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Journal: International Journal of Advances in Engineering & Technology (IJAET) (Vol.7, No. 3)

Publication Date:

Authors : ; ; ; ;

Page : 742-755

Keywords : Microwave Radiometer; Temperature profile; Optimal Estimation; Inversion; Brightness Temperature.;

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Multifrequency Microwave Radiometer (MP3000A) from Radiometrics Corporation is deployed at different places of Southern latitude for the profiling of one of thermodynamic variables like Temperature. The radiative intensity down- welling from the atmosphere and is expressed in an equivalent brightness temperature . The radiation is a nonlinear function of the required quantities and we linearise the expression around a suitably chosen first guess, such as a climatological mean. We describe changes in the brightness temperature around the first guess by means of a weighting function which expresses the sensitivity of to the variation of the humidity or the temperature around their initial values. The variation of brightness temperature with height occurs at 51 ? 53 GHz is observed but on the other hand the constancy of brightness temperature with height at 56 ? 57 GHz is noticeable. This suggests that the measurement of temperature at a certain place by a ground based radiometer may provide good result by exploiting the 56 ? 57 GHz band. In this band we have used four frequencies for the purpose. But to extend our study we have also made an attempt to retrieve the temperature profiles in 51 ? 53 GHz band. The retrieval process starts with the calculations of and for two sub-ensembles of radiometric observations separately. Here and . The measured brightness temperatures at eight specified channel frequencies at Fortaleza, Brazil on 11th April, 2011 at 05:39 and 17:36 UTC are as shown in table 2. The summery of measured brightness temperature in oxygen band at Belem, Brazil on 26th June, 2011 at 05:30 UTC and on 17th June, 2011 at 17:33 UTC and also at Alcantara, Brazil on 12th March, 2010 at 06:03 UTC and on 15th March, 2010 at 17:57 UTC.

Last modified: 2014-07-04 20:08:19