Publications (2)0 Total impact
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ABSTRACT: located at the ground, the atmosphere is horizontally stratified and no clouds are present. To compute the temperature profile T (z) we take into account the brightness temperature measurements (T BM 1 , ... , TBM 9 ) at frequencies # 1 = 50.8 GHz to # 9 = 58.8 GHz at 1 GHz spacing. In a first approximation we assume that all atmospheric parameters except the temperature are given. We consider the quadratic cost functional E[T ] whereby the task is to find a temperature profile T (z) such that E[T ] is minimal. The quadratic cost functional for this problem is E[T ] = 1 9 # i=1 (TBM i - TB(# i )[T ]) , (1) where we set TB(# i )[T ] to be the theoretical brightness temperature. It is obvious that this is an ill-posed problem and that many irregular temperature profiles are solutions. An example of two different solutions is shown in the figure below (red and green profiles on the right). Both profiles lead to the same (vanishing) energy E[T ]. A corresponding simplified ene
03/2004;
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ABSTRACT: We present a new mathematical technique for retrieving the temperature profile from a ground based microwave profiler and ancillary measurements. It is based on a gradient flow approach. We are able to solve the inverse problem of radiative transfer and determine the temperature profile from ten simultaneous brightness temperature measurements in the range from 50.8 to 58.8 GHz. The approach uses no additional statistical information. A physical consistent solution for a temperature profile can be found within five seconds. First results of this technique show promising results with regard to absolute accuracy and inversion height determination, even if the brightness temperature measurements are assumed noisy to 0.5 K.
03/2004;
