Papers by Dhirendra Kumar Pandey
Clouds and the Earth's radiation energy system (CERES), a key experiment in the Earth observi... more Clouds and the Earth's radiation energy system (CERES), a key experiment in the Earth observing system (EOS), is designed to measure the reflected shortwave and the emitted longwave radiances from Earth and its atmosphere. The CERES instrument consists of a scanning thermistor bolometer package with built in flight calibration systems. The first CERES instrument is scheduled for launch in 1997
Nasa Sti Recon Technical Report a, Jul 1, 1991
Two data sets for one geographical scene are used as a comparative validation tool to verify the ... more Two data sets for one geographical scene are used as a comparative validation tool to verify the quality of radiometer measurements taken for NASA's Earth Radiation Budget Experiment (ERBE). The measurements are taken from four independent nonscanning radiometers installed on the Earth Radiation Budget Satellite and two NOAA spacecraft. Two radiometers measure radiation in the 0.2-50-micron range, and two measure solar reflected energy in spectral band ranging from 0.2 to 5 microns. Calculated top-of-atmosphere flux-value measurements for day and night demonstrate significant correlation as well as consistency and stability over a three-year period. It is concluded that intercomparisons of intersections between the satellites are necessary over varied geographical scenes to utilize the subject method in validating the measurements of the ERBE nonscanning radiometer.
The Clouds and Earth Radiant Energy System (CERES) instrument is designed to measure the Earth's ... more The Clouds and Earth Radiant Energy System (CERES) instrument is designed to measure the Earth's radiation budget and also to make measurements from which the anisotropy of reflected solar radiation can be computed. The instrument design, which is based on the Earth Radiation Budget Experiment (ERBE), and its operations are described. The instrument can scan in elevation and azimuth simultaneously. The azimuthal rotation is important for gathering data to describe the anisotropy of the reflected solar radiance field. The ground vacuum calibration facility ties the calibration of the instrument to the International Temperature Scale of 1990. In-flight calibration sources are included to maintain and demonstrate the required 1 percent accuracy of each mission. Flight operations to achieve the accuracy are also discussed. The CERES Proto-Flight Model is flying on the Tropical Rainfall Measurement Mission spacecraft and successive models are scheduled to fly aboard the EOS/AM-1 and EOS/PM-1 platforms. The objectives of each flight of the instrument are discussed.
Journal of Global Research in Computer Science, Oct 10, 2012
Long-term changes in the mean global atmospheric temperature and the total solar irradiance were ... more Long-term changes in the mean global atmospheric temperature and the total solar irradiance were examined utilizing 1979-1989 spacecraft measurements. Outgoing longwave radiation at the top of the atmosphere was employed to infer global atmospheric temperatures. Evidence was determined that indicates the global temperatures should decline in the 1990-1997 period as the magnitude of the incoming solar irradiance declines with decreasing solar magnetic activity.
Global Journal of Multidisciplinary Studies, Jan 31, 2014
Proceedings of Spie the International Society For Optical Engineering, Dec 1, 1999
The Clouds and Earth's Radiant Energy System (CERES thermistor bolometers were calibrated us... more The Clouds and Earth's Radiant Energy System (CERES thermistor bolometers were calibrated using filtered radiances, characterized on an International Temperature Scale of 1990 (ITS-90) derived absolute radiometric scale. Longwave filtered radiances were characterized using the optical and geometric surface properties of the reference Narrow-Field-of-View Blackbody (NFBB), the NFBB temperature measurements from the ITS-90 calibrated platinum resistance thermometers (PRT) embedded in the blackbodies, and the spectral responses of the CERES bolometers. Shortwave filtered radiances were characterized using the cryogenically-cooled Transfer Active Cavity Radiometer (TACR) which was an ITS-90 transfer standard, and using the spectral responses of the bolometers. In ground vacuum facilities, the ITS-90, temperature-based radiometric scale was transferred to the CERES bolometers. As ITS-90 transfer standards, the bolometers were used to characterize the emitted filtered radiances from in-flight systems: (1) the internal calibration module (ICM) which consisted of anodized aluminum blackbodies and tungsten lamp sources; and (2) mirror attenuator mosaic (MAM) which was an aluminum solar diffuser plate, built into the bolometer instrumentation. From the ground [October 1995] through the on-orbit phases [December 1998 - July 1999] of the Tropical Rainfall Measuring Mission (TRMM) Spacecraft CERES instrument mission, the stabilities of the bolometer's responses were assessed from periodical observations of the in-flight calibration systems radiances. Each CERES instrument package consisted of broadband shortwave [0.3 micrometer to 5.0 micrometer], broadband total [0.3 micrometer to greater than 100 micrometer], and narrowband window [8 micrometer and 12 micrometer], scanning thermistor bolometer sensor units; and of in-flight calibration systems. Between the ground and initial on-orbit calibrations, the TRMM CERES bolometers and the built-in, flight calibration system sources maintained their filtered radiance measurement ties to ITS-90 at the plus or minus 0.2 Wm-2sr-1 precision level. On-orbit calibration studies indicate that the radiance measurements were stable at the plus or minus 0.2 Wm-2sr-1 precision level. The ground and on- orbit calibration results are presented and discussed.
Storage and Retrieval For Image and Video Databases, 1998
All physical measuring devices have finite response times determined by the characteristics of th... more All physical measuring devices have finite response times determined by the characteristics of their optical, electrical, and thermal components. In a system which is not time-critical, one merely waits for the system to stabilize, and then reads the measurement. In a system which is in motion, such as the CERES scanners, the spatial location of any measurement is dependent upon the response time of the detector. In order for the remotely sensed data to be accurately geolocated, the systematic delays between the time-of-observation of the scene and the time-of-measurement must be determined. The first CERES instrument was launched aboard the Tropical Rainfall Measuring Mission (TRMM) platform from Japans Tanegashima Island Space Center on 28 November 1997. The next two CERES instruments are scheduled for dual launch on the EOS/AM-1 platform in late 1998. In this paper we specifically address the delay between the time of observation of a scene, and its actual measurement as determined from Point Response Function Source data taken in the CERES calibration chamber at TRW in Redondo Beach; and we compare the theoretically generated Point Spread Functions to these measurements. The agreement between the measured and theoretical contours in excellent, in the total and shortwave channels. For all 3 instruments, the calculated time-delay of 0.023ms to the centroid,and the measured peak delay of 0.022ms are very consistent. The result of on-orbit coastline detection algorithms are currently being analyzed in comparison with the PSF delays used in the geolocation algorithms in order to further validate the proper geolocation of the measured data.
Global Journal of Multidisciplinary Studies, Apr 30, 2014
Global Journal of Multidisciplinary Studies, Apr 30, 2014
Risk is a condition that can result failure of software project and loss in terms of cost and qua... more Risk is a condition that can result failure of software project and loss in terms of cost and quality. Some controls used to reduce the Risk. These controls can be identified as anything that finds the cause and help to reduce the risk like risk analysis and risk assessment. During software development life cycle (SDLC), Risk Analysis and Risk Assessment accomplished to make software more effective and efficient. Risk Analysis is the process of identifying, assessing, and reducing risk to an acceptable level. It defines and control threats and vulnerabilities. Whereas, risk assessment determines existence of risk and it can focus to achieve the software project objectives and minimize the threats. Risk analysis and assessment reduce the reason responsible for the failure of software project. In this paper a review on some method and proper approaches of software risk assessment and risk analysis will be presented. Some significant points could be pondered to reduce threats and vulnerabilities. Finally some Future research directions will be discussed to enhance the software project quality and to achieve the objectives of risk analysis and Risk assessment. In this paper the main objectives of this review is to present research workers contributions on risk assessment on different phases of SDLC. Keywords: Project, Risk, Software Development Life Cycle (SDLC)
Proceedings of Spie the International Society For Optical Engineering, Nov 1, 1996
From spacecraft platforms, the clouds and the Earth's radiant energy system (CERES) scanning ther... more From spacecraft platforms, the clouds and the Earth's radiant energy system (CERES) scanning thermistor bolometers are designed to measure broadband Earth-reflected solar shortwave (0.3 - 5.0 micrometer) and Earth-emitted long wave (5.0 - greater than 100 micrometer) radiances as well as emitted longwave radiances in the 8 - 12 micrometer water vapor window over geographical footprints as small as 10 kilometers at the nadir. In ground vacuum facilities, the thermistor bolometers and in-flight blackbody and tungsten lamp calibration systems are being calibrated using radiometric sources tied to the international temperature scale of 1990 (ITS'90). Using the in-flight calibration systems, the bolometers will be calibrated periodically before and after spacecraft launch to verify the stability of the bolometers responses and to determine response drifts/shifts if they occur. The in-flight systems calibration analyses along with validation analyses will be used to determine the flight data reduction coefficients (instrument gains and offsets) which will be used to convert the bolometer measurements into calibrated radiances at the top-of-the-atmosphere (approximately 30 km). If a bolometer response shifts or drifts more than 0.5% in the longwave region or more than 1.0% in the shortwave region, and if the validation studies verify the bolometer response change, the flight data reduction coefficients will be corrected. A coastline detection method, using strong contrasting longwave ocean-land scenes, will be used to assess error limits on the geographical locations of the radiances. The detection method was successfully used to assess upper limits (6 km) on the geolocation errors for the Earth radiation budget satellite (ERBS) bolometric measurements of longwave radiances. For CERES, the detection method may be extended to shortwave radiances. In this paper, elements of the CERES instrument level 1 validation plan radiometric strategies are presented as well as the geolocation validation approaches.
Agu Spring Meeting Abstracts, May 1, 2006
This paper intercompares the radiative flux values determined by four nonscanning active cavity r... more This paper intercompares the radiative flux values determined by four nonscanning active cavity radiometers of the ERBS (Earth Radiation Budget Satellite) spacecraft launched on October 5, 1984 in a non-sun- synchronous trajectory. Two are the total radiometers: the medium field-of-view total (MFOV-T) and the wide field-of-view total (WFOV-T) which measure the radiation fields in the spectral band of 0.2 - 50 μm and other two are the shortwave radiometers: the medium field-of-view shortwave (MFOV- SW) and the wide field-of- view shortwave (WFOV-SW) which measure the Earth's reflected radiation in the wavelength region of 0.2 - 5.0 μm. The WFOV (FOV: 142.8°) sees the entire Earth's disk while the MFOV (FOV: 88.4°) sees 10° diameter geocentric latitudinal regions. These radiometers were calibrated continuously by observing the in-flight internal black bodies and the Sun every two weeks. The resulting gains and offsets values found to be very stable and accurate within 0.1%. In this paper, we compare the results obtained by MFOV radiometers with the WFOV measurements, which are widely used by the climate scientists throughout the world. We report the results covering the period from January 1985 through December 1990. The MFOV radiometers degradation was found to be less than 0.5% due to exposure to direct solar radiation. The WFOV radiometers degraded approximately 5% during the same period because of considerably greater solar exposure. In addition, the WFOV measurements were affected by the decreasing spacecraft-earth distance while the MFOV measurements were not affected. The measurements were not corrected for the significant measurements variations caused by the varying inverse spacecraft-earth distance. Therefore, the MFOV measurements represent a better data set to analyze long- term climate variations in the Tropics. The 1985-1999 WFOV measurements were reduced and were made available for climate studies. We believe that the raw 1990-1999 ERBS MFOV radiometric measurements should be reduced and made available for long-term climate studies as well as the 1999-2005 measurements.
Journal of Global Research in Computer Science, Oct 10, 2012
The asteroid genus Advenaster Hess, 1955 is being recorded and described for the first time from ... more The asteroid genus Advenaster Hess, 1955 is being recorded and described for the first time from the Indian subcontinent. The specimen has been collected from limestone beds of the Middle Jurassic (Bathonian) Patcham Formation exposed in a deep gorge in the centre of the Habo Dome, south of the village Dhrang, Kachchh, India.
The scleractinian coral genus Favia from the early Pliocene-Holocene sediments and the patch reef... more The scleractinian coral genus Favia from the early Pliocene-Holocene sediments and the patch reefs in intertidal lagoon along the northern and northwestern coastal areas of Saurashtra peninsula, western India is represented by three morphospecies, viz. Favia favus, Favia speciosa and Favia matthaii. These species have been found intricately related and cannot be easily seperated; however, based on combination of characters like anastamosing nature of septa, size and shape of paliform lobes, size and density of septal ornamentation these have been differentiated. The nomenclatural problem has also been discussed. The significance of the genus for palaeoecological reconstruction and their detail morphological variation through time has been given.
Uploads
Papers by Dhirendra Kumar Pandey