Development of ultraviolet absorption photometer for atmospheric ozone measurements and results from mid-latitude investigations

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7164598

Sen, B

This presentation consists of two parts. First, the authors describe the design and construction of a dual-beam ultraviolet-absorption photometer, as a balloon payload, for ozone measurements. They then describe the construction of a rocket-borne version of the instrument and results of tests performed in the laboratory. Results of balloon flights using this instrument and a NASA-JSC/UH ultraviolet photometer are finally presented. Measurement of ozone in the atmosphere can be made using the strong photometric absorption feature of the gas at 253.7 nanometers. An ultraviolet lamp produces identical optical paths through two absorption columns. Two photodetectors measure the intensity of light through the two columns and a third detector just adjacent to the lamp provides a monitor of integrated light intensity, thus allowing detection of (and on board corrections to) changes in lamp output. A four-port valve in series with an ozone scrubber periodically reverses the two columns between ozone measurement and reference cycles. In this way, instrumental drifts and differences in the two optical paths can be monitored, and corrections can be deduced. Fast ozone measurements can be made along with other meteorological parameters, allowing good determination of the vertical profile of ozone. Ozone profiles computed from standard photochemical models are usually lower than those determined from satellite measurements; the discrepancies are typically forty percent of measured values at 50 km, and fifty percent at 80 km. Ozone column density measurements with ground based instruments and rocket-borne detectors agree with satellite data, but with a wide variation in accuracy and precision. In situ measurement of ozone with high accuracy, precision, and good spatial resolution would allow testing of (i) current and future photochemical models and (ii) predicted diurnal and seasonal variation in the mesosphere.

• Research Organization: Houston Univ., TX (United States)
• OSTI ID: 7164598
• Country of Publication: United States
• Language: English

Related Subjects

440600* -- Optical Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ABSORPTION SPECTROSCOPY
ABUNDANCE
CHEMICAL COMPOSITION
DESIGN
EARTH ATMOSPHERE
MEASURING INSTRUMENTS
OZONE
PHOTOMETERS
REMOTE SENSING
SPECTRA
SPECTROSCOPY
ULTRAVIOLET SPECTRA