Identification

Title

A quality control procedure for GPS radio occultation data

Abstract

[1] A quality control ( QC) procedure is applied to the Challenging Minisatellite Payload ( CHAMP) level-2 Global Position System (GPS) radio occultation (RO) data provided by the University Corporation for Atmospheric Research (UCAR) Constellation Observing System for Meteorology, Ionosphere and Climate ( COSMIC) Data Analysis and Archival Center (CDAAC). It consists of a range check removing negative values, a biweight check removing data which deviate from the biweight mean by more than four times the biweight standard deviation, another biweight check removing data with large deviations to the National Center for Environmental Prediction (NCEP) analysis, and finally a symmetric check removing the negative bias of GPS observations in the low troposphere below 4 km. These four QC checks are applied sequentially to identify outliers in GPS bending angle and refractivity data at each vertical level using data primarily in the month of March 2004. Having removed 5.5% outlier data, the GPS RO observations compared much more favorably with the NCEP analyses than the original data without QC, resulting in an improved spatial consistency, a more symmetric probability distribution, significantly reduced error variances, and a nearly diagonal vertical error correlation matrix. The effectiveness of the proposed QC procedure is further confirmed by showing that most RO profiles removed by the QC procedure proposed in this study have those characteristic physical parameter values indicating poor quality of RO data. Similar results are obtained when the same QC procedure is applied to CHAMP data in July 2002, which shows the robustness of the proposed GPS QC procedure.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7r21503

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2006-01-28T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact