an introduction to earth's...

Intro to Earth’s Ionosphere - Bodo Reinisch IRI 2019 Workshop, Nicosia Cyprus

International Reference Ionosphere 2019 Workshop COSPAR Capacity Building Workshop

Frederick University, Nicosia, Cyprus, 2-13 September 2019

An introduction to

EARTH’S IONOSPHERE

Bodo Reinisch

Lowell Digisonde International & University of Massachusetts LowellEmail : [email protected]

Intro to Earth’s Ionosphere - Bodo Reinisch IRI 2019 Workshop, Nicosia Cyprus2

Ionosphere: Support & Obstacle


IONOSPHERE IS A MINUTE PART OF THE

HELIOSPHERE

particles and magnetic fields

SUNEARTH

photons

convection zone

radiative zone

surface

sunspot

bright active region

coronal mass ejection

bow

shock

Atmosphere/IonosphereEarth, RE = 6,400 km

Magnetopause, Rmp = 10RE

Plasmapause, Rpp = 4RE

solar wind:

atmosphere

1 AU = 150 million km

not to scale


5000 A

Solar Spectrum


How was the “Ionosphere” discovered?1. In 1888, Heinrich Hertz (Germany) demonstrates the propagation of

“electromagnetic radio waves”.

2. In 1901, Guglielmo Marconi (Italy) transmits high-frequency (HF) radio

signals from the UK to North America. How do the radio waves get

around the Earth’s curvature?

3. In 1902, Oliver Heaviside (UK) and Arthur Kennelly (USA) independently

postulate the existence of a “conducting layer” in the upper atmosphere,

subsequently referred to as the Kennelly-Heaviside layer.

4. In 1910, William Eccles (UK) describes the layer as “a body of electrons

and positive ions that emerge as sunlight decomposes air”.

5. In 1952, Karl Rawer publishes the first book with the title “Die

Ionosphäre” (translated into English in 1956).

5


Measuring and Modeling the Ionosphere

6

Physicists, mathematicians, and engineers have applied the

Humboldtian approach to explain how radio waves can

propagate beyond the horizon in a then widely unknown

medium, the atmosphere/ionosphere, in the presence of a

conductive boundary, the Earth’s surface:

“Comprehensive and extensive fieldwork, careful preparation

for expeditions, meticulous collection of data”__________________________________

From Chen-Pang Yeang “Probing the Sky with Radio Waves”, University of Chicago Press, 2013

The COSPAR/URSI IRI Working Group has faithfully applied the Humboldt

approach during the last 5 decades

URSI was founded in 1919! Remote sensing of the ionosphere with radio

waves has been the main objective of URSI Commission G


FM radio broadcast as well as GPSsignals penetrate the ionosphere, but they get refracted!

AM radio broadcast waves refract/reflectin the ionosphere.

Ionosphere

(Km)

penetrating rays are refracted

reflected rays

Refraction and Reflection of Radiowaves depend on frequency


Radio Frequency Bands


X h X eν + −+ ⇒ +X P X P e+ −+ ⇒ + +

( )X e X h independent of heightν+ −+ ⇒ +

/Molecules

Formation of the Ionosphere - Aeronomy

[from McNamara, 1991]


Formation of the Ionosphere - Aeronomy

X h X eν + −+ ⇒ +X P X P e+ −+ ⇒ + +

( )X e X h independent of heightν+ −+ ⇒ +

/Molecules[from McNamara, 1991]

IRI 2019 Workshop, Nicosia CyprusIntro to Earth’s Ionosphere - Bodo Reinisch

+2

+2

+

+2 2

+ +2

Dissociate Recombination Reactions:

O + e O+ O+ 6.96eV

N + e N + N + 5.82eV

N O + e N + O+ 2.76eV

Charge-Transfer Reactions:

O + O O + O+1.53eV

O + N N O + N +1.09eV

+

→

→

→

→

→

Important Ion Loss Reactions


Illustration of the Ionospheric Layer Formation

[from McNamara, 1991]

[O] [e-]


Chapman Production function Q

Simple Chapman Layer [1931]

n0=n(h0)


Electron Density DistributionChapman Profile (1932)

At equilibrium, dI/dt = 0, then:

2

0, . .,

( 1 )

since ( ). :

Loss of electrons by radiative recombination

e

e e e

NQ L i e Q L

tE and F region

L N N N plasma is neutral N N Thereforeα α+ +

∂ = − = =∂

= = =

( 2 )

' (since )

Hence

Loss of electrons by attachment

M e e M

F region

L N N N N constβ β= = ≈

Note:Simple Chapman theory does not predict the F2 layer peak“Diffusion” causes the F2 layer peak


Number density profiles for neutrals, ions(+) & electrons(-)

e-

hmF2


Day and Night Profiles at Sunspot Max & Min

Note:At daytime, a ~20 km wide density dip (valley) usually exists between E and F layer (not shown here).

At nighttime, a wide valley usually exists.

Deep nighttime valley


Ionospheric “Regions”

[from Zolesi and Cander, 2014]


Ionosphere and Plasmasphere

Ionosphere EDP Plasmasphere IMAGE/RPI Measurements1

1 from Huang et al., 2004


Measuring Electron Density Profiles

Discontinued!

D layer profiles •Rocket measurements provide the most reliable data, 50-120 km

•HF Seddon experiments•Partial reflection measurements show time-variations of profiles

• ~3 MHz vertical sounding, differential absorption for O and X wavesE and F layer Profiles from the global ionosonde network

•Vertical HF echo sounding routinely measures the bottomside EDP up to hmF2http://giro.uml.edu/

http://dias.space.noa.gr:8080/LatestDias2/homePageMin.jsp

Incoherent Scatter Radars measure profiles from ~90 to ~1000 km•Millstone Hill, USA; Arecibo, Puerto Rico; Tromso and Svalbard, Norway; Jicamarca, Peru; Shigaraki , Japan; St. Santin, France; Malvern, UK; Irkutsk, Russia; Kharkov, Ukraine

Data available at http://madrigal.haystack.mit.edu/madrigal/Satellite Topside Sounding

https://nssdc.gsfc.nasa.gov/space/isis/documentshttps://nssdc.gsfc.nasa.gov/space/isis/documents/papers/topist_rs_final.pdf

Satellite TEC and Radio Occultation measurementsRocket and Satellite in situ measurements

http://spidr.ngdc.noaa.gov/spidr/ SPIDR is discontinued!


Measuring Electron Density Profiles

Discontinued!

D layer profiles •Rocket measurements provide the most reliable data, 50-120 km

•HF Seddon experiments•Partial reflection measurements show time-variations of profiles

• ~3 MHz vertical sounding, differential absorption for O and X wavesE and F layer Profiles from the global ionosonde network

•Vertical HF echo sounding routinely measures the bottomside EDP up to hmF2 http://giro.uml.edu/

http://dias.space.noa.gr:8080/LatestDias2/homePageMin.jsp

Incoherent Scatter Radars measure profiles from ~90 to ~1000 km•Millstone Hill, USA; Arecibo, Puerto Rico; Tromso and Svalbard, Norway; Jicamarca, Peru; Shigaraki , Japan; St. Santin, France; Malvern, UK; Irkutsk, Russia; Kharkov, Ukraine http://madrigal.haystack.mit.edu/madrigal/

Satellite Topside Sounding https://nssdc.gsfc.nasa.gov/space/isis/documentshttps://nssdc.gsfc.nasa.gov/space/isis/documents/papers/topist_rs_final.pdf

Satellite TEC and Radio Occultation measurementsSatellite in situ measurements

http://spidr.ngdc.noaa.gov/spidr/ SPIDR is discontinued!


Radar Sensing of the Ionosphere from the ground

(see Reinisch Ionosonde lecture on Tuesday,and Zhang ISR lecture on Thursday)


Ionospheric Radio Occultation

22

[Jakowski et al., 2007 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006SW000271]

(See Haralambous lecture on Wednesday)


Niighttime ionogram and derived profile

foF2=5.30 MHz

Frequency, MHz

Hei

ght,

km

MH, 23APR2019


Daytime ionogram and derived profile

foF2=5.15 MHz

foF1=4.75 MHz

foE=3.50 MHz

MH, 23APR2019

F1 ledge


Diurnal Variations of Electron Density Profiles

Digisonde at Cachimbo, Brazil

Rea

l hei

ght,

km

Pla

sma

freq

uenc

y, M

Hz

SS SR


Ionosphere Storm Effects

http://ionosphere.meteo.beStankov et al. (2011): Local ionospheric electron density profile reconstruction

in real time. Adv. Space Res. 47(7), 1172-1180.


IRI Electron Density Profile Model

IRI EDP

DE

1. Digisonde ionograms

measure NmF2, hmF2, NmF1,

hmF1, B0, B1

2. IRTAM assimilates measured

values in IRI in real time


Assimilative IRI Parameter Mapshttp://giro.uml.edu/IRTAM/

foF2 hmF2

28

See Galkin lecture next Monday


Summary

• After the discovery of Earth’s ionosphere, it took a full century to

arrive at today’s “reasonable” understanding of the creation and

behavior of the global ionosphere.

• Forces on the ionospheric constituents from above and below the

ionosphere influence the plasma distribution and dynamics.

• Physics-based and data-driven ionospheric models provide good

climatological descriptions, but predictions are not sufficiently

reliable to support many of today’s applications.

• Real time assimilation of measured ionospheric data provide largely

improved ionospheric predictions.


Selected Bibliography

Karl Rawer, The Ionosphere, Crosby Lockwood & Son, LTD, London, 1956.

Henry Rishbeth, Owen Garriott, Ionospheric Physics, Academic Press, New York, 1969.

John Hargreaves, The Upper Atmosphere and Solar-Terrestrial Relations, Van Nostrand Reinhold, New York, 1979.

Ken Davies, Ionospheric Radar, Peter Peregrinus Ltd, London, Malabar, FL, 1990

Leo McNamara, The Ionosphere, Communications, Surveillance, and Direction Finding, Krieger Publishing Co, 1991.

Robert W. Schunk, Andrew F. Nagy, Ionospheres: Physics, Plasma Physics, and Chemistry, Cambridge University Press, 2000.

Michael Kelley, The Earth’s Ionosphere, 2nd Edition, Academic Press, Elsevier, London, 2009

Chen-Pang Yeang, Probing the Sky with Radiowaves, The University of Chicago Press, 2013.

Bruno Zolesi and Ljiljiana Cander, Ionospheric Prediction and Forecasting, Springer Geophysics, Heidelberg, 2014.

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