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Empirical Ionospheric Models from Worldwide Incoherent Scatter Radars

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

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Empirical Ionospheric Models from Worldwide Incoherent Scatter Radars

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  1. 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

  2. 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

  3. World Incoherent Scatter Radars

  4. MADRIGAL: Long-term ISR Database www.openmadrigal.org

  5. Madrigal

  6. 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)

  7. 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.

  8. 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.

  9. Height Profile

  10. Height Profile Basis Function

  11. Data Distribution

  12. Results:Midday Ne Svalbard Sondrestrom Curve Color Code Winter Spring Summer Autumn Tromso Millstone St. Santin Shigariki Arecibo

  13. Results:Latitudinal and Longitudinal features Semiannual components starts to occur highlatitude Semiannual components, longitudinal differences subauroral midlatitude Lower midlatitude Strong semiannual components, asymmetry

  14. O/N2 and SZA change SZA = solar zenith angle O/N2 (from MSIS) O/N2 x cos (SZA)

  15. Ti At Millstone, highest Ti occurs in May.

  16. Yearly variations: Millstone

  17. Yearly variations in midday Ti at 350 km: Millstone Circles: Data Dashed: Model Data - Model difference Percentage difference F107

  18. Comparisons with IRI: diurnal Median solar activity conditions with F107=135 or Rz=88 Ne Ne Ne Ne Ne Ne Ne Ti Ti Ti Ti Ti Ti Ti Te Te Te Te Te Te Te

  19. Comparisons with IRI: profile Median solar activity conditions with F107=135 or Rz=88 Ne Ne Ne Ne Ne Ne Ne Ti Ti Ti Ti Ti Ti Ti Te Te Te Te Te Te Te

  20. Model Applications: Tn and [O] Using a simplified energy equations for ions (widely used in the ISR community for the neutral parameter deduction)

  21. ISR Convection Model

  22. Regional Ionospheric Models:Millstone Areas Millstone Regional Ionospheric Model covers geodetic latitudes 35-55 degrees.

  23. ISR Convection Model: data A Combined Dataset from Millstone and Sondrestrom ISRs Observations

  24. ISR Convection Model:IMF Bz controls

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

  26. Virtual ISRs– current day

  27. Virtual ISRs – current time

  28. Future Projects • Regional ionospheric models for • Eastern America longitudes • European longitudes

  29. 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.

  30. Arecibo: Ne diurnal

  31. Arecibo: Te diurnal

  32. Arecibo: Ti diurnal

  33. MU: Ne diurnal

  34. Millstone: Ne diurnal

  35. Millstone: Ti diurnal

  36. Millstone: Te diurnal

  37. St. Santin: Ne diurnal

  38. St. Santin: Ti diurnal

  39. St. Santin: Te diurnal

  40. Tromso: Ne diurnal

  41. Tromso: Ti diurnal

  42. Tromso: Te diurnal

  43. Sondrestrom: Ne diurnal

  44. Sondrestrom: Ti diurnal

  45. Sondrestrom: Te diurnal

  46. Svalbard: Ne Diurnal

  47. Svalbard: Ti Diurnal

  48. Svalbard: Te Diurnal

  49. Arecibo: Ne profile

  50. Arecibo: Ti profile

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