Search NASA⌕ Search

SEARCH · Search NASA

Results for “CARBON MONOXIDE”

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.

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

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

The carbon monoxide abundance in interstellar clouds

The steady-state abundance of carbon monoxide in interstellar clouds is calculated as a function of optical depth, density, and temperature. The molecular reactions which lead to CO can be initiated by the following ion-molecule reactions: H(+) + O yields O(+) + H, C(+) + H2 yields CH2(+) + a photon, and H3(+) + C and O. As the ultraviolet radiation field is attenuated, C(+) is transformed primarily into CO and C I. There are characteristic column densities for the transition to CO corresponding to the optical depths for attenuating this field at different wavelengths. For thick, low-temperature clouds the attenuation of the fields which ionize carbon, sulfur, and heavy metals is important for CO production initiated by H3(+). Complete conversion to CO does not necessarily occur, and considerable neutral carbon may be expected even in optically thick clouds. Comparison of integrated column densities of CO with extinction are in reasonable agreement with observations.

Langer, W.↗
NASA NTRS1995

Carbon Monoxide Isotopes: On the Trail of Galactic Chemical Evolution

From the early days of the discovery of radio emission from carbon monoxide it was realized that it offered unusual potential for under- standing the chemical evolution of the Galaxy and external galaxies through measurements of molecular isotopes. These results bear on stellar nucleosynthesis, star formation, and gases in the interstellar medium. Progress in isotopic radio measurements will be reviewed.

isotopes nucleosynthesis↗
NASA NTRS1981

Submillimeter heterodyne detection of interstellar carbon monoxide at 434 micrometers

Laser heterodyne observations of submillimeter emissions from carbon monoxide in the Orion molecular cloud are reported. High frequency and spatial resolution observations were made at the NASA Infrared Telescope Facility on Mauna Kea by the use of an optically pumped laser local oscillator and quasi-optical Schottky diode mixer for heterodyne detection of the J = 6 - 5 rotational transition of CO at 434 microns. Spectral analysis of the 434-micron emission indicates that the emitting gas is optically thin and is at a temperature above 180 K. Results thus demonstrate the potential contributions of ground-based high-resolution submillimeter astronomy to the study of active regions in interstellar molecular clouds.

Fetterman, H. R.↗
NASA NTRS1994

Electron energy deposition in carbon monoxide gas

A comprehensive set of electron impact cross sections for carbon monoxide molecules is presented on the basis of the most recent experimental measurements and theoretical calculations. The processes by which energetic electrons lose energy in CO gas are analyzed with these input cross sections. The efficiencies are computed of vibrational and electronic excitation, dissociation, ionization, and heating for CO gas with fractional ionization ranging from 0% to 10%. The calculated mean energy per ion pair for neutral CO gas is 32.3 eV, which is in excellent agreement with the experimental value of 32.2 eV. It increases to 35.6 eV at a fractional ionization of 1%, typical of supernovae ejecta.

Liu, Weihong↗
NASA NTRS2015

On the Feasibility of Monitoring Carbon Monoxide in the Lower Troposphere from a Constellation of Northern Hemisphere Geostationary Satellites (PART 1)

By the end of the current decade, there are plans to deploy several geostationary Earth orbit (GEO) satellite missions for atmospheric composition over North America, East Asia and Europe with additional missions proposed. Together, these present the possibility of a constellation of geostationary platforms to achieve continuous time-resolved high-density observations over continental domains for mapping pollutant sources and variability at diurnal and local scales. In this paper, we use a novel approach to sample a very high global resolution model (GEOS-5 at 7 km horizontal resolution) to produce a dataset of synthetic carbon monoxide pollution observations representative of those potentially obtainable from a GEO satellite constellation with predicted measurement sensitivities based on current remote sensing capabilities. Part 1 of this study focuses on the production of simulated synthetic measurements for air quality OSSEs (Observing System Simulation Experiments). We simulate carbon monoxide nadir retrievals using a technique that provides realistic measurements with very low computational cost. We discuss the sampling methodology: the projection of footprints and areas of regard for geostationary geometries over each of the North America, East Asia and Europe regions; the regression method to simulate measurement sensitivity; and the measurement error simulation. A detailed analysis of the simulated observation sensitivity is performed, and limitations of the method are discussed. We also describe impacts from clouds, showing that the efficiency of an instrument making atmospheric composition measurements on a geostationary platform is dependent on the dominant weather regime over a given region and the pixel size resolution. These results demonstrate the viability of the "instrument simulator" step for an OSSE to assess the performance of a constellation of geostationary satellites for air quality measurements.

GEOS-5↗
NASA NTRS2007

Connecting Surface Emissions, Convective Uplifting, and Long-Range Transport of Carbon Monoxide in the Upper Troposphere: New Observations from the Aura Microwave Limb Sounder

Two years of observations of upper tropospheric (UT) carbon monoxide (CO) from the Aura Microwave Limb Sounder are analyzed; in combination with the CO surface emission climatology and data from the NCEP analyses. It is shown that spatial distribution, temporal variation and long-range transport of UT CO are closely related to the surface emissions, deep-convection and horizontal winds. Over the Asian monsoon region, surface emission of CO peaks in boreal spring due to high biomass burning in addition to anthropogenic emission. However, the UT CO peaks in summer when convection is strongest and surface emission of CO is dominated by anthropogenic source. The long-range transport of CO from Southeast Asia across the Pacific to North America, which occurs most frequently during boreal summer, is thus a clear imprint of Asian anthropogenic pollution influencing global air quality.

upper tropospheric (UT)↗
NASA NTRS1982

Tita: discovery of carbon monoxide in its atmosphere

The 3-D rotation-vibration band of carbon monoxide was identified in the near-infrared spectrum of Titan. A preliminary mixing ratio of CO/N2 = 0.00006 was determined. This result supports the probable detection of CO2 by Samuelson et al and strengthens possible analogies between the atmosphere of Titan and conditions on the primitive Earth.

Lutz, B. L.↗
NASA NTRS1983

Titan - Discovery of carbon monoxide in its atmosphere

The 3-0 rotation-vibration band of carbon monoxide was identified in the near-infrared spectrum of Titan. A preliminary mixing ratio of CO/N2 = 0.00006 was determined. This result supports the probable detection of CO by Samuelson et al and strengthens possible analogies between the atmosphere of Titan and conditions on the primitive earth. Previously announced in STAR as N83-14039

Lutz, B. L.↗
NASA NTRS1972

Collisional excitation of carbon monoxide in interstellar clouds.

Investigation of different models for the collisional excitation of carbon monoxide (CO) by solving the rate equations for the ten lowest energy levels, including stimulated emission and absorption by 3 K isotropic radiation, spontaneous emission, and collisions. The results are qualitatively applicable to other linear molecules. They show that a wide range of rotational excitation temperatures, including population inversions, can be produced by the various kinetic temperatures and particle densities which are likely to occur in the interstellar regions containing molecules.

Goldsmith, P. F.↗
NASA NTRS1985

Foliage plants for indoor removal of the primary combustion gases carbon monoxide and nitrogen dioxide

Foliage plants were evaluated for their ability to sorb carbon monoxide and nitrogen dioxide, the two primary gases produced during the combustion of fossil fuels and tobacco. The spider plant (Chlorophytum elatum var. vittatum) could sorb 2.86 micrograms CO/sq cm leaf surface in a 6 h photoperiod. The golden pothos (Scindapsus aureus) sorbed 0.98 micrograms CO/sq cm leaf surface in the same time period. In a system with the spider plant, greater than or equal to 99 percent of an initial concentration of 47 ppm NO2 could be removed in 6 h from a void volume of approximately 0.35 cu m. One spider plant potted in a 3.8 liter container can sorb 3300 micrograms CO and effect the removal of 8500 micrograms NO2/hour, recognizing the fact that a significant fraction of NO2 at high concentrations will be lost by surface sorption, dissolving in moisture, etc.

Wolverton, B. C.↗
NASA NTRS1995

Spectroscopic study of the seasonal variation of carbon monoxide vertical distribution above Kitt Peak

A method to retrieve elements of the carbon monoxide (CO) vertical distribution from ground-based high-resolution infrared solar spectra has been developed. The method is based on the fact that the total column amount retrieved by nonlinear least squares spectral fitting techniques depends on the shape of the assumed a priori profile and this dependence is a function of the absorption line intensity and the lower state energy of the transition. Four CO lines between 2057 and 2159/cm have been selected and the method has been tested on synthetic spectra. The CO total column content and average concentrations in two atmospheric layers (surface to 400 mbar and 400 mbar to the top of the atmosphere) can be retrieved with precisions of about 1% and less than 10%, respectively. Solar spectra recorded at Kitt Peak from 1982 to 1993 have been analyzed. The CO total column and the average concentration in the two layers show an asymmetrical seasonal cycle with extreme values of (1.1-2.1) x 10(exp 18) molecules cm(exp -2), (50-80) parts per billion by volume (ppbv) in the top layer and (80-160) ppbv in the bottom layer, and precisions of 1, 3, and 6%, respectively; a spring maximum and late summer minimum are observed.

Pougatchev, N. S.↗
NASA NTRS1996

Titan's 5 micrometers spectral window: carbon monoxide and the albedo of the surface

We have measured the spectrum of Titan near 5 micrometers and have found it to be dominated by absorption from the carbon monoxide 1-0 vibration-rotation band. The position of the band edge allows us to constrain the abundance of CO in the atmosphere and/or the location of the reflecting layer in the atmosphere. In the most likely case, 5 micrometers radiation is reflected from the surface and the mole fraction of CO in the atmosphere is qCO=10(+10/-5) ppm, significantly lower than previous estimates for tropospheric CO. The albedo of the reflecting layer is approximately 0.07(+0.02/-0.01) in the 5 micrometers continuum outside the CO band. The 5 micrometers albedo is consistent with a surface of mixed ice and silicates similar to the icy Galilean satellites. Organic solids formed in simulated Titan conditions can also produce similar albedos at 5 micrometers.

Saturn↗
NASA NTRS2006

Nadir Measurements of Carbon Monoxide Distributions by the Tropospheric Emission Spectrometer Instrument Onboard the Aura Spacecraft: Overview of Analysis Approach and Examples of Initial Results

We provide an overview of the nadir measurements of carbon monoxide (CO) obtained thus far by the Tropospheric Emission Spectrometer (TES). The instrument is a high resolution array Fourier transform spectrometer designed to measure infrared spectral radiances from low Earth orbit. It is one of four instruments successfully launched onboard the Aura platform into a sun synchronous orbit at an altitude of 705 km on July 15, 2004 from Vandenberg Air Force Base, California. Nadir spectra are recorded at 0.06/cm spectral resolution with a nadir footprint of 5 x 8 km. We describe the TES retrieval approach for the analysis of the nadir measurements, report averaging kernels for typical tropical and polar ocean locations, characterize random and systematic errors for those locations, and describe instrument performance changes in the CO spectral region as a function of time. Sample maps of retrieved CO for the middle and upper troposphere from global surveys during December 2005 and April 2006 highlight the potential of the results for measurement and tracking of global pollution and determining air quality from space.

carbon monoxide↗
NASA NTRS1978

Venus - Detection of variations in stratospheric carbon monoxide

The reported observations of the J = 0-1 rotational transition (115271.2 MHz) of carbon monoxide in the Venusian atmosphere indicate that the distribution of stratospheric CO is variable. Observations were obtained with a 11-m antenna on several days in February 1977, when Venus was near maximum eastern elongation (k approximately 0.4), and in April 1977 during inferior conjunction (k approximately 0.01). Differences in the line intensities and shapes for the two data sets are described. The results are interpreted to suggest that on the nightside of Venus there is relatively more CO at higher altitudes and relatively less CO at lower altitudes than on the dayside of the planet.

Gulkis, S.↗
NASA NTRS1985

An intercomparison of carbon monoxide measurement techniques

Results from an intercomparison of techniques to measure tropospheric levels of carbon monoxide (CO) are discussed. The intercomparison was conducted as part of the National Aeronautics and Space Administration's Global Tropospheric Experiment (GTE) and was held at Wallops Island, VA, in July 1983. Instruments intercompared included a laser differential absorption method and three grab sample/gas chromatograph methods. The intercomparison consisted of simultaneous measurements of ambient levels of CO and controlled injections of CO from a common manifold. Results from the techniques exhibited a high degree of correlation among themselves and with changes in the CO mixing ratio. The results suggested a level of agreement among the techniques of about 15 percent. However, a day-to-day bias between the techniques was observed, which resulted in differences between techniques as large as 38 percent.

Hoell, J. M., Jr.↗
NASA NTRS1990

Carbon monoxide over the Amazon Basin during the wet season

Measurements of the distribution of carbon monoxide in the lower atmosphere (150-5000 m) over the Amazon region of Brazil during the wet season, taken in conjunction with the 1987 NASA Global Tropospheric Experiment/Amazon Boundary Layer Experiment (ABLE 2B), are analyzed. About 100 hr of airborne, in situ CO measurements were obtained using a tunable diode laser system, providing insights into factors influencing the basin-scale distribution of CO in the Amazonian troposphere during wet season conditions. Distribution of CO over the altitudes 0.15-4.5 km was influenced by such factors as surface emissions from biological sources and long-range transport of pollutants from Northern Hemisphere sources. It is noted that the disruption of mixed layer growth and decay processes has a particularly important influence on CO concentration in the daytime lower troposphere and that the correlation of CO with O3 was positive under conditions influenced by Northern Hemisphere air and negative under all other conditions observed.

Harriss, R. C.↗