Identification

Title

The role of flare‐driven ionospheric electron density changes on the doppler flash observed by SuperDARN HF radars

Abstract

Trans-ionospheric high frequency (HF: 3-30 MHz) signals experience strong attenuation following a solar flare-driven sudden ionospheric disturbance (SID). Solar flare-driven HF absorption, referred to as short-wave fadeout, is a well-known impact of SIDs, but the initial Doppler frequency shift phenomena, also known as "Doppler flash" in the traveling radio wave is not well understood. This study seeks to advance our understanding of the initial impacts of solar flare-driven SID using a physics-based whole atmosphere model for a specific solar flare event. First, we demonstrate that the Doppler flash phenomenon observed by Super Dual Auroral Radar Network (SuperDARN) radars can be successfully reproduced using first-principles based modeling. The output from the simulation is validated against SuperDARN line-of-sight Doppler velocity measurements. We then examine which region of the ionosphere, D, E, or F, makes the largest contribution to the Doppler flash. We also consider the relative contribution of change in refractive index through the ionospheric layers versus lowered reflection height. We find: (a) the model is able to reproduce radar observations with an root-median-squared-error and a mean percentage error (delta) of 3.72 m/s and 0.67%, respectively; (b) the F-region is the most significant contributor to the total Doppler flash (similar to 48%), 30% of which is contributed by the change in F-region's refractive index, while the other similar to 18% is due to change in ray reflection height. Our analysis shows lowering of the F-region's ray reflection point is a secondary driver compared to the change in refractive index.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7wd441z

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

2021-08-01T00:00:00Z

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