TEC introduced high ratios of std(Tbmeas-Tbmodel)/ radio_accuracy

X. Yin, J. Boutin

LOCEAN

At QWG 6, some of us noticed that ratios of std(Tbmeas-Tbmodel)/radio_accuracy are very high in the top-left of the FOV (desc Nov.)

Why? TEC?Given that we have L1c with different versions of TEC now, the effect of strong TEC on the ratios of std(Tbmeas-tbmodel)/radio_resolution can be studied.

Method

1. 5 descending orbits in November 2010 between 5S and 45S. mean TEC is around 20 tecu

2. 3 descending orbits in July 2010 between 5S and 45S. mean TEC is around 10 tecu

Flag: Sun point + Suntail

Part I, Nov 2010, 5 descending

20101101T004554_20101101T013909

20101104T002911_20101104T012223

20101105T013018_20101105T022331

20101106T005122_20101106T014436

20101108T011335_20101108T020647

L1op v504 DPGS reprocessing

Consolidated TECFTT June 2011

L1pp v500 Sun on, Deimos

IRI predicted TECFTT July 2010

5S-45SMean consolidated TEC = 20.2 tecuMean IRI predicted TEC = 25.0 tecu

predicted

Consolidated TEC

IRI TEC

X pol.

std(Tbmeas-Tbmodel)/radio_accuracy

std(Tbmeas)/radio_accuracy

std(Tbmodel)/radio_accuracy

1.6

0.8

1.6

0.8

1.6

0.8

1.6

0.8

1

0

1

0

Consolidated TEC

IRI TEC

Y pol.

std(Tbmeas-Tbmodel)/radio_accuracy

std(Tbmeas)/radio_accuracy

std(Tbmodel)/radio_accuracy

1.6

0.8

1.6

0.8

1.6

0.8

1.6

0.8

1

0

1

0

Consolidated TEC

T3

std(Tbmeas-Tbmodel)/radio_accuracy

std(Tbmeas)/radio_accuracy

IRI TEC

std(Tbmodel)/radio_accuracy

1

0

1

0

1.6

0.8

1.6

0.8

1.6

0.8

1.6

0.8

IRI TEC OTT Consolidated TEC OTT

X pol.

Y pol.

diff

10

-10

10

-10

2

-2

10

-10

10

-10

2

-2

IRI TEC OTT

T3

Consolidated TEC OTT

10

-10

10

-10

2

-2

diff

Part II, July 2010, descending

20100701T003344_20100701T012657

20100703T005556_20100703T014908

20100704T001658_20100704T011011

L1op v504 DPGS reprocessing

Consolidated TECFTT June 2011

L1pp v504 GPOD

IRI predicted TECFTT July 2010

5S-45SMean consolidated TEC = 9.6 tecuMean IRI predicted TEC = 14.5 tecu

predicted

Consolidated TEC

IRI TEC

X pol.

std(Tbmeas-Tbmodel)/radio_accuracy

std(Tbmeas)/radio_accuracy

std(Tbmodel)/radio_accuracy

1.6

0.8

1.6

0.8

1.6

0.8

1.6

0.8

1

0

1

0

Consolidated TEC

IRI TEC

Y pol.

std(Tbmeas-Tbmodel)/radio_accuracy

std(Tbmeas)/radio_accuracy

std(Tbmodel)/radio_accuracy

1.6

0.8

1.6

0.8

1

0

1.6

0.8

1.6

0.8

1

0

Consolidated TEC

T3

std(Tbmeas-Tbmodel)/radio_accuracy

std(Tbmeas)/radio_accuracy

IRI TEC

std(Tbmodel)/radio_accuracy

1.6

0.8

1.6

0.8

1.6

0.8

1.6

0.8

1

0

1

0

IRI TEC OTTDeimos v500

Consolidated TEC OTTreprocessing

X pol.

Y pol.

diff

10

-10

10

-10

2

-2

10

-10

10

-10

2

-2

FTT July 2010 June 2011;less galaxy signal

IRI TEC OTT

T3

Consolidated TEC OTT

10

-10

10

-10

2

-2

diff

Conclusions

1.Consolidated TEC is lower than IRI predicted TEC

2.With consolidated TEC, ratios of std(Tbmeas-Ybmodel)/radio_accuracy are lower than those computed with IRI predicted TEC, but still too high in the front of the FOV compared with other regions in the FOV.

3.High ratios of std(Tbmeas-Tbmodel)/radio_accuracy could be caused by bad TEC: more accurate TEC, especially when and where Tb sensitivity to TEC is strong (see presentation by JLV and PW).

4. Compared to TX and TY, T3 is more sensitive to variations of TEC in the front of FOV , descending orbits, between 45S-5S.

5. Large influence of FTT on OTT!!