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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Water survey of Canada: Application for use of ERTS-A for retransmission of water resources data

The author has identified the following significant results. Over 7000 transmissions were received from six operating DCPs in 1972. Of these, only two were incorrect. One had the wrong date and the other had an invalid digit in the water level reading. Extensive checks have indicated that DCP data are accurate. The maximum number of transmissions received each day varies from 26 to 12 and the minimum from 10 to 3 depending on the site. Data has been received on as many as seven orbits in a day. The number of transmissions received from the two DCPs located in mountainous areas of southern B.C. is lower than the number received from more northerly but more open sites. The unheated DCPs have survived temperatures of -40 F and antenna loadings of two feet of snow and wind speeds over 50 mph. Two DCPs have indicated sensor malfunctions thus alerting field staff to the fact that repairs will be necessary on their next visit to the site. Also in another case, DCP data were used to fill in a period of missing record when a water level recorder malfunctioned for a few days.

Halliday, R. A.↗
NASA NTRS1974

Forest and land inventory using ERTS imagery and aerial photography in the boreal forest region of Alberta, Canada

Satellite imagery and small-scale (1:120,000) infrared ektachrome aerial photography for the development of improved forest and land inventory techniques in the boreal forest region are presented to demonstrate spectral signatures and their application. The forest is predominately mixed, stands of white spruce and poplar, with some pure stands of black spruce, pine and large areas of poorly drained land with peat and sedge type muskegs. This work is part of coordinated program to evaluate ERTS imagery by the Canadian Forestry Service.

Kirby, C. L.↗
NASA NTRS1975

Data retransmission from water survey of Canada gauging stations using the ERTS data collection system

Nine sites were selected for installation of Data Collection Platforms (DCPs) with the objective of obtaining one near real time water level reading a day from each site. Also the dependability, costs and other aspects of the system could be studied and decisions made with respect to the feasibility of operating a much larger network of DCPs. The number of transmissions received each day from the gauging stations varies from a maximum of 26 to 12 and a minimum of 10 to 3, depending on the location. Quality checks of data have indicated that the data are good. None of the nine DCPs have failed once they have been successfully activated. The experience with the ERTS data collection system has been excellent. The DCP appears to be a rugged, reliable piece of equipment. The ones installed at water survey sites have withstood temperatures less than -40 C and the antennas have withstood wind speeds of over 80 kph (50 mph) and snow loads of 0.6 m (2 ft).

Halliday, R. A.↗
NASA NTRS1974

Indications of fluid immiscibility in glass from West Clearwater Lake impact crater, Quebec, Canada

Glass from the West Clearwater Lake hypervelocity impact crater contains numerous spheroids, 10 to 500 microns across, which appear to have formed at high temperatures as fluids immiscible in the enclosing melt. The spheroids are distinguished from small, normal, largely void gas vesicles, which are also present, by being completely filled in all cases; by having fillings which vary in composition from spheroid to spheroid, even between spheroids in close association; and by indications that the present fillings are representative of the contents present before the matrix melt chilled. Most of the spheroids are classified petrographically into three types. The preservation of spheroids in the West Clearwater Lake glass is attributed mainly to the position of the glass masses within the breccias lining the crater floor. It is considered that the glass in this location did not achieve free flight but, as part of a large mass, cooled relatively slowly through the high temperature regime in which the spheroids were generated, and then, when detached, chilled rapidly to preserve a record of this transient stage in their history.

Dence, M. R.↗