1. Calibration Event Logging GSICS meeting, March 2013, Williamsburg USA
Rob Roebeling and Sebastien Wagner
EUMETSAT

2. Outline
Calibration Events Working Group (CE-WG) achievements
Proposed calibration event logging system
Define a high level procedure for logging calibration events
Encourage the use common standards
Encourage populating the calibration event databases with historic events
Open up the database
Plans CE-WG
Work on action set by CGMS to be reported at next CGMS (July 2013)
Work in the CE-WG’s work plan

3. Achievements ( )

4. CE-WG Achievements 2011-2012 Initiation of the CE-WG
Assessment of Eumetsat’s event logging systems (UNS and CHART)
Collection of User Requirements (internal and external presentations)
Discussion of System Requirements (internal)
High level concept of the Calibration Events Logging System
Presentation of a working paper on current status at CGMS-40
CGMS action (before July 2013)
NOAA and EUMETSAT are invited to present a consensus concept and realisation of a calibrations events logging system with emphasis on issues and lessons learned. Due date: CGMS-41.

5. High Level design Calibration Event Logging System

6. General principles
The proposed Calibration Event Logging System should :
log all events impacting radiometric and geometric data quality:
 Platform level  Satellite level  Data processing level
use common Standards and Procedures across missions and instruments;
allow for portability across space agencies;
comprise a database historic events;
allow users to assess and visualize the events database.
Note
no duplication of existing systems (easier development + maintenance) but direct link to them + additional info when required.

7. General concept – Uniform Calibration Event Logging System
Web Interface
Mission
Calibration Events Database
Users
Mission Events Database

8. Virtual hierarchical design – Uniform Calibration Event Logging System
Mission Events Database

9. Main Categories Mission Information
General information on the platform, instruments and sensors operated in the mission that is relevant to all users of the satellite data.
Irregular Events
Events at satellite level that are not occurring systematically and that impact the radiometric or geometric quality of the observations due to instruments calibrations, manoeuvres or miscellaneous.
Processing Events
Updates of the processing algorithms (onboard or ground seg.) or reprocessing events (ground seg.) that modify the radiometric or geometric quality of the observations.
Data Outages
Events that triggered the temporary or definitive end of the data collection.

10. Events Types as logged in existing systems
UNS (Eumetsat): instrument-calibration, data interrupted, instrument-maintenance, ground- segment-maintenance, instrument-gain-change, eclipse-season, spacecraft-anomaly, ground- segment-anomaly, in-plane-manoeuvre, product-change, ..
ASCAT: Manoeuvres; heat refuse , instr. switch off, software probl., processor update, sun eclipse, transponder event,….
GOME: missing scan(s), degraded MDRs (instrument), saturated scan(s), mode changes, data gap, manoeuvre events, tank heater on/off, NEDT-PEAK event, channel swap, …
METEOSAT: ice decontamination, calibration coefficient update, gain changes, update calibration processor, instr. switch off, …
METOP: Antenna correction, channel degradation, update VIS calibration coefficients, ..
VIIRS: stray light, striping issues, roll manoeuvre, lunar calibration, warm up, cool down, anomaly, accuracy switch, calibration Blackbody Warm-up Cool-down, door open…
POES: scan motor, optics, antenna, electronics, channel saturation, data outage, radiant cooler, calibrator, ….
ASCAT
- Manoeuvres (in-plane [shorter data outage] + out-of plane [longer data outage]). Reported as well as the resulting data outage.
- heat refuse, causing exceedence of the noise limit. Causes a data outage.
- Switch off of the instrument (on-board software problem)
- Sun eclipsed by the Moon. But impact on data is not known.
- Processor update
- Events coming from product monitoring (such as the power gain product)
- Calibration campaigns. Causes 1/ data outage during the calibration campaign update of the calibration (2 months, twice a day causing 20 minutes data-outage + poor quality)
Events on transponders if happening when the update on the calibration is performed.
GEO
- ice decontamination for IR bands
- update of the calibration coefficients in the image headers for the VIS/NIR bands
- update of the calibration processor (VIS/NIR) SSCC
- gain changes
- instrument switch off
METOP
Antenna correction (AMSU)
Channel degradation
irregular update of visible calibration parameters
GOME
missing scan(s)
degraded MDRs (instrument)
scan(s) with old dark correction applied
saturated scan(s)
Mode changes
Data gap
Manoeuvre events
TDIF event
Tank heater on/off
Operator events
NEDT-PEAK event
Life Limiting Items
Channel Swap
Anomaly Message
USN
instrument-calibration
Data interrupted
general-announcement
instrument-maintenance
ground-segment-maintenance
instrument-gain-change
eclipse-season
ground-segment-anomaly
in-plane-manoeuvre
spacecraft-anomaly
product-change
new product
VIIRS
Stray light
Striping issues
Roll manoeuvre
Lunar calibration
Warm up
Cool down
Anomaly
Door open
Table update
Calibration Blackbody Warm-up Cool-down
Accuracy switch

11. Events Database – Events Types
Events Types List
Operational status changes
(e.g. Switch to operational..)
Command chain anomalies
(e.g. ..)
Operating mode changes (e.g. Switch to rapid scan or full disk mode, Clock errors, ...)
Platform alteration
Platform damages
Instrument maintenance
(e.g. Stray light correction, Ice decontamination, ...)
Instrument alteration
(e.g. Detector temperature changes, Solar diffuser changes, ..)
Instrument damage
(e.g. CCDs failure, Mechanical anomalies, Switch to redundant systems, ..)
Detector configuration
(e.g. Dark current, Space view position, ...)
The CE-WG will propose to define: -> an EventsType List, comprising standard calibration events names
-> a List of mandatory Attributes to be provided per EventsType

12. Standards and Procedures
Common Standards and Procedures are required to improve traceability and uniformity cross space agencies. This means:
Design data model following inter-national standards (ISO, OGC, …);
Attune to standards used in other CGMS/GSICS/WMO programs;
Use uniform (mandatory) naming conventions and attributes for each EventList Obj.;
Use uniform (mandatory) naming conventions and attributes for the EventType Obj.; (e.g. instrument, date of change, link to online resource, responsible agency, ..)
Provide links to documents with detailed and quantitative Event information ;
Provide the databases in common data formats (e.g. NetCDF, ..).

13. Populating the Database
Many of the existing databases of calibration satellite events  don’t keep all required information,  don’t contain events from historic missions.
Thus:
additional information needs to be collected to complete the database.
historic events need to be mined, and knowledgeable users need to be consulted.
space agencies need to assess what historic events are and can be made available. Some events are confidential, other haven’t been logged (especially older events)).
Note
Populating the database with historic events is a requirement of the climate community,
but has no priority for the CGMS and GSICS!

14. Opening up the Databases
Suggestions for reporting interface (e.g. web based data base);
Open up the databases through a Graphical User Interface (GUI);
GUI shall be high-level enabling intuitive event log searching;
GUI shall be tested on a set of predetermined queries;
GUI shall include manners to display groups of events graphically (e.g. outages).

15. Plans ( )

16. Actions required by CGMS till meeting in 2013
CGMS and GSICS partners to review the draft Calibration Events Logging System;
GSCIS and CGMS partners to discuss and propose the common standards to adopt;
Space Agencies to define the “high-level” and the “specific” system requirements;
Space Agencies to test system concept through small pilot projects;
Space Agencies to identify Climate Users that can provide information on historic calibration events.

17. CE-WG Work Plan - 2013-2014 Initiate an internal project (ECPC):
to further assess requirements;
to explore how to build upon existing systems;
to consolidate user and system requirements;
to set up a pilot calibration event logging system
Collaborate NOAA, GSICS, and other scientific users:
to validate the mandatory EventsList and EventsTypes Objects;
to validate the mandatory Attributes of each EventsList and EventsTypes Object; (following ISO standards)
to validate common data standards to be used.
Report at next CGMS (July 2013).
ITERATIVE PROCESS

18. Thank You
Any Questions?