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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.

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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS2025

Validation of Formaldehyde Products From Three Satellite Retrievals (OMI SAO, OMPS-NPP SAO, and OMI BIRA) in the Marine Atmosphere With Four Seasons of Atom Aircraft Observations

Formaldehyde (HCHO) in the atmosphere is an intermediate product from the oxidation of methane and non-methane volatile organic compounds. In remote marine regions, HCHO variability is closely related to atmospheric oxidation capacity and modeled HCHO in these regions is usually added as a global satellite HCHO background. Thus, it is important to understand and validate the levels of satellite HCHO over the remote oceans. Here we intercompare three satellite retrievals of total HCHO columns (OMI-SAO (v004), OMPS-NPP SAO, and OMI BIRA) and validate them against in situ observations from the NASA Atmospheric Tomography Mission (ATom) mission. All retrievals are correlated with ATom integrated columns over remote oceans, with OMI SAO (v004) showing the best agreement. This is also reflected in the mean bias (MB) for OMI SAO (-0.73±0.87) x 10 15 molec cm -2 , OMPS SAO (-0.76±0.88) x 10 15 molec cm -2 , and OMI BIRA (-1.40±1.11) x 10 15 molec cm -2 . We recommend the OMI-SAO (v004) retrieval for remote ocean atmosphere studies. Three satellite HCHO retrievals and in situ ATom columns all generally captured the spatial and seasonal distributions of HCHO in the remote ocean atmosphere. Retrieval bias varies by latitude and season, but a persistent low bias is found in all products at high latitudes and the general low bias is most severe for the OMI BIRA product. Examination of retrieval components reveals slant column corrections have a larger impact on the retrievals over remote marine regions while AMFs play a smaller role. This study informs that the potential latitude-dependent biases in the retrievals require further investigation for improvement and should be considered when using marine HCHO satellite data, and vertical profiles from in situ instruments are crucial for validating satellite retrievals.

Atom↗
NASA NTRS1993

Abrupt climate change and transient climates during the Paleogene: a marine perspective

Detailed investigations of high latitude sequences recently collected by the Ocean Drilling Program (ODP) indicate that periods of rapid climate change often culminated in brief transient climates, with more extreme conditions than subsequent long term climates. Two examples of such events have been identified in the Paleogene; the first in latest Paleocene time in the middle of a warming trend that began several million years earlier: the second in earliest Oligocene time near the end of a Middle Eocene to Late Oligocene global cooling trend. Superimposed on the earlier event was a sudden and extreme warming of both high latitude sea surface and deep ocean waters. Imbedded in the latter transition was an abrupt decline in high latitude temperatures and the brief appearance of a full size continental ice-sheet on Antarctica. In both cases the climate extremes were not stable, lasting for less than a few hundred thousand years, indicating a temporary or transient climate state. Geochemical and sedimentological evidence suggest that both Paleogene climate events were accompanied by reorganizations in ocean circulation, and major perturbations in marine productivity and the global carbon cycle. The Paleocene-Eocene thermal maximum was marked by reduced oceanic turnover and decreases in global delta 13C and in marine productivity, while the Early Oligocene glacial maximum was accompanied by intensification of deep ocean circulation and elevated delta 13C and productivity. It has been suggested that sudden changes in climate and/or ocean circulation might occur as a result of gradual forcing as certain physical thresholds are exceeded. We investigate the possibility that sudden reorganizations in ocean and/or atmosphere circulation during these abrupt transitions generated short-term positive feedbacks that briefly sustained these transient climatic states.

NASA Program Exobiology↗
NASA NTRS2016

Marine Boundary Layer Cloud Property Retrievals from High-Resolution ASTER Observations: Case Studies and Comparison with Terra MODIS

A research-level retrieval algorithm for cloud optical and microphysical properties is developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard the Terra satellite. It is based on the operational MODIS algorithm. This paper documents the technical details of this algorithm and evaluates the retrievals for selected marine boundary layer cloud scenes through comparisons with the operational MODIS Data Collection 6 (C6) cloud product. The newly developed, ASTERspecific cloud masking algorithm is evaluated through comparison with an independent algorithm reported in Zhao and Di Girolamo (2006). To validate and evaluate the cloud optical thickness (tau) and cloud effective radius (r(sub eff)) from ASTER, the high-spatial-resolution ASTER observations are first aggregated to the same 1000m resolution as MODIS. Subsequently, tau(sub aA) and r(sub eff, aA) retrieved from the aggregated ASTER radiances are compared with the collocated MODIS retrievals. For overcast pixels, the two data sets agree very well with Pearson's product-moment correlation coefficients of R greater than 0.970. However, for partially cloudy pixels there are significant differences between r(sub eff, aA) and the MODIS results which can exceed 10 micrometers. Moreover, it is shown that the numerous delicate cloud structures in the example marine boundary layer scenes, resolved by the high-resolution ASTER retrievals, are smoothed by the MODIS observations. The overall good agreement between the research-level ASTER results and the operational MODIS C6 products proves the feasibility of MODIS-like retrievals from ASTER reflectance measurements and provides the basis for future studies concerning the scale dependency of satellite observations and three-dimensional radiative effects.

marine boundary layer↗
NASA NTRS1970

Optics and the Mariner imaging instrument

TV instruments for Mariners 6 and 7 providing analog and digital data, comparing resolutions and accuracies to earth based telescopes and Mariner 4 photographs

Adams, L. A.↗
NASA NTRS1971

Long-duration firings of a Mariner Mars 1969 catalytic reactor

Two long-duration tests were conducted with a surplus Mariner Mars 1969 monopropellant hydrazine reactor in an attempt to induce the washout phenomenon. The Mariner Mars 1969 reactor was chosen because it has a long development history and thus is well characterized. No washout occurred during either of the two 1000-s tests, although slow transients were observed in the reactor operation during what were nominally steady-state conditions. The 2000-s of operating time represents nearly an order of magnitude increase over the rated life of the engine.

Price, T. W.↗
NASA NTRS1971

Development and testing of the central computer and sequencer for the Mariner Mars 1971 spacecraft

The central computer and sequencer subsystem has been an important part of the Mariner series of interplanetary spacecraft since their inception. As with other spacecraft subsystems, the CC&S has increased in complexity and capability with each spacecraft project. This report describes the design, fabrication, and test associated with the development of the Mariner Mars 1971 CC&S subsystem.

Lingon, U. S.↗
NASA NTRS1971

Radio propagation measurements of the solar corona and gravitational fields: Applications to Mariner 6 and 7

Results from interferometric measurements of the apparent angular deflection of quasi-stellar object are examined. Some preliminary results from Mariner 6 and 7 experiments, particularly from the plasma effect viewpoint, are discussed, along with future experiments and plasma scintillation. Ray bending studies, plasma relativity separation for Mariner 6 and 7, and radio propagation test of general relativity are reviewed. First order approximations and time delay studies are appended, as well as Doppler velocity effect investigations.

Muhleman, D. O.↗
NASA NTRS1971

Reduction and analysis of magnetometer data from Mariners 4 and 5

In studies of data from the Mariner 4 and Mariner 5 magnetometers evidence has been found that during the flights, negative (toward the sun) polarity dominated at latitudes above the solar equatorial plane and positive polarity dominated at latitudes below this plane. A subsequent check of data taken with other spacecraft during 1964 through 1967 provided additional evidence of this effect. It is suggested that the dominant polarity of the interplanetary magnetic field follows the hemisphere-dependent dipolar field of the sun. Thus, the photospheric dipolar field may be an important source of the interplanetary magnetic field, especially at quiet times. It has also been found that, for an interplanetary magnetic field of a given polarity, the north-south component has a nonzero mean value in regions above and below the solar equatorial plane.

Source record↗
NASA NTRS1971

Data user's note: Mariner 6 and 7 photographic data (NSSDC ID no. 69-014A-01 and 69-030A-01

The availability and assistance in the use of the complete set of Mariner 6 and 7 (1969 14A and 1969 20A) pictorial data are announced. The announcement describes the photographic mission of these Mariner spacecrafts, the television camera system, and the photographs that are available from the National Space Data Center. Two appendixes are included: one is a photographic catalog of all enhanced photographs, designated the maximum discriminability photographs; the other is a series of computer produced graphics that are useful in detailed analysis of the photographs.

Anderson, A. T.↗
NASA NTRS1972

Results of the Mariner 6 and 7 Mars occultation experiments

Final profiles of temperature, pressure, and electron density on Mars were obtained for the Mariner 6 and 7 entry and exit cases, and results are presented for both the lower atmosphere and ionosphere. The results of an analysis of the systematic and formal errors introduced at each stage of the data-reduction process are also included. At all four occulation points, the lapse rate of temperature was subdadiabatic up to altitudes in excess of 20 km. A pronounced temperature inversion was present above the surface at the Mariner 6 exit point. All four profiles exhibit a sharp, superadiabatic drop in temperature at high altitudes, with temperatures falling below the frost point of CO2. These results give a strong indication of frozen CO2 in the middle atmosphere of Mars.

Hogan, J. S.↗
NASA NTRS1971

Mariner Mars 1971: Press kit

The news release describes the 1971 launches of Mariner 8 and 9 which were to be the first attempt by NASA to orbit another planet, Mars. Described are: (1) mission capsule; (2) planetary missions; (3) aiming zones; (4) the spacecraft; (5) scientific experiments to be performed; (6) Atlas Centaur launch vehicle; (7) launch operations; (8) tracking and data system and mission operations; and (9) Mariner Mars 71 team and subcontractors.

Mittauer, R. T.↗