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Detailed Reference Information |
Beyerle, G., Schmidt, T., Wickert, J., Heise, S., Rothacher, M., König-Langlo, G. and Lauritsen, K.B. (2006). Observations and simulations of receiver-induced refractivity biases in GPS radio occultation. Journal of Geophysical Research 111: doi: 10.1029/2005JD006673. issn: 0148-0227. |
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An analysis of 206,422 atmospheric refractivity profiles observed by the CHAMP georesearch satellite between 14 May 2001 and 30 June 2005 reveals significant biases compared to European Centre for Medium-Range Weather Forecasts meteorological fields at altitudes below 5 km. The mean bias decreases down to -2% at altitudes below 2 km; in the Amazon region, positive biases exceeding +1% are observed. In order to identify bias contributions caused by the receiver signal tracking process an end-to-end simulation study implementing different signal tracking modes was performed. The end-to-end simulations are based on 1992 radiosonde profiles obtained regularly aboard R/V Polarstern since December 1982 and were conducted with four receiver models using closed-loop, fly wheeling, and open-loop signal tracking methods. The simulation results confirm that open-loop tracking yields significantly smaller biases and standard deviations of the fractional refractivity errors compared to fly wheeling enabled receivers. In addition, we analyze closed-loop tracking with a second-order loop and demonstrate that similar reductions in biases and standard deviations can be obtained. |
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Abstract |
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Keywords
Atmospheric Processes, Remote sensing, Atmospheric Composition and Structure, Pressure, density, and temperature, Radio Science, Radio wave propagation, Radio Science, Remote sensing |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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