer coating including the coating composition, and a substrate at least partially coated with the coating composition is also disclosed. A method of reducing temperature of an article includes applying the coating composition to at least a portion of the article.

Zalich, Michael A.↗

DOE OSTI2023

Infrared fluorescent coatings

Zalich, Michael Andrew↗

NASA NTRS2010

Characterization of LANDSAT Panels Using the NIST BRDF Scale from 1100 nm to 2500 nm

Many earth observing sensors depend on white diffuse reflectance standards to derive scales of radiance traceable to the St Despite the large number of Earth observing sensors that operate in the reflective solar region of the spectrum, there has been no direct method to provide NIST traceable BRDF measurements out to 2500 rim. Recent developments in detector technology have allowed the NIST reflectance measurement facility to expand the operating range to cover the 250 nm to 2500 nm range. The facility has been modified with and additional detector using a cooled extended range indium gallium arsenide (Extended InGaAs) detector. Measurements were made for two PTFE white diffuse reflectance standards over the 1100 nm to 2500 nm region at a 0' incident and 45' observation angle. These two panels will be used to support the OLI calibration activities. An independent means of verification was established using a NIST radiance transfer facility based on spectral irradiance, radiance standards and a diffuse reflectance plaque. An analysis on the results and associated uncertainties will be discussed.

Markham, Brian↗

DOE OSTI2023

Thermally Responsive Hydrogels for Passive Temperature Regulation under Direct Sunlight

By spontaneously emitting midinfrared radiation to outer space through the atmospheric window and reflecting sunlight, daytime radiative coolers achieve notable passive cooling performance. However, existing daytime radiative cooling systems generally lack the ability to adaptively switch between heating and cooling states based on ambient conditions. Herein a passive thermal regulation system that features a temperature‐dependent switchable solar reflectance from 0.05 (low temperature) to 0.8 (high temperature) is presented. This, along with a ≈0.95 midinfrared emittance, it enables automatic switching between radiative cooling and solar heating. Switchablity is enabled using a poly( N ‐isopropylacrylamide) (PNIPAM) hydrogel which exhibits high solar scattering above its tunable lower critical solution temperature (LCST) and transparency below its LCST. The lower part of the hydrogel is loaded with graphite to absorb solar energy in the heating state. In testing under sunny and partly cloudy outside conditions, this system maintains a temperature close to the set LCST.

Xie, Dajie↗

NASA NTRS1987

Reflectance- and radiance-based methods for the in-flight absolute calibration of multispectral sensors

Variations reported in the in-flight absolute radiometric calibration of the Coastal Zone Color Scanner (CZCS) and the Thematic Mapper (TM) on Landsat 4 are reviewed. At short wavelengths these sensors exhibited a gradual reduction in response, while in the midinfrared the TM showed oscillatory variations, according to the results of TM internal calibration. The methodology and results are presented for five reflectance-based calibrations of the Landsat 5 TM at White Sands, NM, in the period July 1984 to November 1985. These show a + or - 2.8 percent standard deviation for the six solar-reflective bands. Analysis and preliminary results of a second, independent calibration method, based on radiance measurements from a helicopter at White Sands, indicate that this is potentially an accurate method for corroborating the results from the reflectance-based method.

Slater, P. N.↗

NASA NTRS2005

Overview of Terra and Aqua MODIS Status

This presentation will consist of two one-hour lectures. The first lecture will review the characteristics of the MODIS instrument and how it responds to the performance specifications. The pre-launch and on-orbit procedures and results to characterize and maintain instrument output so as to allow the prescribed science to be done will also be outlined. This will include defining the equations used to account for gain changes and any degradation in the optics of the instrument or the on-board calibration devices themselves. The changes in the solar diffuser and the radiance versus scan angle performance of the scan mirror will also be reviewed. Overall it will be shown that the instrument has and is meeting specifications of 2% reflectance relative to the sun, 5% in the radiance observed in the reflected solar radiation bands, and 0.5-1% in the thermal bands. The second lecture will review and describe highlights in the geophysical products and related science results. There are approximately 40 geophysical products related to observations of land, ocean and atmosphere features. Many of the results are unprecedented and offer considerable advances over those achievable with heritage instruments such as the NOAA Advanced Very High Resolution Radiometer (AVHRR). The literature is showing a steady growth of publications in scientific journals using MODIS data or products. The future is also bright in that a follow-on instrument based on the MODIS will be flown on the National Polar-Orbiting Environmental Satellite Series (NPOESS) starting around 2010.

Salomonson, Vincent V.↗

NASA NTRSDate not supplied

Seasonal and Dayurnal Planetary Albedo Variability from Six Years of DSCOVR EPIC Data

Deep Space Climate Observatory (DSCOVR) measurements of Earth’s reflected solar radiation from the Lissajous orbital position near the Lagrangian L1 point provide continuous monitoring of the Earth’s sunlit hemisphere. CERES-based angle models were used to convert the near-hourly reflected radiances of the EPIC images into a climate-style planetary albedo data-point over the sunlit hemisphere. Integration over the sunlit hemispheres averages out the meteorological weather noise, but retains the seasonal and planetary-scale variability. As the Earth rotates, this generates variations in the Earth’s planetary albedo that are precisely aligned in longitude, which constitutes the dayurnal cycle. This dayurnal variability in the planetary albedo arises from planetary-scale changes in cloud radiative properties that can be directly compared to similarly sampled climate GCM output data. Six years of EPIC data have been analyzed, showing characteristic patterns in the seasonal and dayurnal variability of the Earth’s planetary albedo. Much of the seasonal change in planetary albedo is associated with the changing DSCOVR viewing geometry and the change in solar declination. But throughout the year, the highest planetary albedos are observed over the Central Asia (Iraq) longitude, while the lowest planetary albedos occur over the Central Pacific longitude. For these longitudes, the relative seasonal changes in the planetary albedo are slowly varying and anti-correlated. Dayurnal amplitude maxima tend to occur during the July-September timeframe, with April-May and December exhibit distinct minima in the dayurnal amplitude. West Africa and the West Pacific longitudes likewise exhibit anti-correlated seasonal variability, while they also undergo anti-correlated short period oscillations. On the other hand, in nearby longitudes, there are short period spikes in planetary albedo of a few-days duration, as well as longer period oscillations that may range from a week to several months, that generally tend to be correlated.

Planetary Albedo↗