P. R. Schwartz

The Millimeter Wave Atmospheric Sounder (MAS): a shuttle-based remote sensing experiment

The Millimeter Wave Atmospheric Sounder (MAS) will be launched in the spring of 1992 as part of the ATLAS 1 (Atmospheric Laboratory for Application and Science) mission. Using passive limb-scanning millimeter-wave radiometry, it will sense the thermal emission produced by ozone at 184 GHz, water vapor at 183 GHz, chlorine monoxide at 204 GHz, and oxygen (for retrieval of temperature and pressure) at 60 GHz. From these observations, concentration profiles of these gases throughout the middle atmosphere will be made. The fundamentals of the measurements, the design of the radiometers, and the approaches used for the data analysis are described. >

Measurements of O3, H2O and ClO in the Middle Atmosphere Using the Millimeter-Wave Atmospheric Sounder (MAS)

The Millimeter-Wave Atmospheric Sounder (MAS) is a shuttle-based limb-sounding instrument designed for global spectroscopic studies of O3, and constituents important in O3 photochemistry, in the middle atmosphere. It is part of the NASAs Atmospheric Laboratory for Applications and Science (ATLAS) spacelab shuttle mission. This paper presents an overview of the instrument, operation, and data analysis. In addition, as an example of the results, we present zonal average retrievals for O3, H2O and ClO obtained in ATLAS 1. The MAS O3 and H2O measurements are shown to agree well with simultaneous observations made with the UARS MLS instrument.

Observations of Galactic Carbon Monoxide Emission at 2.6 Millimeters.

Abstract : A wide variety of galactic sources have been observed at 2.6 mm (115271.2 MHz) to determine the extent and strength of interstellar 12C16O. Extended regions of CO emission were found in the direction of 32 HII regions and five supernova remnants. The CO emission was found to be larger in spatial extent than the 6-cm continuum HII emission and CO emission maxima appear to be related to continuum emission peaks and infrared sources in several sources. Except near optically dark nebulae, little CO emission was detected away from the galactic plane. Radial velocities of the CO emission are within 10/kms of the OH, HII (109 alpha), and H2CO velocities measured by other observers for the same sources. 13C16O was also measured in many of the stronger sources. The optical depths calculated for 12C16O range between 20 and 120, assuming the terrestrial value of 1/89 for the ratio of 13C/12C. For excitation temperatures in the range 10 to 50K, the calculated projected densities range from 10 to the 18th power to 2.5 x 10 to the 19th power molecules/sq cm. (Author)

Polar Ozone and Aerosol Measurement Experiment (POAM-II)

The polar ozone and aerosol measurement experiment (POAM II) was launched on the SPOT 3 satellite on 25 September 1993. POAM II is designed to measure the vertical profiles of the polar ozone, aerosols, water vapor, nitrogen dioxide, atmospheric density and temperature in the stratosphere and upper troposphere. It makes solar occultation measurements in nine channels defined by narrow-band filters. The field of view is 0.01 by 1.2 degrees, with an instantaneous vertical resolution of 0.6 km at the tangent point in the earths atmosphere. The SPOT 3 satellite is in a 98.7-degree inclined sun-synchronous orbit at an altitude of 833 km. From the measured transmissions, it is possible to determine the density profiles of aerosols, O3, H2O, and NO2. Using the assumption of uniformly mixed oxygen, we are also able to determine the temperature. We present details of the POAM II instrument design, including the optical configuration, electronics and measurement accuracy. We also present preliminary results from the occultation measurements made to date.

The relative positions of the OH and H2O masers in W49N and W3/OH/

The relative positions of the OH and H

Ground-based monitoring of water vapor in the middle atmosphere: the NRL water-vapor millimeter-wave spectrometer

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First results of zonally averaged ClO concentrations as measured by MAS on ATLAS-1

O masers in W49N and W3(OH) have been found by simultaneously observing both masering transitions with a very- long-baseline interferometer. In both sources the OH and H

Looking down: large microwave apertures for meteorological and oceanographic remote sensing

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An observational study of water vapor in the mid-latitude mesosphere using ground-based microwave techniques

O features are clearly separated and occupy two distinct regions of space, separated by 48,000 AU and 18,000 AU in W49N and W3(OH), respectively. The two masering regions appear unlikely to have the same source of excitation.

Measurements of mesospheric water vapor in 1984 and 1985 - Results and implications for middle atmospheric transport

A novel mm-wave radiometer system specifically designed for measuring water vapor in the stratosphere is presented. The instrument, which is based on an HEMT front-end amplifier, is described in detail. The data retrieval scheme and the results of an extensive instrument data simulation study are also presented. The devices principal features are its capability to conduct measurements of the water vapor profile simultaneously from 25-75-km altitude, with excellent long-term relative precision, and semiautomatically at a remote site.