Assimilation and Impact of GPS Radio Occultation data

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Earth Observation with COSMIC
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COSMIC at a Glance
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COSMIC Status
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Figure T. Yunck
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Radio occultation for Climate
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COSMIC high resolution profiles
Profile the (sporadic) ionospheric E-layer with
1-km vertical resolution
Area dominated by noise - used for
noise calibration of profile
Area affected by noise - profiles are noisy
and/or affected by climatology
Highest quality profiles 5-30 km
Some profiles affected by boundary layer effects
(super refraction)
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GPS RO Minus NCEP 50 mb S. hemisphere
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Climate Change and Geopotential Heights
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Climate change effect on Temperature and Bending
Angles
Bending Angle change due to 2xCO2
Temperature change due to 2xCO2
Radio occultation (RO) bending angles are a
potentially better indicator for a stratospheric
climate signal than RO temperatures.
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Climate Research with RO Data

• Investigate potential biases in RO time series
• Investigate use of geopotential height, bending
  angles, or refractivity for climate studies
• Climate process studies (Bill Randels work)

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GPS Operational Tracking Scenario

• GPS receiver shall measure GPS L1L2 phase and
  amplitude for (1) ionospheric profiling (2)
  plasmaspheric monitoring (3) scintillation
  studies

POD antennas _at_ 1 Hz
COSMIC S/C With Antennas
Limb Antennas _at_ 50-100 Hz
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Electron Density Profile
Vertical Profile of electron density from GPS/MET

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TIP Payload

• TIP measures nighttime FUV emission of neutral
  atomic oxygen
• TIP and GPS data can be processed together for
  improved ionospheric profiling
• Radiative recombination Oe- ? Oh?
• 135.6 nm produced by radiative recombination of
  O ions and electrons
• O and e- densities equal in the F-region
• 135.6 emission intensity proportional to electron
  density squared
• Simple algorithm relates electron density to
  135.6 nm intensity measured by TIP
• Aurora Oe- ? O e- h?
• 135.6 nm produced in aurora through electron
  impact excitation
• TIP can determine auroral boundaries

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CERTO / TBB Concept
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CDAAC Ionospheric Data Products
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Ionospheric Research with COSMIC Data

• We are talking with NCAR HAO to identify COSMIC
  data products that will be most beneficial to
  ionospheric research community
• Calibration/Validation of other ionospheric
  instruments
• Calibration, improvement, and validation of
  physics based models of ionosphere
• Studies of scintillation (plasma bubbles)
• Ionospheric climatology
• Studies of plasmaspheric depletion and refilling
  during and after storms
• Ionospheric enhancements and depletions during
  storms
• Gravity wave studies
• Traveling Ionospheric Disturbances

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Getting COSMIC Results to Weather Centers
NCEP
Input Data
NESDIS
CDAAC
ECMWF
CWB
GTS
UKMO
BUFR Files WMO standard 1 file / sounding
JMA
Canada Met.
This system is currently under development by
UCAR, NESDIS, UKMO Data available to weather
centers within lt 180 minutes
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Summary

• COSMIC is on track to launch in 1 year
• Will provide data for a wide range of climate,
  weather and space weather investigations
• COSMIC data Collaboration on the optimal use of
  these data at UCAR/NCAR provide a rich
  opportunity for our organization
• Hope to identify scientific opportunities and
  programmatic approaches to them

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Effect of 2xCO2 on Temperature and GPH
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GPS RO Minus ECMWF 50 mb S. hemisphere
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IonosphereGPS/MET - Abel Inversions
Matches 2183 mean 0.001 MHz std 0.81 MHz
Matches 370 mean -9 km std 39 km
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Scintillation Sensing with GPS RO
No scintillation S40.005
Scintillation S40.113
GPS/MET
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Example GPS/MET Sounding

• Main Features of RO Soundings
• High vertical resolution (0.1 - 1 km)
• All weather (no cloud/rain effect)
• Long-term stability (for climate)
• Profiling from 800 km - surface

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GAIM Assimilates Multiple Data Sources
Bottomside Ne Profiles from Ionosondes In Situ
DMSP Satellite Measurements Ground-Based GPS
TECs TECs Between Ground Stations and
Low-Earth-Orbiting Satellites With Radio
Beacons Satellite Occultation Data Line-of-Sight
UV Emissions from DoD Satellites The Data Must
be Real-Time or Near Real-Time.
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Effects of CO2 increase on climate change
simulated by NCAR Climate System Model (CSM)
Vertical cross sections of zonally-averaged model
temperature changes averaged over 20 years (years
60-79) in NCAR Climate System Model in which
carbon dioxide alone is increased by 1 per year
(Meehl et al., 1998).