SEARCH · Engineering Papers
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.
ERS radar interferometry is a powerful new technique to map the grounding line of outlet glaciers, or more precisely to located the limit of tidal flexing of their floating sections, or hinge line.
Exceeding all expectations of measurement precision and accuracy, the US/France TOPEX/Poseidon satellite mission is now in its 5th year. Returning more than 98 percent of the altimetric data, the measured global geocentric height of the sea surface has provided unprecedented opportunities to address a host of scientific problems ranging from the dynamics of ocean circulation to the distribution of internal tidal energy. Scientific highlights of this longest-running altimetric satellite mission include improvements in our understanding of the dynamics and thermodynamics of the large-scale ocean variability, such as, the properties of planetary waves; the energetics of basin-wide gyres; the heat budget of the ocean; and the ocean's response to wind forcing. For the first time, oceanographers have quantitative descriptions of a dynamic variable of the physical state of the global oceans available in near-real-time.
The results from studies of D/Shoemaker-Levy 9 and other recent split comets and comet pairs lead to the recognition of fundamental differences between breakup products of the tidally and nontidally split comets and to the conclusive indentification of the so-called dissipating comets as secondary nuclei of previously split comets, whose separately arriving principal nulei had in most cases been missed.
The tidal disruption and subsequent impact of fragments of comet Shoemaker-Levy 9 on Jupiter have provided important new clues as to the nature of cometary nuclei.
Slow progress is being made in quantifying the mechanical and dynamical states of the lower mantle. The large plastic strength of the mantle above the D layer exhibits a non-tidal gravity field coefficient that is driven by isostatic flow of the deep mantle, as suggested by Yoder et al.
We describe the current state of knowledge about Mercury's interior structure. We review the available observationalconstraints, including mass, size, density, gravity eld, spin state, composition, and tidal response. These data enablethe construction of models that represent the distribution of mass inside Mercury. In particular, we infer radial prolesof the pressure, density, and gravity in the core, mantle, and crust. We also examine Mercury's rotational dynamicsand the inuence of an inner core on the spin state and the determination of the moment of inertia. Finally, we discussthe wide-ranging implications of Mercury's internal structure on its thermal evolution, surface geology, capture in aunique spin-orbit resonance, and magnetic eld generation.
This paper points out that the nutation terms of Zhu and Gorten due to the tidal potential of degree 3 are erroneous. Due to the high accuracy of Very Long Baseline Interferometry (VLBI), present theoretical nutation models should consider amplitudes of theorder of a few micro arcseconds.
Heller and Armstrong (Astrobiology, 2014) describe a number of ways in which an Earth-like world (“Earth twins” with a tidal heat flux Ft less than 0.04 W/m2, and within their star’s habitable zone) might be “superhabitable,” with surface environments that are more amenable to life than the common benchmark of modern Earth. Over Earth history, several time periods are known from the geologic record that could meet these criteria, providing multiple opportunities to explore known superhabitable and inhabited planetary conditions from an astrophysical perspective.
Tidal marshes function as a key ecosystem, by serving as nurseries, improving water quality, protecting biodiversity, preventing erosion of coastlines, and preserving archives of paleoclimate and paleoecology. In the last few decades, researchers have come to appreciate coastal marshes’ carbon sequestration function. However, full peat depth is required for estimating the true carbon content of marshes, and very little research has been done to discover the full peat depth along coastlines. We selected Iona Marsh (73°58’44.972”W, 41°18’6.366”N), situated adjacent to Bear Mountain Park and part of the National Estuarine Research Reserve, to document the belowground storage of blue carbon. In order to calculate marsh volume, three full-depth transects were performed from 2020 to 2022, two from east to west in different regions of the marsh, and one from north to south at a minimum of 10 m intervals. We found that marsh depth ranged from 5.1 m to 13.2 m. We calculated marsh volume from the full peat depth and marsh area, obtained through the National Wetlands Inventory database, by applying the average marsh depth over its entire surface area. In order to calculate carbon content, we extracted a 9m sediment core and used loss-on-ignition (LOI) to determine organic matter, then estimate carbon content as half of the organic matter. We used 198 LOI samples to calculate the carbon, which formed at this site over 6000 years ago. We intend to apply this methodology framework to other marshes in the Hudson region. Because many previous carbon stock estimates only account for the top 1 m of peat, the role of these ecosystems in carbon sequestration is significantly underestimated. By determining the full-depth carbon stock of these marshes, we hope to emphasize the value of marshes to the community, beyond what is traditionally recognized, particularly in light of sea level rise and the vulnerability of marshes to erosion.
This study examines the day-to-day variability of low-latitude ionosphere using global ionospheric specification (GIS) electron density profiles derived from FORMOSAT-7/COSMIC-2 radio occultation measurements during a deep solar minimum period of August 2019 to July 2020. The measurements reveal significant daily variations over dayside low latitudes, yielding about 10-20% standard deviation in equinoxes, 20-30% in solstices, reaching 40-50% in winter. The nighttime deviations could be 30-60%, being largest in solstices. Day-to-day variations are also observed in the longitudinal wave-4 structures. The period mostly remained geomagnetically quiet except for some moderate disturbances on a few days. Tidal decomposition of the GIS electron density shows that in-situ forced migrating diurnal (DW1) terdiurnal (TW3) oscillations and the background zonal mean yield only ~25% of the daily variations despite accounting for almost 75-90% of the observed electron density. Thus, forcing from lower atmosphere dominates the contribution (~75%) to the observed daily variations. Only about one third of this lower atmospheric forcing comes from the migrating semidiurnal SW2 and the usually investigated non-migrating diurnal eastward DE2, DE3, stationary planetary wave SPW3, SPW4, and semidiurnal eastward SE1, and SE2 components. The residual tides other than those mentioned above, including secondary waves through non-linear interactions and other planetary waves, thus significantly influence the day-to-day variations in electron density and modify the longitudinal wave structures.
Theoretical tides on rigid moon compared to gross physical properties of moon from tidal observations
State of u.s. technology for a manned exploration of mars, including bioastronautics and communications programs, tidal history of mars and financial limitations of the space program
Rotation of planet Mercury from radar observation explained by solar gravitational torque on tidal deformation and equatorial plane asymmetry
Historical review of lunar surface events from 5 March 1587 to 15 November 1965 - correlation to earth tidal action
Lunar activity and possible cause due to tidal effects of earth gravitational pull
Winds in upper atmosphere as revealed by sodium vapor trails explained on basis of prevailing and tidal components critically analyzed
Tidal dissipation function in solar system, examining cases having appreciable evolution since origin of planets and satellites
Geomagnetic threshold effects on cosmic ray intensity during geomagnetic storm, and daily lunar tidal variation effect on geomagnetic threshold