{"id":439,"date":"2025-12-10T22:02:05","date_gmt":"2025-12-10T22:02:05","guid":{"rendered":"https:\/\/atmos.ucla.edu\/dkondras\/?page_id=439"},"modified":"2025-12-10T22:02:05","modified_gmt":"2025-12-10T22:02:05","slug":"data","status":"publish","type":"page","link":"https:\/\/atmos.ucla.edu\/dkondras\/data\/","title":{"rendered":"Data"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\" id=\"page-title\">Gap Filling of Solar Wind Data<\/h2>\n\n\n\n<p>Solar wind and interplanetary magnetic \ufb01eld (IMF) data have large gaps before the launch of the WIND spacecraft in 1994.&nbsp;<a href=\"http:\/\/www.atmos.ucla.edu\/tcd\/ssa\">Singular spectrum analysis (SSA)&nbsp;<\/a>can reconstruct missing data by using an iterative algorithm which infers coherent spatio-temporal&nbsp; \u201csignal\u201d modes, while&nbsp; discarding the \u201cnoise\u201d&nbsp;(Kondrashov and Ghil, 2006). Here the gaps of the solar driver (such as solar wind parameters and IMF) are filled-in by smooth modes of co-variability with the continuous response (geomagnetic indices such as AE,Kp and Dst), as captured by the multivariate-SSA&nbsp;(Kondrashov et al. 2010).&nbsp;<\/p>\n\n\n\n<p>SSA gap-filling algorithm has been applied to existing gaps in 1972-Oct. 2013&nbsp;solar wind data data with hourly resolution: IMF components&nbsp;By, Bz,&nbsp;proton density Np,&nbsp;Alpha\/proton ratio Na\/Np,&nbsp;solar wind speed Vsw, and dynamic pressure P (see&nbsp;<a href=\"http:\/\/omniweb.gsfc.nasa.gov\/html\/ow_data.html\">OMNI data set convention<\/a>). Optimal SSA parameters that are obtained after testing on synthetic gaps. Both reconstruction datasets and results of testing with synthetic gaps are available by following the link below as&nbsp; zipped archives (6-20Mb).&nbsp;<\/p>\n\n\n\n<p><strong><a href=\"http:\/\/research.atmos.ucla.edu\/tcd\/cgi-bin.old\/agreesw.pl\">DOWNLOAD<\/a><\/strong><\/p>\n\n\n\n<p>This data is also available online in&nbsp;<a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/2014GL059741\/suppinfo\">SI of Kondrashov et al. 2014 GRL paper.<\/a><\/p>\n\n\n\n<p><strong>References<\/strong><\/p>\n\n\n\n<p>Kondrashov, D., R. Denton, Y. Y. Shprits, and H. J. Singer, 2014:&nbsp;Reconstruction of gaps in the past history of solar wind parameters,&nbsp;Geophys. Res. Lett.,&nbsp;41,&nbsp;2702\u2013270,&nbsp;<a href=\"http:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/2014GL059741\/full\">doi:10.1002\/2014GL059741<\/a>.&nbsp;<\/p>\n\n\n\n<p>Kondrashov, D., Y. Shprits, M. Ghil, 2010: &nbsp;Gap Filling of Solar Wind Data by Singular Spectrum Analysis,&nbsp;Geophys. Res. Lett,&nbsp;37, L15101,&nbsp;<a href=\"http:\/\/www.agu.org\/pubs\/crossref\/2010\/2010GL044138.shtml\">doi:10.1029\/2010GL044138<\/a>.<\/p>\n\n\n\n<p>Kondrashov, D. and M. Ghil, 2006:&nbsp;Spatio-temporal \ufb01lling of missing points in geophysical data sets,&nbsp;Nonlin. Processes Geophys., 13, 151-159,&nbsp;<a href=\"http:\/\/www.nonlin-processes-geophys.net\/13\/151\/2006\/npg-13-151-2006.html\">doi:10.5194\/npg-13-151-2006<\/a><\/p>\n\n\n\n<p>&nbsp;Data source:&nbsp;<a href=\"http:\/\/omniweb.gsfc.nasa.gov\/\">OMNIWEB<\/a><\/p>\n\n\n\n<p><a href=\"http:\/\/virbo.org\/RBW#Input_and_validation_data\">Reconstruction for Radiation Belts and Wave Modeling Group<\/a><\/p>\n\n\n\n<p>This research has been funded by&nbsp;<a href=\"http:\/\/www.nsf.gov\/awardsearch\/showAward?AWD_ID=1102009&amp;HistoricalAwards=false\">National Science Foundation Award AGS-1102009<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Gap Filling of Solar Wind Data Solar wind and interplanetary magnetic \ufb01eld (IMF) data have large gaps before the launch of the WIND spacecraft in 1994.&nbsp;Singular spectrum analysis (SSA)&nbsp;can reconstruct missing data by using an iterative algorithm which infers coherent spatio-temporal&nbsp; \u201csignal\u201d modes, while&nbsp; discarding the \u201cnoise\u201d&nbsp;(Kondrashov and Ghil, 2006). Here the gaps of the&#8230;<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-439","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/pages\/439","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/comments?post=439"}],"version-history":[{"count":1,"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/pages\/439\/revisions"}],"predecessor-version":[{"id":440,"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/pages\/439\/revisions\/440"}],"wp:attachment":[{"href":"https:\/\/atmos.ucla.edu\/dkondras\/wp-json\/wp\/v2\/media?parent=439"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}