Comparison of MSTID and Sporadic E Distributions in Ionosphere Study
Investigating the role of sporadic E in medium-scale traveling ionospheric disturbances by comparing its distribution with MSTID using CHAMP satellite data. Sporadic E and MSTID occurrences, detection methods, and distribution patterns in different hemispheres are explored, revealing seasonal variations and occasional inconsistency in features such as solar cycle dependence and hemispheric distributions.
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Comparison of MSTID and sporadic E Distributions Hyosub Kil and Larry Paxton (JHU/APL) Wookyoung Lee (Korea Astronomy and Space Science Institute)
Introduction MSTID Atmospheric gravity waves and sporadic E (transient high electron density at 80-130 km altitude) are understood as important elements for the development of medium scale traveling ionospheric disturbances (MSTIDs). Here we investigate the role of sporadic E by comparing the distributions of sporadic E and MSTID. Both Sporadic E and MSTID data were derived from CHAMP observations. CHAMP satellite was operated from July 2000 to September 2010 at an altitude of 400 km with an orbital inclination of 87.25 .
Sporadic E detection from GPS radio occultation (RO) data SNR profiles of GPS L1 signal Extract perturbations normalization and smoothing using high band pass filter (Savitzky- Golay filter) Threshold: residuals > 0.2 through Altitude (km) Sporadic E Normalized SNR Residuals
Data distribution Sporadic E distribution
Sporadic E distribution Northern Hemisphere Southern Hemisphere Used data at 25 50 magnetic latitude Sporadic E occurs preferentially during summer months No pronounced solar cycle dependence Local time dependence is not obvious Local Time (h) Month
MSTID detection from CHAMP LP data 1. Background density: Savitzky-Golay filter 2. N = log (N) log (SG filter) 3. N/N = N/ log (N)
Nighttime MSTID distribution Solar min. Solar max. 2001 2003 2004 2006 2007 2009 Used data at 25 50 magnetic latitude at 21-03 LT Semi-annual variation Clear solar cycle dependence Hemispheric asymmetry, especially during solar max.
Sporadic E Nighttime MSTID 2001 2003 2004 2006 2007 2009 Consistent features: Seasonal variation, longitudinal variation Inconsistent features: Solar cycle dependence, hemispheric distributions, longitudinal variation
Conclusions and Future work Conclusions and Future work The MSTID activity can be partially explained in terms of sporadic E based on the sporadic E and MSTID distributions. We will further investigate the sporadic E distribution by using other observation data (COSMIC). The effect of sporadic E and thermospheric conditions on the development of MSTID and conjugacy will be investigated by conducting SAMI3 model simulations.
