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At least 91 records · Page 5

Remote sensing of effects of land-use practices on water quality

Research efforts are presented for the use of remote sensing in environmental surveys in Kentucky. Ground truth parameters were established that represent the vegetative cover of disturbed and undisturbed watersheds in the Cumberland Plateau of eastern Kentucky. Several water quality parameters were monitored of the watersheds utilized in the establishment of ground truth data. The capabilities of multistage-multispectral aerial photography and satellite imagery were evaluated in detecting various land use practices. The use of photographic signatures of known land use areas utilizing manually-operated spot densitometers was studied. The correlation of imagery signature data to water quality data was examined. Potential water quality predictions were developed from forested and nonforested watersheds based upon the above correlations. The cost effectiveness of predicting water quality values was evaluated using multistage and satellite imagery sampling techniques.

Graves, D. H.↗

Earth observations during Space Shuttle mission STS-34 - 18-23 October 1989

An overview is presented of the 31st Space Shuttle mission, whose major objective was to deploy the Galileo spacecraft. Color images are presented of photos taken by the four videocameras in the payload bay, one 16-mm Arriflex in the cabin, a videocamcorder, three 35 mm cameras, two 70 mm cameras, and an IMAX camera. In addition, descriptions of visual observations by the mission astronauts are given. The most significant STS-34 earth photography for the major geographical regions is discussed. Individual highlights of this mission include observation of the apparent recovery of the water level of Lake Nasser to conditions similar to those during the second Space Shuttle mission of 1981; the documentation of the impact of the Yucatan forest blowdown and fires after the passage of Hurricane Gilbert; and the confirmation of the high value of space photography under low and very low sun angle conditions for geomorphological and geological analyses.

Helfert, Michael R.↗

Geologic and mineral and water resources investigations in western Colorado, using Skylab EREP data

The author has identified the following significant results. Skylab photographs are superior to ERTS images for photogeologic interpretation, primarily because of improved resolution. Lithologic contacts can be detected consistently better on Skylab S190A photos than on ERTS images. Color photos are best; red and green band photos are somewhat better than color-infrared photos; infrared band photos are worst. All major geologic structures can be recognized on Skylab imagery. Large folds, even those with very gentle flexures, can be mapped accurately and with confidence. Bedding attitudes of only a few degrees are recognized; vertical exaggeration factor is about 2.5X. Mineral deposits in central Colorado may be indicated on Skylab photos by lineaments and color anomalies, but positive identification of these features is not possible. S190A stereo color photography is adequate for defining drainage divides that in turn define the boundaries and distribution of ground water recharge and discharge areas within a basin.

Lee, K.↗

Applications experiments in the Houston region

Organization, staffing, and planning for experimental applications of remote sensing data to gain land use and water management information are described. Work was started on an experimental data base, aerial multispectral photography, and forest and wild life surveys as part of a regional inventory and monitory program.

Erb, R. B.↗

Geography From Another Dimension

The GEODESY software program is intended to promote geographical awareness among students with its remote sensing capabilities to observe the Earth's surface from distant vantage points. Students and teachers using GEODESY learn to interpret and analyze geographical data pertaining to the physical attributes of their community. For example, the program provides a digital environment of physical features, such as mountains and bodies of water, as well as man-made features, such as roads and parks, using aerial photography, satellite imagery, and geographic information systems data in accordance with National Geography Standards. The main goal is to have the students and teachers gain a better understanding of the unique forces that drive their coexistence. GEODESY was developed with technical assistance and financial support from Stennis Space Center's Commercial Remote Sensing Program Office, now known as the Earth Science Applications Directorate.

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Remote sensing in the detection of regional change.

Investigation of the impact of the California State Water Project on the west side of the San Joaquin Valley, using aerial photo mosaics and high-altitude photography for 1957 and 1971. Particular attention is paid to a determination of gross land use change and to the detection of specific patterns of development emerging from this change. Information derived from the mapping and tabulating of data acquired in this study indicates a definite trend toward the development of an agricultural landscape and increasing intensification of land use on the west side of the San Joaquin Valley. The introduction of water into this arid region is resulting in large acreages of land being brought under cultivation. Consequently, cropland is assuming a more dominant position with respect to areal extent.

Estes, J. E.↗

A study of Minnesota land and water resources using remote sensing

A pilot study of 60 lakes in Minnesota shows that LANDSAT data correlate very well with the Carlson trophic state index which is derived from measurements in the field. Nimbus satellite data reveal improvement in water quality in Lake Superior since the dumping of taconite tailings stopped in 1980. A feasibility study of using color infrared photography as a near real time tool for soil and crop management in corn and soybean areas of the state generated strong interest from farmers and agribusiness firms. The state geological survey had success in the use and applications of LANDSAT images. Subtleties of changes in vegetation, soil, and topography are such that ground water presence and depth to water table are nearly always impossible to qualify except for broad scale applications. Bedrock and structural differences as shown in lineaments offer great potential for resolution of some kinds of geologic studies. A synergistic concept is to be used to search for mineral resources in the northeastern part of the state.

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Making The Invisible Visible

In public and private archives throughout the world there are many historically important documents that have become illegible with the passage of time. They have faded, been erased, acquired mold, water and dirt stain, suffered blotting or lost readability in other ways. While ultraviolet and infrared photography are widely used to enhance deteriorated legibility, these methods are more limited in their effectiveness than the space-derived image enhancement technique. The aim of the JPL effort with Caltech and others is to better define the requirements for a system to restore illegible information for study at a low page-cost with simple operating procedures. The investigators' principle tools are a vidicon camera and an image processing computer program, the same equipment used to produce sharp space pictures. The camera is the same type as those on NASA's Mariner spacecraft which returned to Earth thousands of images of Mars, Venus and Mercury. Space imagery works something like television. The vidicon camera does not take a photograph in the ordinary sense; rather it "scans" a scene, recording different light and shade values which are reproduced as a pattern of dots, hundreds of dots to a line, hundreds of lines in the total picture. The dots are transmitted to an Earth receiver, where they are assembled line by line to form a picture like that on the home TV screen.

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Photography from space to help solve problems on earth

Varied uses of ERTS imagery are briefly discussed. Applications to mineral/land resources, environment, land use, water resources, maps/charts, marine resources, and agriculture/forestry/range resources are also provided.

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Correlation studies of passive and active microwave data in the marginal ice zone

The microwave radiative and backscatter characteristics of sea ice in an Arctic marginal ice zone have been studied using near-simultaneous passive and active synthetic aperture radar microwave data. Intermediate-resolution multichannel passive microwave data were registered and analyzed. Passive and active microwave data generally complement each other as the two sensors are especially sensitive to different physical properties of the sea ice. In the inner pack, undeformed first-year ice is observed to have low backscatter values but high brightness temperatures while multiyear ice has generally high backscatter values and low brightness temperatures. However, in the marginal ice zone, the signature and backscatter for multiyear ice are considerably different and closer to those of first-year ice. Some floes identified by photography as snow-covered thick ice have backscatter similar to that of new ice or open water while brash ice has backscatter similar to or higher than that of ridged ice.

Comiso, J. C.↗

Analysis of seasonal characteristics of Sambhar Salt Lake, India, from digitized Space Shuttle photography

Sambhar Salt Lake is the largest salt lake (230 sq km) in India, situated in the northwest near Jaipur. Analysis of Space Shuttle photographs of this ephemeral lake reveals that water levels and lake basin land-use information can be extracted by both the digital and manual analysis techniques. Seasonal characteristics captured by the two Shuttle photos used in this study show that additional land use/cover categories can be mapped from the dry season photos. This additional information is essential for precise cartographic updates, and provides seasonal hydrologic profiles and inputs for potential mesoscale climate modeling. This paper extends the digitization and mensuration techniques originally developed for space photography and applied to other regions (e.g., Lake Chad, Africa, and Great Salt Lake, USA).

Lulla, Kamlesh P.↗

Using reflectance and photography to detect ozone damage to cantaloupe plants

Laboratory and field reflectance measurements showed that ozone-damaged cantaloupe (Cucumis melo L.) leaves had lower water contents and higher reflectance than nondamaged leaves. Cantaloupe plants with lightly, severely, and very severely ozone-damaged leaves were distinguishable from nondamaged plants by reflectance measurements in the 1.35-2.5-micron near-IR water absorption band. Ozone-damaged leaf areas were detected photographically 16 hours before the damage was visible.

Gausman, H. W.↗

Monitoring of deltaic wetland processes with seasonal aerial photography

A year-long study of four river deltas, using color infrared photography at three-month intervals, showed clearly the impact of damming the lower river or channelizing its outlet on the wetland environment. An important result of the season's photography was the dramatic appearance of the detrital material being flushed out of the deltaic wetlands by flood waters, and moved down into the lower estuaries for use by the marine organisms in the lower tropical levels. The species makeup and relative vigor of the deltaic plant communities were well recognizable on the imagery, as was the flushing mechanism in one still viable delta marsh.

Benton, A. R., Jr.↗

Analysis of the Tanana River Basin using LANDSAT data

Digital image classification techniques were used to classify land cover/resource information in the Tanana River Basin of Alaska. Portions of four scenes of LANDSAT digital data were analyzed using computer systems at Ames Research Center in an unsupervised approach to derive cluster statistics. The spectral classes were identified using the IDIMS display and color infrared photography. Classification errors were corrected using stratification procedures. The classification scheme resulted in the following eleven categories; sedimented/shallow water, clear/deep water, coniferous forest, mixed forest, deciduous forest, shrub and grass, bog, alpine tundra, barrens, snow and ice, and cultural features. Color coded maps and acreage summaries of the major land cover categories were generated for selected USGS quadrangles (1:250,000) which lie within the drainage basin. The project was completed within six months.

Morrissey, L. A.↗

All that flashes... ...might cause crashes

Flashing lights may create challenging environments due to personnel photosensitivity. People can be photosensitive for a variety of reasons including illness, stress, and brain injury. All brains have limits. Flashing lights can be found in surprising places including reflecting off rippling water. To have environments to minimize photosensitivity, consider other people and ask before using any flashing lights including flash photography. Consider travel conditions and let your visitor rest upon arrival. Let's start a conversation to discuss lighting in our environment, our brains, and our health. The purpose of this presentation is to increase awareness of photosensitivity and encourage communication about it.

99 - GENERAL AND MISCELLANEOUS↗

Nearshore coastal mapping

Two test sites of different water quality and bottom topography were used to test for maximum water depth penetration using the Skylab S-192 MSS for measurement of nearshore coastal bathymetry. Sites under investigation lie along the Lake Michigan coastline where littoral transport acts to erode sand bluffs and endangers developments along 1,200 miles of shore, and on the west coast of Puerto Rico where unreliable shoal location and depth information constitutes a safety hazard to navigation. The S-192 and S-190A and B provide data on underwater features because of water transparency in the blue/green portion of the spectrum. Depth of 20 meters were measured with the S-192 in the Puerto Rico test site. The S-190B photography with its improved spatial resolution clearly delineates the triple sand bar topography in the Lake Michigan test site. Several processing techniques were employed to test for maximum depth measurement with least error. The results are useful for helping to determine an optimum spectral bandwidth for future space sensors that will increase depth measurements for different water attenuation conditions where a bottom reflection is detectable.

Polcyn, F. C.↗

Analytical ice shape predictions for flight in natural icing conditions

LEWICE is an analytical ice prediction code that has been evaluated against icing tunnel data, but on a more limited basis against flight data. Ice shapes predicted by LEWICE is compared with experimental ice shapes accreted on the NASA Lewis Icing Research Aircraft. The flight data selected for comparison includes liquid water content recorded using a hot wire device and droplet distribution data from a laser spectrometer; the ice shape is recorded using stereo photography. The main findings are as follows: (1) An equivalent sand grain roughness correlation different from that used for LEWICE tunnel comparisons must be employed to obtain satisfactory results for flight; (2) Using this correlation and making no other changes in the code, the comparisons to ice shapes accreted in flight are in general as good as the comparisons to ice shapes accreted in the tunnel (as in the case of tunnel ice shapes, agreement is least reliable for large glaze ice shapes at high angles of attack); (3) In some cases comparisons can be somewhat improved by utilizing the code so as to take account of the variation of parameters such as liquid water content, which may vary significantly in flight.

Berkowitz, Brian M.↗