NDLI: The Solar Rotation in the 1930s from the Sunspot and Flocculi Catalogs of the Ebro Observatory

Content Provider	Springer Nature Link
Author	de Paula, V. Curto, J. J. Casas, R.
Copyright Year	2016
Abstract	The tables of sunspot and flocculi heliographic positions included in the catalogs published by the Ebro Observatory in the 1930s have recently been recovered and converted into digital format by using optical character recognition (OCR) technology. We here analyzed these data by computing the angular velocity of several sunspot and flocculi groups. A difference was found in the rotational velocity for sunspots and flocculi groups at high latitudes, and we also detected an asymmetry between the northern and southern hemispheres, which is especially marked for the flocculi groups. The results were then fitted with a differential-rotation law [ $\omega=a+b \sin^{2} B$ ] to compare the data obtained with the results published by other authors. A dependence on the latitude that is consistent with former studies was found. Finally, we studied the possible relationship between the sunspot/flocculi group areas and their corresponding angular velocity. There are strong indications that the rotational velocity of a sunspot/flocculi group is reduced (in relation to the differential rotation law) when its maximum area is larger.
Starting Page	2269
Ending Page	2279
Page Count	11
File Format	PDF
ISSN	00380938
Journal	Solar Physics
Volume Number	291
Issue Number	8
e-ISSN	1573093X
Language	English
Publisher	Springer Netherlands
Publisher Date	2016-09-06
Publisher Place	Dordrecht
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Rotation Active regions, velocity field Sunspots, velocity Solar cycle, observations Astrophysics and Astroparticles Atmospheric Sciences Space Sciences (including Extraterrestrial Physics, Space Exploration and Astronautics)
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

Investigation of Sunspot Area Varying with Sunspot Number

70 Years of Sunspot Observations at the Kanzelhöhe Observatory: Systematic Study of Parameters Affecting the Derivation of the Relative Sunspot Number

The New Sunspot Number: Assembling All Corrections

Sunspot Observations of Rudolf Wolf from 1849 – 1893

A Revised Collection of Sunspot Group Numbers

The Revised Brussels–Locarno Sunspot Number (1981 – 2015)

Sunspot Observations During the Maunder Minimum from the Correspondence of John Flamsteed

Sunspot Numbers from ISOON: A Ten-Year Data Analysis

Sunspot Observations and Counting at Specola Solare Ticinese in Locarno Since 1957

The Solar Rotation in the 1930s from the Sunspot and Flocculi Catalogs of the Ebro Observatory

Similar Documents

Investigation of Sunspot Area Varying with Sunspot Number

70 Years of Sunspot Observations at the Kanzelhöhe Observatory: Systematic Study of Parameters Affecting the Derivation of the Relative Sunspot Number

The New Sunspot Number: Assembling All Corrections

Sunspot Observations of Rudolf Wolf from 1849 – 1893

A Revised Collection of Sunspot Group Numbers

The Revised Brussels–Locarno Sunspot Number (1981 – 2015)

Sunspot Observations During the Maunder Minimum from the Correspondence of John Flamsteed

Sunspot Numbers from ISOON: A Ten-Year Data Analysis

Sunspot Observations and Counting at Specola Solare Ticinese in Locarno Since 1957

The Solar Rotation in the 1930s from the Sunspot and Flocculi Catalogs of the Ebro Observatory