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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 NTRS2017

Habitable Moist Atmospheres on Terrestrial Planets near the Inner Edge of the Habitable Zone Around M Dwarfs

Terrestrial planets in the habitable zones (HZs) of low-mass stars and cool dwarfs have received significant scrutiny recently. Transit spectroscopy of such planets with the James Webb Space Telescope (JWST) represents our best shot at obtaining the spectrum of a habitable planet within the next decade. As these planets are likely tidally locked, improved 3D numerical simulations of such planetary atmospheres are needed to guide target selection. Here we use a 3D climate system model, updated with new water-vapor absorption coefficients derived from the HITRAN 2012 database, to study ocean-covered planets at the inner edge of the HZ around late M to mid- K stars (2600 K less than or equal to T(sub eff) less than or equal to 4500 K). Our results indicate that these updated water-vapor coefficients result in significant warming compared to previous studies, so the inner HZ around M dwarfs is not as close as suggested by earlier work. Assuming synchronously rotating Earth-sized and Earth-mass planets with background 1 bar N2 atmospheres, we find that planets at the inner HZ of stars with T(sub eff) greater than 3000 K undergo the classical ''moist greenhouse'' (H2O mixing ratio greater than 10(exp -3) in the stratosphere) at significantly lower surface temperature (approx. 280 K) in our 3D model compared with 1D climate models (approx. 340 K). This implies that some planets around low-mass stars can simultaneously undergo water loss and remain habitable. However, for stars with T(sub eff) less than or equal to 3000 K, planets at the inner HZ may directly transition to a runaway state, while bypassing the moist greenhouse water loss entirely. We analyze transmission spectra of planets in a moist greenhouse regime and find that there are several prominent H2O features, including a broad feature between 5 and 8 micron, within JWST MIRI instrument range. Thus, relying only on standard Earth-analog spectra with 24 hr rotation period around M dwarfs for habitability studies will miss the strong H2O features that one would expect to see on synchronously rotating planets around M dwarf stars, with JWST.

Kopparapu, Ravi kumar↗
NASA NTRS1977

Investigation of the effect of atmospheric dust on the determination of total ozone from the earth's ultraviolet reflectivity measurements

Results are presented on the effect of atmospheric aerosols on the value of total ozone, in an atmospheric column of the terrestrial atmosphere, estimated from the simulated measurements of the ultraviolet radiation back scattered by the earth atmosphere models. Simulated measurements were used in five (configuration of the BUV experiment of Nimbus-4 satellite), and in six (configuration of the TOMS section of the SBUV/TOMS experiment on Nimbus-G) narrow spectral regions in the ultraviolet part of the spectrum.

Dave, J. V.↗
NASA NTRS1984

Global N2O cycles - Terrestrial emissions, atmospheric accumulation and biospheric effects

Recent findings concerning the budget and cycles of nitrous oxide on earth are summarized, and the sources and sinks for N2O on land, in the ocean, and in the atmosphere are examined in view of the N2O concentration increase of 0.2-0.4 percent per year, observed over the period of 1975-1982. Possible atmospheric and biospheric consequences of the N2O concentration increase are evaluated. N2O emission values are given for several major ecosystem types, such as forest, desert, cultivated land; values from different sources are compared and discussed. Analysis shows an excess of documented sources over sinks by 0-51 Tg N2O-N/yr.

Banin, A.↗
NASA NTRS1986

A new source of ozone in the terrestrial upper atmosphere?

The simultaneous measurements of atomic O, O2, O3, and N2 between 90 and 110 km obtained by a rocket-borne mass spectrometer flown during the Aladdin 74 program provide an opportunity to test directly the simple atmosphperic chemical model first proposed more than 50 years ago by S. Chapman, which is today the core of the complex chemistry controlling stratospheric O3. The Aladdin 74 O3 results are found to be significantly in excess of model abundances computed using the most current values of the key chemical parameters. The calculations may possibly be in error due to uncertainties in these key parameters and/or in the measurement of the related species. However, the extra O3 may be a consequence of reactions between ground state O2 and electronically excited O2 resulting from the recombination of atomic O.

Allen, M.↗
NASA NTRS1990

Calculation of infrared limb emission by ozone in the terrestrial middle atmosphere. I - Source functions. II - Emission calculations

The departure from LTE in the vibration-rotation bands of ozone in the middle atmosphere is analyzed using two statistical equilibrium models: the energy gap model and the simplified single model. The diurnal variations in the fundamental band source functions nu(1) and nu(3) is determined by the diurnal change in the rate of ozone photolysis by the solar radiation. Source functions are presented for the vibration-rotation bands of ozone that emit in the 9-11-micron spectral interval, over an altitude range of 1-110 km. Results are also reported of the evaluation of the radiative transfer equation incorporating these source functions and energy level populations. Using the results of the two statistical equilibrium models, calculations are carried out of the spectrally integrated limb radiance for the limb viewing geometry for daytime conditions. Results indicate that the interpretation of the measurements of spectrally integrated limb radiance from ozone will be greatly complicated by the breakdown of LTE in the vibration-rotational bands of ozone.

Mlynczak, Martin G.↗
NASA NTRS1995

Interaction of the terrestrial and atmospheric hydrological cycles in the context of the North American southwest summer monsoon

Work under this grant has used information on precipitation and water vapor fluxes in the area of the Mexican Monsoon to analyze the regional precipitation climatology, to understand the nature of water vapor transport during the monsoon using model and observational data, and to analyze the ability of the TRMM remote sensing algorithm to characterize precipitation. An algorithm for estimating daily surface rain volumes from hourly GOES infrared images was developed and compared to radar data. Estimates were usually within a factor of two, but different linear relations between satellite reflectances and rainfall rate were obtained for each day, storm type and storm development stage. This result suggests that using TRMM sensors to calibrate other satellite IR will need to be a complex process taking into account all three of the above factors. Another study, this one of the space-time variability of the Mexican Monsoon, indicate that TRMM will have a difficult time, over the course of its expected three year lifetime, identifying the diurnal cycle of precipitation over monsoon region. Even when considering monthly rainfalls, projected satellite estimates of August rainfall show a root mean square error of 38 percent. A related examination of spatial variability of mean monthly rainfall using a novel method for removing the effects of elevation from gridded gauge data, show wide variation from a satellite-based rainfall estimates for the same time and space resolution. One issue addressed by our research, relating to the basic character of the monsoon circulation, is the determination of the source region for moisture. The monthly maps produced from our study of monsoon variability show the presence of two rainfall maxima in the analysis normalized to sea level, one in south-central Arizona associated with the Mexican monsoon maximum and one in southeastern New Mexico associated with the Gulf of Mexico. From the point of view of vertically-integrated fluxes and flux divergence of water vapor from ECMWF data, most moisture at upper levels arrives from the Gulf of Mexico, while low level moisture comes from the northern Gulf of California. Composites of ECMWF analyses for wet and dry periods (classified by rain gauge data) show that both regimes show low level moisture arriving from northern and central Gulf of California. Above 700 MB, moisture comes from both source regions and the Sierra Madre Occidental. During wet periods a longer fetch through the moist air mass above western Mexico results in a greater moisture flux into the Sonoran Desert region, while there is less moisture from the Gulf of Mexico both above and below 700 mb. Work on the grant subcontract at the University of Colorado concentrated on the development of a technique useful to TRMM combining visible, infrared and passive microwave data for measuring precipitation. Two established techniques using either visible or infrared data applied over the US Southwest correlated with gauges at the 0.58 to 0.70 level. The application of some established passive microwave techniques were less successful for a variety of reason, including problems in both the gauge and satellite data quality, sampling problems and weaknesses inherent in the algorithms themselves. A more promising solution for accurate rainfall estimation was explored using visible and infrared data to perform a cloud classification, which when combined with information about the background (e.g. Iand/ocean), was used to select the most appropriate microwave algorithm from a suite of possibilities.

Dickinson, Robert E.↗
NASA NTRS1999

Insects at low pressure: applications to artificial ecosystems and implications for global windborne distribution

Insects have a number of potential roles in closed-loop life support systems. In this study we examined the tolerance of a range of insect orders and life stages to drops in atmospheric pressure using a terrestrial atmosphere. We found that all insects studied could tolerate pressures down to 100 mb. No effects on insect respiration were noted down to 500 mb. Pressure toleration was not dependent on body volume. Our studies demonstrate that insects are compatible with plants in low-pressure artificial and closed-loop ecosystems. The results also have implications for arthropod colonization and global distribution on Earth.

Atmospheric Pressure↗
NASA NTRS2009

Solar Wind Ablation of Terrestrial Planet Atmospheres

Internal plasma sources usually arise in planetary magnetospheres as a product of stellar ablation processes. With the ignition of a new star and the onset of its ultraviolet and stellar wind emissions, much of the volatiles in the stellar system undergo a phase transition from gas to plasma. Condensation and accretion into a disk is replaced by radiation and stellar wind ablation of volatile materials from the system- Planets or smaller bodies that harbor intrinsic magnetic fields develop an apparent shield against direct stellar wind impact, but UV radiation still ionizes their gas phases, and the resulting internal plasmas serve to conduct currents to and from the central body along reconnected magnetic field linkages. Photoionization and thermalization of electrons warms the ionospheric topside, enhancing Jeans' escape of super-thermal particles, with ambipolar diffusion and acceleration. Moreover, observations and simulations of auroral processes at Earth indicate that solar wind energy dissipation is concentrated by the geomagnetic field by a factor of 10-100, enhancing heavy species plasma and gas escape from gravity, and providing more current carrying capacity. Thus internal plasmas enable coupling with the plasma, neutral gas and by extension, the entire body. The stellar wind is locally loaded and slowed to develop the required power. The internal source plasma is accelerated and heated, inflating the magnetosphere as it seeks escape, and is ultimately blown away in the stellar wind. Bodies with little sensible atmosphere may still produce an exosphere of sputtered matter when exposed to direct solar wind impact. Bodies with a magnetosphere and internal sources of plasma interact more strongly with the stellar wind owing to the magnetic linkage between the two created by reconnection.

Moore, Thomas Earle↗
NASA NTRS2021

Understanding the Impacts of Land Surface and PBL Observations on the Terrestrial and Atmospheric Legs of Land-Atmosphere Coupling

Accurately representing land-atmosphere (L-A) interactions and coupling in NWP systems remains a challenge. New observations, incorporated into models via assimilation or calibration, hold the promise of improved forecast skill, but erroneous model coupling can hinder the benefits of such activities. To better understand model representation of coupled interactions and feedbacks, this study demonstrates a novel framework for coupled calibration of the Single Column Model (SCM) capability of the NASA Unified Weather Research and Forecasting (NU-WRF) system coupled to NASA’s Land Information System (LIS). The local land-atmosphere coupling (LoCo) process chain paradigm is used to assess the processes and connections revealed by calibration experiments. Two summer case studies in the U. S. Southern Great Plains are simulated in which LSM parameters are calibrated to diurnal observations of LoCo process chain components including 2-meter temperature, 2-meter humidity, surface fluxes (Bowen ratio), and PBL height. Results show a wide range of soil moisture and hydraulic parameter solutions depending on which L-A variable (i.e. observation) is used for calibration, highlighting that improvement in either SHP or ISM when not in tandem with the other can provide undesirable results. Overall, this work demonstrates that a process chain calibration approach can be used to assess L-A connections, feedbacks, strengths, and deficiencies in coupled models, as well as quantify the potential impact of new sources of observations of land-PBL variables on coupled prediction.

Patricia Lawston-Parker↗
NASA NTRSDate not supplied

Global Ocean Mass Change Derived From Atmospheric Reanalyses

Barystatic sea level change is a significant climate variable and a gauge for water exchanges between land, atmosphere, and ocean, with consequential relevance to stakeholders. The monitoring and attribution of globally averaged sea level variations represents substantial challenges to the climate community. Atmospheric reanalyses provide a level of monitoring for elements of the climate system that are in communication with the ocean, including the atmosphere, terrestrial land, and the surfaces of glaciated land. Global atmospheric reanalyses comprise model output that is statistically adjusted to available observations. Potentially, reanalyses offer a climatic context to observed changes in water mass distribution. Improvement in the representation of the water cycle and in water mass conservation have been stated goals of reanalysis projects. Here, we assess the capability of atmospheric reanalyses to represent variations in the global water budget from the perspective of ocean mass balance. The purpose of this work is to provide a detailed evaluation of current atmospheric reanalyses and their ability to reproduce spatial and temporal variations in atmospheric and terrestrial water storage. A second goal is to identify and characterize recent apparent trends in the water balance. We examine the ERA5, MERRA-2, and JRA-3Q reanalyses with a focus on the radio-occultation observing period from 2007 to the present. For terrestrial water storage we also compare with ERA5-Land, a surface reanalysis. The primary validation is from the NASA/DLR Gravity Recovery and Climate Experiment (GRACE) and its follow-on, GRACE-FO. The Atmospheric Infrared Sounder (AIRS) onboard NASA's Aqua satellite is also used for evaluation of the atmospheric moisture budget. Comparisons reveal strengths and weaknesses in the reanalyses of each component of the climate system. Reanalyses agree closely on atmospheric moisture storage trends, although mean values differ. Reanalyses show significant differences in land water storage. They also apply large corrections to the land water budget. Finally, reanalyses have differing abilities in representing the surface mass balance over glaciated land. Using the observed gravimetry record, changes in the underlying glaciated land ice are examined as a residual.

Richard Cullather↗
NASA NTRS1977

Mars and earth - Origin and abundance of volatiles

An investigation is conducted concerning the factors which are responsible for the tenuous nature of the Martian atmosphere in comparison to the terrestrial atmosphere, taking into account new data obtained in connection with the Viking missions. It is found that Mars was poor in volatiles from the start and fell further behind earth by less complete outgassing, by extensive retrapping, and by the partial loss of lighter gases. Attention is given to noble gases on earth and Mars, the condensation of noble gases and other volatiles, the sources of earth's volatiles, the bulk composition of earth, the release of volatiles from earth, clues to the volatile endowment of Mars, an abundance table for Mars, a comparison of terrestrial and Martian conditions, isotopic data on noble gases, xenon-129 on Mars and earth, possibilities concerning the loss of an early Martian atmosphere, the evolution of the atmosphere of Mars, conditions in the case of planet Venus, and the reasons for the poorness of small planets in volatiles.

Anders, E.↗
NASA NTRS1979

Middle atmosphere electrodynamics: Report of the Workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar Terrestrial Coupling

The middle atmosphere (MA), which is defined as the region bounded below by the tropopause near 10 km and above by the mesopause near 90 to 100 km, is regarded as a passive medium through which electric fields and currents are transmitted from sources above and below. A scientific background is given for: sources of MA electric fields; MA conductivity and currents; and MA plasma characteristics. Recommendations are given for research in MA electrodynamics in the following areas: (1) MA electrodynamical parameters; (2) models and supportive laboratory measurements; and (3) investigation of specific problems in the coupled systems.

Source record↗
NASA NTRS1972

Problem of photochemical equilibrium of ozone in planetary atmospheres: Ozone distribution in the lower atmosphere of Mars

The inherent errors of applying terrestrial atmospheric ozone distribution studies to the atmosphere of other planets are discussed. Limitations associated with some of the earlier treatments of photochemical equilibrium distributions of ozone in planetary atmospheres are described. A technique having more universal application is presented. Ozone concentration profiles for the Martian atmosphere based on the results of the Mariner 4 radio occultation experiment and the more recent results with Mariner 6 and Mariner 7 have been calculated using this approach.

Grams, G. W.↗
NASA NTRS1983

Photochemistry of methane in the earth's early atmosphere

The photochemical behavior of methane in the early terrestrial atmosphere is investigated with a detailed model in order to determine how much CH4 might have been present and what types of higher hydroocarbons could have been formed. It is found that any primordial methane accumulated during the course of earth accretion would have been dissipated by photochemical reactions in the atmosphere in a geologically short period of time after the segregation of the core. Abiotic sources of methane are not likely to have been large enough to sustain CH4 mixing ratios as high as 10 to the -6th, the threshold for a possible methane greenhouse, with a CO-rich atmosphere being a possible exception. After the origin of life an increasing biogenic source of methane may have driven CH4 mixing ratios well above 10 to the 6th. The rise of atmospheric oxygen in the early Proterozoic may have led to a more rapid photochemical destruction of methane, lowering the mixing ratio to its present value.

Kasting, J. F.↗
NASA NTRS1977

Composition and structure of Mars' upper atmosphere - Results from the neutral mass spectrometers on Viking 1 and 2

The upper atmospheric mass spectrometers flown on Viking 1 and 2 are described, and results obtained for the composition and structure of Mars' upper atmosphere are summarized. Carbon dioxide is the major constituent of the atmosphere at all heights below 180 km. The thermal structure of the upper atmosphere is complex and variable with average temperatures below 200 K for both Viking 1 and 2. The atmosphere is mixed to heights in excess of 120 km. The isotopic composition of carbon and oxygen in the Martian atmosphere is similar to that in the terrestrial atmosphere: N-15 is enriched in Mars' atmosphere by a factor of 1.62 + or - 0.16.

Nier, A. O.↗