Empirical Ionospheric Models from Worldwide Incoherent Scatter Radars

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Empirical Ionospheric Models from Worldwide
Incoherent Scatter Radars

• Shun-Rong Zhang and John Holt
• MIT Haystack Observatory, USA
• Tony van Eyken
• EISCAT Association, Norway
• Mary McCready
• SRI International, USA
• Christine Amory-Mazaudier
• Centre for the Study of Earth and Planets
  Environments, CNRS, France
• Shoichiro Fukao
• Research Institute for Sustainable
  Humanosphere, Kyoto University, Japan
• Michael Sulzer
• Arecibo Observatory, National Astronomy
  Ionosphere Center, Puerto Rico

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Outline

• ISR long-term database
• Modeling technique
• Results local models
• A case study Annual variations
• Comparisons with IRI
• Applications
• Regional Models
• ISR Convection Model
• Model Availability
• Future Projects

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World Incoherent Scatter Radars
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MADRIGAL Long-term ISR Database
www.openmadrigal.org
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Madrigal
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Existing Long-term Data

• The European Chain
• EISCAT Svalbard Radar (1997-), in polar cap, the
  highest latitude
• EISCAT Tromsø UHF radar (1984-) and VHF radar
  (1990-),
• St. Santin Radar (1973-1986)
• East America Chain
• Sondrestrom Radar (1990-)
• Millstone Hill Radar (1970-)
• Arecibo Radar (1966-)
• East Asia
• MU Radar (1986-2003)

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Binning and Fitting technique

• Data are binned according to local time and month
• Piece-wise linear height profile is used for
  initial data binning with 17-19 height nodes.
• Solar activity dependency is determined by a
  leaset-squares fit to a linear function to F107.
• Median filter (3 months x 3 hours) is applied to
  the fitting coefficients.

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Analytic representations of bin-fit results

• Seasonal variations harmonics with 12, 6 and 3
  month components
• Local time variations harmonics with 24, 12, 6
  and 3 hour components
• Height variations cubic B-spline with 17 breaks
  and gradient controls at upper and lower
  boundaries.

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Height Profile
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Height Profile Basis Function
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Data Distribution
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ResultsMidday Ne
Svalbard
Sondrestrom
Curve Color Code Winter Spring Summer Autumn
Tromso
Millstone
St. Santin
Shigariki
Arecibo
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ResultsLatitudinal and Longitudinal features
Semiannual components starts to occur
highlatitude
Semiannual components, longitudinal differences
subauroral
midlatitude
Lower midlatitude
Strong semiannual components, asymmetry
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O/N2 and SZA change
SZA solar zenith angle
O/N2 (from MSIS)
O/N2 x cos (SZA)
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Ti
At Millstone, highest Ti occurs in May.
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Yearly variations Millstone
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Yearly variations in midday Ti at 350 km
Millstone
Circles Data Dashed Model
Data - Model difference
Percentage difference
F107
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Comparisons with IRI diurnal
Median solar activity conditions with F107135 or
Rz88
Are MU StS MH Tro Son Sva



Ne
Ne
Ne
Ne
Ne
Ne
Ne
Ti
Ti
Ti
Ti
Ti
Ti
Ti
Te
Te
Te
Te
Te
Te
Te
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Comparisons with IRI profile
Median solar activity conditions with F107135 or
Rz88
Are MU StS MH Tro Son Sva



Ne
Ne
Ne
Ne
Ne
Ne
Ne
Ti
Ti
Ti
Ti
Ti
Ti
Ti
Te
Te
Te
Te
Te
Te
Te
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Model Applications Tn and O
Using a simplified energy equations for ions
(widely used in the ISR community for the
neutral parameter deduction)
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ISR Convection Model
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Regional Ionospheric Models Millstone Areas
Millstone Regional Ionospheric Model covers
geodetic latitudes 35-55 degrees.
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ISR Convection Model data
A Combined Dataset from Millstone and Sondrestrom
ISRs Observations
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ISR Convection Model IMF Bz controls
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ISR Model Availability

• Virtual Incoherent Scatter Radars
• Web interface
• FTP
• http//madrigal.haystack.mit.edu/models
• OR
• http//www.openmadrigal.org

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Virtual ISRs current day
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Virtual ISRs current time
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Future Projects

• Regional ionospheric models for
• Eastern America longitudes
• European longitudes

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A New Space Weather Project

• Multiple incoherent scatter radar long-term
  database study of upper atmosphere climatology
  and variability
• to generate databases of thermospheric Tn, O,
  winds for multiple ISRs
• to develop local and regional models of the
  thermospheric parameters
• to create variability models of the ionospheric
  as well as thermospheric parameters
• to study latitudinal/longitudinal features of
  the ionosphere and thermosphere.

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Arecibo Ne diurnal
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Arecibo Te diurnal
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Arecibo Ti diurnal
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MU Ne diurnal
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Millstone Ne diurnal
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Millstone Ti diurnal
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Millstone Te diurnal
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St. Santin Ne diurnal
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St. Santin Ti diurnal
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St. Santin Te diurnal
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Tromso Ne diurnal
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Tromso Ti diurnal
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Tromso Te diurnal
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Sondrestrom Ne diurnal
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Sondrestrom Ti diurnal
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Sondrestrom Te diurnal
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Svalbard Ne Diurnal
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Svalbard Ti Diurnal
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Svalbard Te Diurnal
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Arecibo Ne profile
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Arecibo Ti profile
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Arecibo Te profile
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MU Ne profile
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Millstone Ne profile
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Millstone Ti profile
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Millstone Te profile
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St Santin Ne profile
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St Santin Ti profile
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St Santin Te profile
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Tromso Ne profile
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Tromso Ti profile
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Tromso Te profile
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Sondrestrom Ne profile
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Sondrestrom Ti profile
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Sondrestrom Te profile
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Svalbard Ne profile
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Svalbard Ti profile
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Svalbard Te profile