Structure and Variability of the Main Ionospheric

Trough: Empirical Modeling, Validation

and Physical Explanation

Maxim Klimenko1, Alexander Karpachev2, Vladimir Klimenko1, Nikolai Chirik1,

Gennadii Zhbankov3, Lubov Pustovalova2, David Themens4

1West Department of Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation

RAS Kaliningrad, Russia, e-mail: maksim.klimenko@mail.ru2Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation RAS Moscow, Russia,

e-mail: karp@izmiran.ru3Southern Federal University, Rostov-on-Don, Russia, e-mail: zhbankov_ga@rambler.ru

4University of New Brunswick, New Brunswick, Canada, e-mail: david.themens@gmail.com

UNIWERSYTET WARMINSKO MAZURSKI W OLSZTYNIE

Beacon Satellite Symposium 2019

August 19 – 23, 2019

IRI options for NmF2 (foF2) calculation

CCIR – 1967

Jones и Gallet, 1962

Jones et al., 1969

Ionosonde 1954-1958

Ocean and southern

hemisphere screen points

through extrapolation

along lines of constant

magnetic-dip angle.

IRTAM – 2012

Galkin, Reinisch, Huang и Bilitza,

2012

45 digisonde stations

Non-Linear Error Compensating

Technique for Associative Restoration

(NECTAR) is used to adjust the

CCIR coefficients to much real-time

digisonde measurements by the

Global Ionosphere Radio Observatory

(GIRO) network of digisondes.

URSI – 1988

Fox и McNamara,1988

Rush et al.,1989

45,000 station month of

ionosonde data

Theoretical model was

adjusted such that it agreed

with measured foF2 values

over land.

Seasonal dependence of effectiveness of model

correction procedure based on GNSS TEC data

360º

NeQuickIRI-Plas

Rz12

TECobs TECobs

TECmod

http://irimodel.org/

indices/ig_rz.dat

new Rz12

20º

Ovodenko et al., 2015; Kotova et al., 2017, 2018

corrected model results (foF2, TEC, etc.)

greatest improvement for Spring, worst efficiency for Winter

Main Ionospheric Trough (MIT) as the main structure of the subauroral

ionosphere

40 50 60 70

1E+005

200000

400000

80000

60000

40 50 60 70 80 90

1E+004

1E+005

20000

40000

60000

80000

200000

Ne, cm-3

ILAT, degree

CHAMP10/12/2004, 12.4LT400 km

Intercosmos-1930/09/1980, 4.6LThmF2

Cosmos-90026/07/1979, 0.9LT375 km

40 50 60 70

1E+005

200000

400000

600000

80000

60000

Seasonal variation of MIT

occurrence probabilityP%

Months

Two trough problem signature

in statistical data analysis

Northern hemisphere, HSA

40 50 60 70 80 90Latitude, deg

1

1.5

2

2.5

3January 24, 2006, 52E, 7.9LT, Kp=3-

72.9o

73.6o

62.1o

February 02, 2006, 75E, 8LT, Kp=3

fp, MHz

50

60

70

80

60

70

80

0 90 180 270 360Longitude, deg

60

70

80

07 LT 10 LT

12 LT

0 90 180 270 360Longitude, deg

50

60

70

80 7-8 LT 8-9 LT

Northern hemisphere, HSAGMLat, deg

=2.1, r=0.68

=3.1, r=0.72=4.1, r=0.62

Our Database for empirical model~5 000 000 COSMIC Ne-profiles (2006-2017)~200 000 GRACE Ne-profiles (2007-2015)~300 000 CHAMP Ne-profiles (2001-2008)http://cdaac-www.cosmic.ucar.edu/cdaac/products.html - data massivehttp://lasp.colorado.edu/lisird/tss/noaa_radio_flux.html - F10.7 values

Data for Main Ionospheric Trough (MIT) model200 000 Ne(h) - Intercosmos-19 profiles, CHAMP in-situ NeIonosonde measurements data

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

Measurements count

-90

-60

-30

0

30

60

90

Lat

itud

e (d

eg)

0

40

80

120

160

200

240

280

320

360

400

June, 12:00 LT December, 24:00 LT

Number of COSMIC, CHAMP, GRACE Data

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

Measurements count

-90

-60

-30

0

30

60

90

Lat

itud

e (d

eg)

0

40

80

120

160

200

240

280

320

360

400

-180 -150 -120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

Measurements count

-90

-60

-30

0

30

60

90

Lat

itud

e (d

eg)

0

40

80

120

160

200

240

280

320

360

400

Main Ionospheric Trough (MIT) Model

Developed in IZMIRAN

• Empirical MIT model is valid for quiet (Kp = 2) local winter conditions over the Northern and Southern Hemispheres for all local times and levels of solar activity.

• The model describes the trough position and its shape (i.e. foF2 distribution in the trough region).

• Experimental basis of the model: Cosmos-900 (2500 orbits of in situ Ne measurements at ~550 km), Intercosmos-19 (3000 obits topside sounding foF2 observation), CHAMP (15000 orbits of in situ Ne measurements at 350-550 km) satellites data.

MIT model (IZMIRAN)Karpachev et al, 2016

MIT Model Results (Online Service)

http://www.izmiran.ru/ionosphere/sm-mit/

IRI

model

MIT

model

RO

data

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Dec. F10.7 = 80

45

55

65

75

Lat

itud

e (d

eg)

1

1.5

2

2.5

3

3.5

Northern Hemisphere Southern Hemisphere

Comparison for F10.7=120

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Dec. F10.7 = 120

45

55

65

75

Lat

itud

e (d

eg)

1

1.5

2

2.5

3

3.5

4

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Jun. F10.7 = 120

-80

-70

-60

-50

-40

Lat

itud

e (d

eg)

1

1.5

2

2.5

3

3.5

4

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Dec. F10.7 = 120

45

55

65

75

Lat

itud

e (d

eg)

1

1.5

2

2.5

3

3.5

4

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Jun. F10.7 = 120

-80

-70

-60

-50

-40

Lat

itud

e (d

eg)

1

1.5

2

2.5

3

3.5

4

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Dec. F10.7 = 120

45

55

65

75

Lat

itud

e (d

eg)

1

1.5

2

2.5

3

3.5

4

-180-150-120 -90 -60 -30 0 30 60 90 120 150 180

Longitude (deg)

foF2 (MHz) 24:00 LT Jun. F10.7 = 120

-80

-70

-60

-50

-40L

atit

ud

e (d

eg)

1

1.5

2

2.5

3

3.5

4

C) MIT ModelB) IRI

Mechanisms for longitudinal variation of MIT

daytime

nighttime

important for daytime important for nighttime

Conclusion

We do the following steps:

• extended and modified Main Ionospheric Trough (MIT) empirical model

(http://www.izmiran.ru/ionosphere/sm-mit/)

• created Python program code for F2 peak parameters (NmF2, hmF2)

global empirical model development based on radiooccultation data

• explained mechanisms for daytime and nighttime longitudinal structure

of the main ionospheric trough for winter solar MIN condition

5

Work was supported by the Russian Science Foundation grant 17-77-20009

Mechanisms for daytime longitudinal variation of MIT

Mechanisms for nighttime longitudinal variation of MIT