COSMIC: Constellation Observing System for Meteorology, Ionosphere and Climate Status and Results with Emphasis on the Ionosphere Christian Rocken, Stig.
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COSMIC: Constellation Observing System for Meteorology, Ionosphere
and Climate
Status and Results with Emphasis on the Ionosphere
Christian Rocken, Stig Syndergaard, Zhen Zeng
UCAR COSMIC Project
FORMOSAT-3
Outline
COSMIC Introduction Results
– Some neutral Atmosphere Results
– Ionosphere» GPS TEC Arcs
» GPS Electron Density Profiles
» Scintillation
» Validation / Comparison to Models
» TIP
» TBB
– Latency and Data Distribution
Summary
COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate)
6 Satellites launched01:40 UTC 15 April 2006
Three instruments:GPS receiver, TIP, Tri-band beacon
Weather + Space Weather data Global observations of:
Pressure, Temperature, HumidityRefractivityIonospheric Electron DensityIonospheric Scintillation
Demonstrate quasi-operational GPS limb sounding with global coverage in near-real time
Climate Monitoring
The velocity of GPS relative to LEO must be estimated to ~0.2 mm/sec (velocity of GPS is ~3 km/sec and velocity of LEO is ~7 km/sec) to determine precise temperature profiles
The LEO tracks the GPS phase while the signal is occulted to determine the Doppler
QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.LEO
vleo
vGPS
Tangent point
The velocity of GPS relative to LEO must be estimated to ~0.2 mm/sec (20 ppb) to determine precise temperature profiles
The LEO tracks the GPS phase while the signal is occulted to determine the Doppler
QuickTime™ and aTIFF (LZW) decompressorare needed to see this picture.LEO
vleo
vGPS
Tangent point
COSMIC
Radiosondes
COSMIC Soundings in 1 Day
Sec 3, Page 10
Atmospheric refractive index where is the light velocityin a vacuum and is the light velocity in the atmosphere
Refractivity
26
25 103.401073.36.77
f
n
T
P
T
PN ew ×−×+=
vcn /= cv
)1(106 −= nN
• Hydrostatic dry (1) and wet (2) terms dominate below 70 km
• Wet term (2) becomes important in the troposphere and can constitute up to 30% of refractivity at the surface in the tropics
• In the presence of water vapor, external information information is needed to obtain temperature and water vapor
• Liquid water and aerosols are generally ignored
• Ionospheric term (3) dominates above 70 km
(1) (2) (3)
6 Micro Satellites - USAF Minotaur Rocket Integration
COSMIC launch picture provided by Orbital Sciences Corporation
• All six satellites stacked and launched on a Minotaur rocket
• Initial orbit altitude ~500 km; inclination ~72°
• Will be maneuvered into six different orbital planes for optimal global coverage (at ~800 km altitude)
• Satellites are in good health and providing data-up to 2200 soundings per day to NOAA
Launch on April 14, 2006, Vandenberg AFB, CA
COSMIC Current Constellation
COSMIC - Final Deployment
•6 Planes
•71 Degrees inclination
•800 Km
•2500 Soundings per day
•Latency 50-140 minutes from observation to NOAA
Some Neutral Atmosphere Results
Vertical profiles of “dry” temperature (black and red lines) from two independent receivers on separate COSMIC satellites (FM-1 and FM-4) at 00:07 UTC April 23, 2006, eight days after launch. The satellites were about 5 seconds apart, which corresponds to a distance separation at the tangent point of about 1.5 km. The latitude and longitude of the soundings are 20.4°S and 95.4°W.
00:07 UTC 23 April 2006,
eight days after launch
Comparison of Pairs of COSMIC soundings with GFS analysis
Using COSMIC for Hurricane Ernesto Prediction
Without COSMICWith COSMIC
Results from Hui Liu, NCAR
Using COSMIC for Hurricane Ernesto Prediction
GOES ImageWith COSMIC
GOES Image from Tim Schmitt, SSEC
Southern Hemisphere Forecast Improvements from COSMIC Data
Sean Healey, ECMWF
Northern Hemisphere Forecast Improvements from COSMIC Data
Sean Healey, ECMWF
Space Weather
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GPS Antennas on COSMIC Satellites
Nadir
2 Antennas for orbits, TEC_pod (1-sec), EDP
VleoCOSMIC s/c
High-gain occultation antennasfor atmospheric profiling (50 Hz)
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Total electron content data (podTEC)
COSMIC generates 2500 - 3000 TEC arcs per day Sampling rate is 1 -sec
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Absolute TEC processing
Correct Pseudorange for local multipath
Fix cycle slips and outliers in carrier phase data
Phase-to-pseudorange leveling
Differential code bias correction
P1 Multipath P2 Multipath
Satellite Multipath and Solar Panel Orientation
Pseudorange multipath calibration
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Phase-to pseudorange leveling statistics
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COSMIC DCBs for ~ 1 year
Quality of absolute TEC from COSMIC ~2 TECU
Observed TEC Rays in 12-hour period
… observed in Local time
Latency of COSMIC podTec data
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Profile retrieval method
TEC = solid - dashed [Schreiner et al., 1999]
Inverted via onion-peeling approach to obtain electron density N(r) Assumption of spherical symmetry
€
TEC(p) = 2rN(r)
r2 − p2dr
p
p top∫
First collocated ionospheric profilesFrom presentation by Stig Syndergaard, UCAR/COSMIC
Comparisons with ISR data[Lei et al., submitted to JGR 2007]
Comparison of Ne(h) between COSMIC (red), Ionosondes (green)and TIEGCM (black) on Aug. 17 - 21nd
COSMIC agree well with ionosonde obs, especially the HmF2;
Vertical structures from COSMIC coincide well with TIEGCM in the mid-lat, but not in the tropics.
TIEGCM shows a bit higher HmF2 compared with obs.
Quiet
Storm
COSMIC #2 GAIM
COSMIC #2 GAIM
Comparisons during quiet and disturbed Conditions
Global Assimilation of Ionospheric MeasurementsUtah State University, (435)797-2962, schunk@cc.usu.edu;
Universities of Colorado (Boulder), Texas (Dallas), and Washington“Bringing the pieces together”
From presentation by Ludger Scherliess, Utah State University
Comparison of NmF2 and HmF2 between COSMIC and GAIM during Apr. 21-28, 2006
Good agreement of NmF2 between COSMIC and GAIM;
Higher peak heights from GAIM than those from COSMIC
From presentation by Zhen Zeng, NCAR/HAO
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Using GAIM to correct for gradientsFrom presentation by Stig Syndergaard, UCAR/COSMIC
Courtesy of Zhen Zeng
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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?
RED = COSMIC satBLUE = GPS sat
Formosat-3/COSMIC Observations of Scintillations
From presentation by Chin S. Lin, AFRL
Observed TEC Rays in 12-hour period
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TIP 135.6-nm passes 14 Sep 2006
FM1 FM3 FM6
0-24 UT (2100 LT) From presentation by Clayton Coker, NRL
Chung-Li COSMIC TBB/CERTOTEC and Elevation Angle From presentation by
Paul A. Bernhardt, NRL
Input
Data
CDAAC
NESDIS
GTS
NCEP
ECMWF
CWB
UKMO
Canada Met.
JMA
BUFR FilesWMO standard1 file / sounding
Getting COSMIC Results to Weather Centers
Data available to weather centers within < 180 minutes of on-orbit collection
JCSDA
NRL
Neutral Atmosphere Operational Processing
Science & Archive
TACC
Summary
COSMIC generates large amount of high quality space weather data
Data available for real-time (significant amount of data with less than 60 min latency) and for post-processing
Data are used for model comparison /improvement
Global scintillation data will be available within months
A COSMIC Education Module
A joint effort by COMET and COSMIC.
It covers:
- Basics of GPS radio occultation science
- Applications to weather, climate, and ionosphere
- COSMIC Mission description
http://www.meted.ucar.edu/COSMIC/
http://www.cosmic.ucar.edu
* Select the 'Sign Up ' link under COSMIC
•Accept data use agreement
* Enter information: Name, Address, email, user_id,Password, planned use of data
• An email will be sent within 2-3 business days to indicateaccess has been granted.
COSMIC Data Access
More than 350 users have registered
Ionospheric profiles availability
Total Electron Content availability
Comparisons with ground-based dataFrom presentation by Stig Syndergaard, UCAR/COSMIC
Courtesy of Jiuhou Lei
First Formosat3 / COSMIC Workshop
Space Weather Presentations 4-D Modeling of Ionospheric Electron Density with GNSS Data and the International Reference Ionosphere (IRI), D. Bilitza, M.
Schmidt and C. Shum C.K. Shum - Ohio State University Occultation Measurements of the E-Region Ionosphere Paul Strauss - The Aerospace Corporation Ionospheric electron density specification using the FORMOSAT-3/COSMIC data Lung-Chih Tsai - Center for Space and
Remote Sensing Research, NCU Validation of COSMIC ionospheric data Jiuhou Lei - NCAR/HAO Processing of FORMOSAT-3/COSMIC Ionospheric Data at CDAAC Stig Syndergaard - UCAR/COSMIC First Observations of the Ionosphere using the Tiny Ionospheric Photometer Clayton Coker - Naval Research Laboratory First NRL Results for the TBB/CERTO Radio Beacon Measurements Paul Bernhardt - Naval Research Laboratory Does FS3/COSMIC Data Improve Ionospheric Specification? Craig Baker - AFRL Global 3D Imaging of the August 19-20 2006 Storm using COSMIC Data Gary Bust - Atmospheric & Space Technology Research
Associates
First Formosat3 / COSMIC Workshop
Space Weather Presentations (contd.) Characteristic Analysis of COSMIC Ionospheric Electron Density Profile: Preliminary Results Yen-Hsyang Chu Observations of Global Ionospheric Sructure by FORMOSAT-3/COSMIC Charles Lin - National Space Organization (NSPO) Ionospheric F2-layer Parameter Mapping Based on the FORMOSAT-3/COSMIC Data Lung-Chih Tsai - National Central Univ,
Taiwan, ROC Comparisons of Formosat-3/COSMIC ionospheric data with ground based measurements and model simulations Zhen Zeng -
UCAR/COSMIC On the use of COSMIC podTEC data in the Electron Density Assimilative Model (EDAM) Matthew Angling - QinetiQ,
UK Assimilating Formosat-3/COSMIC Ionospheric Data Into A Global Model: Preliminary GAIM Results Brian Wilson - JPL Assimilation of COSMIC Data with the USU GAIM Model Ludger Scherliess - Utah State University Preliminary results from COSMIC Campaigns Santimay Basu - Air Force Research Laboratory Calibration of COSMIC Ionospheric Occultation Profiles using the Arecibo Incoherent Scatter Radar Michael Kelley - Cornell
University Formosat-3 COSMIC Campaign Observations at Kwajalein Atoll Chin Lin - Air Force Research Laboratory
A compilation of selected slides presented at the First FORMOSAT-3/COSMIC Data Users WorkshopBoulder, CO, October 16-18, 2006&COSMIC Retreat, October 26-27, 2006
COSMIC NmF2 - 1 week
TIP observations over large area on 14 Sep 2006
FM6 pass 1042UT FM6 pass 0907UT FM6 pass 0730UT
FM3 pass 1050UT FM3 pass 0914UT FM3 pass 0738UT
FM4-PINH pass 1050UT FM4-PINH pass 0914UT FM4-PINH pass 0738UT
FM1 pass 1140UT FM1 pass 1005UT FM1 pass 0828UT
From presentation by Santimay Basu, AFRL
COSMIC agree well with ionosonde observations;
Global map of NmF2 revealed from COSMIC is well represented by TIEGCM model, though TIEGCM shows higher peak density in the low latitude.
Maps of NmF2 for COSMIC (dots), Ionosondes (stars), TIEGCM (contour)
COSMIC agree well with ionosonde observations;
Global map of NmF2 revealed from COSMIC is well represented by TIEGCM model, though TIEGCM shows higher peak density in the low latitude.
Maps of NmF2 for:
COSMIC (dots), Ionosondes (stars), TIEGCM (contour)
From presentation by Zhen Zeng, NCAR/HAO
NmF2 (left) and HmF2 (right) Comparison between TIEGCM and COSMIC on Aug. 2nd
Compared with COSMIC, TIEGCM show smaller peak density in the summer hemisphere, but larger one in the winter hemisphere;
TIEGCM have lower HmF2 in the polar region.
Sample Comparison Between Arecibo, UCAR, and JPL Sample Comparison Between Arecibo, UCAR, and JPL Profiles: Best AgreementProfiles: Best Agreement
From presentation by Mike Kelley, Cornell University
COSMIC Occultation Over South Atlantic: 1815 UTC
Black: CosmicBlue: IRIRed: IDA3D
Horizontal LinesRepresentationError
From presentation by Gary S. Bust, Atmospheric & Space Technology Research Associates
Precision of GPS RO soundings
Comparison of PPUTLS by Region
0
0.1
0.2
0.3
0.4
0.5
0.6
0 50 100 150 200 250 300
Tangent Point Separation Distance (km)
PPMT
PPMT Tropics PPMT South MidLatitde PPMT South Polar PPMT North MidLatitude PPMT North Polar
PPUTLS = Precision Parameter of Upper Troposphere and Lower Stratosphere, which is the mean absolute differences in the 10-20 km layer
0.02% difference in refractivity, which is equivalent of 0.05 C in temperature
Two COSMIC Occultations taking place right next to each other, passing through nearly the same portion of the atmosphere.
Deviation of pairs of RO soundings separated by less than 10 km
CHAMP vs. ionosondes (NmF2)
August 2002 August 2005
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