Advances in Space Research, Jan 15, 2014, Vol.53(2), p.272(8)
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.asr.2013.11.013 Byline: Florian Zus, Ludwig Grunwaldt, Stefan Heise, Grzegorz Michalak, Torsten Schmidt, Jens Wickert Abstract: On 21 June 2010 the TerraSAR-X satellite was joined by the TanDEM-X satellite. A Global Positioning System (GPS) radio occultation (RO) experiment using the twin satellites has been carried out to estimate the precision of GPS atmospheric soundings. For the Day Of Year (DOY) 330-336, 2011, we analyze phase and amplitude data recorded by GPS receivers separated by a few hundred meters in a low earth orbit and derive collocated atmospheric refractivity profiles. In the altitude range 10-20km the standard deviation between TerraSAR-X and TanDEM-X refractivity does not exceed 0.15%. The standard deviation is rapidly increasing for lower and higher altitudes; close to the surface and at an altitude of 30km the standard deviation reaches 0.8% and 0.5%, respectively. Systematic deviations between TerraSAR-X and TanDEM-X refractivity in the considered altitude range (0-30km) are negligible. The results confirm the anticipated high precision of the GPS RO technique. However, the difference in the retrieved refractivity in the lower troposphere for different Open Loop (OL) signal tracking parameters, altered onboard TanDEM-X for DOY 49-55, 2012, calls for an in depth analysis. At the moment we can not exclude that a potential bias in the OL Doppler model introduces a bias in our retrieved refractivity at altitudes 〈8 km. Article History: Received 8 January 2013; Revised 15 October 2013; Accepted 1 November 2013 Article Note: (footnote) [star] This template can be used for all publications in Advances in Space Research.
Troposphere -- Analysis
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