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  • Author or Editor: K. F. Kunzi x
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J. W. Waters, K. F. Kunzi, R. L. Pettyjohn, R. K. L. Poon, and D. H. Staelin

Abstract

This article discusses remote sensing of atmospheric temperatures with the NEMS microwave spectrometer on the Nimbus 5 satellite, and the accuracy with which atmospheric temperatures can be determined by NEMS. The sensitivity of the NEMS instrument allows measurement of temperature profiles having vertical resolution of the respective NEMS weighting functions (∼10 km) with an rms accuracy of a few tenths of a degree Kelvin for a 16 s integration time. The accuracy of NEMS in estimating atmospheric temperatures at the discrete levels (∼2 km vertical resolution in the lower troposphere) used in the operational numerical model of the National Meteorological Center (NMC) is ∼2 K rms, as determined by comparing NEMS results with ground truth data obtained from the NMC operational analysis and from coincident radiosondes. These accuracies are consistent with the theoretical accuracies expected for NEMS.

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D. H. Staelin, K. F. Kunzi, R. L. Pettyjohn, R. K. L. Poon, R. W. Wilcox, and J. W. Waters

Abstract

The passive microwave spectrometer on the Nimbus 5 satellite has two channels that measure atmospheric water vapor and liquid water abundances over ocean. Observed water vapor abundances range up to 6 g cm−2 and differ from nearby radiosondes by ∼0.4 g cm−2. Average liquid water abundances over a 300 km observation zone range from −0.01 to 0.2 g cm−2, and have an rms error estimated to be ∼0.01 g cm−2 for most circumstances. These quantitative measurements can be used to construct global maps or to accumulate global statistics.

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D. H. Staelin, A. L. Cassel, K. F. Kunzi, R. L. Pettyjohn, R. K. L. Poon, P. W. Rosenkranz, and J. W. Waters

Abstract

The microwave spectrometer on the Nimbus 5 earth observatory satellite has been used to measure thermal radiation in five frequency bands between 22.235 and 58.8 GHz. Clouds were observed to affect less than 0.5% of the temperature profile soundings. Most such effects occur in the intertropical convergence zone and alter the inferred temperature profile by less than a few degrees Centigrade. These effects are evident as cold spots at 53.65 GHz and can be identified by virtue of their small spatial extent, in contrast to smooth variations characteristic of normal atmospheric temperature fields. These effects at 53.65 GHz are sufficiently well correlated with inferred liquid water abundances that they can be used for detecting major storm systems over both land and sea.

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