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  • Author or Editor: Bjorn Lambrigtsen x
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Ramesh K. Kakar
and
Bjorn H. Lambrigtsen

Abstract

A statistical correlation technique is applied to the retrieval of vertical moisture profiles under clear-skyconditions from down-looking radiometric measurements of atmospheric radiation at microwave wavelengths. For a given set of channels, the method selects the optimum radiometric channels for estimating water vapor at specific pressure levels between the surface and 300 mb. The water vapor mixing ratio at these pressure levels is then calculated from a linear combination of the selected channel brightness temperatures. To test its validity the algorithm was applied, in a numerical experiment, to fifty independent tropical radiosondes.The rms absolute deviation of the estimated moisture profiles from the actual profiles was comparable to that obtained using an iterative retrieval method reported earlier. The statistical method, however, requires several orders of magnitude less computer time than the iterative method; it is suitable for high speed processing of large amounts of data.

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Bjorn H. Lambrigtsen
and
Ramesh K. Kakar

Abstract

We have applied a multiple linear regression technique to retrieve continuous sequences of atmospheric moisture profiles from a set of measured data. In this method the selection of an optimal subset of sensor channels plays a crucial role, in order to reduce the impact of data noise and redundancy. The data were obtained with a 4-channel remote-sensing microwave instrument carried aboard an aircraft. In contrast, most previously reported moisture profile retrievals from microwave radiometry have been used on simulated, discontinuous data. Although our data were obtained over a land surface with only a limited amount of correlative data, the retrievals were quite successful.

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