A. Stair - Academia.edu (original) (raw)
Papers by A. Stair
Journal de Chimie Physique, 1967
2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542), 2001
The strong polarization signatures of many man-made surface targets suggest their use for detecti... more The strong polarization signatures of many man-made surface targets suggest their use for detection and discrimination in satellite reconnaissance and surveillance. Since thin clouds on average cover more than 40% of the Earth's surface, they are likely to contribute frequently to the obscuration and apparent polarization of such targets. We have carried out theoretical calculations of cloud particle scattering functions
Journal of Atmospheric and Oceanic Technology, 2009
This paper describes a newly designed Sun and Aureole Measurement (SAM) aureolegraph and the firs... more This paper describes a newly designed Sun and Aureole Measurement (SAM) aureolegraph and the first results obtained with this instrument. SAM measurements of solar aureoles produced by cirrus and cumulus clouds were taken at the Atmospheric Radiation Measurement Program (ARM) Central Facility in Oklahoma during field experiments conducted in June 2007 and compared with simultaneous measurements from a variety of other ground-based instruments. A theoretical relationship between the slope of the aureole profile and the size distribution of spherical cloud particles is based on approximating scattering as due solely to diffraction, which in turn is approximated using a rectangle function. When the particle size distribution is expressed as a power-law function of radius, the aureole radiance as a function of angle from the center of the solar disk also follows a power law, with the sum of the two powers being −5. This result also holds if diffraction is modeled with an Airy function. ...
1999 IEEE Aerospace Conference. Proceedings (Cat. No.99TH8403), 1999
ABSTRACT Ground-based measurements of cloud properties were made in conjunction with A-Train over... more ABSTRACT Ground-based measurements of cloud properties were made in conjunction with A-Train overpasses to enable additional correlative comparisons with CALIPSO and other space-based measurements. The ground-based SAM (Sun and Aureole Measurement) instrument provides information on optical depth and the size distribution of particles in the 5 to 75 micrometer range in the column between the Sun and the instrument. The SAM instrument was sited so that the line-of-sight would intercept a cirrus layer at roughly the same location that the CALIPSO nadir beams would intercept the SAM viewing field. This paper provides examples of the comparison of the data collected on two separate days.
UNCLASS IFI IO 2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION I AVAILABILITY OF REPORT 20.... more UNCLASS IFI IO 2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION I AVAILABILITY OF REPORT 20. DISTRIBUTION I AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION MUNCLASSIFIEDIUNLIMITED 13 SAME AS RPT. (3IDTIC USERS UNCLASSIFIED 22a NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Inchud Area Code) 22c. OFFICE SYMBOL MAJOR AMOS OTIS (202)767-4971 AFOSR/XO DD FORM 1473. s4 MAR B3 APR edition may be used until exhausted SECURITY CLASSIFICATION OF THIS PAGE All other edeto is are obsolete UNCLASSIFIED SECURITY CLASIFICATIOi OF THIS PA0E • 19. (ConLinued)-5)This pilot program was judged a success by both the Scholars and their Laboratory Associates. Their comments were solicited by questionnaire and are included. The Scholars were judged to be beneficial to the Laboratory. The opportunity of having new Research people on a short term basis was felt to be very stimulating and worth while. Their interaction with the Laboratory was very positive. At the initiation of this program, travel funds were provided only for travel to the Laboratory site at the start of the appointment and return funds at the end. Some difficulties were subsequently encountered in transferring funds and authorizing travel to technical meetings. This caused some distress among the Scholars. However, overall, the Scholars felt their experiences at the Laboratory were constructive steps in their professional development.
Springer Series in Optical Sciences, 1983
RAMOS (Russian American Observational Satellites), scheduled for launch in 2009, is a joint missi... more RAMOS (Russian American Observational Satellites), scheduled for launch in 2009, is a joint mission of the Russian Federation and the United States of America. Two low earth-orbit satellites with complementary instrument suites will fly in tandem orbits at an altitude of ˜ 500 km and a variable mean separation of ˜ 300 km. The satellites will be capable of simultaneous viewing of the same location on or above the earth's surface, allowing for real-time stereoscopic imaging of the earth's environment. The sensors suite is composed of pointable multifiltered infrared (1.5 - 7.5 mu m), visible, and ultraviolet imaging radiometers. The nominal spatial footprints are ˜ 100 m at the earth's surface. One satellite will have polarization capability, and the other will have an infrared spectrometer built into the radiometer. During its projected two-year lifetime, RAMOS will be used as a testbed for a variety of space-based measurements of the terrestrial environment that requ...
All Graduate Theses and Dissertations, 2008
To understand and model the energetics of the Sun-Earth connection, measurements of specific atmo... more To understand and model the energetics of the Sun-Earth connection, measurements of specific atmospheric molecules are beneficial. Our objective is to formulate an algorithm to derive temporally varying atmospheric water vapor concentrations as a function of altitude, latitude, and longitude from solar irradiance absorption measurements. The Visidyne SAM instrument is used to study the size distribution of cloud particles. By introducing a spectrometer to the SAM instrument, column water vapor values are produced as an additional data product. A new model algorithm was developed and tested against existing algorithms. Through a least-squares analysis, the new algorithm showed an improvement of a factor of up to 23 over the industry standard. A test was also conducted to ascertain which water absorption bandpass produces the least error. Through these tests an improved model algorithm has been produced.
Journal of Geophysical Research, 1978
Prior to the study we report here it had been thought that the sole undisturbed nighttime mechani... more Prior to the study we report here it had been thought that the sole undisturbed nighttime mechanisms for producing CO•. vibrationally excited in the v3 mode were (1) vibrational excitation by thermal collisions and (2) absorption of 4.3-um earthshine by CO•.. In this paper we show detailed evidence that the mechanism OH(v) + N•. • OH(v-1) + N•. •, followed by N•." + CO•.-• N•. + CO4v0, may be the dominant excitation mechanism for producing CO•.(v0 in the 85-km altitude region. The evidence is based on 4.3-•tm zenith radiance data obtained on April 11, 1974, via a rocket-borne liquid N•. nitrogen cooled circular variable-filtered radiometer. The rocket was launched at night from the Poker Flat Research Range, Alaska. The data were obtained under conditions of essentially zero auroral activity. There is a feature in these data near 85-km altitude which can be explained by the mechanism OH(v)• N•." • CO,(its)-} CO•. q-hp4.a,m. A column transfer of 0.12 ñ 0.025 erg/cm 2 s from OH • to N•. is required to explain the feature. An alternate explanation on the basis of just the mechanisms I and 2 which are cited above requires that there existed a very unlikely mesospheric temperature profile on the evening of April 11, 1974. A similar nonauroral feature appears consistently near 85 km in preliminary 4.3-um zenith data
… : proceedings of a …, 1971
Title: Infrared Investigations of Aurora and Airglow. Authors: Stair, AT, Jr.; Huppi, ER; Sandfor... more Title: Infrared Investigations of Aurora and Airglow. Authors: Stair, AT, Jr.; Huppi, ER; Sandford, BP; Murphy, RE; O'Neil, RR; Hart, AM; Huppi, RJ; Pendleton, WR. Publication: The Radiating Atmosphere, Proceedings of a Symposium, org. ...
Acta Astronautica, 1992
Venting of excess water from spacecraft, besides leading to physical and optical contamination, h... more Venting of excess water from spacecraft, besides leading to physical and optical contamination, has application to studies of the transport of outgas, the interaction of the vehicle with the ionospheric plasma, the energy balance of cometary material, and the uses of liquid streams in space operations. Analysis of intensified video images of a twilight venting of fuel-cell product water from Shuttle Orbiter shows that the initially coherent stream forms within about 0.1 s into a ~ 10°-quasiconical cloud of irregular, polydisperse ice/water droplets (the product of cavitational rupturing) and submicron ice spherules (from partial recondensation of overexpanded vacuum-evaporated water gas). The retrograde velocities of both particle components are experimentally indistinguishable from that calculated for the dumped liquid. The visible radiance distribution of the ~ 2 ½ km of wake trail detectable in projections to a precisely-tracked groundbased telescope becomes consistent with predictions from the energy balance of the submicron particles when a sublimation rate-enhancing correction to their emissivities (and thus temperature), arising from the progressive roughening of their surfaces, is applied. A similar calculation of the thermal radiation, scattering and absorption of earthshine and sunlight, and sublimation of the larger (~ mm-radius) particles prominent in the onboard photographs shows that their lifetimes are several orbital periods. The relative discrete and spatially-continuous irradiances in images from the two camera locations impose a rough joint constraint on the fraction of water vapor that recondenses and the mean geometric scattering cross-section of the stream-fragmentation droplets.
Geophysical Research Letters, 1990
... Received 5 June 1990; accepted 20 August 1990; . Citation: Murad, E., et al. (1990), Visible ... more ... Received 5 June 1990; accepted 20 August 1990; . Citation: Murad, E., et al. (1990), Visible light emission excited by interaction of space shuttle exhaust with the atmosphere, Geophys. Res. Lett., 17(12), 22052208, doi:10.1029/GL017i012p02205. Cited By. ...
Journal of the Optical Society of America, 1961
Photosensitive instruments which measure absolute irradiance in four spectral bands (2000-2500 A,... more Photosensitive instruments which measure absolute irradiance in four spectral bands (2000-2500 A, 2500-4000 A, 4000-5000 A, and 5000-10 000 A) are described. One instrument is used to cover each range. The basic unit is a prism-type spectrometer that weighs 2 lb ...
The Journal of Chemical Physics, 1957
The Raman spectra of liquid sym-trioxane contained in a sealed, electrically heated Raman tube, a... more The Raman spectra of liquid sym-trioxane contained in a sealed, electrically heated Raman tube, and of a crystalline aggregate and a single crystal of the compound, have been photographed with a 3-prism glass spectrograph of reciprocal linear dispersion 15 A/mm at 4358 A. The infrared spectrum of trioxane vapor has been reinvestigated with the aid of a 1-m absorption cell
19th Aerospace Sciences Meeting, 1981
The Russian American Observational Satellites (RAMOS) program represents a new direction for coop... more The Russian American Observational Satellites (RAMOS) program represents a new direction for cooperative space-based research and development between the Russian Federation and the United States. The objective of the RAMOS project is to engage in a joint program employing simultaneous stereo-optical techniques from two co-orbiting satellites to address global defense and environmental issues. The satellites are equipped with American- and
Journal of Geophysical Research, 1986
Applied Optics, 1974
Atmospheric emission spectra in the 700-2800-cm(-1) region have been measured from an aircraft at... more Atmospheric emission spectra in the 700-2800-cm(-1) region have been measured from an aircraft at 9.45-11.89-km altitudes. All measurements were made viewing at the zenith at a spectral resolution of 2 cm(-1). The measurements were obtained using interferometer spectrometers, and the atmospheric radiation was modulated with a liquid nitrogen cooled chopper that eliminated the thermal emission of the spectrometers from the measured spectra. Essentially all the features of the spectra can be identified with known constituents of the atmosphere. The comparison with a theoretical emission calculation using a tropical atmospheric model was satisfactory except for the H(2)O that showed a smaller concentration by a factor of 5 than was assumed in the model at these altitudes.
Applied Optics, 1971
The chemiluminescent nature of the reaction N + O(2) ? NO + O followed by N + NO ? N(2) + O has b... more The chemiluminescent nature of the reaction N + O(2) ? NO + O followed by N + NO ? N(2) + O has been investigated in the steady state through detection of characteristic infrared radiation emitted by NO molecules. Both Deltaupsilon = 1 radiation at 5.4 micro and Deltaupsilon = 2 at 2.7 mu exhibit linear dependence on O(2) pressure. In the case of the overtone, low-resolution spectra are obtained at several O(2) pressures, and it is shown that under the experimental conditions reported here the spectra should closely reflect the initial vibrational distribution of the NO molecules as they are formed. From the spectral results we are able to estimate an overtone quantum efficiency for the reaction N + O(2) ? NO(double dagger) + O. Depending upon the experimentally reported value of the rate for this reaction, the quantum efficiency is between 0.2 and 0.5.
Journal de Chimie Physique, 1967
2001 IEEE Aerospace Conference Proceedings (Cat. No.01TH8542), 2001
The strong polarization signatures of many man-made surface targets suggest their use for detecti... more The strong polarization signatures of many man-made surface targets suggest their use for detection and discrimination in satellite reconnaissance and surveillance. Since thin clouds on average cover more than 40% of the Earth's surface, they are likely to contribute frequently to the obscuration and apparent polarization of such targets. We have carried out theoretical calculations of cloud particle scattering functions
Journal of Atmospheric and Oceanic Technology, 2009
This paper describes a newly designed Sun and Aureole Measurement (SAM) aureolegraph and the firs... more This paper describes a newly designed Sun and Aureole Measurement (SAM) aureolegraph and the first results obtained with this instrument. SAM measurements of solar aureoles produced by cirrus and cumulus clouds were taken at the Atmospheric Radiation Measurement Program (ARM) Central Facility in Oklahoma during field experiments conducted in June 2007 and compared with simultaneous measurements from a variety of other ground-based instruments. A theoretical relationship between the slope of the aureole profile and the size distribution of spherical cloud particles is based on approximating scattering as due solely to diffraction, which in turn is approximated using a rectangle function. When the particle size distribution is expressed as a power-law function of radius, the aureole radiance as a function of angle from the center of the solar disk also follows a power law, with the sum of the two powers being −5. This result also holds if diffraction is modeled with an Airy function. ...
1999 IEEE Aerospace Conference. Proceedings (Cat. No.99TH8403), 1999
ABSTRACT Ground-based measurements of cloud properties were made in conjunction with A-Train over... more ABSTRACT Ground-based measurements of cloud properties were made in conjunction with A-Train overpasses to enable additional correlative comparisons with CALIPSO and other space-based measurements. The ground-based SAM (Sun and Aureole Measurement) instrument provides information on optical depth and the size distribution of particles in the 5 to 75 micrometer range in the column between the Sun and the instrument. The SAM instrument was sited so that the line-of-sight would intercept a cirrus layer at roughly the same location that the CALIPSO nadir beams would intercept the SAM viewing field. This paper provides examples of the comparison of the data collected on two separate days.
UNCLASS IFI IO 2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION I AVAILABILITY OF REPORT 20.... more UNCLASS IFI IO 2a. SECURITY CLASSIFICATION AUTHORITY 3. DISTRIBUTION I AVAILABILITY OF REPORT 20. DISTRIBUTION I AVAILABILITY OF ABSTRACT 21. ABSTRACT SECURITY CLASSIFICATION MUNCLASSIFIEDIUNLIMITED 13 SAME AS RPT. (3IDTIC USERS UNCLASSIFIED 22a NAME OF RESPONSIBLE INDIVIDUAL 22b TELEPHONE (Inchud Area Code) 22c. OFFICE SYMBOL MAJOR AMOS OTIS (202)767-4971 AFOSR/XO DD FORM 1473. s4 MAR B3 APR edition may be used until exhausted SECURITY CLASSIFICATION OF THIS PAGE All other edeto is are obsolete UNCLASSIFIED SECURITY CLASIFICATIOi OF THIS PA0E • 19. (ConLinued)-5)This pilot program was judged a success by both the Scholars and their Laboratory Associates. Their comments were solicited by questionnaire and are included. The Scholars were judged to be beneficial to the Laboratory. The opportunity of having new Research people on a short term basis was felt to be very stimulating and worth while. Their interaction with the Laboratory was very positive. At the initiation of this program, travel funds were provided only for travel to the Laboratory site at the start of the appointment and return funds at the end. Some difficulties were subsequently encountered in transferring funds and authorizing travel to technical meetings. This caused some distress among the Scholars. However, overall, the Scholars felt their experiences at the Laboratory were constructive steps in their professional development.
Springer Series in Optical Sciences, 1983
RAMOS (Russian American Observational Satellites), scheduled for launch in 2009, is a joint missi... more RAMOS (Russian American Observational Satellites), scheduled for launch in 2009, is a joint mission of the Russian Federation and the United States of America. Two low earth-orbit satellites with complementary instrument suites will fly in tandem orbits at an altitude of ˜ 500 km and a variable mean separation of ˜ 300 km. The satellites will be capable of simultaneous viewing of the same location on or above the earth's surface, allowing for real-time stereoscopic imaging of the earth's environment. The sensors suite is composed of pointable multifiltered infrared (1.5 - 7.5 mu m), visible, and ultraviolet imaging radiometers. The nominal spatial footprints are ˜ 100 m at the earth's surface. One satellite will have polarization capability, and the other will have an infrared spectrometer built into the radiometer. During its projected two-year lifetime, RAMOS will be used as a testbed for a variety of space-based measurements of the terrestrial environment that requ...
All Graduate Theses and Dissertations, 2008
To understand and model the energetics of the Sun-Earth connection, measurements of specific atmo... more To understand and model the energetics of the Sun-Earth connection, measurements of specific atmospheric molecules are beneficial. Our objective is to formulate an algorithm to derive temporally varying atmospheric water vapor concentrations as a function of altitude, latitude, and longitude from solar irradiance absorption measurements. The Visidyne SAM instrument is used to study the size distribution of cloud particles. By introducing a spectrometer to the SAM instrument, column water vapor values are produced as an additional data product. A new model algorithm was developed and tested against existing algorithms. Through a least-squares analysis, the new algorithm showed an improvement of a factor of up to 23 over the industry standard. A test was also conducted to ascertain which water absorption bandpass produces the least error. Through these tests an improved model algorithm has been produced.
Journal of Geophysical Research, 1978
Prior to the study we report here it had been thought that the sole undisturbed nighttime mechani... more Prior to the study we report here it had been thought that the sole undisturbed nighttime mechanisms for producing CO•. vibrationally excited in the v3 mode were (1) vibrational excitation by thermal collisions and (2) absorption of 4.3-um earthshine by CO•.. In this paper we show detailed evidence that the mechanism OH(v) + N•. • OH(v-1) + N•. •, followed by N•." + CO•.-• N•. + CO4v0, may be the dominant excitation mechanism for producing CO•.(v0 in the 85-km altitude region. The evidence is based on 4.3-•tm zenith radiance data obtained on April 11, 1974, via a rocket-borne liquid N•. nitrogen cooled circular variable-filtered radiometer. The rocket was launched at night from the Poker Flat Research Range, Alaska. The data were obtained under conditions of essentially zero auroral activity. There is a feature in these data near 85-km altitude which can be explained by the mechanism OH(v)• N•." • CO,(its)-} CO•. q-hp4.a,m. A column transfer of 0.12 ñ 0.025 erg/cm 2 s from OH • to N•. is required to explain the feature. An alternate explanation on the basis of just the mechanisms I and 2 which are cited above requires that there existed a very unlikely mesospheric temperature profile on the evening of April 11, 1974. A similar nonauroral feature appears consistently near 85 km in preliminary 4.3-um zenith data
… : proceedings of a …, 1971
Title: Infrared Investigations of Aurora and Airglow. Authors: Stair, AT, Jr.; Huppi, ER; Sandfor... more Title: Infrared Investigations of Aurora and Airglow. Authors: Stair, AT, Jr.; Huppi, ER; Sandford, BP; Murphy, RE; O'Neil, RR; Hart, AM; Huppi, RJ; Pendleton, WR. Publication: The Radiating Atmosphere, Proceedings of a Symposium, org. ...
Acta Astronautica, 1992
Venting of excess water from spacecraft, besides leading to physical and optical contamination, h... more Venting of excess water from spacecraft, besides leading to physical and optical contamination, has application to studies of the transport of outgas, the interaction of the vehicle with the ionospheric plasma, the energy balance of cometary material, and the uses of liquid streams in space operations. Analysis of intensified video images of a twilight venting of fuel-cell product water from Shuttle Orbiter shows that the initially coherent stream forms within about 0.1 s into a ~ 10°-quasiconical cloud of irregular, polydisperse ice/water droplets (the product of cavitational rupturing) and submicron ice spherules (from partial recondensation of overexpanded vacuum-evaporated water gas). The retrograde velocities of both particle components are experimentally indistinguishable from that calculated for the dumped liquid. The visible radiance distribution of the ~ 2 ½ km of wake trail detectable in projections to a precisely-tracked groundbased telescope becomes consistent with predictions from the energy balance of the submicron particles when a sublimation rate-enhancing correction to their emissivities (and thus temperature), arising from the progressive roughening of their surfaces, is applied. A similar calculation of the thermal radiation, scattering and absorption of earthshine and sunlight, and sublimation of the larger (~ mm-radius) particles prominent in the onboard photographs shows that their lifetimes are several orbital periods. The relative discrete and spatially-continuous irradiances in images from the two camera locations impose a rough joint constraint on the fraction of water vapor that recondenses and the mean geometric scattering cross-section of the stream-fragmentation droplets.
Geophysical Research Letters, 1990
... Received 5 June 1990; accepted 20 August 1990; . Citation: Murad, E., et al. (1990), Visible ... more ... Received 5 June 1990; accepted 20 August 1990; . Citation: Murad, E., et al. (1990), Visible light emission excited by interaction of space shuttle exhaust with the atmosphere, Geophys. Res. Lett., 17(12), 22052208, doi:10.1029/GL017i012p02205. Cited By. ...
Journal of the Optical Society of America, 1961
Photosensitive instruments which measure absolute irradiance in four spectral bands (2000-2500 A,... more Photosensitive instruments which measure absolute irradiance in four spectral bands (2000-2500 A, 2500-4000 A, 4000-5000 A, and 5000-10 000 A) are described. One instrument is used to cover each range. The basic unit is a prism-type spectrometer that weighs 2 lb ...
The Journal of Chemical Physics, 1957
The Raman spectra of liquid sym-trioxane contained in a sealed, electrically heated Raman tube, a... more The Raman spectra of liquid sym-trioxane contained in a sealed, electrically heated Raman tube, and of a crystalline aggregate and a single crystal of the compound, have been photographed with a 3-prism glass spectrograph of reciprocal linear dispersion 15 A/mm at 4358 A. The infrared spectrum of trioxane vapor has been reinvestigated with the aid of a 1-m absorption cell
19th Aerospace Sciences Meeting, 1981
The Russian American Observational Satellites (RAMOS) program represents a new direction for coop... more The Russian American Observational Satellites (RAMOS) program represents a new direction for cooperative space-based research and development between the Russian Federation and the United States. The objective of the RAMOS project is to engage in a joint program employing simultaneous stereo-optical techniques from two co-orbiting satellites to address global defense and environmental issues. The satellites are equipped with American- and
Journal of Geophysical Research, 1986
Applied Optics, 1974
Atmospheric emission spectra in the 700-2800-cm(-1) region have been measured from an aircraft at... more Atmospheric emission spectra in the 700-2800-cm(-1) region have been measured from an aircraft at 9.45-11.89-km altitudes. All measurements were made viewing at the zenith at a spectral resolution of 2 cm(-1). The measurements were obtained using interferometer spectrometers, and the atmospheric radiation was modulated with a liquid nitrogen cooled chopper that eliminated the thermal emission of the spectrometers from the measured spectra. Essentially all the features of the spectra can be identified with known constituents of the atmosphere. The comparison with a theoretical emission calculation using a tropical atmospheric model was satisfactory except for the H(2)O that showed a smaller concentration by a factor of 5 than was assumed in the model at these altitudes.
Applied Optics, 1971
The chemiluminescent nature of the reaction N + O(2) ? NO + O followed by N + NO ? N(2) + O has b... more The chemiluminescent nature of the reaction N + O(2) ? NO + O followed by N + NO ? N(2) + O has been investigated in the steady state through detection of characteristic infrared radiation emitted by NO molecules. Both Deltaupsilon = 1 radiation at 5.4 micro and Deltaupsilon = 2 at 2.7 mu exhibit linear dependence on O(2) pressure. In the case of the overtone, low-resolution spectra are obtained at several O(2) pressures, and it is shown that under the experimental conditions reported here the spectra should closely reflect the initial vibrational distribution of the NO molecules as they are formed. From the spectral results we are able to estimate an overtone quantum efficiency for the reaction N + O(2) ? NO(double dagger) + O. Depending upon the experimentally reported value of the rate for this reaction, the quantum efficiency is between 0.2 and 0.5.