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W. L. Smith

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W. L. Smith

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W. L. Smith

The importance of global atmospheric temperature soundings determined from satellite radiometric measurements has long been recognized by the scientific community. Several remote sounding techniques have been proposed for determining the thermal structure of the atmosphere. This paper reviews the physical concepts of various satellite sounding methods showing empirical results to demonstrate their viability.

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W. L. Smith

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W. L. Smith and C. M. R. Platt

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Cloud altitudes specified from the Infrared Temperature Profile Radiometer on the Nimbus 5 satellite are compared with simultaneous observations by radiosonde and ground-based ranging measurements conducted with the lidar system at CSIRO in Aspendale, Victoria, Australia, during September 1976. The results show that the cloud altitudes deduced by the CO2 channel absorption method are in general agreement with the lidar and radiosonde determinations, regardless of the cloud opacity and amount.

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W. L. Smith and H. M. Woolf

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A new technique is formulated for using eigenvectors of covariance matrices to retrieve atmospheric parameters from spectral radiance observations. The eigenvector method permits the use of all spectral radiances in a simultaneous solution for cloud-free infrared sounding radiances from cloud-contaminated observations as well as for the vertical profiles of temperature, moisture and cloudiness. The effects of random observation errors are minimized without suppressing the influence of any real information structure contained in the spectral radiance distribution. Also, since the method provides for the most economical representation of any variable from a number of “terms required” point of view, computer storage and computation requirements are much less than those of other methods.

The eigenvector method is tested using radiance observations synthesized for the Nimbus-6 infrared and microwave sounding instruments. Although the method has been successfully applied for the routine processing of observations obtained from the Nimbus-6 satellite, these results will be presented in a future report.

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W. A. SCHULZ and D. L. SMITH

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No Abstract Available.

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ROBERT L. SMITH and DAVID W. HOLMES

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The U.S. Weather Bureau has been experimenting with a radar operating on the Doppler principle to determine whether apparatus of this type would detect and uniquely identify tornadoes. The principles of Doppler radar as applied to meteorology and results of recent experiments with equipment of this type are discussed. Calculations of anomalous wind speeds of 206 m.p.h. in a funnel cloud and 94 m.p.h. in a dust devil are presented in detail. In addition, data have been gathered from squall lines and isolated thunderstorms. Recommendations are made for an optimum Doppler radar system for the detection of tornadoes.

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W. L. Smith and H. B. Howell

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In this paper, the algorithm used for calculating the water vapor distribution from SIRS-B spectral radiances is given. Examples are presented illustrating the effects of errors in the water vapor absorption coefficients and the specified temperature profile on the retrieval of the water vapor profile. Comparisons of satellite-derived and radiosonde-observed water vapor profiles indicate that the errors of the SIRS-derived relative humidity in the middle troposphere (i.e., the 400–600 mb layer) are less than 20%. Relative humidity errors in the lower troposphere (600–1000 mb) are somewhat larger but still less than 30%.

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W. L. Smith, W. C. Shen, and H. B. Howell

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A seven-channel Multi-spectral Scanning Radiometer (MSR) was flown aboard the NASA Convair-990 aircraft during the GARP Atlantic Tropical Experiment (GATE) from June–September, 1974. The radiometer measures the total shortwave (0.2–5 μm) and longwave (5–50 μm) components of radiation and the radiation in specific absorption band and window regions that modulate the total radiation flux. Measurements of the angular distribution of radiation, including the upward and downward components, were obtained. The principal scientific objective of the MSR experiment was to obtain the atmospheric absorption data required for precise computations of radiative heating profiles from atmospheric state parameters. The method used to construct the infrared radiation heating computational model based on in situ GATE MSR observations is described. Radiative heating profiles computed with this model for both cloudy and cloudless atmospheres were compared with direct observations by flux radiometers and with profiles computed with the Rodgers and Walshaw model. The results indicate that the empirically based computational model should provide tropospheric radiative heating profiles sufficiently accurate for diagnostic and prognostic applications of GATE data.

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