Open AccessIdentification and replacement of proton‐contaminated real‐time ACE solar wind measurements
Author(s) -
Machol Janet L.,
Reinard Alysha A.,
Viereck Rodney A.,
Biesecker Douglas A.
Publication year - 2013
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1002/swe.20070
Subject(s) - solar wind , environmental science , space weather , flagging , meteorology , space environment , wind speed , coronal mass ejection , atmospheric sciences , remote sensing , physics , geology , geophysics , plasma , geography , archaeology , quantum mechanics
Abstract Real‐time solar wind speed measurements derived from measurements by the Solar Wind Electron, Proton, and Alpha Monitor (SWEPAM) aboard the Advanced Composition Explorer (ACE) satellite are critical to specifying and forecasting current space weather and its impacts. When solar energetic protons produce high background levels in SWEPAM, the real‐time solar wind speed measurements can be corrupted due to errors in the onboard algorithm. We analyzed 14 years of ACE real‐time solar wind data for the years 1998 through 2011 to determine how to identify the contaminated measurements and what proxy might be substituted for these corrupt data. We find that good criteria for flagging contaminated data are that (1) the measured solar wind speeds are below 305 km s –1 , and (2) the >10 MeV ion fluxes measured by the ACE Solar Isotope Spectrometer (SIS) are above 180 pfu. We also compare several potential proxies for the contaminated solar wind and determine that the best proxy depends on the last valid measured wind speed, v initial , and the duration of the contamination period. For the first 25 h, the best proxy is simply v initial . At later times, if v initial < 400 km s –1 , then v initial continues to be the best proxy, while if v initial > 400 km s –1 , the best proxy is a linear function of the Kp geomagnetic index.