SEARCH · Search NASA

Results for “Basin area”

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.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11

All sources NASA NTRS DOE OSTI

NASA NTRS1974

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 snowcover on 10 individual drainage basins in the North Cascades, Washington, has been determined by use of a semi-automatic radiance threshold technique. The result is a unique record of the changing water storage as snow in these important hydrologic units, the runoff of which is utilized for hydroelectric power, dilution of wastes and heat, support of salmon migration, and irrigation. These data allow a new type of hydrologic modelling to proceed which should permit more accurate forecasts of streamflow. A new technique has been developed for measuring snow-covered area or snowline altitude semi-automatically. This variable contour overlay method permits the snowcover to be matched efficiently to the best fit contour of altitude. The motion of the Yentna Glacier during the concluding phase of its surge was successfully measured by a flicker technique using images of two dates. It appears that displacements as small as 100 to 200 m can be measured. Motion of the Tweedsmuir Glacier in Alaska was measured using ERTS-1 images enlarged to 1:50,000. Changes detected included a shock wave moving down the glacier, the margin expanding, the moraine pattern deforming, and the marginal valley deepening.

Meier, M. F.↗

NASA NTRS1982

Mare basin filling on the moon - Laboratory simulations

Laboratory simulations of lavas filling a stylized lunar multi-ringed basin demonstrate several relationships between the morphology of the emplaced lavas and various eruption conditions. The rate of effusion is the primary control on the gross shape of the accumulated lavas, with relatively low rates (e.g., Hawaiian style) leading to shield volcanoes and high rates (e.g., flood eruptions) producing flat, ponded lavas. Pre-flow topography can have a significant effect on the general form of individual flows and the position of flow features such as lava channels. Rootless vents develop in many parts of the flow, including areas apparently related to the position of basin rings, giving the false appearance of aligned true vent systems.

Greeley, R.↗

NASA NTRS1985

Foreland Basin Structures and Remote Sensing

Rocky Mountain foreland basins are somewhat unique in that the basins may exhibit a variety of structural styles. It is generally agreed that shortening has occurred in the foreland basement but the cause is controversial: vertical vs compressional horizontal tectonics. Even when shortening is attributed to compression, the attitude (dip) of the fault plane and whether the horizontal or vertical component of movement is dominant is unconstrained. The controversy is difficult to resolve from surface data alone due to the variety of possible interpretations. Detailed surface mapping and geologic modeling are needed to constrain subsurface interpretations. In many areas of the Wind River and Bighorn basins detailed geologic maps do not exist. State-of-the-art remote sensing data could potentially provide an efficient means of mapping surface geology. State-of-the-art remote sensing systems now provide geometrically correct data at 30 meter pixel size and increased spectral coverage, capable of more detailed geologic analyses. These data can be photographically enlarged to 1:24,000 scale and combined with 7 1/2' uses topographic quads to provide an excellent base map for geologic interpretations.

Paylor, E. D.↗

NASA NTRS1972

Interdisciplinary applications and interpretations of remotely sensed data

An interdisciplinary approach to use remote sensor for the inventory of natural resources is discussed. The areas under investigation are land use, determination of pollution sources and damage, and analysis of geologic structure and terrain. The geographical area of primary interest is the Susquehanna River Basin. Descriptions of the data obtained by aerial cameras, multiband cameras, optical mechanical scanners, and radar are included. The Earth Resources Technology Satellite and Skylab program are examined. Interpretations of spacecraft data to show specific areas of interest are developed.

Peterson, G. W.↗

NASA NTRS1974

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

The author has identified the following significant results. Snowlines on a small (6 sq km) drainage basin were accurately measured without use of digital processing, and snow patches as small as 150 m (maximum dimension) were correctly identified, proving that the resolution of ERTS is ample for snow mapping needs. The area of snow cover on 10 individual drainage basins in the North Cascades, Washington, has been determined at 12 different times; these data can be used for more accurate forecasts of streamflow. Progress has been made in distinguishing snow in trees using multispectral analysis. Motion of the surging Tweedsmuir Glacier was measured. Velocities ranged from 2 to 88 m per day; a zone of intense crevassing also appeared to spread up and down the glacier (at about 200 m per day upglacier). This tentative result may be of great importance to an understanding of surging glacier dynamics. ERTS images also show that the most recent debris flow (20-21 August 1973) from Mount Baker can be clearly discerned and mapped, in order to monitor this potential hazard.

Meier, M. F.↗

NASA NTRS1977

Application of Landsat data to wetland study and land use classification in West Tennessee

Landsat data were employed in determining land use of a 32,300-hectare watershed area within the Obion-Forked Deer River Basin in northwest Tennessee. Black and white transparency chips for all four wavelength bands were interpreted by use of a video-input analog/digital automatic analysis and classification facility; densitometric methods showed that wetlands, urban areas, agricultural lands and forests could be discriminated by analysis of band 6 or 7 together with band 4 or 5. Comparison with high- and low-altitude photography indicated that the Landsat data could provide sufficiently accurate resource information and determine drainage trends.

Jones, N. L.↗

NASA NTRS1981

Ridge systems of Mars

Mare-type ridges on the Planet Mars were mapped and described based on Viking images. The ridges mapped range from 5 to 400 km long and 1 to 8 km wide. Most ridges on Mars are on plains and plateau units; 4,321 ridges with a total length of 153,835 km were mapped on these unit types. Ridges which resemble lunar mare ridges were also mapped in craters, basins, and several volcanic calderas on Mars. Mapping of ridges on a global scale reveals that they are preferentially developed in older, thinner plains units probably of flood basalt origin. Measuring the trends of ridges in plains units on Mars shows that there is a planetwide predominance of north, northwest and northeast trends. It is proposed that ridges are compressional tectonic features which have formed in response to changes in the planet's rotational equilibrium figure early in its history. In addition, the Tharsis uplift has created a regional stress system which accounts for the trends of ridges in areas near by. Ridges in craters and basins are similarly caused by shortening across the basin in response to regional stresses.

Gifford, A. W.↗

NASA NTRS1994

Amazon Rain Forest Classification Using J-ERS-1 SAR Data

The Amazon rain forest is a region of the earth that is undergoing rapid change. Man-made disturbance, such as clear cutting for agriculture or mining, is altering the rain forest ecosystem. For many parts of the rain forest, seasonal changes from the wet to the dry season are also significant. Changes in the seasonal cycle of flooding and draining can cause significant alterations in the forest ecosystem.Because much of the Amazon basin is regularly covered by thick clouds, optical and infrared coverage from the LANDSAT and SPOT satellites is sporadic. Imaging radar offers a much better potential for regular monitoring of changes in this region. In particular, the J-ERS-1 satellite carries an L-band HH SAR system, which via an on-board tape recorder, can collect data from almost anywhere on the globe at any time of year.In this paper, we show how J-ERS-1 radar images can be used to accurately classify different forest types (i.e., forest, hill forest, flooded forest), disturbed areas such as clear cuts and urban areas, and river courses in the Amazon basin. J-ERS-1 data has also shown significant differences between the dry and wet season, indicating a strong potential for monitoring seasonal change. The algorithm used to classify J-ERS-1 data is a standard maximum-likelihood classifier, using the radar image local mean and standard deviation of texture as input. Rivers and clear cuts are detected using edge detection and region-growing algorithms. Since this classifier is intended to operate successfully on data taken over the entire Amazon, several options are available to enable the user to modify the algorithm to suit a particular image.

J-ERS-1↗

NASA NTRS2003

Evidence for a Thick Mantle of Volatile-rich Materials in the Utopia Basin, Mars, Based on Crater Depth/Diameter Measurements

This study focuses on the depth/diameter (d/D) relationships of impact craters within Utopia Basin (25 deg. N - 70 deg. N, 88 deg. W - 150 deg. W), Mars. In order to search for spatial variations in the study area, d/D values for a total of 1,430 craters have been grouped by sub-regions based upon their similar d/D characteristics. This has revealed a significant difference in d/D relationship for craters in north central Utopia basin compared with other parts of the basin, and withother areas on Mars. Preliminary measurements have also been collected in four additional test areas (Acidalia, Sinai, Sirenum, and south of Argyre) for comparison purposes.

Boyce, Joseph M.↗

NASA NTRS1991

The lunar farside - The nature of highlands east of Mare Smythii

A study of lunar orbital data to determine the origin and nature of geochemical variation in a portion of the farside highlands east of the Smythii basin is presented. Averages and ranges of concentrations for the elements Al, Mg, Fe, Ti, and Th are calculated and correlated for photogeologically defined units associated with some specific features and with the region as a whole. The region east of Smythii contains regolith that is far removed from, and therefore largely uncontaminated by, nearside basin material. By conducting a geochemical characterization of this area, the degree of heterogeneity in 'uncontaminated' highlands can be determined, and by implication the extent to which volcano-tectonic activity unrelated to the nearside basins has occurred on the moon.

Clark, Pamela E.↗

NASA NTRS2007

Emissions from Forest Fires near Mexico City

The emissions of NOx (defined as NO (nitric oxide) + NO2 (nitrogen dioxide)) and hydrogen cyanide (HCN), per unit amount of fuel burned, from fires in the pine forests that dominate the mountains surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burning. The ammonia (NH3) emissions are about average for forest burning. The upper limit for the mass ratio of NOX to volatile organic compounds (VOC) for these MC-area mountain fires was approximately 0.38, which is similar to the NOx/VOC ratio in the MC urban area emissions inventory of 0.34, but much larger than the NOx/VOC ratio for tropical forest fires in Brazil (approximately 0.068). The nitrogen enrichment in the fire emissions may be due to deposition of nitrogen-containing pollutants in the outflow from the MC urban area. This effect may occur worldwide wherever biomass burning coexists with large urban areas (e.g. the tropics, southeastern US, Los Angeles Basin). The molar emission ratio of HCN to carbon monoxide (CO) for the mountain fires was 0.012 +/- 0.007, which is 2-9 times higher than widely used literature values for biomass burning. The ambient molar ratio HCN/CO in the MC-area outflow is about 0.003 +/- 0.0003. Thus, if only mountain fires emit significant amounts of HCN, these fires may be contributing about 25% of the CO production in the MCarea (approximately 98-100 W and 19-20 N). Comparing the PM10/CO and PM2.5/CO mass ratios in the MC Metropolitan Area emission inventory (0.01 15 and 0.0037) to the PM1/CO mass ratio for the mountain fires (0.133) then suggests that these fires could produce as much as approximately 79-92% of the primary fine particle mass generated in the MC-area. Considering both the uncertainty in the HCN/CO ratios and secondary aerosol formation in the urban and fire emissions implies that about 50 +/- 30% of the "aged" fine particle mass in the March 2006 MC-area outflow could be from these fires.

Yokelson, R.↗

NASA NTRS2021

Financial feasibility of water conservation in agriculture

Global water use for food production needs to be reduced to remain within planetary boundaries, yet the financial feasibility of crucial measures to reduce water use is poorly quantified. Here, we introduce a novel method to compare the costs of water conservation measures with the added value that reallocation of water savings might generate if used for expansion of irrigation. Based on detailed water accounting through the use of a high-resolution hydrology-crop model, we modify the traditional cost curve approach with an improved estimation of demand, increasing marginal cost per water conservation measure combination and add a correction to control for impacts on downstream water availability. We apply the method to three major river basins in the Indo-Gangetic plain (Indus, Ganges and Brahmaputra), a major global food producing region but increasingly water stressed. Our analysis shows that at basin level only about 10% (Brahmaputra) to just over 20% (Indus and Ganges) of potential water savings would be realised; the equilibrium price for water is too low to make the majority of water conservation measures cost effective. The associated expansion of irrigated area is moderate, about 7% in the Indus basin, 5% in the Ganges and negligible in the Brahmaputra, but farmers' gross profit increases more substantially, by 11%. Increasing the volumetric cost of irrigation water influences supply and demand in a similar way and has little influence on water reallocation. Controlling for the impact on return flows is important and more than halves the amount of water available for reallocation.

Geography / Land Utilization↗

NASA NTRS1973

Water demand studies

The areas of focus of the Santa Barbara and Riverside groups in conducting water demand studies are the central and southern California regional test sites, respectively. Within each test site, sub-areas have been selected for use in the making of detailed investigations. Within each of these sub-areas an in-depth evaluation is being made as to the capability of remote sensing systems to provide pertinent data relative to water demand phenomena. These more limited sub-areas are: (1) Kern County and the San Joaquin Basin; (2) Chino-Riverside Basin; and (3) the Imperial Valley. Rational for the selection of these subareas included the following: Much of the previous remote sensing research had been conducted in these areas and therefore a great deal of remote sensing imagery and pertinent ground truth for the areas was already available.

Bowden, L. W.↗

NASA NTRS1972

Dynamics of playa lakes in the Texas High Plains

The author has identified the following significant results. Three small playa lake basins on the southern High Plains, Texas, have been examined by geologists, pedologists, hydrologists, and botanists to establish ground truth for correlation with ERTS-1 imagery. Although the sites are recognizable, details of the three playa basins are too small, at present resolution, to be accurately determined by the available MSS imagery. However, a fourth study site, consisting of a dual playa complex approximately 5 miles long in a basin of 9 square miles, does resolve available imagery allowing accurate measurement of water fluctuations and water depth. Of the available MSS imagery, Band 5 is the most usable. Definition of Band 4 is less due to reduced tonal contrast. The greatest tonal contrast appears on Band 6 and Band 7 between dry land and water areas. Band 6 is particularly good for defining large water areas, Band 7 being best for small lake basins, and Band 5 for growing fields.

Reeves, C. C., Jr.↗

NASA NTRS1978

HCMM energy budget data as a model input for assessing regions of high potential groundwater pollution

The author has identified the following significant results. In early April 1978, heavy spring runoff from snowmelt caused significant flooding along a portion of the Big Sioux River Basin in southeastern South Dakota. The flooded area was visible from surrounding areas on a May 15 HCMM IR test image. On May 15, the flood waters had receded but an area of anomalous residual high soil moisture remained. The high soil moisture area was not visible on a HCMM day visible test image of the same scene, or on LANDSAT imagery. To evaluate the effect of water table depth on surface temperatures, thermal scanner data collected on September 5 and 6, 1978 at approximate HCMM overpass times at an altitude of 3650 m were analyzed. Apparent surface temperatures measured by the scanner included emittance contributions from soil surface and the land cover. Results indicated that the shallow water tables produced a damping of the amplitude of the diurnal surface temperature wave.

Moore, D. G.↗

NASA NTRS1980

Pioneer Venus radar results - Geology from images and altimetry

An unimodal distribution of relief for Venus was obtained from the Pioneer Venus altimetry measurements. The 'upland' rolling plains constituting 65% of the surface show dark circular lava-filled impact basins; highlands in the 8% of the area comprise Ishtar Terra and Aphrodite Terra; and the lowlands consist of crudely circular surfaces with low relief within the highlands. The complex ridge-and-trough regions east of Ishtar Terra and in the southern Aphrodite Terra may be due to large-scale crustal motions.

Masursky, H.↗

NASA NTRS1988

Methane emissions to the troposphere from the Amazon floodplain

The magnitudes of CH4 emissions to the troposphere from the Amazon River floodplain and the mechanism of these emissions were investigated using the data of 94 individual flux measurements made along a 1700-km stretch of the river during July/August 1985. The overall average rate of CH4 emission from wetlands was found to be 390 mg CH4/sq m per day, with the highest emissions (590 mg CH4/sq m per day) attributed to the water surfaces covered by aquatic macrophytes. Ebullition was the dominant mechanism of emission, accounting for 85 percent of the total. Surface-water CH4 concentrations were highly supersaturated, averaging 6.4 micromolar. The annual emission of CH4 from the Amazon Basin to the troposphere, estimated from the area and the known emission rate, is about 10 CH4 Tg/yr, indicating the importance of the area in the global atmospheric CH4 cycle.

Devol, Allen H.↗

NASA NTRS1989

AVHRR for monitoring global tropical deforestation

Advanced Very High Resolution Radiometer (AVHRR) data have been used to assess the dynamics of forest trnsformations in three parts of the tropical belt. A large portion of the Amazon Basin has been systematically covered by Local Area Coverage (LAC) data in the 1985-1987 period. The analysis of the vegetation index and thermal data led to the identification and measurement of large areas of active deforestation. The Kalimantan/Borneo forest fires were monitored and their impact was evaluated using the Global Area Coverage (GAC) 4 km resolution data. Finally, High Resolution Picture Transmission (HRPT) data have provided preliminary information on current activities taking place at the boundary between the savanna and the forest in the Southern part of West Africa. The AVHRR approach is found to be a highly valuable means for carrying out deforestation assessments in regional and global perspectives.

Malingreau, J. P.↗