Identification

Title

Signature of extended solar cycles as detected from Ca II K synoptic maps of Kodaikanal and Mount Wilson Observatory

Abstract

In recent years there has been a resurgence of the study of extended solar cycles (ESCs) through observational proxies mainly in extreme ultraviolet. But most of them are limited only to the space-based era covering only about two solar cycles. Long-term historical data sets are worth examining for the consistency of ESCs. The Kodaikanal Solar Observatory (KSO) and the Mount Wilson Observatory (MWO) are two major sources of long-term Ca II K digitized spectroheliograms covering the temporal spans of 1907-2007 and 1915-1985 respectively. In this study, we detected supergranule boundaries, commonly known as networks, using the Carrington maps from both KSO and MWO data sets. Subsequently we excluded the plage areas to consider only the quiet Sun (QS) and detected small-scale bright features through intensity thresholding over the QS network. Latitudinal density of those features, which we named "Network Bright Elements," could clearly depict the existence of overlapping cycles with equatorward branches starting at latitude similar to 55 degrees and taking about 15 +/- 1 yr to reach the equator. We performed a superposed epoch analysis to depict the similarity of those extended cycles. Knowledge of such equatorward band interaction, for several cycles, may provide critical constraints on solar dynamo models.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7jh3q6s

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

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South bounding latitude

Temporal reference

Temporal extent

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End position

Dataset reference date

date type

publication

effective date

2019-03-20T00:00:00Z

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Conformity

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Constraints related to access and use

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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