Comparison of MSTID and Sporadic E Distributions in Ionosphere Study
Comparison of MSTID and sporadic E
Distributions
Hyosub Kil and Larry Paxton
(JHU/APL)
Wookyoung Lee
(Korea Astronomy and Space Science Institute)
Introduction
•
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°.
MSTID
Sporadic E
•
SNR profiles of GPS L1 signal
•
Extract perturbations through
normalization and smoothing using
high band pass filter (Savitzky-
Golay filter)
•
Threshold: residuals > 0.2
Normalized SNR Residuals
Altitude (km)
Sporadic E detection from GPS radio occultation (RO) data
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
Month
Local Time (h)
1.
Background density: Savitzky-Golay filter
2.
ΔN = log (N) – log (SG filter)
3.
ΔN/N = ΔN/ log (N)
MSTID detection from CHAMP LP data
Nighttime MSTID distribution
Solar max.
Solar min.
•
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
MSTID
•
Consistent features:
•
Seasonal variation, longitudinal variation
•
Inconsistent features:
•
Solar cycle dependence, hemispheric distributions, longitudinal variation
Nighttime
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F
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k
•
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.
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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Presentation Transcript
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.
