INSTRUMENT

STATUS AND

PERFORMANCE

Guido Levrini

Page 2ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

ASAR

Instrument operability issues solved: Echo shift -> fine tuning of on board parameters Historic swath parameters (‘Neustrelitz effect’) N-2 timing patch Incorrect Wave mode exit -> solved by MP rules Wave mode switch down -> patch AP mode SWST annotations -> patch Incorrect GMM exit -> hopefully solved this week!

Instrument completely operable: no remaining open problem

No TRM failure since launch (4 TRM’s lost in Tx due to PSU) Excellent instrument stability (~0.2 dB, better than expected) Antenna patterns completely characterized (all beams/ all pol *)

* All HH, VV, VH beams

5/7 HV beams

* All HH, VV, VH beams

5/7 HV beams

Page 3ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

Page 4ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

MERIS

Instrument availability: ~ 100% Calibration technique & mechanism: perfectly working Spectral calibration: characterization confirmed (± 1 Å) by

recent spectral campaigns (begin Nov) Spectral stability: excellent Radiometric calibration: very good overall stability.

Slow degradation in the blue (@412 nm) -> now in the order of 2 % Smile correction fully verified -> under implementation in Level

1b.

Page 5ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

AATSR Nominal operations, 100% instr.

availability Temperatures nominal, Cal S/S OK,

Coolers functioning nominally, Blanking Pulses OK

Scan mechanism: small jitter (on occasions)

Spectral calibration: OK Pointing characterization: OK Dynamic range (all channels) optimized Radiometric stability: visible channels

affected by water condensation. Outgassing: water removed each time, it

comes back at lower rate -> we gradually -but inefficiently - get rid of the water

Page 6ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

RA-2

Over Ice: excellent tracking capabilities Over Ocean: excellent range noise performance (1.8 cm) On board parameters optimized: no change since Cal Review S band accumulation anomaly cured by operational work-around Datation correction implemented in Level 1b

Absolute Sigma zero calibration (1st time ever) -> the computed bias is:

Range Absolute Calibration all data collected analysis to be finalized (to reduce error bars)

Page 7ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

DORIS / LRR / MWR

DORIS Orbit radial accuracy (rms) Navigator: < 30 cm Preliminary (2d): < 5 cm Precise (20d): < 3 cm

LRR: good laser coverage

MWR 23.8 GHz channel perfectly stable Suspected slow drift of the 36.5 GHz channel: under

investigation

Page 8ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

MIPAS Good NESR performance Detector non linearity in spec

(lower end of dynamic range under optimization) Radiometric stability: in spec, but affected by ice formation

After warm-up, the water builds up slower -> periodic decontamination

In-flight ILS within budget L2 more sensitive than expected -> scheme under improvement

Spectral calibration: OK (including refined NL component in L2) Pointing: OK. Update on 13 Nov (~25 mdeg in pitch). LOS OK FOV characterization: OK (using the planet Mercury). Cooler Anomaly (6-22 Aug, 1-11 Oct). No H/W problem.

VCS sensitive to environmental conditions -> Use coarse balancing only.

MIPAS NESR0

(High Resolution Calibrated Spectrum)

1.0E-09

1.0E-08

1.0E-07

500 700 900 1100 1300 1500 1700 1900 2100 2300 2500

Wavenumber (cm-1)

NE

SR

(W

cm

-2 s

r-1 c

m)

In-Flight (223K)

Requirement

On-Ground (231K)

Page 9ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

GOMOS Good instrument operability Excellent tracking capabilities (down to 3 km!) Radiometric stability: excellent Spectral calibration: OK (± 1/30 pixel) Spectral stability: excellent No ghosts on the CCD CCD sensitive to proton radiation (-> hot pixels and RTS):

operating temperature decreased (+10 -> -4 C, minimum achievable)

dark charge calibration approach changed (every orbit now) ground processing under update

Independent CCD Expert Investigation Board set-up

Page 10ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

SCIAMACHY

All mechanisms working ‘Flash’ Ice decontamination (during ‘Leonids’) worked. Dark current stability: excellent in ch.1-6, affected by ice in

ch.7-8 Straylight: Ok in nadir for ch.1-6. Ch.7-8 under investigation Etalon correction: OK. PPG: OK for ch. 1-6, under investigation for ch. 7-8. Spectral calibration: excellent stability Sun mean reference: recently determined offset under

investigation (does not affect DOAS)

Polarization: Nadir is OK, Limb just starting.

Page 11ENVISAT Validation Workshop - ESRIN - 9–13 December 2002

CALENDAR OF MAIN PROCESSOR UPGRADES

AATSR 21 June 4 July On-going

ASAR 31 May 13 Sept 12 Nov this week ?

MERIS 8 April 21 June 14 August On-going

RA-2/MWR 21 April 5 July 18 Nov

GOMOS 21 June 7 August On-going

MIPAS 18 April 30 May On going

SCIAMACHY 30 May 5 Sept this week ?

N. B. = Updates of Aux Data files to be added