Engineering topics

Helms, D. R.

Publications and source records attributed to Helms, D. R..

3 records

NASA NTRS1992

Ground support for Space Shuttle earth observations by the NASA environment remote sensing analysis facility (ERSAF)

The functions and capabilities of the NASA Environment Remote Sensing Analysis Facility (ERSAF) located at the Johnson Space Center are described. ERSAF provides dedicated support to earth-observation activities and Earth-looking payloads conducted aboard the Space Shuttle. This support merges environmental satellite imagery with high-resolution film products and digital imagery acquired aboard the Space Shuttle. ERSAF utilizes several computer systems with specialized software to process and analyze environmental information as well as data acquired from the Space Shuttle. These computer systems and the image analysis capabilities are discussed.

Chambers, M. A.↗

NASA NTRS1992

Clouds as indicators of atmospheric processes - As viewed from Space Shuttle

The Space Shuttle provides a unique perspective for cloud observation. From it, an observer can simulataneously view the grand scale and individual microscale components. An observer can differentiate between the exceptional and the routine and rapidly identify the phenomenon of interest. The capabilities include multiple aspect viewing, vision enhancement, instant data transmission, and the intelligence and decision-making ability required for meaningful selective observations. When these observations are used with other information, an improved understanding of the processes follows. Examples of these data and their application with other information sources are given along with suggestions for research.

Whitehead, V. S.↗

NASA NTRS1992

Albedo patterns and gypsum generation in the central Namib Desert - Land, sea and air interactions on an arid West Coast

In the central Namib Desert, dune-free surfaces are separated abruptly from a sea of yellow and red sand dunes at the Kuiseb River canyon. The off-white hues of the dune-free area result from anomalously high surficial gypsum enrichment. Satellite imagery indicates that the gypsum surfaces are associated with lower surface maximum temperatures than those of the darker dune surfaces to the south. One of various sources of sulfate for the gypsum bodies is oceanic H2S, supplied to desert land-surfaces by regular fog incursions. Since fog events are widespread along the coast, the question of anomalous gypsum accumulations north of the dune sea arises. Satellite imagery, in conjunction with more detailed handheld photography from the space shuttle, indicates that the penetration of fog inland is significantly greater over the gypsum surfaces than it is over the dunes. It is postulated that the thermal gradient between these surfaces generates a heat low centered over the northern part of dune sea and that this enhances fog and H2S advection on its north side onto the nearby dune-free zone. In such a system, gypsum/caliche surfaces reinforce advection of fog over themselves in a positive feedback mode.

Wilkinson, M. J.↗