| Energetics and Dynamics of the Reactions of O(3P) with Dimethyl Methylphosphonate and Saria |
15-Sep-2009 |
11 pages |
| Authors:
Matthew Braunstein; Patrick F Conforti; James A Dodd; SPECTRAL SCIENCES INC BURLINGTON MA
|
 | Electronic structure and molecular dynamics calculations were performed on the reaction systems O(3P) + sarin and O(3P) + dimethyl methylphosphonate (DMMP), a sarin simulant. Transition state geometries, energies, and heats of reaction for the major reaction pathways were determined at several levels of theory, including AM1, B3LYP/6-311+G(d,p), and CBS-QB3. The major reaction pathways for both systems are similar and include H-atom abstraction, H-atom elimination, and methyl elimination, in rough order ... |
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| Classical Collision Spectrum of O + CO (Preprint) |
07-Apr-2009 |
21 pages |
| Authors:
M Braunstein; J W Duff; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The work of Noid et al. [J. Chem. Phys., 67, 404 (1977)] has shown that sharp molecular spectra can be obtained through a Fourier transform of the autocorrelation function of a classical trajectory. In the present work, we extend this idea to obtain a spectrum by Fourier transform of the dipole moment function of collision product trajectories. We show that this classical collision spectrum (CCS) is related to the cross ... |
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| IR Structured Emission-Based Speciation, Thermometry, and Tomography of CO and H2O in High-Pressure Combustors |
May-2006 |
11 pages |
| Authors:
Jamine Lee; Neil Goldstein; Brian Gregor; Stephen K Kramer; Stuart Kozola; Kenneth J Semega; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Passive optical probes and high-resolution emission spectroscopy are used to provide a general-purpose real-time temperature and chemical species sensing capability. Probes can be inserted in the combustor, at the turbine inlet, in the augmenter, or at the engine exit with application as an engine development diagnostic tool that provides spatially resolved measurements of the key combustion parameters: temperature, CO concentration, and H2O concentration. Multiple probes are arrayed to collect the ... |
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| The Convergence of CASSCF-CISD Energies to the Complete Basis Set Limit |
16 FEB 2006 |
30 pages |
| Authors:
George A. Petersson; David K. Malick; Michael J. Frisch; Braunstein Matthew; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Examination of the convergence of full valence CASSCF-CISD energies with expansion of the one-electron basis set reveals a pattern very similar to the convergence of single determinant CCSD energies. Calculations on the lowest four singlet states and the lowest four triplet states of N2 with the sequence of ntuple-zeta augmented polarized (nZaP) basis sets (n = 2,3,4,5, and 6) are used to establish the complete basis set (CBS) limits. Full ... |
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| Programmable Adaptive Spectral Imagers for Mission-Specific Application in Chemical/Biological Sensing |
Jan-2006 |
13 pages |
| Authors:
Steven Adler-Golden; Latika S Becker; Shawn D Higbee; Brian Gregor; Pajo Vujkovic-Cvijin; Neil Goldstein; Alan C Samuels; Jason Cline; Jamine Lee; Marsha Fox; Teng Ooi; SPECTRAL SCIENCES INC BURLINGTON MA
|
| There is a long-standing need for standoff sensors capable to detect, identify and quantify chemical and biological warfare agents and other hazardous species. Currently dominant Fourier transform infrared spectrometers (FTIR) are based on interferometry, and are therefore mechanically complex, expensive, and susceptible to mechanical disturbances. Adaptive multispectral sensors, based on mathematical transforms other than Fourier's which do not require macroscopic moving parts to provide the same spectral multiplexing capability (Felgett's ... |
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| Use of the Vis-SWIR to Aid Atmospheric Correction of Multispectral and Hyperspectral Thermal Infrared (TIR) Imagery: The TIR Model |
2006 |
14 pages |
| Authors:
John Gruninger; Marsha Fox; Jamine Lee; Anthony J. Ratkowski; Michael L. Hoke; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The atmospheric correction of thermal infrared (TIR) imagery involves the combined tasks of separation of atmospheric transmittance, downwelling flux and upwelling radiance from the surface material spectral emissivity and temperature. The problem is ill posed and is thus hampered by spectral ambiguity among several possible feasible combinations of atmospheric temperature, constituent profiles, and surface material emissivities and temperatures. For many materials, their reflectance spectra in the Vis-SWIR provide a means ... |
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| Prediction of AMOS Observations of Shuttle Engine Firing |
08 NOV 2005 |
20 pages |
| Authors:
Matthew Braunstein; Lawrence Bernstein; SPECTRAL SCIENCES INC BURLINGTON MA
|
| In this report, we discuss predictions for observations of on-orbit Shuttle plumes from the Air Force Maui Optical Station (AMOS). The focus is a 2-5 micrometers spectral region. The major light-producing mechanisms considered are 0+H20->20H* and O+H20->H20*+0. Recently computed velocity-dependent cross sections for these mechanisms are used in conjunction with the Spacecraft Orbiter Contamination Representation Accounting for Transiently Emitted Species (SOCRATES) flow-field code to predict the emissions for a PRCS ... |
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| Contributions of the OH Airglow to Resident Space Object Irradiance |
25 OCT 2005 |
19 pages |
| Authors:
John Gruninger; James W. Duff; SPECTRAL SCIENCES INC BURLINGTON MA
|
| A goal of space situational awareness is the detection and characterization of resident space objects. An around-the-clock capability depends on the ability to observe the space object under a variety of illumination conditions. In this report, we focus on space-based sensors operating in the visible, near-infrared and short-wave infrared where reflected light sources are the dominant signature components. of particular interest is the ability to observe space objects from above ... |
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| A Correlated-k Based Ultra-Fast Radiative Transfer (kURT) Method |
2005 |
11 pages |
| Authors:
Prabhat K. Acharya; Raphael Panfili; Alexander Berk; Steve M. Adler-Golden; Marsha Fox; Alan Wetmore; Irwin E. Alber; SPECTRAL SCIENCES INC BURLINGTON MA
|
| A new sensor-specific correlated-k (c-k) ultra-fast radiative transfer (RT) formalism, kURT has been designed for fast broad-bandpass scene simulations from UV-visible to LWIR wavelengths. A higher resolution RT code (1 /cm MODTRAN) has been adapted to output 1 /cm correlated-k parameters for ozone water and the combined uniformly mixed species on a pressure-temperature grid which are merged to form a compact c-k set incorporating the sensor bandpass response function. The ... |
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| A New Method for Atmospheric Correction and Aerosol Optical Property Retrieval for VIS-SWIR Multi- and Hyperspectral Imaging Sensors: QUAC (QUick Atmospheric Correction) |
2005 |
5 pages |
| Authors:
L. S. Bernstein; S. M. Adler-Golden; R. L. Sundberg; R. Y. Levine; T. C. Perkins; A. Berk; A. J. Ratkowski; G. Felde; M. L. Hoke; SPECTRAL SCIENCES INC BURLINGTON MA
|
| We describe a new VNIR-SWIR atmospheric correction method for multi- and hyperspectral imagery, dubbed QUAC (QUick Atmospheric Correction) that also enables retrieval of the wavelength-dependent optical depth of the aerosol or haze and molecular absorbers. It determines the atmospheric compensation parameters directly from the information contained within the scene using the observed pixel spectra. The approach is based on the empirical finding that the spectral standard deviation of a collection ... |
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| Full Optical Spectrum Hyperspectral Scene Simulation |
2005 |
5 pages |
| Authors:
Robert L. Sandberg; Steven Richtsmeier; Raymond Haren; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Full optical spectrum (UV to LWIR) hyperspectral scene simulation provides an accurate, robust, and efficient means for algorithm validation and sensor design trade studies. This paper reviews the development of a first-principles, high fidelity HSI/MSI image simulation capability, dubbed MCScene and demonstrates how the model can be used for sensor design trade studies. MCScene incorporates all optical effects important for solar-illuminated and thermal scenes, including molecular and aerosol scattering, absorption ... |
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| Potential Surfaces and Dynamics of the O(3P) + H2O(X1A1) yields OH(X2Pi) + OH(X2Pi) Reaction |
DEC 2004 |
47 pages |
| Authors:
M. Braunstein; R. Panfili; R. Shroll; L. Bernstein; SPECTRAL SCIENCES INC BURLINGTON MA
|
| We present global potential energy surfaces for the three lowest triplet states in O(3P) + H2O(X1A1) collisions and present results of classical dynamics calculations on the O(3P) + H2O(X1A1) yields OH(X2Pi) + OH(X2Pi) reaction using these surfaces. The surfaces are spline-based fits of approx. 20, 000 fixed geometry ab-initio calculations at the CASSCF+MP2 level with a O(4s3p2d1f)/H(3s2p) one electron basis set. Computed rate constants compare well to measurements in the ... |
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| High Altitude Chemical Injections: Non-Thermal Chemical Dynamics and Flow Field Modeling |
NOV 2004 |
16 pages |
| Authors:
Lawrence Bernstein; Matthew Braunstein; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Near UV OH(A->X) and NH(A->X) emission bands at ^3100 and 3360 A, respectively, have been observed in Space Shuttle engine exhaust using the GLO imager spectrograph located in the payload bay. Spectra were collected at a resolution of 4 A for daytime solar illumination conditions during low-Earth orbit (LEO) maneuvers. While it is now understood that the OH(A-X) emissions stem from solar-induced fluorescence and photodissociation of OH and H2O in ... |
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| SAMM2, SHARC-4 and MODTRAN4 Merged (User's Manual) |
07 JUN 2004 |
218 pages |
| Authors:
H. Dothe; J. W. Duff; J. H. Gruninger ; P. K. Acharya ; A. Berk; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The SAMM2 (SHARC and MODTRAN Merged Code version 2) combines the capabilities of the Strategic High-Altitude Radiance Code, SHARC-4, and MODerate resolution TRANsmittance code, MODTRAN4. The code calculates atmospheric Infrared radiance and transmission over a 1 - 40 micrometer spectral region for arbitrary lines of sight (LOS) from the ground to 300 km altitude using an approximate line-by-line radiative transport (RT) algorithm capable of a fine spectral resolution of 0.001 ... |
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| Theoretical Studies of High Energy Oxygen Atom Chemistry |
13 APR 2004 |
46 pages |
| Authors:
M. Braunstein; J. Duff; R. Shroll; L. Bernstein; S. Adler- Golden; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Ab-initio Modeling of the Following Reactions: O + H2 yields OH + H; O + H2O yields O + H2O* or OH** + OH*; O + HCl yields O = HCl* or Cl + OH* |
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| MODTRAN5: A Reformulated Atmospheric Band Model with Auxiliary Species and Practical Multiple Scattering Options |
2004 |
9 pages |
| Authors:
Alexander Berk; Gail P. Anderson; Prabhat K. Acharya; Lawrence S. Bernstein; Marsha Fox; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The MODTRAN5 radiation transport (RT) model is a major advancement over earlier versions of the MODTRAN atmospheric transmittance and radiance model. The new model's features include the following: (1) finer spectral resolution via the Spectrally Enhanced Resolution MODTRAN (SERTRAN) molecular band model, (2) a fully coupled treatment of auxiliary molecular species, and (3) a rapid and high-fidelity multiple scattering (MS) option. The finer spectral resolution improves model accuracy, especially in ... |
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| User's Manual for SAG-2 SHARC/SAMM Atmosphere Generator |
14 OCT 2003 |
60 pages |
| Authors:
Robert M. Shroll; Steven Adler-Golden; James W. Duff; James H. Brown; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The SHARC Atmosphere Generator (SAG) is a stand-alone, interactive program that utilizes a combination of empirical models to generate atmospheric profiles for Air Force IR radiation codes that account for systematic variability of the atmosphere, including solar terminator effects. Using information on the day of the year, local time, solar and geomagnetic activity indices, etc., SAG reasonably models the variabilities in temperature and CO2, O3, OH, NO3, H2O and O ... |
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| Status of Atmospheric Correction using a MODTRAN4-Based Algorithm |
APR 2000 |
11 pages |
| Authors:
Michael W. Matthew; Steven M. Adler-Golden; Alexander Berk; Steven C. Richtsmeier; Robert Y. Levine; Lawrence S. Bernstein; Prabhat K. Acharya; Gail P. Anderson; Gerry W. Felde; Michael P. Hoke; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This paper presents an overview of the latest version of a MODTRAN4-based atmospheric correction (or "compensation") algorithm developed by Spectral Sciences, Inc. and the Air Force Research Laboratory for spectral imaging sensors. New upgrades to the algorithm include automated aerosol retrieval, cloud masking, and speed improvements. In addition, MODTRAN4 has been updated to correct recently discovered errors in the HITRAN-96 water line parameters. Reflectance spectra retrieved from AVIRIS data are ... |
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| Infrared Airglow and Contamination Modeling |
OCT 1999 |
124 pages |
| Authors:
S. M. Adler-Golden; A. Berk; P. K. Acharya; L. S. Bernstein; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This report describes work performed to evaluate our understanding of infrared (IR) atmospheric phenomenology through comprehensive analysis of spectral and in-band radiance field data. Computer models of atmospheric IR radiation used for these analyses include the standard AFRL codes MODTRAN, SHARC, and SAMM. MODTRAN is a rapid, local thermodynamic equilibrium (LTE) code for low- to moderate-resolution spectra. SHARC calculates emission and transmission spectra in the 2 - 40 micrometers region ... |
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| Electronic Structure and Dynamics of O(3P)+CO(1E+) Collisions |
SEP 1999 |
37 pages |
| Authors:
M. Braunstein; J. W. Duff; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The potential energy surfaces of the three lowest electronic triplet states of CO2 which lead to O((sup 3 P))+CO((sup 1)SIGMA(+)), (sup 3)A', 1(sup 3)A', and 2(sup 3)A", have been computed at the complete-active-space-self consistent-field plus second-order perturbation theory (CASSCF-MP2) level with a modest G631+d basis. Potential energy surfaces are fit with a global functional form. The (sup 3)A' state has a well 0.9 eV deep and the 1(sup 3)A" state ... |
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| Recent Upgrades to MODTRAN - New Solar Irradiance and Instrument Scanning Functions |
28 SEP 1998 |
19 pages |
| Authors:
P. K. Acharya; A. Berk; L. S. Bernstein; D. C. Robertson; J. H. Chetwynd; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Recent upgrades are intended to make MODTRAN a more accurate, convenient and versatile atmospheric modeling tool. The current default solar irradiance database due to Kurucz was corrected in the 310-340 nm region using measured data. Several other data sets are also made available to the user. The user can also use his/her won data residing in a file. Examination confirms that the corrected Kurucz data is ... |
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| Radiation Transport Effects and the Interpretation of Infrared Images of Gravity Waves and Turbulence |
1998 |
15 pages |
| Authors:
John Gruninger; James W. Duff; James H. Brown; William A. Blumberg; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Radiation transport modulates the spatial frequencies of atmospheric structures, acting as a low pass filter, which causes the power spectra of the accumulated radiance to have different power spectral slopes than the underlying atmospheric structure. Additional effects arise because of the non-stationarity of the atmosphere. The SHARC atmospheric radiance code is used to model both equilibrium and non-equilibrium radiance and radiance fluctuation statistics. It predicts two dimensional radiance spatial covariance ... |
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| Development of Atmospheric Infrared Emission Models |
19 DEC 1997 |
79 pages |
| Authors:
J. W. Duff; J. H. Gruninger; R. L. Sundberg; P. K. Acharya; S. M. Adler-Golden; A. Berk; L. S. Bernstein; D. C. Robertson; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This report describes the development of atmospheric infrared (IR) radiance models to describe atmospheric NLTE radiation and structure in the IR spectral region for arbitrary diurnal conditions, Several of the models have been included into the suite of standard Air Force atmospheric radiation computer models. These models calculate the radiation from quiescent, auroral, and structured atmospheres in the 2-40 microns spectral region for arbitrary paths above 30 km under nighttime, ... |
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| Kinetic Parameters for OH Nightglow Modeling Consistent with Recent Laboratory Measurements |
1997 |
22 pages |
| Authors:
Steven Adler-Golden; SPECTRAL SCIENCES INC BURLINGTON MA
|
| An improved kinetic model for the Meinel bands of OH has been constructed from rate constants and Einstein A coefficients derived in recent laboratory experiments. Using a semiempirical parameterization of the state-to-state rate constants for OH(v) quenching by O2, the absolute OH(v) nightglow radiances are modeled to within the accuracies of the atmospheric constituent concentrations and the radiometric calibrations. Collisional quenching is found to be predominantly multiquantum at high v ... |
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| Gallium Arsenide Semiconductor-Laser Multigas Analyzer (GASMAN) |
SEP 1996 |
24 pages |
| Authors:
Jamine Lee; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The U. S. Army requires an instrument for monitoring gaseous by- products, including HCL, NO2, CO2, CO, etc. generated by newly developed gunpowder and combustion fuels, and in evaluating their threats to the health of soldiers. It is desired to perform simultaneous real time monitoring of these gas concentrations in ambient air with detection sensitivities at or below the Threshold Limit Value (TLV) levels. This Phase II SBIR final report ... |
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| Research into Artificially Induced Atmospheric Disturbances |
30 JUN 96 |
56 pages |
| Authors:
James W. Duff; Fritz Bien; SPECTRAL SCIENCES INC BURLINGTON MA
|
| A detailed chemical kinetics model describing the interaction of an electron beam with the atmsophere is used to investigate N(4S), N(2D) and N(2P) formation and the subsequent reaction of metastable N atoms with O2 on NO formation and emission during the EXCEDE III artificial auroral experiment. Of particular significance is the result that rotationally hot NO can be explained by the reaction of nonthermal N(4S) atoms with O2. The rate ... |
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| User's Manual for SAMM, SHARC And MODTRAN Merged |
30 APR 96 |
135 pages |
| Authors:
R. D. Sharma; J. H. Brown; A. Berk; P. K. Acharya; J. Gruninger; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The SAMM, SHARC And MODTRAN Merged model calculates atmospheric radiance and transmission over the 1 - 40 micrometers spectral region for arbitrary lines of sight (LOS) from the ground through the thermosphere, 300 km altitude. It models radiation due to non-local thermodynamic equilibrium (non- LTE) molecular emissions. the dominant source at the higher altitudes. In the lower atmosphere, LOS bending due to refraction is modeled. Molecular and aerosol scattering is ... |
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| ADDITION OF A CORRELATED-K CAPABILITY TO MODTRAN, |
APR 1996 |
|
| Authors:
L. S. Bernstein; A. Berk; D. D. Robertson; P. K. ACHARYA; G. P. Anderson; J. H. CHETWYND; SPECTRAL SCIENCES INC BURLINGTON MA
|
 | (U) THIS PAPER DESCRIBES THE APPROACH USED TO ADD A CORRELATED-K (CK) CAPABILITY TO THE MODTRAN ATMOSPHERIC TRANSMITTANCE.RADIANCE COMPUTER CODE WITH THE OBJECTIVE OF PROVIDING AN ACCURATE AND FAST MEANS FOR EVALUATION OF THE EFFECTS OF VOLCANIC AEROSOLS AND CLOUDS ON ATMOSPHERIC RADIATIVE HEATING/COOLING AND ON RETRIEVALS OF SPECIES CONCENTRATION PROFILES. A MONTE CARLO LINE-BY-LINE SPECTRAL SIMULATION IS USED TO GENERATE THE CK ABSORPTION COEFFICIENT DISTRIBUTIONS. A COMPACT DATABASE REPRESENTATION ... |
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| Analysis of N(2D) and N(2P) Emissions Observed During an Artificial Auroral Experiment |
JUL 95 |
21 pages |
| Authors:
James W. Duff; Fritz Bien; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The EXCEDE III rocketborne electron beam experiment was successfully launched from White Sands Missile Range on April 27, 1990. An 18 A, 2.4 keV electron beam was pulsed along the Earth's magnetic field lines over an altitude range of 60 to 115 km. Measurements were made of 5200 A N(2D), 3466 A N(2P), as well as the 3914 A (0,0) and 5228 A (0,3) N2+ first negative band emissions, between ... |
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| Research into Artificially Induced Atmospheric Disturbances |
JUN 94 |
27 pages |
| Authors:
James W. Duff; Fritz Bien; SPECTRAL SCIENCES INC BURLINGTON MA
|
| A detailed chemical kinetics model describing the interaction of an electron beam with the atmosphere is used to study the effects of the reaction of translationally hot N(45) atoms with O2 on NO formation and emission during the EXCEDE III artificially auroral experiment. The rate constants and vibrational distributions for rotationally hot NO are obtained from extensive quasiclassical trajectory calculations for the N(4S) + O2 reaction using realistic ab initio ... |
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| Optimization of Atmospheric Radiance Algorithms for Remote Sensing: MODTRAN upgrades and Applications |
26 MAY 1994 |
9 pages |
| Authors:
P. Acharya; L. Bernstein; A. Berk; S. Adler-Golden; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This report summarizes the work performed by Spectral Sciences Inc. (SSI) during FY under the SERDP program for atmospheric radiance algorithm optimization. The task consisted of (1) adding infrared CFC cross sections and concentration profiles to MODTRAN for transmittance and radiance calculations, and (2) investigation the use of MODTRAN for radiative flux calculations, as a step towards assessing the effects of flux alterations brought about ... |
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| Mesospheric Water Vapor Sounding Using Earth-Limb Pure-Rotational Emission in the LWIR, |
03 SEP 1993 |
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| Authors:
Steven Adler-Golden; Piali De; Donald Smith; Anthony D'Agati; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Limb sounding of mesospheric water vapor using pure rotational emission in the long-wavelength infrared region has been demonstrated using data from the ELC-1 rocket experiment, launched in October, 1983. By simultaneously analyzing Hsub2O emission at 23-29 microns and COsub2 emission in the nu sub 2 band region, effects due to uncertainties in the atmospheric temperature and instrument calibration are minimized. The Hsub2O profile obtained from ELC-1 is consistent with other ... |
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| SHARC-3 Calculations of Atmospheric IR Radiance in the Solar Terminator Region |
02 JUL 93 |
23 pages |
| Authors:
S. M. Adler-Golden; M. W. Matthew; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The Air Force SHARC-3 Atmospheric IR radiance code has been used to simulate CO2, O3, and OH limb radiances observed in the solar terminator region during the 1977 SPIRE and 1991 CIRRIS-1A experiments. These calculations represent the first direct comparisons with field data using the new multiple- profiles and multiple-atmospheres features in SHARC-3. The good agreement between the SHARC-3 predictions and the data provide substantial validation of the kinetic and ... |
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| Upgraded Line-of-Sight Geometry Package and Band Model Parameters for MODTRAN |
MAY 93 |
22 pages |
| Authors:
P. K. Acharya; D. C. Robertson; A. Berk; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The MODTRAN atmospheric transmittance and radiance code was upgraded with new band model parameters calculated using the HITRAN-92 line atlas. The (1/d) band model parameters for O sub 3 were adjusted to give better agreement with the corresponding line-by-line FASCOD3 calculations for long paths in the 20-50 km altitude region. More accurate line-of-sight (LOS) geometry routines were incorporated for greater consistency between the geometry parameters. Furthermore, MODTRAN can now handle ... |
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| The Theory Behind the SOCRATES Code |
06 AUG 92 |
88 pages |
| Authors:
J. B. Elgin; L. S. Bernstein; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The SOCRATES contamination model is described at length. The model allows for unsteady or steady simulation of contamination aboard a spacecraft via the direct simulation Monte Carlo method. The basis for the model is discussed, and sample calculations are given for an RCS engine firing at 320 kilometer altitude for three different orientations. These calculations are compared to visible data in the 6300 A region which is attributed to the ... |
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| Data Analysis for Bark and Leaf Reflectance Measurements |
JUN 92 |
54 pages |
| Authors:
J. H. Gruninger; D. C. Robertson; M. M. Pervaiz; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This study addresses the incorporation of the effects associated with natural environments and backgrounds in the simulation models which are essential to the development of smart weapons. The effects of leaves and bark in the visible and IR spectral regions is discussed and a computational model is presented for the bi-directional reflectance (BRDF) measurement carried out. A singular value decomposition (SVD) technique is used to justify an important model assumption, ... |
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| Data Analysis for Bark and Leaf Reflectance Measurements |
JUN 92 |
52 pages |
| Authors:
J. H. Gruninger; D. C. Robertson; M. M. Pervaiz; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This report addresses the incorporation of the effects associated with natural environments and backgrounds in the simulation models which are essential to the development of smart weapons. The effect of leaves and bark in the visible and IR spectral regions is discussed and a computational model is presented for the bi-directional reflectance (BRDF) measurement carried out by Surface Optics Corporation (SOC). A singular value decomposition (SVD) technique is used to ... |
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| Analysis of H sub 2 O Infrared Radiance Measured during the ELC-1 Rocket Experiment |
15 MAY 92 |
26 pages |
| Authors:
P. De; S. M. Adler-Golden; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This report presents an analysis of selected long-wavelength infrared (LWIR) limb radiance data measured in the ELC-1 radiometer experiment, launched on October 25, 1983, from the White Sands Missile Range, NM at local time 0426 hrs. From the CO sub 2 nu sub 2 band emission, information on the mesospheric profile and the radiometer absolute calibration is extracted. The results are combined with a measurement of water vapor rotational emission ... |
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| Raman Hydrogen Sensor, Phase 1 |
NOV 91 |
39 pages |
| Authors:
S. M. Adler-Golden; J. Lee; SPECTRAL SCIENCES INC BURLINGTON MA
|
| A fast-response (0.25 sec or faster) gaseous hydrogen (H2) sensor is required in process air ducting at AEDC to support the testing of engines for the National Aerospace Plane. A sensitivity of around 0.1% H2, over a sample pressure range of 2 to 15 PSIA is desired at humidity levels of up to 20% by weight. In the Phase I Raman Hydrogen Sensor Program, Spectral Sciences, Inc. (SSI) has built ... |
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| Investigations into Atmospheric Radiative Processes in the 50 - 300 km Regime |
30 APR 91 |
112 pages |
| Authors:
D. C. Robertson; P. K. Acharya; S. M. Adler-Golden; L. S. Bernstein; F. Bien; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This study describes research into high-altitude infrared (IR) radiance models to describe sources of high-altitude NLTE radiation in the IR spectral region. Many of the models have been combined into SHARC, the Strategic High Altitude Radiance Code. SHARC calculates the radiation from quiescent and auroral atmospheres in the 2-40 micrometer spectral region for arbitrary paths that lie above 50 km, including space viewing. In related activities, analyses of data taken ... |
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| Surface Response to Cloud Shadowing |
20 FEB 91 |
|
| Authors:
A. Berk; D. C. Robertson; P. K. Acharya; SPECTRAL SCIENCES INC BURLINGTON MA
|
| This study investigated the response of surface temperature to cloud shadows. A quantitative model applicable to IR backgrounds was developed. Time- dependent heat flow and energy budget equations have been solved to determine the diurnal variation in surface ground temperatures for a dry, sandy soil with a simple vegetation layer under various cloud conditions. Ground temperatures were determined to vary up to 2K in the first minute following cloud shadowing ... |
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| Strategy Combining Regionally Adapted Processes (SCRAP) |
30 JAN 91 |
|
| Authors:
M. M. Pervaiz; SPECTRAL SCIENCES INC BURLINGTON MA
|
| A local Navier-Stokes (NS) algorithm to simulate a physically and geometrically complex flow is presented. The domain is subdivided into blocks which facilitate the generation of global mesh and splitting of schemes. Basic types are inviscid, viscous and interaction blocks. In the interaction block a local procedure is used to decide whether to use NS or Euler equations. Each block also employs subdomain adaptation to capture small scale features. The ... |
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| Description of the Strategic High-Altitude Atmospheric Radiation Code (SHARC) |
27 NOV 90 |
|
| Authors:
J. W. Duff; R. L. Sundberg; J. H. Gruninger; L. S. Bernstein; D. C. Robertson; R. J. Healey; SPECTRAL SCIENCES INC BURLINGTON MA
|
| The report describes an upgraded version of the strategic high- altitude radiance code, SHARC-2. SHARC calculates atmospheric radiance and transmittance over the 2-40 micrometer spectral region for arbitrary paths within 50 and 300 km altitude, including space viewing. It models radiation due to NLTE (Non-Local Thermodynamic Equilibrium molecular emissions which are the dominant sources at these altitudes. This new version, which is now ready for distribution, has been upgraded to ... |
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| OH Contamination Flux Estimates |
10 SEP 90 |
|
| Authors:
James B. Elgin; SPECTRAL SCIENCES INC BURLINGTON MA
|
| Contamination on a cryogenic mirror is considered from two sources. The first source is the deposition of OH formed by the gas phase reaction of atmospheric atomic oxygen with outgassing H2 coolant. The second source is deposition of OH formed by surface reaction of atomic oxygen and atomic hydrogen from the atmosphere. Variations in atmospheric temperature and direction of the mirror with respect to the ram are evaluated. It is ... |
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| Limb Retrieval Capability of the Spirit 3 Radiometer |
17 AUG 90 |
|
| Authors:
A. S. Zachor; SPECTRAL SCIENCES INC BURLINGTON MA
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| Noise levels were predicted as a function of tangent height for limb radiance profiles that will be measured by the SPIRIT 3 radiometer. Synthetic data was inverted to quantify the corresponding uncertainties in retrieved volume emission rates, and to quantify expected errors due to horizontal variations in atmospheric density. A new computer routine for derivative-free Abel inversion is described. |
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| Thermal Imaging Assessment |
22 FEB 90 |
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| Authors:
S. C. Richtsmeier; M. E. Gersh; SPECTRAL SCIENCES INC BURLINGTON MA
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| This report investigates the feasibility of using advanced focal plane arrays coupled with telescopes as thermal imaging systems for orbiting targets. The infrared signature of a target will depend on a host of intercoupled factors including (1) surface properties (temperature, emissivity, reflectivity), (2) illumination conditions (solar position, earth background temperature), (3) target orientation, location, and dynamics with respect to the observer, and (4) atmospheric conditions along the illumination and target- ... |
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| Atmospherically Induced Optical Contamination from Orbiting Thrusters |
19 SEP 89 |
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| Authors:
J. B. Elgin; M. Tautz; SPECTRAL SCIENCES INC BURLINGTON MA
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| This paper presents the result of the SOCRATES (Shuttle Orbiter Contamination Representation Accounting for Transiently Emitted Species) code which has been developed to assess the effects of contamination of measurements aboard spacecraft in low earth orbit. SOCRATES is a Monte Carlo code which includes in its present version scattering, collisions leading to kinetic-to- vibrational energy transfer, and reactive collisions. The application of this code to actual measurements aboard spacecraft in ... |
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| MODTRAN: A Moderate Resolution Model for LOWTRAN 7 |
30 APR 89 |
48 pages |
| Authors:
Alexander Berk; Lawrence S. Bernstein; David C. Robertson; SPECTRAL SCIENCES INC BURLINGTON MA
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| The LOWTRAN computer codes, with LOWTRAN 7 being the most current version, are widely used to calculate atmospheric transmittance and/or radiance in the infrared, visible and near ultraviolet spectral regions; LOWTRAN 7 has been extended to include the microwave spectral region. The code is easily used, runs quickly and provides the user with a wide variety of atmospheric models and options. Its spectral resolution is 20 1/cm Full Width/Half Maximum ... |
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| HCl Monitor. Phase 2 |
MAR 89 |
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| Authors:
L. S. Bernstein; F. Bien; W. K. Cheng; R. P. Domingue; S. C. Richtsmeier; SPECTRAL SCIENCES INC BURLINGTON MA
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| At present, the short- and long-term environmental impacts of massive HC1 releases from the Space Shuttle and other solid-rocket launches are not well characterized. It is important to measure the atmospheric HC1 content in both the vapor and aerosol forms. Spectral Sciences, Inc., (SSI) has developed a combination vapor-aerosol HC1 monitor under a Phase II SBIR (Small Business Innovative Research program) contract from the Air Force Engineering Services Center (AFESC), ... |
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| The Strategic High-Altitude Atmospheric Radiation Code (SHARC) User Instructions |
03 FEB 89 |
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| Authors:
R. L. Sundberg; J. W. Duff; L. S. Bernstein; P. K. Acharya; J. H. Gruninger; SPECTRAL SCIENCES INC BURLINGTON MA
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| This report describes how to implement and use the Strategic High- Altitude Radiance Code (SHARC). SHARC calculates atmospheric radiation for paths from 60 to 300 km altitude in the 2-40 micron spectral region. It models radiation due to NLTE (Non-Local Thermodynamic Equilibrium) molecular emissions which are the dominant sources at these altitudes. This initial version of SHARC includes the five strongest IR radiators, CO2, NO, O3, H20, and CO. The ... |
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