Institut für Umweltphysik/Fernerkundung Physik/Elektrotechnik Fachbereich 1 ENVIVAL-LIFE Meeting...
-
Upload
kaiser-kasun -
Category
Documents
-
view
103 -
download
0
Transcript of Institut für Umweltphysik/Fernerkundung Physik/Elektrotechnik Fachbereich 1 ENVIVAL-LIFE Meeting...
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
ENVIVAL-LIFE Meeting 6/7 Dec 2010
S. Noël, K. Bramstedt, C. v. Savigny
IFE/IUP
SCIAMACHY Performanceafter the ENVISAT Orbit
Change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
ENVISAT Orbit Change• Required because original orbit is ‘booked’ for other missions
• New orbit: About 17 km lower, slightly shorter orbital period Drifting inclination and local time of equator crossing (about ± 10 min around
22:00 until 2013) New repeat cycle and cycle length of 30 days / 431 orbits
• Time for orbit change has been chosen to optimally use remaining fuel
• Schedule: First manoeuvre 22 October 2010 Most instruments switched off until 27 October 2010 Between 27 October and 2 November YSM instead of SYSM (reduced
pointing accuracy) Last orbit change manoeuvre 4 November 2010 Quasi-nominal service until end of 2010 (data to users with quality disclaimer) From January 2011 on everything nominal again
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Impact on SCIAMACHY• SCIAMACHY operations had to be slightly adapted to new
orbit: Updated limb states:
• One horizontal scan less to guarantee limb-nadir matching
• Planned: Skip first tangent height (~3 km) and start at ~0 km
Updated timelines
• Some discussion about possible contamination before orbit change due to thrusters exhaust (but considered low risk at that time)
• Main performance checks after the orbit change: Thermal performance Geolocation performance (esp. limb and occultation measurements) Optical performance (throughput)
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Temperatures• SCIAMACHY detector temperatures increased by about 0.5 K after the
orbit change
• Related to higher ENVISAT temperatures, caused by permanent use of KBS1 and KBS3 after Ka band antenna anomaly (not related to orbit change)
• ENVISAT temperatures will remain higher
• Adaptation of SCIAMACHY detector temperatures planned
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Limb nadir matching
Limb nadir matching OK
Minor problem:Limb corner co-ordinates are flipped in L1b states ADS (NOT in measurement dataset!) due to removed limb level.
Red: Nadir state Green: Limb State Corners from states ADS
10 Oct 27 Oct
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Limb THs in L1 product -1- Changes in limb state:
– Continuation of limb-nadir matching with changed orbit required modification
– One horizontal scan less (removal of -3 km scan).
General Scan Sequence:– General OK.– Step size OK.– Altitudes not changed?
Not OK!
Red : before mission extensionGreen : during mission extensionBased on L1b geolocation!
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Limb THs in L1 product -2- TH first readout:
Still at ~-4.2 km
TH last readout(dark meas.)Moved from 263km → 269km
Note: NRT data, no AUX_FRAs!
Red : before mission extensionGreen : during mission extension
TH first readout
TH last readout (dark meas.)
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Limb Geolocation: AUX_FRAs AUX_FRA files contain
attitude correction Orbit 45331
2010-Oct-31 no AUX_FRAs :
Geolocation as given in NRT product
with AUX_FRAs :Re-calculated with CFIs using AUX_FRAs
No larger change in tangent height.
→ AUX_FRAs will not correct for too low limb TH !
Lowest tangent altitude for each vertical profile (Up-down pattern is horizontal scan)
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Accuracy of L1 Geolocation: Limb TH from TRUE version 1.8 retrievals
YSM
Method: – Determine tangent
height from UV ‘knee’
– Compare with L1 altitudes
Altitudes during YSM ~1.8 km too low
About zero offset in SYSM, also after orbit change.
OK!
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Accuracy of L1 Geolocation: Solar Occultation TH: -Measure centre of sun-
Method: – Fit center of sun
from scans over solar disk
– Compare with TH in product
Altitudes during YSM ~3km too low, with large scatter.
Back to previous values with SYSM.
In line with state 47 analysis (jump of elevation mirror after switch to sun-follower)
OK!
Note: NRT data, no AUX_FRAs!
SYSMYSM
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
SCIAMACHY Degradation Monitoring
• Main method:– Ratio (calibrated) signal of well known source (sun above atmosphere, internal
white light source (WLS)) at time t to corresponding measurement at reference time t0
– Reference time for SCIAMACHY: 2 August 2002 (begin of nominal meas.)
– Performed for different light paths, corresponding to different viewing geometries
– Degradation correction factors (m-factors) are regularly produced and used in operational 1-2 processing (see: http://www.iup.uni-bremen.de/sciamachy/mfactors)
• Limitations:– No polarised light source available, therefore no monitoring of changing
polarisation sensitivity possible
– Scan angle dependent degradation correction in preparation
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
SCIAMACHY Light Path Monitoring
• The different SCIAMACHY light paths are regularly monitored using measurements of the unobscured sun above the atmosphere and the internal WLS
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring results (L1b / m-factors) General: Slightly enhanced variability during YSM period Throughput slightly affected by higher detector temperatures (caused
by higher ENVISAT temperatures) Limb light path:
– No significant effect. – Very slightly throughput loss in channel 2.
Calibration light path:– No significant effect.
Nadir light path:– Reduced signal for 27/28 Oct sub-solar (pointing mode) due to YSM
(excluded from operational m-factor calculation)– No signal for 27 Oct sub-solar (fast-sweep mode), due to blocking by
Ka-band antenna– Very slightly enhanced throughput for channel 3,4,5
Conclusion: No significant throughput changes.
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors)
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors)
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Summary• Limb states:
– Limb nadir matching: OK!– Limb sequence (with 30 levels) and stepping: OK!– Limb tangent height: First horizontal scan at -4 km, not ~0 km!
To be adapted in the near future– TRUE: ~-1.8 km TH offset during YSM period, later (SYSM) OK.
• Solar occultation TH/elevation angles:– Reduced performance during YSM (~-3km TH offset)– Back to nominal with SYSM (since 2 Nov 2010)
• Throughput monitoring:– No significant changes.
• Status of other instruments and platform: – No major problems– ENVISAT temperature increased due to permanent use of KBS1 &
KBS3 after Ka antenna anomaly
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Backup slides
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 1
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 2
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 3
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 4
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 5
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 6
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 7
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Nadir, ch. 8
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 1
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 2
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 3
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 4
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 5
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 6
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 7
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Limb, ch. 8
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 1
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 2
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 3
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 4
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 5
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 6
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 7
Orbit change
Institut für Umweltphysik/Fernerkundung Physik/ElektrotechnikFachbereich 1
[email protected] ENVIVAL-LIFE Meeting 6/7 Dec 2010
Throughput monitoring (L1b / m-factors) Cal., ch. 8
Orbit change