Space weather phenomena in the ionosphere and their effect on GNSS (Presented by Japan) IPXX ICAO...
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Transcript of Space weather phenomena in the ionosphere and their effect on GNSS (Presented by Japan) IPXX ICAO...
Space weather phenomena in the ionosphere and their effect on GNSS
(Presented by Japan)
IPXX ICAO ISTF/4 New Delhi, India, 5th to 7th February 2014
SUMMARY
This paper presents a short review of major space weather phenomena observed in mid- and low-latitude ionosphere. Their effect on GNSS also mentioned.
Sudden Ionospheric Disturbance (SID)G
OE
SX
-ray
flu
x[W
/m2 ]
UT [hour]
SO
HO
/SE
ME
UV
[co
un
t/s]
GP
ST
EC
[TE
CU
]
TIM
ED
/GU
VI
O,
N2
[R]
[Tsurutani et al., 2005]
10 15
0
35
[Tsugawa et al., 2007]
Sudden Ionospheric Disturbance (SID)
Amplitude +Several 10 TECU
Depending on flare class
Time scale Increase in several minutes
Enhancement lasts for several hours
Spatial structure Global scale in the sunlit hemisphere
Depending on solar zenith angle
Other characteristics
HF radio absorption (Dellinger phenomena)
Possibility of loss-of-lock on GNSS signals due to solar radio burst
Effect on GNSS Augmented GPS (due to TEC model correction error)
Loss-of-lock on GPS signals
JST
Wakkanai
Okinawa
foF
2 [M
Hz]
JST (UT+9h)
Ionospheric Storm
One-month Average
Negative Storm
Kp
PositiveStorm
Ionospehric Storm
Amplitude ±Several 10 TECU compared to quiet conditions
Time scale Several hours to several days
Spatial structure Small spatial TEC gradient
Other characteristics
Basically occurring during and/or after magnetic storms
Effect on GNSS Augmented GPS (due to TEC model correction error)
Equatorial Ionization Anomaly
Amplitude ±Several 10 TECU
Time scale
Spatial structure Large latitudinal TEC gradient
Other characteristics
Day-to-day variation is not negligible(increase, disappearance, hemispheric asymmetry, etc)
Affected by magnetic storms
Effect on GNSS Augmented GPS (due to TEC model correction error)
Short summary of SED
Amplitude +Several 10 to 100TECU
Time scale Several hours (?)
Spatial structure Steep horizontal TEC gradient
Narrow in zonal direction
Extending in NW-SE direction
Other characteristics
Often observed from noon to sunset during the large geomagnetic storm
Sometimes accompanied with ionospheric irregularity
Effect on GNSS Differential GPS
Augmented GPS (due to TEC model correction error)
Loss-of-lock on GPS signals
GPS-TEC Observations for Space WeatherAbsolute TEC ROTI (~10km scale
irregularity)Loss-of-Lock (~100m scale irregularity)
12:20 UT
(21:20 JST)
12:40 UT
(21:40 JST)
13:00 UT
(22:00 JST)
3D simulation of plasma bubble [Courtesy of Dr. T. Yokoyama (NICT) ]
Short summary of EPB
Amplitude -Several 10 to -100TECU
Time scale Several 10 minutes to several hours
Spatial structure Steep horizontal TEC gradient
Narrow in zonal direction
Extending along the magnetic field line
Other characteristics
Often observed mid- to low latitudes after the sunset.
Almost always accompanied with ionospheric irregularity
Effect on GNSS Differential GPS
Augmented GPS (due to TEC model correction error)
Loss-of-lock on GPS signals
Traveling Ionospheric Disturbances (TID)
[Tsugawa et al., GPS solut., 2007]
[Tsugawa et al., JGR., 2003]
Large
-scale
TID
(LSTID)
Medium
-scale
TID
(MSTID)
Amplitude A few TECU
Time scale MS: Several 10 minutes
LS: Several hours
Spatial structure MS: Wavelengths of several 100 km
LS: Wavelengths of 1,000 – 3,000 km, Zonally extended wavefront
Other characteristics
MS: Southwestward and Southeastward propagations in nighttime and daytime, respectively.
LS: Related with magnetic storm
Effect on GNSS Differential GPS
Augmented GPS (due to TEC model correction error)
Traveling Ionospheric Disturbances (TID)