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Explore key lessons learned for efficient science data processing, focus on role of Measurement System Engineer, Science Team Participation, Processing Testbed, Consistency in data handling, Computing Power importance, and Early Delivery strategy. Benefit from insights on Altimeter Measurement System, maintaining Error Budget, collaborating with Science Team, Algorithm Development, Calibration/Validation processes, and responding to user feedback effectively.
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Lessons Learned for Science Processing Phil Callahan March 13, 2006
Overview • Background • Measurement System Engineer Role • Science Team Participation • Processing Testbed • Consistency: Terms, Units, Corrections, Data Flagging • Figure out what the data mean • Have more than adequate computing power • Deliver documents early, data soon after sensor turn on
Altimeter Measurement System Measurement Sys Eng Role • Maintain Error Budget • Liaison w/ Science Team • Product Definition • Algorithm Development • Calibration / Validation • Focal point for questions, complaints from data users Photo courtesy of JPL/NASA
Science Team Participation • Engaged with Project management, engineering aspects, science team members • Participate in • Data product definition • Algorithm definition / development • Calibration / Validation • Continuing interaction with Project throughout the mission • Publish • Public Outreach
Processing Testbed • Build early during algorithm development to define, test algorithms • Add software backbone as available • Use real products • Process test or simulated data • Process instrument test data as far forward as possible • Push simulated data backwards as far as possible • Use outputs to test final processing system • Will find bugs in both, but overall beneficial • Update and use throughout mission • Especially valuable during Cal/Val to try fixes, new constants • Data quality monitoring, quick-look processing
Consistency • Terms • Common, logical meanings, but make distinctions where useful • Example: Height Vs Range Vs Altitude • Units – in Products, among Algorithms • Correction and Sign Convention • Corrections ADD to value to bring closer to truth • Flag Convention and Design through entire processing chain • Design early, Use in Testbed • Document clearly for users – flags at later stages of processing depend on those earlier and may not be meaningful • Separate data and flags (avoid “flag values”); output calculated value if possible • Example: Bad(1) until test Good(0), clear spares at end
El Nino – Painting the Pacific Photo courtesy of JPL/NASA
Figure out what the data mean / If you don’t understand an answer – Ask • Waveform features • TOPEX Oscillator drift error • SWH drift as PTR changed • Tide Gauge Calibration • Trust, but Verify
Computing Power • Computer hardware is cheap compared to people’s time • Being able to process, reprocess, and reprocess again is extremely important during Cal/Val • Having a substantial amount of data, at least all of the Cal/Val period, on line is crucial • Separate Development, Integration & Test, Operational Systems • Aim for ~10X throughput • After ~ 2 yrs, reprocess all data in <~3 months
TOPEX – Jason-1 – Jason-2: 15+ yr Record Photo courtesy of JPL/NASA