edu.ucar.opensky::articles:17347 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T16:03:48.256218 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7r78ghx Effect of superrefraction on inversions of radio occultation signals in the lower troposphere 2003-06-14T00:00:00Z publication https://n2t.org/ark:/85065/d7r78ghx https://doi.org/10.1029/2002RS002728 Sokolovskiy, Sergey author UCAR/NCAR - Library publisher Radio occultation remote sensing of the Earth's atmosphere by use of GPS encounters problems in the moist lower troposphere (planetary boundary layer). The negative errors in retrieved refractivity (bias) may not be explained by the horizontal inhomogeneity in refractivity. In part, these errors can be attributed to the use of signal tracking algorithms inappropriate for the complicated structure of radio occultation signals propagated through the moist troposphere. However, another fraction of the negative bias in retrieved refractivity can be related to the superrefraction. In this study we introduce the problem and give an estimate of the negative refractivity errors in the moist planetary boundary layer, which in some cases can be as large as ~10%. We show that the magnitude of these errors significantly varies over oceanic areas. We validate the canonical transform method by use of the radio occultation signals simulated for complicated refractivity structures, including multiple superrefraction layers and small-scale irregularities. We find that this method does not introduce errors additional to those existing in geometric optics. Also, we discuss and estimate an additional error source when inverting occultation signals by radioholographic methods: insufficient extension of the acquired signal, which can contribute to about 1% error of the retrieved refractivity. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication An edited version of this paper was published by AGU. Copyright 2003 American Geophysical Union. None eng geoscientificInformation