MODIS OCEAN QA Browse Imagery

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MODIS OCEAN QA Browse Imagery (MQABI Browse Tool)
NASA Goddard Space Flight Center Sept 4, 2003
http//jeager.gsfc.nasa.gov/browsetool/
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MQABI/QAPS Team
Kevin Turpie - technical lead, statistics,
graphics software Aumber Bhatti - web site and
system software Donna Thomas - L2 graphics and
operations support Ron Vogel - time series
graphics
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MQABI as a portal to MODIS Ocean Data

• QA browse tool provides access to 39 km
  resolution global maps for all Ocean products as
  they are produced in forward and reprocessing
  streams.
• Temporal resolutions of daily, weekly, monthly,
  and yearly
• Images filtered for each quality level (best,
  good, fair, all)
• Quality level map image (spatial distribution of
  quality levels)

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MQABI Data analysis tools

• Histograms of data for all quality levels for
  nominal range statistics for global maps (all
  temporal resolutions)
• Full range statistics of all quality levels for
  global maps
• Time series statistics (weekly, monthly) for
  global and 16 oceanographic regions (all quality
  levels)
• Time series plots of weekly means (select
  parameters)
• Toggle global images between different quality
  levels
• Download Level 3 Mean and Quality HDF files
  directly from the web site
• Time Series movie loop feature (display
  successive images), Movie maker feature (create a
  movie and download it)

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MODIS Ocean QA Website
modis-ocean.gsfc.nasa.gov/qa

• Access to browse tool
• Data Quality Summaries
• Known Problems
• Quality Level Flags

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All parameters displayed (weekly 39 km
images) Thumbnail GIFs are QL 0
Pull down menu for each product has links to
stats
Click on each individual product in the View All
Page and you get a pop up image that has direct
links to GDAAC to order data for that product,
for any resolution and map type
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Order from GDAAC 4km, 36km, 1 degree resolution
Common Flags, Std. Deviation, Number of
Observations, Mean, Quality Map for this product
and this data date
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From daily to weekly to monthly, lower quality
levels are not included in the binning average,
unless thats all thats available. Results in
more complete coverage at better quality.
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Time series statistics are calculated for global
maps and 17 oceanographic regions 15 regions
modified from Watson Gregg Open ocean and
coastal regions gt 1000m isobath lt 1000m isobath
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All Chlorophyll time series plots also include
SeaWiFS chlorophyll on the same plot
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Chlorophyll time series Overview page of all
regions
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Terra Mission Time Series overview of the data
values for the entire mission
North Atlantic weekly chlorophylls QL0-1
Global weekly water-leaving radiances QL0
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Aqua Primary Productivity Time series
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MQABI as part of the MODIS Ocean QA Process
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Aspects of QA

• Run-time QA automatic setting of QL flags at
  pixel level, internal to the code
• Processing QA Using 39 km maps, identify
  problems and track down system errors or
  processing code errors. Every single parameter
  (imagery and statistics) is viewed for daily
  weekly, monthly, yearly files as they are
  produced.
• Science QA calibration relevant to ocean
  radiances, analysis of upstream products
  impacting downstream, refinement of algorithms,
  validation against in-situ measurements - ongoing
  by U.Miami and individual algorithm scientists

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Processing QA
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Conclusion

• Much information for data analysis already
  resides on the web at MQABI
• http//jeager.gsfc.nasa.gov/browsetool/
• Images of 39 km maps, statistics, time series
  (text listing and plots), and movie loops are
  available
• Mean and Quality HDF files can be downloaded
• MQABI dual use a browse tool for the science
  community and for routine processing QA
• QA web page contains Data Quality Summaries,
  Known Problems, and many other documents
• http//modis-ocean.gsfc.nasa.gov/qa