J/other/SoPh/294ivo://CDS.VizieR/J/other/SoPh/294.144CDSHeinemann S.G.Temmer M.Heinemann N.Dissauer K.Samara E.Jercic V.,Hofmeister S.J.Veronig A.M.2025-10-13T12:35:46Z2019-11-06T13:29:46ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frthe-sunmagnetic-fieldsstellar-atmospheresCoronal holes are usually defined as dark structures seen in the extreme ultraviolet and X-ray spectrum which are generally associated with open magnetic fields. Deriving reliably the coronal hole boundary is of high interest, as its area, underlying magnetic field, and other properties give important hints as regards high speed solar wind acceleration processes and compression regions arriving at Earth. In this study we present a new threshold-based extraction method, which incorporates the intensity gradient along the coronal hole boundary, which is implemented as a user-friendly SSW-IDL GUI. The Collection of Analysis Tools for Coronal Holes (CATCH) enables the user to download data, perform guided coronal hole extraction and analyze the underlying photospheric magnetic field. We use CATCH to analyze non-polar coronal holes during the SDO-era, based on 193{AA} filtergrams taken by the Atmospheric Imaging Assembly (AIA) and magnetograms taken by the Heliospheric and Magnetic Imager (HMI), both on board the Solar Dynamics Observatory (SDO). Between 2010 and 2019 we investigate 707 coronal holes that are located close to the central meridian. We find coronal holes distributed across latitudes of about +/-60{deg}, for which we derive sizes between 1.6x10^9^ and 1.8x10^11^km^2^. The absolute value of the mean signed magnetic field strength tends towards an average of 2.9+/-1.9G. As far as the abundance and size of coronal holes is concerned, we find no distinct trend towards the northern or southern hemisphere. We find that variations in local and global conditions may significantly change the threshold needed for reliable coronal hole extraction and thus, we can highlight the importance of individually assessing and extracting coronal holes.2019SoPh..294..144Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/other/SoPh/294.144CatalogResearchIsServedByTAP VizieR generic servicerelated-toIII/238 : Synthetic spectra in the near-IR (Munari+, 2000-2001)VI/138 : Sunspots catalogues, 1853-1870 (Casas+, 2013)VI/152 : SOVAP-PICARD total solar irradiance (Meftah+, 2016)J/other/SoPh/291.3527 : SOLAR/SOLSPEC UV SSI from 2008-2015 (Meftah+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/other/SoPh/294.144https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/other/SoPh/294.144http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/other/SoPh/294.144https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/other/SoPh/294.144https://vizier.iucaa.in/viz-bin/votable?-source=J/other/SoPh/294.144http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/other/SoPh/294.144GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/other/SoPh/294.144/paramsCoronal hole parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintCHNrCoronal Hole (CH) Number (CHNr)meta.idintObsYear of observation date (YYYY)stime.epochThrIntensity Thr in % I_med units (thr)phot.flux;em.opt;arith.ratiointe_ThrUncertainty in Thr in % I_med units (uthr)stat.errorfloatThrdnIntensity Thr in DN units (thrdn)phot.count;em.optfloate_ThrdnUncertainty in Thrdn in DN units(uthrdn)stat.errorfloatCFCategroy Factor (cf)meta.codefloatmagUSUnsigned Mean Magnetic Field Strength (mag_us)Gphys.magField;phys.mol.dipole.magneticfloate_magUSUncertainty in magUS (umag_us)Gstat.errorfloatfluxSSigned Magnetic Flux in 10^20^Mx units (flux_s)phys.magFieldfloate_fluxSUncertainty in fluxS in 10^20^Mx units (uflux_s)stat.errorfloatfluxUSUnsigned Magnetic Flux in 10^20^Mx units (flux_us)phys.magFieldfloate_fluxUSUncertainty in fluxUS in 10^20^Mx units (uflux_us)stat.errorfloatfluxBFlux Balance (flux_b)%phys.magFieldfloate_fluxBUncertainty in fluxB (uflux_b)%stat.errorfloatskewSkewness of the Magnetic Field (skew)phys.magField;phys.mol.dipole.magneticfloate_skewUncertainty in skew (uskew)stat.errorfloatftnrWNumber of Flux Tubes (Weak) (ftnr_w)meta.numberinte_ftnrWUncertainty in ftnrW (uftnr_w)stat.errorintftnrSNumber of Flux Tubes (Strong) (ftnr_s)meta.numberinte_ftnrS? Uncertainty in ftnrS (uftnr_s)stat.errorintnullableftarWFlux Tube Area Ratio (Weak) (ftar_w)%phot.flux;arith.ratiofloate_ftarWUncertainty in ftarW (uftar_w)%stat.errorfloatAreaCoronal Hole Area (area)1e+10km**2phys.areafloate_AreaUncertainty in Area (uarea)1e+10km**2stat.error;phys.areafloatmeanIntMean Coronal Hole Intensity in DN units (meanint)phot.count;em.optfloate_meanIntUncertainty in meanInt in DN units (umeanint)stat.errorfloatmeanInt50Mean CH Intensity of the lowest 50% in DN units (meanint50)phot.count;em.optfloate_meanInt50Uncertainty in meanInt50 in DN units (umeanint50)stat.errorfloatmeanInt25Mean CH Intensity of the lowest 25% in DN units (meanint25)phot.count;em.optfloate_meanInt25Uncertainty in meanInt25 in DN units (umeanint25)stat.errorfloatmedIntMedian Coronal Hole Intensity in DN units in DN units (medint)phot.count;em.optfloate_medIntUncertainty in medInt in DN units (umedint)stat.errorfloatmedInt50Median CH Intensity of the lowest 50% in DN units (medint50)phot.count;em.optfloate_medInt50Uncertainty in medInt50 in DN units (umedint50)stat.errorfloatmedInt25Median CH Intensity of the lowest 25% in DN units (medint25)phot.count;em.optfloate_medInt25Uncertaintys in medInt25 in DN units (umedint25)stat.errorfloatcomLONCH Center of Mass Longitude in HEEQ (comlng)degpos.framefloate_comLONUncertainty in comLON (ucomlng)degstat.errorfloatcomLATCH Center of Mass Latitude in HEEQ (comlat)degpos.framefloate_comLATUncertainty in comLAT (ucomlat)degstat.errorfloatLONEMax Longitudinal Eastward Extent (HEEQ) (lng_e)degphys.angSize;stat.maxfloate_LONEUncertainty in LONE (ulng_e)degstat.errorfloatLONWMax Longitudinal Westward Extent (HEEQ) (lng_w)degphys.angSize;stat.maxfloate_LONWUncertainty LONW (ulng_w)degstat.errorfloatLATSMax Latitudinal Southward Extent (HEEQ) (lat_s)degphys.angSizefloate_LATSUncertainty in LATS (ulat_s)degstat.errorfloatLATNMax Latitudinal Northward Extent (HEEQ) (lat_n)degphys.angSizefloate_LATNUncertainty in LATN (ulat_n)degstat.errorfloatmagSSigned Mean Magnetic Field Strength (mag_s)Gphys.magField;phys.mol.dipole.magneticfloate_magSUncertainty in magS (umag_s)Gstat.errorfloatftarSFlux Tube Area Ratio (Strong) (ftar_s)%phot.flux;arith.ratiofloate_ftarSUncertainty in ftarS (uftar_s)%stat.errorfloatftfluxWFlux Tube Flux Ratio (Weak) (ftflux_w)%phot.flux;arith.ratiofloate_ftfluxWUncertainty in ftfluxW (uftflux_w)%stat.errorfloatftfluxSFlux Tube Flux Ratio (Strong) (ftflux_s)%phot.flux;arith.ratiofloate_ftfluxS? Uncertainty ib ftfluxS (uftflux_s)%stat.errorfloatnullable