Scintillation Occurrences and Analysis

What is Scintillation?

From past several centuries’ educators who are actively

interested and keen to known the truth and hidden knowledge

of nature and sky upon us have observed sparkling light like

crystals spreaded across the sky in the backdrop. Twinkling

effect gives beautiful effect on the vast open skies. The

astronomers were very much inspired from this strange

phenomenon.

This phenomena is termed as Scintillation, the technical term

for the twinkling of stars, is defined as the rapid and irregular

variation of intensity of celestial objects. [5]

Scintillation is although appears beautiful of the sky lines but it

has negative impact on astronomy. Relatively small fractions of

S to the order of 0.04 to the incident energy E is converted into

N fluorescence photons of mean energy Ep, which provide the

scintillation.

The fluctuation in amplitude and phase caused are termed and

classified as scintil lation. Thereby it is stated that Scintil lation refers

to the rapid fluctuation in signal amplitude and phase often observed

on satellite links. These fluctuations are caused by random spatial

and temporal changes of the atmosphere’s radio refractive index

within the link’s first Fresnel ellipsoid. Scintil lation statistics are

necessary for experiment planning and in design of signal processing

procedures. [1]

Phase scintil lation paused by propagation through solar wind,

ionosphere and troposphere irregularities is a noise process for

many spacecraft radio science experiments. In precision Doppler

tracking observation, scintil lation can be the domain noise process.

[2]

A well known stellar scintil lation phenomena that arises when

observing the stars through the earth atmosphere. The data

reliability is also required before analysis of the current that is

effect of the element of effectiveness. The scintil lation emission is

same as fluorescence spectrum when modelled and its categorized

into different types depending upon the sky region is it effecting

such as equatorial scintil lation, high latitude scintil lation etc.

Scintillation Properties

• The absolute scintil lation efficiency index S4 fallen data comm;

• The scintil lation emission is spectrum;

• The scintil lation has decay time Ƭ.

• Slow is scintil lation component on the dependence of the pulse

shape on the nature of the incident radiation.

Scintillation Models

There are number of scintil lation models for analyzing the effective

generated fluctuation caused.

• Global Ionospheric Scintil lation Model (GISM)

• WBMOD Ionospheric Scintil lation Model

• DPSP, MSP

• STH2, STN2 Model induced in sept

• STHV2, STHV2

Past Work

• GPS phase scintil lation observed over a high-latitude Antarctic

station during solar minimum, Chigomezyo M.Ngwira a,b, Lee-

AnneMcKinnell a,b, PierreJ.Cill iers, 2010, Journal of

Atmospheric and Solar-Terrestrial Physics , 72 (2010) 718–725

• Forecasting Ionospheric Real-time Scintil lation Tool (FIRST)

Anderson, D. N.; Redmon, R.; Bullett,  T.; Caton, R. G.;

Retterer, J. M.

American Geophysical Union, Spring Meeting 2009, abstract

#SA11B-05

• Co-ordinated studies using imaging riometer and incoherent

scatter radar, Journal of Atmospheric and Solar-Terrestrail, P.

N. Collis* and J. K. Hargreaves, 1996, Physical Vol. 59. No. 8.

pp. 873 890. 1997

• Scintil lation and cycle slips observed at high latitudes during

solar minimum, P. Prikryl1, P. T. Jayachandran2, S. C. Mushini2,

D. Pokhotelov2, J.W. MacDougall3, E. Donovan4, E. Spanswick4,

and J.-P. St.-Maurice5, June 2010, GPS TEC, Ann. Geophys., 28,

1307–1316, 2010

• Climatology of GNSS ionospheric scintil lation at high latitudes,

L. Spogli, L. Alfonsi, G. De Franceschi, V. Romano, M. H. O.

Aquino, A. Dodson, 2008 American Geophysical Union, Fall

Meeting 2009, abstract #SM33A-1562

• ISACCO: an Italian project to monitor the high latitudes

ionosphere by means of GPS receivers, Giorgiana De Franceschi

Æ Lucilla Alfonsi Æ Vincenzo Romano, 2006, GPS Solut (2006)

10:263–267; DOI 10.1007/s10291-006-0036-6

Resources Available

Electromagnetism vs Non Electromagnetism

• The Rytov and Born Approximation

She showed that variances of logarithm amplitude variations should

be less than unity in all situations. The electromagnetism theory:

Born condition : (∞)^2 + (x)^2 < 1

Phase and amplitude should be less than 1 where ∞ denotes phase

and x amplitude.

• Longitudinal waves

Including sound waves as example (alternation in pressure, particle

displacement, or particle velocity propagated in an elastic material).

In this form the amplitude of the wave is pressure of the

undistributed wave and maximum pressure.

Prediction and Software

Name Input Outputs

Cornell Scintil lation Model Coordinates Simulation

SCINDA (Scintil lation Network

Decision)

Requires

GPS

coordinate

values

Stream of GPS

scintil lation

data from the

server.

NWR Ionospheric Scintil lation

Predictions

- Stores all the

recorded data

from Nasa.

Model-Based Prediction of Amplitude

Scintil lation Variance

Radio

Sounding

Data

Graphs

Haystack InterPlanetary Scintil lation

Software

Frequency

band

Scans the

beam, record

data

SimGEN Coordinates Simulation

Scintil lation Prediction Using

Improved Pre-Processed

Radiosounding Data

Pre-

processed

radiosonde

data

Structure

constant C2n of

the

troposphere

A Forecasting Ionospheric Real-time

Scintil lation Tool (FIRST)

Coordinates Graphs

References

1) GURVICH Alexandre ; CHUNCHUZOV Igor ; “ Estimates of

characteristics scales in the spectrum of internal waves in the

stratosphere obtained from the space observations of stellar

scintil lation” : Journal of Geophysics research ISSN 0148-0227

2005, vol. 110

2) E.N Bramley; “The accuracy of computing ionosphere radio-

wave scintil lation by the thin-phase-screen approximation”:

Journal of Atmospheric and Terrestrial Physics Volume 39, Issue

3, March 1977

3) Armstrong, J. W. (1998), “Radio wave phase scintil lation and

precision Doppler tracking of spacecraft” , Radio Sci. , 33(6),

1727–1738, doi:10.1029/98RS02317.

4) Canadian High Artic Ionospheric Network

http://chain.physics.unb.ca ; Date Accessed 22 Dec 2010

5) Jayachandran, P. T., et al. (2009), Canadian High Arctic Ionospheric

Network (CHAIN), Radio Sci., 44, RS0A03, doi:10.1029/2008RS004046

6) Imaging Riometer for Ionospheric Studies

http://www.dcs.lancs.ac.uk/iono/iris/ Date Accessed: 20-Dec-

2010

7) M. Colleen Gino “

http://www.astrophys-assist.com/educate/starry/starrynight.ht

m ”

Date Accessed : 05/01/2011