Ground Visibility Research Articles

Application Possibilities of Passive Remote-Sensing Systems in the Millimeter-Wave Region

Passive remote sensing in the microwave and millimeter-wave region, in short "microwave radiometry," is a powerful method for environmental observation. The advantages in comparison with optical and active microwave methods, respectively, are all-weather capability, penetration depth, low power consumption, and the missing of biological and environmental impacts. This presentation gives, after a discussion of advantages and disadvantages of microwave radiometry and a short reference to the state of the art, several application possibilities based on airborne DFVLR measurements at 32 and 90 GHz: earth observation with respect to vegetation conditions, ground moisture, and snow cover; traffic control at land and sea and sensing of road conditions; and earth observation during bad ground visibility. An outlook to expectable future developments will be given on the basis of present requirements. Main goals are the increase of data rates as well as geometrical and temperature resolution improvements by use of multireceiver systems in order to get operational microwave radiometry systems for remote sensing.

An Archaeological Survey of a Pipeline Route Near Sabine Pass, Jefferson County, Texas

In May 1980, the Center for Archaeological Research, The University of Texas at San Antonio, carried out an archaeological survey of the proposed route of an eight-inch pipeline to be installed by the Tennessee Gas Pipeline Company. The pipeline will extend from the Scurlock Oil Company tank farm about one kilometer southwest of Sabine Pass to a landfall on the Gulf Coast at a point about six kilometers west of Texas Point (Fig. 1). The survey was done under contract between the Center for Archaeological Research and the Tennessee Gas Pipeline Company (Independent Contractor-Letter Agreement of May 1980). The fieldwork was carried out by Kenneth M. Brown, Research Associate, under the supervision of Dr. Thomas R. Hester, Center Director, and Jack D. Eaton, Associate Director. The pipeline route is about 4.6 km long; crossing the chenier plain with a north-south orientation. The chenier plain consists of long, low sand and shell ridges, or cheniers, subparallel to the present coast, alternating with saline or brackish marsh and mudflats (Fisher et ale 1973; Kane 1959; Byrne, LeRoy, and Riley 1959). The area is also dotted with many elongate to irregular ponds. Ground visibility during the survey was fair to good on the cheniers, especially on the seaward side where the coarsest sediments were exposed; sandy deflated surfaces are common there. Washovers where the cheniers have been breached during high water also offered good visibility. The marsh between the cheniers, although dry enough during the survey to walk on in most places, is heavily vegetated, with a substrate of wet silt, clay, and organic muck. Ground visibility here was very unfavorable.