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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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NASA NTRS1977

Verification by Viking landers of earlier radio occultation measurements of surface atmospheric pressure on Mars

The landing of Viking 1 in Chryse Planitia on July 20, 1976 provided the first opportunity to obtain measurements of atmospheric pressure directly from the surface of Mars. A computation was conducted to predict the atmospheric pressure at the landing site before the landing itself. The relative altitude between occultation points and the Viking 1 site was obtained with the aid of earth-based planetary radar data taken in 1967. The data cover Martian latitudes from 19 deg N to 24 deg N. The investigation indicates that the radio occultation results from Mariner 9 closely correspond to the actual surface pressure on Mars.

Kliore, A. J.↗
NASA NTRS1993

Discovery Venera surface: Atmosphere geochemistry experiments mission concept

The phenomenal increase in our understanding of Venus provided by the Magellan Mission has raised a series of focused, fundamental scientific questions about the geochemistry of the surface of Venus, the nature of the lower atmosphere, and the relationship of the lower atmosphere and surface. First, surface geochemical measurements from the Venera/Vega spacecraft showed that widely spaced regions of the venusian plains are made of basalts; thus basalts are significant and may be the only component of the venusian crust. But we lack information on the composition of several key elements of Venus geology: (1) Tessera terrain (which may be outcrops of continental-like non-basaltic crustal material) and steep-sided domes/festoons are promising candidates for non-basaltic geochemically evolved material. The composition of the lower part of the Venusian crust is unknown: however, ejecta from large venusian craters provides us with the possibility of sampling this material on the surface; (2) bulk chemistry (structure and dynamics) of the venusian atmosphere are known. The altitude profiles of water vapor content and minor admixtures relevant to redox conditions in the lower atmosphere (less than 20 km altitude) remain uncertain. Lack of that knowledge means that we do not understand the fine chemical structure of the main mass of the Venusian atmosphere; and (3) thermodynamic models predict that igneous materials on the surface of Venus should react with gases of the venusian atmosphere. But because the water vapor content and redox conditions in the lower atmosphere are not well known, we do not understand the nature of venusian weathering: oxidation, sulfatization, carbonatization, and hydration. The answers to these questions are critical to the understanding of Venus, the most Earth-like of the terrestrial planets.

Surkov, Yuri A.↗
NASA NTRS1986

Dependence of snow melting and surface-atmosphere interactions on the forest structure

The surface albedo and the surface roughness for forested areas with snow on the ground are expressed in terms of the tree silhouette parameter, the projection on the vertical plane of trees per unit area. The absorption of insolation (direct solar beam) is quantitatively described for a horizontal snow surface with vertical tree trunks, stressing the role of the bark at snow level as triggering the snowmelt.

Ottermann, J.↗
NASA NTRS1988

Dependence of snow melting and surface-atmosphere interactions on the forest structure

The surface albedo and the surface roughness for forested areas with snow on the ground are expressed in terms of the tree silhouette parameter, s, the projection on the vertical plane of trees per unit area. The absorption of insolation (direct solar beam) is quantitatively described for a horizontal snow surface with vertical tree trunks, stressing the role of the bark at snow level as triggering the snow melt. Measurement of s by field sampling in two forested sites in central Switzerland yielded values ranging from 1.8 to 2.1.

Otterman, J.↗
NASA NTRS1993

Dust-dynamic feedbacks in the Martian atmosphere: Surface dust lifting

Numerical models have been developed to study surface dust lifting in the Martian atmosphere. The present model is comprised of interactively coupled 3-D dynamical and aerosol transport/microphysical models. The nature of possible feedbacks between surface dust lifting and the amplification/damping of near-surface wind and thermal fields and their implications for additional lifting is investigated. These studies have examined large scale Martian topography for its impact upon the ability of the atmospheric circulation to lift dust from the surface, and the particular component(s) responsible for the lifting (e.g. overturning circulation, thermal tides, baroclinic waves). Analogous experiments in which the lifted dust is radiatively inactive (passive tracer) have been conducted to act as a control against which feedbacks are defined.

Murphy, James R.↗
NASA NTRS1984

Determination of monthly mean humidity in the atmospheric surface layer over oceans from satellite data

A simple statistical technique is described to determine monthly mean marine surface-layer humidity, which is essential in the specification of surface latent heat flux, from total water vapor in the atmospheric column measured by space-borne sensors. Good correlation between the two quantities was found in examining the humidity soundings from radiosonde reports of mid-ocean island stations and weather ships. The relation agrees with that obtained from satellite (Seasat) data and ship reports averaged over 2 deg areas and a 92-day period in the North Atlantic and in the tropical Pacific. The results demonstrate that, by using a local regression in the tropical Pacific, total water vapor can be used to determine monthly mean surface layer humidity to an accuracy of 0.4 g/kg. With a global regression, determination to an accuracy of 0.8 g/kg is possible. These accuracies correspond to approximately 10 to 20 W/sq m in the determination of latent heat flux with the bulk parameterization method, provided that other required parameters are known.

Liu, W. T.↗
NASA NTRS1985

Remote sensing of atmosphere-surface interaction parameters

Examples are given of the accuracy of the results obtained from the HIRS 2/MSU (High Resolution Infrared Sounder and Microwave Sounding Unit) analysis of ocean, atmosphere, and land parameters. Sea surface temperatures are compared with available ship and buoy radiosonde data, and land surface temperatures are compared with shelter temperatures. The seasonal change in land and ocean skin surface temperature is reviewed. The distribution of clouds is examined and their opacities in the visible and infrared parts of the spectrum are compared.

Chahine, M. T.↗
NASA NTRS2018

Venera-D Mission Concept to Study Atmosphere, Surface and Plasma Environment: Phase II Report of the Venera-D Joint Science Definition Team

Venus and Earth were formed approximately the same distance from the Sun, and have almost the same masses and volumes: they should be the most similar pair of planets in the Solar System. A vital, outstanding question is how and when these planets diverged in their atmospheric evolutions. Significantly, recent investigations present evidence for microbial life in Venus' cloud deck. Venus presents us with fundamental questions about the origin and evolution of planetary bodies and life in our Solar System.Venera-D (D stands for the Russian word for "long-lived:" dolgozhivushaya) is a potential mission that would combine simultaneous observations of Venus' atmosphere, plasma environment, and surface to try to answer these essential questions.

Zasova, L.↗
NASA NTRS1999

Airborne Spectral Measurements of Surface-Atmosphere Anisotropy for Arctic Sea Ice and Tundra

Angular distributions of spectral reflectance for four common arctic surfaces: snow-covered sea ice, melt-season sea ice, snow-covered tundra, and tundra shortly after snowmelt were measured using an aircraft based, high angular resolution (1-degree) multispectral radiometer. Results indicate bidirectional reflectance is higher for snow-covered sea ice than melt-season sea ice at all wavelengths between 0.47 and 2.3 pm, with the difference increasing with wavelength. Bidirectional reflectance of snow-covered tundra is higher than for snow-free tundra for measurements less than 1.64 pm, with the difference decreasing with wavelength. Bidirectional reflectance patterns of all measured surfaces show maximum reflectance in the forward scattering direction of the principal plane, with identifiable specular reflection for the melt-season sea ice and snow-free tundra cases. The snow-free tundra had the most significant backscatter, and the melt-season sea ice the least. For sea ice, bidirectional reflectance changes due to snowmelt were more significant than differences among the different types of melt-season sea ice. Also the spectral-hemispherical (plane) albedo of each measured arctic surface was computed. Comparing measured nadir reflectance to albedo for sea ice and snow-covered tundra shows albedo underestimated 5-40%, with the largest bias at wavelengths beyond 1 pm. For snow-free tundra, nadir reflectance underestimates plane albedo by about 30-50%.

Arnold, G. Thomas↗
NASA NTRS1992

Simulation of Martian surface-atmosphere interaction in a space-simulator: Technical considerations and feasibility

The Space Simulator of the German Aerospace Research Establishment at Cologne, formerly used for testing satellites, is now, since 1987, the central unit within the research sub-program 'Comet-Simulation' (KOSI). The KOSI team has investigated physical processes relevant to comets and their surfaces. As a byproduct we gained experience in sample-handling under simulated space conditions. In broadening the scope of the research activities of the DLR Institute of Space Simulation an extension to 'Laboratory-Planetology' is planned. Following the KOSI-experiments a Mars Surface-Simulation with realistic minerals and surface soil in a suited environment (temperature, pressure, and CO2-atmosphere) is foreseen as the next step. Here, our main interest is centered on thermophysical properties of the Martian surface and energy transport (and related gas transport) through the surface. These laboratory simulation activities can be related to space missions as typical pre-mission and during-the-mission support of the experiments design and operations (simulation in parallel). Post mission experiments for confirmation and interpretation of results are of great value. The physical dimensions of the Space Simulator (cylinder of about 2.5 m diameter and 5 m length) allows for testing and qualification of experimental hardware under realistic Martian conditions.

Moehlmann, D.↗
NASA NTRS1987

Atmospheric surface and boundary layers of the Amazon Basin

Three phases of work were performed: design of and preparation for the Amazon Boundary Layer Experiment (ABLE 2-A); execution of the ABLE 2-A field program; and analysis of the ABLE 2-A data. Three areas of experiment design were dealt with: surface based meteorological measurements; aircraft missions; and project meteorological support. The primary goal was to obtain a good description of the structure of the atmosphere immediately above the rain forest canopy (top of canopy to a few thousand meters), to describe this region during the growing daytime phase of the boundary layer; and to examine the nighttime stratified state. A secondary objective was to examine the role that deep convective storms play in the vertical transport of heat, water vapor, and other trace gases. While significant progress was made, much of the analysis remains to be done.

Garstang, Michael↗
NASA NTRS2003

Mars Odyssey THEMIS-VIS: Surface-Atmosphere Separation and Derivation of Aerosol Properties

Scattering by atmospheric aerosols can contribute a substantial fraction of the visible-light radiance observed in any remote sensing of Mars. Our objective is to develop techniques to separate this aerosol component from the surface-reflectance component in Mars Odyssey's THEMIS Visible Imaging Subsystem (THEMIS-VIS) dataset. The primary purpose of this study is the production of accurate surface reflectance data in order to allow for reliable color and mineralogical unit mapping. The second principal goal is to study the feasibility of using VIS measurements to derive quantitative information about ice and dust aerosol properties such as particle size and optical depth.

T H McConnochie↗
NASA NTRS2004

Aqueous Chemical Modeling of Sedimentation on Early Mars with Application to Surface-Atmosphere Evolution

This project was to investigate models for aqueous sedimentation on early Mars from fluid evaporation. Results focused on three specific areas: (1) First, a fluid evaporation model incorporating iron minerals was developed to compute the evaporation of a likely solution on early Mars derived from the weathering of mafic rock. (2) Second, the fluid evaporation model was applied to salts within Martian meteorites, specifically salts in the nakhlites and ALH84001. Evaporation models were found to be consistent with the mineralogy of salt assemblages-anhydrite, gypsum, Fe-Mg-Ca carbonates, halite, clays-- and the concentric chemical fractionation of Ca-to Mg-rich carbonate rosettes in ALH84001. We made progress in further developing our models of fluid concentration by contributing to updating the FREZCHEM model. (3) Third, theoretical investigation was done to determine the thermodynamics and kinetics involved in the formation of gray, crystalline hematite. This mineral, of probable ancient aqueous origin, has been observed in several areas on the surface of Mars by the Thermal Emission Spectrometer on Mars Global Surveyor. The "Opportunity" Mars Exploration Rover has also detected gray hematite at its landing site in Meridiani Planum. We investigated how gray hematite can be formed via atmospheric oxidation, aqueous precipitation and subsequent diagenesis, or hydrothermal processes. We also studied the geomorphology of the Aram Chaos hematite region using Mars Orbiter Camera (MOC) images.

Catling, David C.↗
NASA NTRS1981

Anomalous behavior of the atmospheric surface layer over a melting snowpack

During March, 1978 on a snow-covered field near Lee Vining, California, measurements were made that included: (1) variations above the snow surface of the net radiative flux and the profile of wind speed, air temperature and relative humidity; and (2) variations beneath the snow surface of the conductive heat flux and the temperature profile. The period was marked by clear skies, warm air and calm winds during the day, and cold air and moderate winds at night. During the day, a highly stable sublayer formed near the surface, with a persistent warm layer at approximately 0.5 m above the surface. At night, profiles agreed more with classical log-linear forms found in stable air. Numerical simulation of long and shortwave radiative fluxes near the surface, using observed humidity profiles, produced the daytime warm level in agreement with observations. It was concluded that in the absence of turbulent mixing, strong solar radiation and a supply of moisture from the snow will cause a raised maximum of temperature during the day.

Halberstam, I.↗