Identification

Title

Use of GPS for estimation of bending angles of radio waves at low elevations

Abstract

The paper compares three methods of calculating the bending angles of radio waves propagated from space to a ground-based receiver: (1) from refractivity climatology corrected for refractivity at the receiving antenna, (2) from radiosonde refractivity profiles, and (3) from the refractivity at the antenna and the measured Doppler frequency shift of the GPS signals. The methods are tested with the use of radiosonde and GPS observations collocated in space and in time. We analyzed seven cases during October-November 1999 where GPS satellites were observed to below 0.5° elevation from Point Loma, California, and which coincided closely in time with radiosonde launches from the nearby Miramar station. In all cases the bending angles calculated from Doppler and from radiosondes agree fairly well at all elevations, but in a number of cases both differ significantly at low elevations from the bending angles calculated from climatology corrected for the refractivity at the antenna. Thus GPS has the potential of being used for the correction of radar observations at low elevations instead of (or complementary to) radiosondes. The differences between the bending angles calculated from climatology corrected for the refractivity at the antenna and those calculated from the Doppler frequency shift indicate anomalies in the refractivity profile in the lower troposphere and can thus be used as an indicator of ducting conditions.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7hd7vtp

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