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Dolan, R.

Publications and source records attributed to Dolan, R..

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

LANDSAT application of remote sensing to shoreline-form analysis

The author has identified the following significant results. Using Assateague Island, Cape Hatteras, and Cape Lookout, significantly high correlations were found for most of the six barrier island sections that were examined. Relationships were not consistent from island to island. It was concluded that coastal vulnerability to storm damage can not be assessed based on coastal orientation alone. When orientation data were combined with erosion data for individual barrier islands, the relationship could be used as a basis for barrier island classification. A method was developed to obtain large amounts of historical data on surface coastal process from aerial photography, which was called the orthogonal grid address system. Data on shoreline change and overwash penetration gathered on over 400 km of the mid-Atlantic coast, are being used by various federal and state agencies for planning purposes.

Dolan, R.↗
NASA NTRS1977

LANDSAT application of remote sensing to shoreline-form analysis

The author has identified the following significant results. Correlations for 55 segments were quite low, showing few values greater than .6. Most of the correlations substantially increased when they were run for the breakdown of Assateague into eight coastal segments. Some of these correlations reflect strong and important relationships. The correlations between coastal orientation and the standard deviation of rate of shoreline erosion is .93 at the .01 level of significance. Other significant relationships were orientation and swash slope (.84); standard deviation of erosion and subaerial beach slope a(-.79); foredune height and subaerial beach width (-.89); foredune height and mean plus standard deviation of erosion (-.81); and rate of erosion over time and subaerial beach width (.72). Low correlation was found between sand grain size and erosion and between sand grain size and orientation.

Dolan, R.↗
NASA NTRS1976

LANDSAT application of remote sensing to shoreline-form analysis

The author has identified the following significant results. LANDSAT imagery of the southern end of Assateague Island, Virginia, was enlarged to 1:80,000 and compared with high altitude (1:130,000) and low altitude (1:24,000) aerial photography in an attempt to quantify change in land area over a nine month period. Change in area and configuration was found with LANDSAT and low altitude photography. Change in configuration, but no change in area was found with high altitude photography. Due to tidal differences at time of image obtention and lack of baseline data, the accuracy of the LANDSAT measurements could not be determined. They were consistent with the measurements from the low altitude photography.

Dolan, R.↗
NASA NTRS1976

LANDSAT application of remote sensing to shoreline-form analysis

The author has identified the following significant results. Data for Assateague Island and Ocracoke Island show significantly high correlations between coastal orientation and erosion. However, South Hatteras has low correlations, and North Hatteras has low negative correlations. Because all four areas are essentially in the same mid-Atlantic climatic regime, process/response relationships should be similar. Correlations for the four areas may differ considerably because of inadequate assumptions; the key is the mean orientation of the specific coastline being studied. There appears to be an orientation window surrounding due northeast (135 deg north of south) in which this hypothesis holds.

Dolan, R.↗
NASA NTRS1976

LANDSAT application of remote sensing to shoreline-form analysis

The author has identified the following significant results. Orientation of the shoreline segments of Assateague Island (55 km) was measured from LANDSAT 2 imagery enlarged to 1:250,000 and 1:80,000. Long term trends in shoreline dynamics were established by mapping shoreline and storm-surge penetration changes from historical low altitude aerial photography spanning four decades.

Dolan, R.↗
NASA NTRS1975

Landsat Application of Remote Sensing to Shoreline-form Analysis

The author has identified the following significant results. Areas of the coast were selected which have historically shown vulnerability to storm damage. On Assateague Island, there are six such areas: the western tip of Fishing Point; the southern National Park Service parking lot; Smith Hammocks; Fox Hill Level; Little Fox Hill Level; and the northern five kilometers of the island. Comparative analysis of these areas with other data and with large and small scale aerial photographs shows them to be associated with large overwash fans and shoreline cusping. Initial analysis of Landsat imagery and high altitude photography indicates that the areas of high vulnerability are also associated with the angular orientation of the shoreline.

Dolan, R.↗
NASA NTRS1975

Shoreline configuration and shoreline dynamics: A mesoscale analysis

The author has identified the following significant results. Atlantic coast barrier island shorelines are seldom straight, but rather sinuous. These shoreline curvatures range in size from cusps to capes. Significant relationships exist between the orientation of shoreline segments within the larger of these sinuous features and shoreline dynamics, with coefficients ranging up to .9. Orientation of the shoreline segments of Assateague Island (60 km) and the Outer Banks of North Carolina (130 km) was measured from LANDSAT 2 imagery (1:80,000) and high altitude aerial photography (1:120,000). Long term trends in shoreline dynamics were established by mapping shoreline and storm-surge penetration changes.

Dolan, R.↗
NASA NTRS1973

Evaluation of land use mapping from ERTS in the shore zone of CARETS

Imagery of the Atlantic shoreline zone of the Central Atlantic Regional Ecological Test Site (CARETS) was evaluated for classifying land use and land cover, employing the USGS Geographic Application Program's land use classification system. ERTS data can provide a basis for land cover and land use mapping within the shoreline zone, however because of the dynamic nature of this environment, two additional terms are considered: vulnerability of classes to storms and progressive erosion, and sensitivity of the classes to man's activities.

Dolan, R.↗
NASA NTRS1972

Hardening electronic devices against very high total dose radiation environments

The possibilities and limitations of hardening silicon semiconductor devices to the high neutron and gamma radiation levels and greater than 10 to the eighth power rads required for the NERVA nuclear engine development are discussed. A comparison is made of the high dose neutron and gamma hardening potential of bipolar, metal insulator semiconductors and junction field effect transistors. Experimental data is presented on device degradation for the high neutron and gamma doses. Previous data and comparisons indicate that the JFET is much more immune to the combined neutron displacement and gamma ionizing effects than other transistor types. Experimental evidence is also presented which indicates that p channel MOS devices may be able to meet the requirements.

Buchanan, B.↗