Engineering topics

Krueger, Arlin J.

Publications and source records attributed to Krueger, Arlin J..

40 records · Page 3

NASA NTRS1987

Volcanic eruption detection with TOMS

The Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) is designed for mapping of the atmospheric ozone distribution. Absorption by sulfur dioxide at the same ultraviolet spectral wavelengths makes it possible to observe and resolve the size of volcanic clouds. The sulfur dioxide absorption is discriminated from ozone and water clouds in the data processing by their spectral signatures. Thus, the sulfur dioxide can serve as a tracer which appears in volcanic eruption clouds because it is not present in other clouds. The detection limit with TOMS is close to the theoretical limit due to telemetry signal quantization of 1000 metric tons (5-sigma threshold) within the instrument field of view (50 by 50 km near the nadir). Requirements concerning the use of TOMS in detection of eruptions, geochemical cycles, and volcanic climatic effects are discussed.

Krueger, Arlin J.↗

NASA NTRS1987

A geostationary imaging spectrometer TOMS instrument

One design for a geostationary Total Ozone Mapping Spectrometer (TOMS) with many desirable features is an imaging spectrometer. A preliminary study makes use of a 0.25 m Czerny-Turner spectrometer with which the Earth is imaged on a charge-coupled device (CCD) in dispersed light. The wavelength is determined by a movable grating which can be set arbitrarily by ground control. The signal integration time depends on wavelength but this system allows arbitrary timing by command. Special circumstances such as a requirement to track a low-lying sulfur dioxide cloud or a need to discriminate high level ozone from total ozone at midlatitudes could be obtained by adding a particular wavelength to the normally pre-programmed time sequence. The incident solar irradiance is measured by deploying a diffuser plate in the field of view. Individual detector elements correspond to scene elements in which the several wavelengths are serially sampled and the Earth radiance is compared to the incident sunlight. Thus the problem of uncorrelated drift of multiple detectors is removed.

Krueger, Arlin J.↗

NASA NTRS1986

Atlas of TOMS ozone data collected during the Genesis of Atlantic Lows Experiment (GALE), 1986

Data from the TOMS (Total Ozone Mapping Spectrometer) instrument aboard the Nimbus-7 satellite were collected daily in real time during the GALE (Genesis of Atlantic Lows Experiment) from January 15 through March 15, l986. The TOMS ozone data values were processed into GEMPAK format and transferred from the Goddard Space Flight Center to GALE operations in Raleigh-Durham, NC, in as little as three hours for use, in part, to direct aircraft research flights recording in situ measurements of ozone and water vapor in areas of interest. Once in GEMPAK format, the ozone values were processed into gridded form using the Barnes objective analysis scheme and contour plots of the ozone created. This atlas provides objectively analyzed contour plots of the ozone for each of the sixty days of GALE as well as four-panel presentations of the ozone analysis combined on the basis of GALE Intensive Observing Periods (IOP's).

Larko, David E.↗

NASA NTRS1986

The morphology of Antarctic total ozone as seen by TOMS

A more detailed examination of the TOMS observations reveals a number of important aspects of the Antarctic ozone depletion. First, it is noted that the presence of large scale disturbances around the edge of the ozone hole can lead to highly variable station observations. Second, an examination of the zonal mean total ozone for the seven Octobers shows that the large systematic decline is not simply confined to the polar region but exists at midlatitudes as well. Integrations of the total ozone from the South Pole northwards show that a portion of the systematic trend of decreasing Antarctic total ozone (prior to 1985) seems to be due to a redistribution of total ozone to subpolar and midlatitude regions. That is, decreases at high latitudes are compensated by increases at lower latitudes. The correlation between zonal mean total ozone and 70 mb zonal mean temperatures from polar to midlatitudes shows that the systematic decreases in total ozone is well correlated with a systematic decrease in stratospheric temperatures.

Schoeberl, Mark R.↗