NDLI: Automatic Detection and Classification of Coronal Holes and Filaments Based on EUV and Magnetogram Observations of the Solar Disk

Content Provider	Springer Nature Link
Author	Scholl, Isabelle F. Habbal, Shadia Rifai
Copyright Year	2007
Abstract	A new method for the automated detection of coronal holes and filaments on the solar disk is presented. The starting point is coronal images taken by the Extreme Ultraviolet Telescope on the Solar and Heliospheric Observatory (SOHO/EIT) in the Fe ix/x 171 Å, Fe xii 195 Å, and He ii 304 Å extreme ultraviolet (EUV) lines and the corresponding full-disk magnetograms from the Michelson Doppler Imager (SOHO/MDI) from different phases of the solar cycle. The images are processed to enhance their contrast and to enable the automatic detection of the two candidate features, which are visually indistinguishable in these images. Comparisons are made with existing databases, such as the He i 10830 Å NSO/Kitt Peak coronal-hole maps and the Solar Feature Catalog (SFC) from the European Grid of Solar Observations (EGSO), to discriminate between the two features. By mapping the features onto the corresponding magnetograms, distinct magnetic signatures are then derived. Coronal holes are found to have a skewed distribution of magnetic-field intensities, with values often reaching 100 – 200 gauss, and a relative magnetic-flux imbalance. Filaments, in contrast, have a symmetric distribution of field intensity values around zero, have smaller magnetic-field intensity than coronal holes, and lie along a magnetic-field reversal line. The identification of candidate features from the processed images and the determination of their distinct magnetic signatures are then combined to achieve the automated detection of coronal holes and filaments from EUV images of the solar disk. Application of this technique to all three wavelengths does not yield identical results. Furthermore, the best agreement among all three wavelengths and NSO/Kitt Peak coronal-hole maps occurs during the declining phase of solar activity. The He ii data mostly fail to yield the location of filaments at solar minimum and provide only a subset at the declining phase or peak of the solar cycle. However, the Fe ix/x 171 Å and Fe xii 195 Å data yield a larger number of filaments than the Hα data of the SFC.
Starting Page	425
Ending Page	439
Page Count	15
File Format	PDF
ISSN	00380938
Journal	Solar Physics
Volume Number	248
Issue Number	2
e-ISSN	1573093X
Language	English
Publisher	Springer Netherlands
Publisher Date	2007-12-24
Publisher Place	Dordrecht
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Sun: coronal holes Sun: filaments Sun: magnetic field Automatic detection and classification Extraterrestrial Physics, Space Sciences Meteorology/Climatology Astrophysics
Content Type	Text
Resource Type	Article
Subject	Astronomy and Astrophysics Space and Planetary Science

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Automated detection of EUV Polar Coronal Holes during Solar Cycle 23

Automated Coronal Hole Detection Using Local Intensity Thresholding Techniques

Parameters of the Magnetic Flux inside Coronal Holes

Characteristics of EUV Coronal Jets Observed with STEREO/SECCHI

Modeling of Local Magnetic Field Enhancements within Solar Flux Ropes

Slow and Fast Rotating Coronal Holes from Geomagnetic Indices

A New Forecasting Index for Solar Wind Velocity Based on EIT 284 Å Observations

Solar Flare and CME Observations with STEREO/EUVI

Study of Coronal Jets During Solar Minimum Based on STEREO/SECCHI Observations

Automatic Detection and Classification of Coronal Holes and Filaments Based on EUV and Magnetogram Observations of the Solar Disk

Similar Documents

Automated detection of EUV Polar Coronal Holes during Solar Cycle 23

Automated Coronal Hole Detection Using Local Intensity Thresholding Techniques

Parameters of the Magnetic Flux inside Coronal Holes

Characteristics of EUV Coronal Jets Observed with STEREO/SECCHI

Modeling of Local Magnetic Field Enhancements within Solar Flux Ropes

Slow and Fast Rotating Coronal Holes from Geomagnetic Indices

A New Forecasting Index for Solar Wind Velocity Based on EIT 284 Å Observations

Solar Flare and CME Observations with STEREO/EUVI

Study of Coronal Jets During Solar Minimum Based on STEREO/SECCHI Observations

Automatic Detection and Classification of Coronal Holes and Filaments Based on EUV and Magnetogram Observations of the Solar Disk