Search NASA⌕ Search

SEARCH · Search NASA

Results for “VEGETATION COVER”

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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Coastal and Inland Aquatic Data Products for the Hyperspectral Infrared Imager (HyspIRI)

The HyspIRI Aquatic Studies Group (HASG) has developed a conceptual list of data products for the HyspIRI mission to support aquatic remote sensing of coastal and inland waters. These data products were based on mission capabilities, characteristics, and expected performance. The topic of coastal and inland water remote sensing is very broad. Thus, this report focuses on aquatic data products to keep the scope of this document manageable. The HyspIRI mission requirements already include the global production of surface reflectance and temperature. Atmospheric correction and surface temperature algorithms, which are critical to aquatic remote sensing, are covered in other mission documents. Hence, these algorithms and their products were not evaluated in this report. In addition, terrestrial products (e.g., land use land cover, dune vegetation, and beach replenishment) were not considered. It is recognized that coastal studies are inherently interdisciplinary across aquatic and terrestrial disciplines. However, products supporting the latter are expected to already be evaluated by other components of the mission. The coastal and inland water data products that were identified by the HASG, covered six major environmental and ecological areas for scientific research and applications: wetlands, shoreline processes, the water surface, the water column, bathymetry and benthic cover types. Accordingly, each candidate product was evaluated for feasibility based on the HyspIRI mission characteristics and whether it was unique and relevant to the HyspIRI science objectives.

Infrared↗
NASA NTRS1984

Effects of nontropical forest cover on climate

The albedo of a forest with snow on the ground is much less than that of snow-covered low vegetation such as tundra. As a result, simulation of the Northern Hemisphere climate, when fully forested south of a suitably chosen taiga/tundra boundary (ecocline), produces a hemispheric surface air temperature 1.9 K higher than that of an earth devoid of trees. Using variations of the solar constant to force climate changes in the GLAS Multi-Layer Energy Balance Model, the role of snow-albedo feedback in increasing the climate sensitivity to external perturbations is reexamined. The effect of snow-albedo feedback is found to be significantly reduced when a low albedo is used for snow over taiga, south of the fixed latitude of the ecocline. If the ecocline shifts to maintain equilibrium with the new climate - which is presumed to occur in a prolonged perturbation when time is sufficient for trees to grow or die and fall - the feedback is stronger than for a fixed ecocline, especially at high latitudes. However, this snow/vegetation-albedo feedback is still essentially weaker than the snow-albedo feedback in the forest-free case. The loss of forest to agriculture and other land-use would put the present climate further away from that associated with the fully forested earth south of the ecocline and closer to the forest-free case. Thus, the decrease in nontropical forest cover since prehistoric times has probably affected the climate by reducing the temperatures and by increasing the sensitivity to perturbations, with both effects more pronounced at high latitudes.

Otterman, J.↗
NASA NTRS1971

Remote sensing of some sedimentary rocks.

Sedimentary rocks including varying sized clastics and carbonates were overflown by aircraft between 1966 and 1971 producing data in the ultraviolet to microwave regions of the electromagnetic spectrum. This paper reports that multispectral analysis increases the ease and rapidity of discrimination of rock types having subtle differences in physical characteristics, but fails to enhance and may degrade distinctions where physical characteristics are significantly different. Brief resumes of color and color IR photographic data are presented. Thermal infrared is found to be useful in the mapping of rock units, but limitations such as moisture variation, soil cover, and vegetation may exceed in one formation the distinction between differing lithologies. A brief review of previously published SLAR data is included for completeness. Remote sensing techniques should reduce field geological effort by as much as 50%.

Brennan, P. A.↗
NASA NTRS1973

Evaluate ERTS imagery for mapping and detection of changes of snowcover on land and on glaciers

The author has identified the following significant results. The area of snow cover on land was determined from ERTS-1 imagery. Snow cover in specific drainage basins was measured with the Stanford Research Institute console by electronically superimposing basin outlines on imagery, with video density slicing to measure areas. Snow covered area and snowline altitudes were also determined by enlarging ERTS-1 imagery 1:250,000 and using a transparent map overlay. Under very favorable conditions, snowline altitude was determined to an accuracy of about 60 m. Ability to map snow cover or to determine snowline altitude depends primarily on cloud cover and vegetation and secondarily on slope, terrain roughness, sun angle, radiometric fidelity, and amount of spectral information available. Glacier accumulation area ratios were determined from ERTS-1 imagery. Also, subtle flow structures, undetected on aerial photographs, were visible. Surging glaciers were identified, and the changes resulting from the surge of a large glacier were measured as were changes in tidal glacier termini.

Meier, M. F.↗
NASA NTRS1973

Application of Earth Resources Technology Satellite data to urban development and regional planning: Test site, County of Los Angeles

The author has identified the following significant results. Signigicant results have been obtained from the analyses of ERTS-1 imagery from five cycles over Test Site SR 124 by classical photointerpretation and by an interactive hybrid multispectral information extraction system (GEMS). Photointerpretation has produced over 25 overlays at 1:1,000,000 scale depicting regional relations and urban structure in terms of several hundred linear and areal features. A possible new fault lineament has been discovered on the northern slope of the Santa Monica mountains. GEMS analysis of the ERTS-1 products has provided new or improved information in the following planning data categories: urban vegetation; land cover segregation; manmade and natural impact monitoring; urban design; land suitability. ERTS-1 data analysis has allowed planners to establish trends that directly impact planning policies. For example, detectable grading and new construction sites quantitatively indicated the extent, direction, and rate of urban expansion which enable planners to forecast demand and growth patterns on a regional scale. This new source of information will not only assist current methods to be more efficient, but permits entirely new planning methodologies to be employed.

Raje, S.↗
NASA NTRS1973

Evaluation of ERTS imagery for mapping and detection of changes of snowcover land and on glaciers

The percentage of snowcover area on specific drainage basins was measured from ERTS imagery by video density slicing with a repeatability of 4 percent of the snowcovered area. Data from ERTS images of the melt season snowcover in the Thunder Creek drainage basin in the North Cascades were combined with existing hydrologic and meteorologic observations to enable calculation of the time distribution of the water stored in this mountain snowpack. Similar data could be used for frequent updating of expected inflow to reservoirs. Equivalent snowline altitudes were determined from area measurements. Snowline altitudes were also determined by combining enlarged ERTS images with maps with an accuracy of about 60 m under favorable conditions. Ability to map snowcover or to determine snowline altitude depends primarily on cloud cover and vegetation and secondarily on slope, terrain roughness, sun angle, radiometric fidelity, and amount of spectral information available.

Meier, M. F.↗
NASA NTRS1973

First look analyses of five cycles of ERTS-1 imagery over County of Los Angeles: Assessment of data utility for urban development and regional planning

Significant results have been obtained from the analyses of ERTS-1 imagery from five cycles over Test Site SR 124 by classical photointerpretation and by an interactive hybrid multispectral information extraction system (GEMS). The synopticity, periodicity and multispectrality of ERTS coverage, available for the first time to LA County planners, have opened up both a new dimensionality in data and offer new capability in preparation of planning inputs. Photointerpretation of ERTS images has produced over 25 overlays at 1:1,000,000 scale depicting regional relations and urban structure in terms of several hundred linear and areal features. To mention only one such result, a possible new fault lineament has been discovered on the northern slope of the Santa Monica mountains in the scene 1144-18015, composited of MSS bands 4, 5, 6,. GEMS analysis of the ERTS products has provided new or improved information in the following planning data categories: urban vegetation; land cover segregation; man-made and natural impact monitoring; urban design; and suitability. ERTS data analysis has allowed planners to establish trends that directly impact planning policies. This new source of information will not only assist current methods to be more efficient, but permits entirely new planning methodologies to be employed.

Raje, S.↗
NASA NTRS1973

A Multidisciplinary Survey for the Management of Alaskan Resources Utilizing ERTS Imagery

The application of ERTS-1 imagery for a multidisciplinary study of Alaskan resources is discussed. ERTS-1 data form a politically neutral base from which resource surveys can be made without arousing suspicions from groups which have mutually confliciting goals. The specific use of ERTS-1 imagery for monitoring migratory animals, pipeline locations, road construction, snow cover, and vegetation growth is reported. Maps, illustrations, and photographs are provided to support the data.

Miller, J. M.↗
NASA NTRS1975

Status of coastal zone management techniques

Remote panchromatic imagery was applied to develop a coastal zone management atlas that provides for land cover or vegetation surveys as well as land use stereographic mapping for regional planning purposes.

Tilton, E. L., III↗
NASA NTRS1979

Cropping management using color and color infrared aerial photographs

The Universal Soil Loss Equation (USLE) is a widely accepted tool for erosion prediction and conservation planning. Solving this equation yields the long-term average annual soil loss that can be expected from rill and inter-rill erosion. In this study, manual interpretation of color and color infrared 70 mm photography at the scale of 1:60,000 is used to determine the cropping management factor in the USLE. Accurate information was collected about plowing practices and crop residue cover (unharvested vegetation) for the winter season on agricultural land in Pheasant Branch Creek watershed in Dane County, Wisconsin.

Morgan, K. M.↗
NASA NTRS1979

The joint measuring campaign 1979 in Ruthe (West Germany) description and preliminary data

The measurements and observations performed as part of the TELLUS project on soil moisture and heat budget evaluations of selected areas in the vecinity of Ruthe, West Germany are presented and discussed. The main lines of investigation include evapotranspiration and moisture content in bare soils covered by vegetation, interactions between natural phenomena and mesoscale heat budget, and man made changes and their impact on regional heat budget.

Vanderploeg, R. R.↗
NASA NTRS1986

The First International Satellite Land Surface Climatology Project (ISLSCP) field experiment FIFE

The purpose of ISLSCP is to verify the use of satellite data for the estimation of land-surface properties. This is to be done through a series of field experiments using a combination of point measurements on the ground and areal measurements from aircraft overflights. In addition to validating satellite estimates of surface properties, approaches for obtaining areal averages of the radiation, moisture, and heat fluxes from remotely sensed data are to be studied. The procedure for doing this is to combine the surface point measurements of the fluxes with the aircraft areal observations using a surface-energy-balance model. This should make it possible to interpolate between the point estimates of these fluxes and calculate area-averaged quantities. The surface parameters to be estimated from aircraft observations include: surface radiation temperature, albedo, land-cover or vegetation index, and surface soil moisture.

Schmugge, T. J.↗
NASA NTRS1990

System development and early biological tests in NASA's biomass production chamber

The Biomass Production Chamber at Kennedy Space Center was constructed to conduct large scale plant growth studies for NASA's CELSS program. Over the past four years, physical systems and computer control software have been continually upgraded and the degree of atmospheric leakage from the chamber has decreased from about 40 to 5 percent of the total volume per day. Early tests conducted with a limited degree of closure showed that total crop (wheat) growth from the best trays was within 80 percent of reported optimal yields for similar light levels. Yields from subsequent tests under more tightly closed conditions have not been as good--up to only 65 percent of optimal yields. Yields appear to have decreased with increasing closure, yet potential problems exist in cultural techniques and further studies are warranted. With the ability to tightly seal the chamber, quantitative data were gathered on CO2 and water exchange rates. Results showed that stand photosynthesis and transpiration reached a peak near 25 days after planting, soon after full vegetative ground cover was established. In the final phase of testing when atmospheric closure was the highest, ethylene gas levels in the chamber rose from about 10 to nearly 120 ppb. Evidence suggests that the ethylene originated from the wheat plants themselves and may have caused an epinastic rolling of the leaves, but no apparent detrimental effects on whole plant function.

Wheeler, R. M.↗
NASA NTRS1990

Remote sensing contribution to land surface hydrology

Progress that has been made over the past decade in developing technology for hydrological observations from operational aircraft is described. Particular attention is given to research on soil moisture, snow cover, and vegetation. Future missions such as the ESA ERS-1 and Canada's Radarsat mission are considered.

Salomonson, V. V.↗
NASA NTRS1989

Column atmospheric water vapor retrievals from airborne imaging spectrometer data

High-spatial-resolution column atmospheric water vapor amounts were derived from spectral data collected by the Airborne Visible Infrared Imaging Spectrometer (AVIRIS). The quantitative derivation is made by curve fitting observed spectra with calculated spectra in the 1.14- and 0.94-micron water-vapor band absorption regions with a nonlinear least-squares technique. The precision of the retrieved column water vapor is approximately 5 percent. The derived column water vapor amounts are independent of the absolute surface reflectance. Curve fitting of spectra near 1 micron from areas covered with vegetation indicates that both the amount of atmospheric water vapor and the moisture content of vegetation can be retrieved simultaneously. It should be possible to measure column water vapor over land areas from satellite altitude with the proposed high-resolution imaging spectrometer or even the moderate-resolution imaging spectrometer.

Gao, Bo-Cai↗
NASA NTRS1993

Discrimination of poorly exposed lithologies in AVIRIS data

One of the advantages afforded by imaging spectrometers such as AVIRIS is the capability to detect target materials at a sub-pixel scale. This paper presents several examples of the identification of poorly exposed geologic materials - materials which are either subpixel in scale or which, while having some surface expression over several pixels, are partially covered by vegetation or other materials. Sabol et al. (1992) noted that a primary factor in the ability to distinguish sub-pixel targets is the spectral contrast between the target and its surroundings. In most cases, this contrast is best expressed as an absorption feature or features present in the target but absent in the surroundings. Under such circumstances, techniques such as band depth mapping (Clark et al., 1992) are feasible. However, the only difference between a target material and its surroundings is often expressed solely in the continuum. We define the 'continuum' as the reflectance or radiance spanning spectral space between spectral features. Differences in continuum slope and shape can only be determined by reduction techniques which considers the entire spectral range; i.e., techniques such as spectral mixture analysis (Adams et al., 1989) and recently developed techniques which utilize an orthogonal subspace projection operator (Harsanyi, 1993). Two of the three examples considered herein deal with cases where the target material differs from its surroundings only by such a subtle continuum change.

Farrand, William H.↗
NASA NTRS1995

Sub-pixel localization of highways in AVIRIS images

Roads and highways show up clearly in many bands of AVIRIS images. A typical lane in the U.S. is 12 feet wide, and the total width of a four lane highway, including 18 feet of paved shoulders, is 19.8 m. Such a highway will cover only a portion of any 20x20 m AVIRIS pixel that it traverses. The other portion of these pixels wil be usually covered by vegetation. An interesting problem is to precisely determine the location of a highway within the AVIRIS pixels that it traverses. This information may be used for alignment and spatial calibration of AVIRIS images. Also, since the reflection properties of highway surfaces do not change with time, and they can be determined once and for all, such information can be of help in calculating and filtering out the atmospheric noise that contaminates AVIRIS measurements. The purpose of this report is to describe a method for sub-pixel localization of highways.

Salu, Yehuda↗
NASA NTRS2004

Improving the Representation of Land in Climate Models by Application of EOS Observations

The PI's IDS current and previous investigation has focused on the applications of the land data toward the improvement of climate models. The previous IDS research identified the key factors limiting the accuracy of climate models to be the representation of albedos, land cover, fraction of landscape covered by vegetation, roughness lengths, surface skin temperature and canopy properties such as leaf area index (LAI) and average stomatal conductance. Therefore, we assembled a team uniquely situated to focus on these key variables and incorporate the remotely sensed measures of these variables into the next generation of climate models.

Source record↗