The Communication/Navigation Forecasting System (C/NOFS) Mission to Predict Equatorial Ionospheric Density and Scintillation

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The Communication/Navigation Forecasting System
(C/NOFS) Mission to Predict Equatorial
Ionospheric Density and Scintillation
O. de La Beaujardière, L. Jeong, K. Ray, J.
Retterer, B. Basu, W. Burke, F. Rich, K. Groves,
C. Huang, L. Gentile, D. Decker, W. Borer, C.
Lin NSPWX meeting, Jan 2006
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Why do we Care About the Ionosphere and
Scintillation?

• Scintillation prevents communications with
  satellites
• Ionosphere reflects, refracts, diffracts
  scatters radio waves
• Global Positioning Satellite (GPS) relies on
  transmissions at GHz frequencies (L band)
• GPS signal is affected by L Band scintillation
• Effect is max at equator
• Many systems depend on GPS
• Aviation (FAA)
• Navigation
• Timing
• Many more

Scintillation priority number 1 for AF Sp Wx
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C/NOFS Mission

• C/NOFSFirst satellite to provide continuous,
  global ambient ionosphere and scintillation
  forecasts
• Mission elements
• Satellite
• Ground-based instruments
• Models
• Data center
• Mission Goals
• Nowcasts and forecast ionospheric electron
  density and presence of irregularities
• Develop capability to produce long term outlook
  (2 to 5 days)
• Develop improved understanding of equatorial
  ionosphere and processes that trigger / inhibit
  irregularities

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C/NOFS Mission Components

• Satellite low altitude / low inclination
• Inclination 13 deg (target)
• Perigee/ Apogee 375 and 720 Km
• Orbital Period 96 min/rev
• TDRSS transmitter for near-real-time downlink
• Launch
• April 2006
• Dedicated Pegasus XL launch
• Ground-based component
• Scintillation and beacon receivers
• Other Ground-based instruments

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Payload DescriptionSix Instruments

• GPS Receiver
• C/NOFS Occultation Receiver for Ionospheric
  Sensing and Specification (CORISS)
• Developed by Aerospace (P. Straus PI)
• Measures Remote sensing of LOS TEC

RAM Plasma Sensors

• Planar Langmuir Probe (PLP)
• Developed by AFRL/VS (D. Hunton PI)
• Measures Ion Density, Ion Density Variations,
  Electron Temperature

• Ion Velocity Meter (IVM)
• Developed by Univ. of Texas(R. Heelis PI)
• Measures Vector Ion Velocity, Ion Density, Ion
  Temperature

• Electric Field Instrument
• Vector Electric Field Instrument (VEFI)
• Developed by NASA/GSFC (R. Pfaff PI)
• Measures Vector AC and DC electric fields

• Neutral Wind Meter (NWM)
• Developed by Univ. of Texas(R. Heelis PI)
• Measures Vector Neutral Wind Velocity

• RF Beacon
• Coherent EM Radio Tomography (CERTO)
• Developed by NRL (P. Bernhardt PI)
• Measures Remote sensing of RF scintillations
  and LOS TEC

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C/NOFS ground based instruments
SCINDA Ground Stations (2008 plan)
30N
0
30S
0
210E
240E
300E
330E
60E
90E
120E
150E
270E
30E
SCINDA Scintillation Decision Aid a network of
receivers monitoring radio scintillation along
lines of sight to satellite-based
transmitters Additional ground instruments
include GPS TEC Rx, all sky cameras, ionosondes,
radars, etc
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C/NOFS Forecast Model
Iono model
Turbulence model
Global Ambient Forecast Model
Plasma Instability Calculator
Global Turbulence Modeler
Scintillation Statistics Calculator
Display
Bubble Evolution Calculator
Turbulence Seed
Scintillation
Display
Retterer et al. 2003, 2006
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Ionospheric Models

• C/NOFS Models
• PBMOD (AFRL) being used in CNOFS forecast
• ASSIM_IONOS (SEC) being used for CNOFS
  specification
• Models validated both pre- and post-launch
• Other models being considered
• Three data assimilation models
• GAIM (USU) is being transitioned for operational
  use at AFWA
• In FY 2005 demonstrated superiority of GAIM over
  PRISM, previous operational model
• In FY 2006 continue validation work in support of
  transition
• GAIM (USC/JPL) being used in study on impact of
  CNOFS data in assimilation models
• Results are being tested in National Program
  Systems
• Fusion Numerics model being regularly exercised
  by developer

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C/NOFS Validation and Campaigns

• Pre-C/NOFS campaigns
• April 2002, Oct 2003 mag storms
• May 31-June 1, 2002
• COPEX (Oct-Nov 2002)
• World days 2002 to 2005
• Numerous validation periods with satellite data
• Instrument Validation Campaigns
• E-Field and winds are most critical
• Flux Tube Campaign
• To calculate parameters along magnetic flux
  tube, including E- region conductivity
• Seeding Campaigns
• To determine if waves (TIDs, Gravity waves,
  tropospheric storms, other) play a role in
  triggering turbulence
• Global campaigns (using world days)
• For validating density and scintillation at all
  longitudes during a 1 to 5 day period
• Shuttle Engine Burn Campaign

Ex of validation can C/NOFS models reproduce
observed airglow intensity?
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Questions Addressed Using C/NOFS

• Questions that will be addressed by the C/NOFS
  Mission include
• Ambient Ionosphere
• Nowcast and forecast global Ne profiles
• E field
• Longitude variations
• Pre reversal enhancement
• Penetration E field, disturbance dynamo E field
• Wind
• Present average models are inaccurate
• Variation as a function of LT, lat, long, season,
  solar activity, magnetic activity
• How do bubbles evolve in time and space?
  Bubbles birth, growth and decay
• What triggers their growth
• What prevents them from growing
• Can we determine a bubbles age from observations
  of its irregularity spectrum, drift speed, AC
  E-field
• How detrimental to Nav and Comm are old bubbles
• Turbulence and scintillation climatology

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Concluding Remarks

• Appleton fountain and bubbles dominate equatorial
  ionospheric weather
• Ionospheric irregularities cause scintillation,
  which prevents communication, navigation,
  surveillance
• C/NOFS satellite launched to forecast ambient
  ionosphere and scintillation
• Will be the only US satellite dedicated to the
  ionosphere
• DMSP and TIMED will also provide ionospheric
  data, but these are secondary to the mission
• Important array of ground-based instruments are
  part of C/NOFS
• Sophisticated models will provide forecast
• Many important space weather science questions
  remain that will hopefully be answered by the
  C/NOFS mission
• C/NOFS data will be not be restricted
• NSF and NASA have C/NOFS Guest-Investigator type
  initiatives
• C/NOFS Web site http//www.vs.afrl.af.mil/Factsh
  eets/cnofs.html

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Questions?
Jicamarca Radar, Peru Oct 22, 1996
GUVI