Analysis of L1b files with restituted attitude

Bianca M. DinelliE. Papandrea

• L1b files with pointing information coming from the satellite restituted attitude have been provided

• The spectra contained in the L1b files previously delivered are compared with the new ones

• Examined orbits: – 12963 (Reduced Resolution)– 10600 (Full Resolution)

12963 (RR 17 limb views per scan)• Old:

MIP_NL__1PTETB20040822_163350_000055582029_00384_12963_0000.N1

• New: MIP_NL__1P_12963-RES_ATT.04822

Tangent points location

Old – New (sweep 8)

Old – New (sweep 9)

Old – New (sweep 10)

Old – New (sweep 11)

• Orbit 10600 of 10/3/2004• full resolution (0.025cm-1)• 17 sweep per scan• Old: tangent points information as in

the L1b file delivered via tape• New: tangent points information

coming from satellite restituted attitude

L1B files of Orbit 10600• Old:

MIP_NL__1PPDPA20040310_144033_000038662025_00025_10600_2930.N1

• New: MIP_NL__1P_10600-RES_ATT.040310

Comparison of Old and New spectra (Seq: 14 - Limb 6)

Old – New – Band A

GMTR analysis

• The spectra of the two L1-b files have been analyzed with the GMTR system

• Pressure, Temperature O3 and H2O VMR have been simultaneously retrieved

• Retrieval performed at the nominal altitudes of the Occupation Matrix (same in the two analyses)

• Note that pointing is NOT retrieved (LOS as in L1-b files)

GMTR analysis -test evolution Old: -test = 504 - 20.06 - 2.34 - 2.13 - 2.11 New:- test = 542 - 20.06 - 3.46 - 2.40 - 2.46

BUT: some sweeps in the new file are flagged as corrupted while previously they were fine

Corrupted sweeps in orbit 10600

Old spectrum of Band A – flagged as corrupted in new file

Old spectrum of Band AB – flagged as corrupted in new file

Tangent points location

OLD NEW

GMTR retrieval

GMTR retrieval

OLD NEW

GMTR retrieval

OLD NEW

GMTR retrieval

OLD NEW

GMTR retrieval

OLD NEW

GMTR retrieval

OLD NEW

GMTR retrieval

OLD NEW

GMTR retrieval

OLD NEW

Conclusions

• L1b spectra differences > noise• Forward and Reverse sweeps show

different behavior• New tangent point locations lower than

previous ones• New algorithm flags corrupted apparently

good sweeps• New retrieved profiles smoother that

before