Search NASA⌕ Search

SEARCH · Search NASA

Results for “water studies”

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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Skylab study of water quality

The author has identified the following significant results. Radiometric data derived from S-190A photography appears to correlate reasonably well with suspended solids without the need of rationing the radiances of different bands.

Yarger, H. L.↗
NASA NTRS1975

Atmospheric corrections for satellite water quality studies

Variations in the relative value of the blue and green reflectances of a lake can be correlated with important optical and biological parameters measured from surface vessels. Measurement of the relative reflectance values from color film imagery requires removal of atmospheric effects. Data processing is particularly crucial because: (1) lakes are the darkest objects in a scene; (2) minor reflectance changes can correspond to important physical changes; (3) lake systems extend over broad areas in which atmospheric conditions may fluctuate; (4) seasonal changes are of importance; and, (5) effects of weather are important, precluding flights under only ideal weather conditions. Data processing can be accomplished through microdensitometry of scene shadow areas. Measurements of reflectance ratios can be made to an accuracy of plus or minus 12%, sufficient to permit monitoring of important eutrophication indices.

Piech, K. R.↗
NASA NTRS1975

Skylab fluid mechanics demostration - A study of water droplet oscillations in space

In the Skylab experiment a drop of water was caused to oscillate at its natural oscillation frequency. The drop was observed until its oscillation began to decay due to its internal damping. A determination of the change in amplitude with time made it possible to verify the applicability of a theoretical model. The fundamental concept of the model is that fluid surfaces tend to an equilibrium shape produced by the balance of the forces of fluid pressure and surface tension. The theoretical model is based on the assumption that the wave amplitude is small compared with the wavelength.

Vaughan, O. H.↗
NASA NTRS1975

Skylab study of water quality

The author has identified the following significant results. Apparent reflectance levels in the Skylab S190A and S192 bands, from one pass over three Kansas reservoirs, exhibit good statistical correlation with suspended solids. Band ratios appear to yield the best results. The concentration of suspended solids, mostly inorganic sediment, has the most effect on the reflected energy. Dissolved solids concentrations up to 200 ppm were not detectable by the Skylab sensors.

Yarger, H. L.↗
NASA NTRS1981

Processing multispectral data obtained by orbital platforms of the LANDSAT series for studies of water quality in Guanabara Bay

The relationship existing between Guanabara Bay water quality ground truth parameters and LANDSAT MSS video data was investigated. The parameters considered were: chorophyll content, water transparency usng the Secchi disk, salinity, and dissolved ammonia. Data from two overflights was used, and methods of processing digital data were compared. Linear and nonlinear regression analyses were utilized, comparing original data with processed data by using the correlation coefficient and the estimation mean error. It was determined that better quality data are obtained by using radiometric correction programs with a physical basis, contrast ratio, and normalization. Incidental locations of floating vegetation, changes in bottom depth, oil slicks, and ships at anchor were made.

Dejesusparada, N.↗
NASA NTRS1990

A simulation and diagnostic study of water vapor image dry bands

Limited Area Mesoscale Prediction System model simulation and a special 3-hr radiosonde data set were used to investigate warm bands in the 6.7-micron water-vapor satellite imagery on March 6-7, 1982. It was found that the model reproduces major characteristics of the observed blackbody temperature, T(B), field. A 'development' dry image feature was found to occur in conjunction with an upper level shortwave trough, and an 'advective' feature was found associated with a polar jet streak. Both model and observed T(B) features were associated with vorticity maxima.

Muller, Bradley M.↗
NASA NTRS1991

Studies of water storage and other contributions to changes in the rotation of the Earth

The effects were determined of the global redistribution of water mass on various geodetic observables, especially polar motion, and complementary observables such as geodetic satellite positions. The effect of water mass redistribution has been and continues to be less well known and more difficult to observe than effects of air mass distribution, yet the water contribution is potentially significant over a large range of periods. The current understanding is reviewed of the contribution of polar drift, decadal polar motion, Chandler and annual wobbles, and higher frequency polar motion, as determined through the efforts of the funded work within the NASA Crustal Dynamics Project, and in the context of the general literature on the subject. Water mass redistribution is either demonstrably important to the excitation of each of these, or is probably important given a lack of other likely excitation sources.

Wilson, Clark R.↗
NASA NTRS2013

Spectral Study of Water Tracks as an Analog for Recurring Slope Lineae

Liquid water is a key requirement for life on Earth, and serves as an important constraint on present day habitability on Mars. Recurring Slope Lineae (RSL) are a unique phenomenon on Mars that may be formed by brine seeps. Their morphological, seasonal and temporal characteristics support this hypothesis; however, spectral evidence has been lacking. Ojha et al., 2013 recently analyzed CRISM images from all confirmed RSL in the southern mid-latitudes and equatorial regions and found no spectro-scopic evidence for water. Instead, enhanced abun-dances or distinct grain sizes of both ferric and ferrous minerals are observed at most sites. The strength of these spectral signatures changes as a function of sea-son, possibly indicating removal of a fine-grained sur-face component during RSL flow, precipitation of fer-ric oxides, and/or wetting of the substrate. Water tracks (WT) have been suggested as a terrestrial analog for RSL by Levy et al., 2011. WT are defined as dark surface features that extend downslope in a linear or branching fashion, usually oriented along the steepest local gradient, in the Dry Valleys of Antarctica. They can be 1-3 m in width and can have lengths up to 2 km. They share many morphological and seasonal characteristics with RSL including active growth during summer seasons and fading during winter. Snowmelt, ground ice melt and deliquescence by hygroscopic salts have been suggested as possible formation mechanisms for water tracks. No spectral work to date has been reported for water tracks.

volumet-ric water content (VWC)↗
NASA NTRSDate not supplied

Numerical Study of Water Ice and Molecular Contamination Build Up during JWST Deployment

This paper summarizes a recent numerical analysis of water vapor and volatile condensible material deposition on the James Webb Space Telescope from the initial orbit insertion up to 180 days post launch. The analysis utilized 17 distinct geometry files capturing observatory configuration changes during the deployment. Surface temperature was set from a time-dependent thermal analysis solution. A vapor pressure model was used to calculate the net water ice adsorption. Molecular contamination included a contribution from UV photopolymerization. The analysis predicted levels of ice and molecular accumulation were found to be within the allowable limits specified by the observatory contamination control plan.

James Webb Space Telescope↗
NASA NTRSDate not supplied

Numerical Study of Water Ice and Molecular Contamination Build Up during JWST Deployment

This paper summarizes a recent numerical analysis of water vapor and volatile condensible material deposition on the James Webb Space Telescope from the initial orbit insertion up to 180 days post launch. The analysis utilized 17 distinct geometry files capturing observatory configuration changes during the deployment. Surface temperature was set from a time-dependent thermal analysis solution. A vapor pressure model was used to calculate the net water ice adsorption. Molecular contamination included a contribution from UV photopolymerization. The analysis predicted levels of ice and molecular accumulation were found to be within the allowable limits specified by the observatory contamination control plan.

James Webb Space Telescope↗
NASA NTRS2020

Airborne Radiometry for Calibration, Validation, and Research in Oceanic, Coastal, and Inland Waters

Present-day ocean color satellite sensors, which principally provide reliable data on chlorophyll, sediments, and colored dissolved organic material in the open ocean, are not well suited for coastal and inland water studies for a variety of reasons, including coarse spatial and spectral resolution plus challenges with atmospheric correction. National Aeronautics and Space Administration (NASA) airborne mission concepts tested in 2011, 2013, 2017, and 2018 over Monterey Bay, CA, and nearby inland waters have demonstrated the feasibility of improving airborne monitoring and research activities in case-1 and case-2 aquatic ecosystems through the combined use of state-of-the-art above- and in-water measurement capabilities. These competencies have evolved through time to produce a sensor-web approach: imaging spectrometer, microradiometers, and a sun photometer (airborne) with their analogous algorithms, and with corresponding in-water radiometers and ground-based sun photometry. The NASA airborne instrument suite and mission concept demonstrations, leveraging high quality above- and in-water data, significantly improves the fidelity as well as the spatial and spectral resolution of observations for studying and monitoring water quality in oceanic, coastal, and inland water ecosystems. The goal of this series of projects was to develop and fly a portable airborne sensor suite for NASA science missions focusing on a gradient of water types from oligotrophic to turbid waters addressing the challenges of an optically complex coastal ocean zone and inland waters. The airborne radiometry in this range of aquatic conditions and sites has supported improved results of studies of water quality and biogeochemistry and provides capabilities for research areas such as ocean productivity and biogeochemistry; aquatic impacts of coastal landscape alteration; coastal, estuarine, and inland waters ecosystem productivity; atmospheric correction; and regional climate variability.

atmospheric correction↗
NASA NTRS2015

Mars Soil-Based Resource Processing and Planetary Protection

The ability to extract and process resources at the site of exploration into products and services, commonly referred to as In Situ Resource Utilization (ISRU), can have significant benefits for robotic and human exploration missions. In particular, the ability to use in situ resources to make propellants, fuel cell reactants, and life support consumables has been shown in studies to significantly reduce mission mass, cost, and risk, while enhancing or enabling missions not possible without the incorporation of ISRU. In December 2007, NASA completed the Mars Human Design Reference Architecture (DRA) 5.0 study. For the first time in a large scale Mars architecture study, water from Mars soil was considered as a potential resource. At the time of the study, knowledge of water resources (their form, concentration, and distribution) was extremely limited. Also, due to lack of understanding of how to apply planetary protection rules and requirements to ISRU soil-based excavation and processing, an extremely conservative approach was incorporated where only the top several centimeters of ultraviolet (UV) radiated soil could be processed (assumed to be 3% water by mass). While results of the Mars DRA 5.0 study showed that combining atmosphere processing to make oxygen and methane with soil processing to extract water provided the lowest mission mass, atmosphere processing to convert carbon dioxide (CO2) into oxygen was baselined for the mission since it was the lowest power and risk option. With increased knowledge and further clarification of Mars planetary protection rules, and the recent release of the Mars Exploration Program Analysis Group (MEPAG) report on "Special Regions and the Human Exploration of Mars", it is time to reexamine potential water resources on Mars, options for soil processing to extract water, and the implications with respect to planetary protection and Special Regions on Mars.

Sanders, G. B.↗