Identification

Title

The physical mechanisms for the sunrise enhancement of equatorial ionospheric upward vertical drifts

Abstract

Satellite and incoherent scatter radar observations have shown frequently a strong enhancement of upward vertical E x B drifts in the equatorial ionospheric F region near sunrise. Previous studies suggested that this enhancement is associated with the local equatorial wind dynamo, the same process used to explain the prereversal enhancement after sunset. However, this hypothesis has never been tested in a first-principles way. In this study, we explore the physical mechanisms responsible for the sunrise enhancement of equatorial upward vertical drifts using the Thermosphere-Ionosphere-Electrodynamics General Circulation Model. The model well reproduces the sunrise enhancement of upward vertical drifts observed at Jicamarca on 10 June 2004. The simulation results show that large eastward zonal electric fields occur around sunrise at all latitudes but with a peak at middle latitudes. Further numerical experiments reveal that the equatorial sunrise enhancement at solar minimum is primarily driven by the E region zonal wind dynamo at middle latitudes rather than by the local dynamo effect in the equatorial region. Specifically, the intensity of the equatorial eastward electric field near sunrise is determined by the magnitudes of westward wind and its longitudinal gradient at middle latitudes and the declination of the dawn termination.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.org/ark:/85065/d7z322xj

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

2020-08-22T00:00:00Z

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