DOI: 10.7910/dvn/y5cxm8
title: Bipolar magnetic regions determined from NSO synoptic carrington maps

description: &lt;h2&gt;Citation and Acknowledgements&lt;/h2&gt;

&lt;p&gt;&lt;br&gt;Please cite both this database the paper describing it, as well as adding the following acknowledgement:

&lt;p&gt;&lt;br&gt;&lt;b&gt;"Bipolar magnetic regions determined from NSO synoptic carrington maps were downloaded from the solar dynamo dataverse (https://dataverse.harvard.edu/dataverse/solardynamo), maintained by Andrés Muñoz-Jaramillo." &lt;/b&gt;&lt;/p&gt;

&lt;p&gt;&lt;br&gt; Database citation format is shown at the top of this page, underneath the database title. It can be downloaded in a variety of formats directly from this page&lt;/p&gt;

&lt;p&gt;&lt;br&gt;The paper describing this database is&lt;/p&gt;

&lt;p&gt;&lt;br&gt;&lt;b&gt;A.R. Yeates, D.H. Mackay, and A.A. van Ballegooijen, Modelling the Global Solar Corona: Filament Chirality Observations and Surface Simulations, Solar Physics 245, 87, (2007).&lt;/b&gt; &lt;a href="http://adsabs.harvard.edu/abs/2007SoPh..245...87Y"&gt;http://adsabs.harvard.edu/abs/2007SoPh..245...87Y&lt;/a&gt;&lt;br&gt;
&lt;/p&gt;

&lt;h2&gt;Main Limitations&lt;/h2&gt;

&lt;p&gt;&lt;br&gt;The main limitations of these data are:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;The need to approximate all active regions as one (or more) bipoles.&lt;/li&gt;
&lt;li&gt;Regions are only mapped as they cross the central meridian and thus their properties are measure during an arbitrary point of their lifetimes.&lt;/li&gt;
&lt;li&gt;Difficulty in accounting for newly-emerged flux within existing regions.&lt;/li&gt;
&lt;li&gt;Observational gaps present in the original NSO synoptic maps means that some regions are missing here and there.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;For these reasons, care is necessary when using these data to drive numerical simulations. Note also that the date assigned to each BMR corresponds to its first observation at central meridian - this may be up to 20 days after it first emerged.&lt;br&gt;&lt;/p&gt;

&lt;h2&gt;Description&lt;/h2&gt;


&lt;img src="http://solardynamo.org/dataverse/ARY_bipole_butterfly.png" alt="NSO Bipoles" width="840"&gt;


&lt;p&gt;Database of bipolar magnetic regions (BMRs) determined from NSO synoptic carrington maps of the Sun's photosperic line-of-sight magnetic flux between carrington rotations cr1911 and cr2196 inclusive. The attached plots summarize the dataset.&lt;/p&gt;

&lt;p&gt;In the data file itself, the columns are as follows:&lt;/p&gt;

&lt;ol&gt;
&lt;li&gt;Day of central-meridian crossing (numbered sequentially with 1 being 1st January 1996).&lt;/li&gt;

&lt;li&gt;Carrington longitude of bipole centre (degrees).&lt;/li&gt;

&lt;li&gt;Latitude of bipole centre (degrees).&lt;/li&gt;

&lt;li&gt;&lt;b&gt;Half of the&lt;/b&gt; angular separation between the centroids of each polarity, in heliocentric degrees.&lt;/li&gt;

&lt;li&gt;Total magnetic flux of each polarity (Maxwells). The sign indicates the polarity: + means the negative polarity is leading (westward) while - means the positive polarity is leading.&lt;/li&gt;

&lt;li&gt;Tilt angle, i.e. the angle between a line connecting the centroids and the east-west direction.&lt;/li&gt;
&lt;/ol&gt;

&lt;p&gt;The original carrington maps were downloaded from the NSO website:&lt;/p&gt;

&lt;p&gt;http://solis.nso.edu/0/vsm/vsm_maps.php&lt;/p&gt;

&lt;p&gt;Before cr2007 data from the KPVT (868.8nm line) were used, and from cr2007 onwards we used data from SOLIS/VSM (630.2nm, line-of-sight magnetic flux, 360x180 resolution).&lt;/p&gt;

&lt;p&gt;The bipole data were determined from the sequence of carrington maps using a semi-automated procedure. Essentially, this searches for new regions of strong magnetic flux, and a user oversees the division into separate bipoles.&lt;/p&gt;

&lt;p&gt;For further information, see &lt;a href="http://www.maths.dur.ac.uk/~bmjg46/index.html"&gt; http://www.maths.dur.ac.uk/~bmjg46/index.html&lt;/a&gt;&lt;/p&gt;