Identification

Title

Validation of line-of-sight water vapor measurements with GPS

Abstract

We present a direct comparison of nonisotropic, integrated water vapor measurements between a ground-based Global Positioning System (GPS) receiver and a water vapor radiometer (WVR). These line-of-sight water vapor observations are made in the straight line path between a ground station and a GPS satellite. GPS double-difference observations are processed, and the residual line-of-sight water vapor delays are extracted from the double-difference residuals. These water vapor delays contain the nonisotropic component of the integrated water vapor signal. The isotropic component is represented by the zenith precipitable water vapor measurement and can be scaled to a specific elevation angle based on a mapping function. The GPS observations are corrected for station-dependent errors using site-specific multipath maps. The resulting measurements are validated using a WVR which pointed in the direction of the observed satellites. The double-difference technique used to make these water vapor observations does not depend on accurate satellite clock estimates. Therefore it is especially well suited for near-real-time application in weather prediction and allows for sensing atmospheric structure that is below the noise level of current satellite and receiver clock errors. This paper describes the analysis technique and provides precision estimates for the GPS-measured nonisotropic water vapor as a function of elevation angle for use with data assimilation systems.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7ng4rxk

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

2001-05-01T00:00:00Z

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