Preliminary studies on Galactic Noise Model

Xiaobin Yin, Jacqueline Boutin

LOCEAN

5-Day SSS from Ascending orbits (Mar. 17-21)Tx & Ty in a xi/eta=0.25 square

SSS climatology of March

31

41

1. Compared with ascending orbits, SSS from descending orbits is lower in the north pacific but higher in the south hemisphere at high latitude.2. There is a gradient in retrieved SSS, espescially at high latitude

why?

5-Day SSS from Descending orbits (Mar. 17-21)Tx & Ty in a xi/eta=0.25 square

SSS climatology of March

SSS from Descending orbits (Mar. 18)Tx & Ty in a xi/eta=0.23 squareUsing GN 1 for OTT and SSS retrieval

SSS from Descending orbits (Mar. 18)Tx & Ty in a xi/eta=0.23 squareUsing GN 2 for OTT and SSS retrieval

Mar.18T125114_20100318T1345150N ~ 50S

OTT computed from an ascending orbit in the East Pacific with different GN models could lead to different retrieved SSS

(Not talking about which GN is better)

SCSD1C_20100318T125114_20100318T134515_330_001_1, averaged from 0N ~ 50S

SCSD1C_20100319T135222_20100319T144622_330_001_1, averaged from 0N ~ 50S

Two ascending orbits in March, 2010Gal2 - Gal1

Tx Ty

Tx Ty

Two ascending orbits in August, 2010Gal2 - Gal1

SCSF1C_20100804T142022_20100804T151421_344_001_1, averaged from 0N ~ 50S

SCSF1C_20100805T134125_20100805T143524_344_001_1, averaged from 0N ~ 50S

Tx

Tx

Ty

Ty

SCSD1C_20100319T135222_20100319T144622_330_001_1Dual pol without TECthe own OTT of each GN computed within [0S 50S] are used

SSS1 (Gal1 - Gal2) SSS1 (Gal1) SSS1 (Gal2)0.3

-0.3

40

30

Gal 1, SSS (retri - prior) Gal 2, SSS (retri - prior)

March

0.3

-0.3

Chi2 (Gal 1) Chi2 (Gal 2)

1.5

0.5

Chi2 (Gal 1 - Gal2)

SSS1 (Gal1 - Gal2)

0.3

-0.3

WS1 (Gal1 - Gal2)

1

-1

SCSD1C_20100319T135222_20100319T144622

Mean Gal 1 for all incidence angles, H pol Mean Gal 2 for all incidence angles, H pol Mean Gal 2- Gal1 for all incidence angles, H pol

V pol

March, TB_gal averaged over all incidence angles for each GP

2K

4.5K

gradient

2K

4.5K

2K

4.5K

2K

4.5K

-0.5K

0.2K

-0.5K

0.2K

SCSF1C_20100805T134125_20100805T143524_344_001_1Dual pol without TECthe own OTT of each GN computed within [0S 50S] are used

SSS1 (Gal1 - Gal2) SSS1 (Gal1) SSS1 (Gal2)0.3 40

-0.3 30

Gal 1, SSS (retri - prior) Gal 2, SSS (retri - prior)

Chi2 (Gal1 - Gal2)

0.3

Chi2 (Gal1) Chi2 (Gal2)

1.5

-0.3 0.5

WS1 (Gal1 - Gal2)SSS1 (Gal1 - Gal2)

0.3

-0.3

SCSF1C_20100805T134125_20100805T143524

Mean Gal 1 for all incidence angles, H pol Mean Gal 2 for all incidence angles, H pol Mean Gal 2- Gal1 for all incidence angles, H pol

2.5K

3.5K

2.5K

3.5K

-0.3K

0.3K

1K

3K

1K

3K

-0.3K

0.3K

V pol

August, TB_gal averaged over all incidence angles for each GP

Conclusions

It’s possible that the inaccuracy of GN model lead to

1) Differences of retrieved SSS between ascending and descending orbits.

2) Gradient in retrieved SSS across swath, espescially at high latitude

3) Seasonal differences in SSS

4) Different behavior of OTT w.r.t to retrieved SSS at different latitude

gradient

-0.5K

0.2K

Argan's TEC DPGS’s TEC

LOCEAN’s TEC, Gal1, xi/eta = 0.23

LOCEAN’s TEC, Gal2, xi/eta= 0.23

LOCEAN’s TEC, Gal1, xi/eta= EAFFOV

Retrieved TEC in August