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First Validation of Level 2 Cat-2 products: EEF

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Presentation on theme: "First Validation of Level 2 Cat-2 products: EEF"— Presentation transcript:

1 First Validation of Level 2 Cat-2 products: EEF
Patrick Alken1 Arnaud Chulliat1 Stefan Maus1 Pierre Vigneron2 Olivier Sirol2 Gauthier Hulot2 1 University of Colorado at Boulder, Boulder, USA 2 Institut de Physique du Globe de Paris, Paris, France Swarm Cal/Val Meeting 6/18/2014

2 Outline Introduction Equatorial Electrojet Signature in Swarm data
Validation of EEF Comparison with EFI measurements Ground magnetic observatories JULIA coherent scatter radar Swarm Cal/Val Meeting 6/18/2014

3 Introduction – Step 1 Subtraction from scalar (ASM) data: main, crustal, external field Fit to high-latitude data to remove Sq Swarm Cal/Val Meeting 6/18/2014

4 Introduction – Step 2 Swarm Cal/Val Meeting 6/18/2014

5 Introduction – Step 3 Invert for the E-region current density which produces the observed magnetic signal Swarm Cal/Val Meeting 6/18/2014

6 Introduction – Step 4 Peak height determined by EEF Side lobes determined by winds The EEF (E) is a free parameter in the equations, chosen to maximize the agreement between the modeled and observed EEJ current Swarm Cal/Val Meeting 6/18/2014

7 Equatorial Electrojet Signature
Step 2 after removing main, crustal, external and Sq fields Data period: November 2013 to May 2014 EEJ magnetic signature from all 3 satellites combined in figure to the right (all day-time local times, all satellite passes) EEJ follows magnetic equator as expected Swarm Cal/Val Meeting 6/18/2014

8 Equatorial Electrojet Signature (11-12 LT, Kp < 2)
B C Swarm Cal/Val Meeting 6/18/2014

9 Sample modeled and observed current profiles
Swarm-C data during January 2014 Blue curves show Swarm-derived EEJ current profiles Purple curves show reproduced profiles from climatological modeling The primary goal is to reproduce the main peak at 0 degrees QD latitude (non-equatorial latitude structure is due to winds and is highly variable). Swarm Cal/Val Meeting 6/18/2014

10 Comparison with Ground Observatory H
SAM-MBO R = 0.85 WAMNET observatory network (SAM, BAK, KOR) near the dip equator Can be combined with INTERMAGNET observatories MBO and TAM to compute H observations of the EEJ Data period: Jan/Feb 2014 Simultaneous observation: Swarm flies within 10 degrees longitude of SAM with a time window of 5 minutes SAM-TAM R = 0.83 Swarm Cal/Val Meeting 6/18/2014

11 Comparison with Ground Observatory H (continued)
SAM-MBO R = 0.83 R = 0.86 R = 0.86 SAM-TAM R = 0.84 R = 0.87 R = 0.80 Swarm Cal/Val Meeting 6/18/2014

12 Validation with JULIA radar
R = 0.78, rms = 0.16 mV/m R = 0.76, rms = 0.15 mV/m Simultaneous measurements: within 10 degrees longitude and 5 minutes of JULIA Swarm Cal/Val Meeting R = 0.80, rms = 0.16 mV/m 6/18/2014

13 Conclusion Swarm EEF chain is computing clean signals of the EEJ from all 3 satellites EEF estimates are highly correlated with H measurements by the WAMNET observatories in Africa EEF estimates in good agreement with the JULIA radar measurements in Peru Future work: compare with EFI measurements Swarm Cal/Val Meeting 6/18/2014


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