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The FORMOSAT3/COSMIC MissionSpace Weather Application

AMS San Diego Jan. 11, 2005Christian Rocken rocken@ucar.edu

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Concept & Goals Constellation Observing System for Meteorology Ionosphere

and Climate (COSMIC) 6 satellites launched in 2005 Weather + Space Weather data Global observations of:

– Pressure, Temperature, Humidity– Refractivity, Bending– Ionospheric Electron Density, TEC

– Ionospheric Scintillation

Demonstrate quasi-operational GPS limb sounding with global coverage in near-real time

Demonstrate highly synergistic space weather observations from three payloads: GPS-OS, TIP, and TBB

Total project cost is ~$100 M, $80 M will be paid by NSPO in Taiwan, and $20 M will be funded by US agencies.

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Mission science payloads

•High-resolution (1 Hz) absolute total electron content (TEC) to all GPS satellites in view at all times (useful for global ionospheric tomography and assimilation into space weather models)

•Occultation TEC and derived electron density profiles (1 Hz below the satellite altitude and 50 Hz below ~140 km), in-situ electron density

•Scintillation parameters for the GPS transmitter–LEO receiver links

•Data products available within 15 - 120 minutes of on-orbit collection

Tri-band Beacon (TBB)•Phase and amplitude of radio signals at 150, 400, and 1067 MHz transmitted from the COSMIC satellites and received by chains of ground receivers.•TEC between transmitter and receivers•Scintillation parameters for LEO transmitter - receiver links

Tiny Ionosphere Photometer (TIP)•Nadir intensity on the night-side (along the sub-satellite track) from radiative recombination emission at 1356 Å•Derived F layer peak density•Location and intensity of ionospheric anomalies (Auroral Oval)

GPS Occultation receiver

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JOINT CERTO/TBB, GPS-GOX, TIP OPERATIONS ON COSMIC

From GPS Satellite

Ground Receivers

TIP EUV Field of View

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COSMIC Status

6Figure: T. Yunck

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Location of Profiles

1.5 months after launch

Final constellation

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CHAMP Electron Density profiles

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GPS and Langmuir Probe Comparison

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GPS vs. Ionosonde Comparisons

Matches = 2183mean = 0.001 MHzstd = 0.81 MHz

Matches = 370mean = -9 kmstd = 39 km

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COSMIC high resolution profiles

Area dominated by noise - used for noisecalibration 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)

Profile the (sporadic) ionosphericE-layer with ~1-km vertical resolution

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Figure from the paper by Nishida et al., J. Met. Soc. Japan, 78(6), p.693, 2000.

RO provides best results between 8-10 and 25-30 km (effects of moistureand ionosphere are negligible). Is capable of resolving the structure of thetropopause and gravity waves above the tropopause.

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Scintillation Sensing with COSMIC

No scintillationS4=0.005

ScintillationS4=0.113

GPS/MET SNR data

Where is the sourceRegion of the scintillation?

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Localization of Irregularities

3000 4000 5000 6000 7000 8000 9000

X2-X (km)

-20

-10

0

10

20

Y (km)

3000 4000 5000 6000 7000 8000 9000-20

-10

0

10

20

Y (km)

-0.8 -0.4 0.0 0.4 0.8

B

C

Numerical Simulations 2 GPS/MET Occultations

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Input

Data

CDAAC

NESDIS

GTS

NCEP

ECMWF

CWB

UKMO

Canada Met.

JMA

BUFR FilesWMO standard1 file / sounding

Getting COSMIC Results to Weather CentersThis system is currently under development by UCAR, NESDIS, + UKMOData available to weather centers within < 180 minutes of on-orbit collection

A similar system needs to be developed to deliver COSMICSpace Weather data to users!

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GPS radio occultation missions

Mission Launch-Duration # Soundings/day Remarks

GPS-MET 4/1995 2+ ~125 Proof of Concept

CHAMP 11/2000 ~5 ~250 Improved receiver, tracking

SAC-C 11/2000 ~3 ~500 Improved receiver, open loop tracking test

GRACE 5/2002 ~5 ~500 Only few RO data available

ROAD RUNNER 6/2005 1-3 ~300 COSMIC receiver tests and risk reduction

COSMIC

FORMOSAT 3

9/2005 ~5 2500-3000 Real time-ops

TerraSAR-X 7/2005 ~5 ~400 COSMIC RX & Antennas

EQUARS 7/2006 ~3 ~400 COSMIC RX & Antennas

METOP 5/2007 ~5 ~500 Real time - ops

NPOESS 3/2011 ~10 ~500 May fly COSMIC II instead

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Radio Beacon Receiver Chainsto Observe CERTO Beacons

UK

ARCTIC

Alaska

India

Taiwan

South America

Americas

South Africa

Ascension Kwajalein

Finland

Indonesia

Spain

Christmas

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Orbit

Receiver

Irregularity

CERTO BeaconTransmissions

Antenna Orientation for Electron Density and Scintillation Region Tomography

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TIP / GPS Occultation Concept

COSMIC

GPS Occultation Ray Path

TIP Line-of-Sight

COSMIC Orbit Track

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CDAAC Processing Flow

LEO data Level 0--level 1

Orbits and clocks

Excess Phase(27 sec)

Can. Transf.Abel Inversion354 sec

1-D VarMoisture Correction23 sec

Fiducial data

Atmospheric processing

Excess Phase Abel InversionCombinationwith other data

Ionospheric processing

Profiles

Real time Task Scheduling Software

2 min

6.7 min

Current processing time for 35 occultations + 100 minutes of fid data: 9min

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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: O++e- O+h– 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: O+e- O +e- +h

– 135.6 nm produced in aurora through electron impact excitation

– TIP can determine auroral boundaries