Estimating the uncertainty of using GPS radio occultation data for climate monitoring: Intercomparison of CHAMP refractivity climate records from 2002 to 2006 from different data centers

AMS Citation:
Ho, S. -peng, and Coauthors, 2009: Estimating the uncertainty of using GPS radio occultation data for climate monitoring: Intercomparison of CHAMP refractivity climate records from 2002 to 2006 from different data centers. Journal of Geophysical Research-Atmospheres, 114, D23107, doi:10.1029/2009JD011969.
Date:2009-12-09
Resource Type:article
Title:Estimating the uncertainty of using GPS radio occultation data for climate monitoring: Intercomparison of CHAMP refractivity climate records from 2002 to 2006 from different data centers
Abstract: To examine the suitability of GPS radio occultation (RO) observations as a climate benchmark data set, this study aims at quantifying the structural uncertainty in GPS RO-derived vertical profiles of refractivity and measured refractivity trends obtained from atmospheric excess phase processing and inversion procedures. Five years (2002 - 2006) of monthly mean climatologies (MMC) of retrieved refractivity from the experiment aboard the German satellite CHAMP generated by four RO operational centers were compared. Results show that the absolute values of fractional refractivity anomalies among the centers are, in general, ≤0.2% from 8 to 25 km altitude. The median absolute deviations among the centers are less than 0.2% globally. Because the differences in fractional refractivity produced by the four centers are, in general, unchanging with time, the uncertainty of the trend for fractional refractivity anomalies among centers is ±0.04% per 5 years globally. The primary cause of the trend uncertainty is due to different quality control methods used by the four centers, which yield different sampling errors for different centers. We used the National Centers for Environmental Prediction reanalysis in the same period to estimate sampling errors. After removing the sampling errors, the uncertainty of the trend for fractional refractivity anomalies among centers is between -0.03 and 0.01% per 5 years. Thus 0.03% per 5 years can be considered an upper bound in the processing scheme-induced uncertainty for global refractivity trend monitoring. Systematic errors common to all centers are not discussed in this article but are generally believed to be small.
Subject(s):Regional model, Stratocumulus clouds, Indirect effect
Peer Review:Refereed
Copyright Information:An edited version of this paper was published by AGU. Copyright 2009 by the American Geophysical Union
OpenSky citable URL: ark:/85065/d7wd41vg
Publisher's Version: 10.1029/2009JD011969
Author(s):
  • Shu-peng Ho - NCAR/UCAR
  • Gottfried Kirchengast
  • Stephen Leroy
  • Jens Wickert
  • Anthony Mannucci
  • Andrea Steiner
  • Douglas Hunt - NCAR/UCAR
  • William Schreiner - NCAR/UCAR
  • Sergey Sokolovskiy - NCAR/UCAR
  • Chi Ao
  • Michael Borsche
  • Axel von Engeln
  • Ulrich Foelsche - NCAR/UCAR
  • Stefan Heise
  • Byron Iijima
  • Ying-Hwa Kuo - NCAR/UCAR
  • Rob Kursinski
  • Barbara Pirscher
  • Mark Ringer
  • Christian Rocken - NCAR/UCAR
  • Torsten Schmidt
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