ERTS-1 Views the Great Lakes Area
ERTS-1 study of mesoscale atmospheric phenomena associated with Great Lakes
Lyons, W. A.↗
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A study of Minnesota forests and lakes using data from earth resources technology satellites
This project is to foster and develop new applications of remote sensing under an interdisciplinary effort. Seven reports make up the specific projects presently being conducted throughout the State of Minnesota in cooperation with several agencies and municipalities. These are included under the general headings of: (1) applications of aerial photography and ERTS-1 data to agricultural, forest, and water resources management; (2) classification and dynamics of water and wetland resources of Minnesota; (3) studies of Lake Superior Bay; and (4) feasibility of detecting major air pollutants by earth-oriented satellite-borne sensors.
Source record↗
Preliminary evaluation of ERTS-1 for determining numbers and distribution of prairie ponds and lakes
ERTS-1 and aircraft multispectral data collected over a North Dakota test site during July 1972, are compared to evaluate the capability of the satellite sensors to detect numbers and distribution of prairie ponds and lakes. Recognition maps using ERTS-1, MSS 7 data are generated using a level slicing technique. Surface water areas larger than two acres are recognized, but ponds in the one-to two-acre range are detected only at random. The proportion estimation technique will improve the accuracy of area determination and small pond detection.
Work, E. A., Jr.↗
Dynamics of Playa Lakes in the Texas High Plains
The author has identified the following significant results. This project is designed to correlate ERTS-1 satellite imagery signatures with the water balance ecosystem and geology of select playa lake basins in West Texas. The principal work consisted of monitoring the weather instruments, the measurement of water levels and water depths examination of MSS imagery, and measurement of water and mud areas by use of ESIAC (Electronic Satellite Image Analysis Console) at Stanford Research Center, Menlo Park, California. A cost/benefit analysis, comparing the use of ERTS-1 data to more conventionally secured data, revealed that use of ERTS-1 data for such a survey reduces cost from $2.00 to $0.03/square mile.
Reeves, C. C., Jr.↗
Application of thermal imagery to the development of a Great Lakes ice information system
Recent measurements and analysis have shown that thermal infrared imagery (wavelength, 8-14 microns) can be employed to delineate the relative thicknesses of various regions of freshwater ice, as well as, differentiate new ice from both open water areas and thicker (young)ice. Thermal imagery was observed to be generally superior to visual (0.4 - 0.7 microns) and our SLAR (3.3 cm) imagery for estimating relative ice thicknesses and delineating open water from new ice growth. In a real-time Great Lakes Ice Information System, thermal imagery can not only provide supplementary imagery but also aid in developing interpretative methods for all-weather SLAR imagery, as well as, establishing the areal extent of spot thickness measurements.
Schertler, R. J.↗
The Interdependence of Lake Ice and Climate in Central North America
The author has identified the following significant results. A comparison of lake freeze transition zone migration with the movement of large pressure centers reveals the following consistencies: (1) polar continental cyclones originate within and/or travel along the trend of the transition zone; (2) polar continental anticyclones fail to cross the transition zone; (3) polar outbreak anticyclones pass through the transition zone, apparently unaffected. In addition, storm centers associated with the transition zone undergo significant intensification manifest by a deepening of the pressure through and increased precipitation outside the zone.
Jelacic, A. J.↗
Aircraft and satellite monitoring of water quality in Lake Superior near Duluth
Satellite images and low altitude aerial photographs often show vivid discolorations in water bodies. Extensive laboratory analysis shows that water reflectance, which causes brightness on aerial images, positively correlates to the water quality parameter of turbidity, which on a particular day correlates to suspended solids. Work with low altitude photography on three overcast days and with ERTS images on five clear days provides positive correlation of image brightness to the high turbidity and solids which are present in Lake Superior near Duluth over 50% of the time. Proper use of aerial images would have shown that an $8,000,000 drinking water intake constructed in the midst of this unpotable, turbid water should have been located 6 miles north in clear, usable water. Noise effects such as skylight reflection, atmospheric effects, and depth penetration also must be understood for operational use of remote sensing for water quality monitoring and are considered in the paper.
Scherz, J. P.↗
Dynamics of suspended sediment plumes in Lake Ontario
The absence of turbidity plumes during the winter was well documented in an ususually successful sequence of images obtained February 10 - 12, 1974. Useful imagery of the south shore of Lake Ontario was obtained on 3 successive days at a time when sky cover over the area normally approaches complete coverage. Imagery of the Oswego, Genesee, and Niagara rivers failed to detect any plumes, however faint. Despite strong northwest winds on February 11 there was no indication of shoreline erosion generated by wave action. Frozen ground, snow cover, shoreline icing and minimal construction and farm activity without doubt reduces the probability of sediment movement in winter. Thunderstorm activity over the study area is very rare during the cold season so that the erosive energy of rainfall is greatly reduced. Moreover, a fairly high percentage of the winter precipitation is in the form of snow or sleet further reducing the impact of rainfall energy on sediment transport.
Pluhowski, E. J.↗
The log-periodic array at the Clark Lake Radio Observatory
A log-periodic array, 3 km in length, is operating at Clark Lake Radio Observatory. It makes one-dimensional sweeps of the solar brightness distribution in the frequency range 20 to 65 MHz once per sec. The phasing of the array and the receiving system are described, as well as how the dynamic spectra are analyzed for the positions of solar radio sources. Simultaneous measurements at many frequencies enable the observer to remove the effects of ionospheric refraction and to obtain fundamental positions to an accuracy of about one arc min at decametric wavelengths. Fundamental positions are given for Cassiopeia A.
Erickson, W. C.↗
Application of thermal imagery to the development of a Great Lakes ice information system
Recent measurements and analysis have shown that thermal infrared imagery can be employed to delineate the relative thicknesses of various regions of freshwater ice and to differentiate new ice from both open water areas and thicker (young) ice. Thermal imagery was observed to be generally superior to visual (0.4 - 0.7 micron) and SLAR (3.3 cm) imagery for estimating relative ice thicknesses and delineating open water from new ice growth. In a real-time Great Lakes ice information system, thermal imagery can not only provide supplementary imagery but can also aid in developing interpretative methods for all-weather SLAR imagery.
Schertler, R. J.↗
A new wideband, fully steerable, decametric array at Clark Lake
A new, fully steerable, decametric array for radio astronomy is under construction at the Clark Lake Radio Observatory near Borrego Springs, California. This array will be a T of 720 conical spiral antennas (teepee-shaped antennas, hence the array is called the TPT), 3.0 by 1.8 km capable of operating between 15 and 125 MHz. Both its operating frequency and beam position will be adjustable in less than one msec, and the TPT will provide a 49-element picture around the central beam position for extended-source observations. Considerable experience has been gained in the operation of completed portions of the array, and successful operation of the final array is assured. This paper describes the results of the tests which have been conducted with the conical spirals and outlines the planned electronics.
Erickson, W. C.↗
Lake Superior water quality near Duluth from analysis of aerial photos and ERTS imagery
ERTS imagery of Lake Superior in the late summer of 1972 shows dirty water near the city of Duluth. Water samples and simultaneous photographs were taken on three separate days following a heavy storm which caused muddy runoff water. The water samples were analyzed for turbidity, color, and solids. Reflectance and transmittance characteristics of the water samples were determined with a spectrophotometer apparatus. This same apparatus attached to a microdensitometer was used to analyze the photographs for the approximate colors or wavelengths of reflected energy that caused the exposure. Although other parameters do correlate for any one particular day, it is only the water quality parameter of turbidity that correlates with the aerial imagery on all days, as the character of the dirty water changes due to settling and mixing.
Scherz, J. P.↗
New sensor on NOAA-2 satellite monitors the 1972-73 Great Lakes ice season
The NOAA-2 satellite was launched Oct. 15, 1972 in a 790 nautical mile-high near-polar sun-synchronous orbit. The Very High Resolution Radiometer (VHRR) views earth in both the visible and thermal-IR regions of the electromagnetic spectrum at 1-kilometer resolution. Its orbit permits the satellite to acquire imagery on a daily basis over any given location at approximately 0900 and 2100 local time. Visible data at 1-kilometer resolution represents a 16-fold increase in data density over previous NOAA satellite capabilities. Thermal data are now available over an area at 100 times the previous NOAA-1 thermal data density. Following the onset of ice formation in Lake Erie early in January, ice buildup and thaw were observed as cloud cover permitted throughout the short winter season.
Strong, A. E.↗
Remote sensing of Myriophyllum spicatum L. in a shallow, eutrophic lake
An aerial 35 mm system was used for the acquisition of vertical color and color infrared imagery of the submergent aquatic macrophytes of Lake Wingra, Wisconsin. A method of photographic interpretation of stem density classes is tested for its ability to make standing crop biomass estimates of Myriophyllum spicatum. The results of film image density analysis are significantly correlated with stem densities and standing crop biomass of Myriophyllum and with the biomass of Oedogonium mats. Photographic methods are contrasted with conventional harvest procedures for efficiency and accuracy.
Gustafson, T. D.↗
Remote profiling of lake ice thickness using a short pulse radar system aboard a C-47 aircraft
Description of the design and operation of two new short-pulse radar systems developed for use aboard aircraft for remote profiling of lake ice thickness. The principle of operation is based on the fact that the return signal is composed of a pulse return from the top of the ice and another, delayed in time, from the ice-water interface. The delay time between these two pulses directly gives the ice thickness when allowance is made for the slower RF propagation through the ice. The two systems are the S band and the C band systems, and their comparative merits are discussed.
Cooper, D. W.↗
A New Wideband, Fully Steerable, Decametric Array at Clark Lake
A fully steerable, decametric array for radio astronomy is under construction at the Clark Lake Radio Observatory near Borrego Springs, California. This array will be a T of 720 conical spiral antennas (teepee-shaped antennas, hence the array is called the TPT), 3.0 km by 1.8 km capable of operating between 15 and 125 MHz. Both its operating frequency and beam position will be adjustable in less than one millisecond, and the TPT will provide a 49-element picture around the central beam position for extended source observations. Considerable experience was gained in the operation of completed portions of the array, and successful operation of the final array is assured. The results are described of the tests which were conducted with the conical spirals, and the planned electronics and data processing systems are described.
Erickson, W. C.↗
Geological applications of LANDSAT-1 imagery to the Great Salt Lake area
The ERTS program has been designed as a research and development tool to demonstrate that remote sensing from orbital altitudes is a feasible and practical approach to efficient management of earth resources. From this synoptic view and repetitive coverage provided by ERTS imagery of the Great Salt Lake area, large geological and structural features, trends, and patterns have been identified and mapped. A comparative analysis of lineaments observed in September and December data was conducted, existing mineral locations were plotted, and areas considered prospective for mineralization based on apparent structure-mineralization relationships were defined. The additional information obtained using ERTS data provides an added source of information to aid in the development of more effective mineral exploration programs.
Anderson, A. T.↗
Remote profiling of lake ice using an S-band short pulse radar aboard an all-terrain vehicle
An airborne short-pulse radar system to measure ice thickness was designed. The system supported an effort to develop an all-weather Great Lakes Ice Information System to aid in extending the winter navigation season. Experimental studies into the accuracy and limitations of the system are described. A low power version was operated from an all-terrain vehicle on the Straits of Mackinac during March 1975. The vehicle allowed rapid surveying of large areas and eliminated the ambiguity in location between the radar system and the ground truth ice auger team. It was also possible to the effects of snow cover, surface melt water, pressure ridging, and ice type upon the accuracy of the system. Over 25 sites were explored which had ice thicknesses from 29 to 60 cm. The maximum radar overestimate was 9.8 percent, while the maximum underestimate was 6.6 percent. The average error of the 25 measurements was 0.1 percent.
Cooper, D. W.↗