16 The Past, Present, and Future of the AVHRR Pathfinder SST Program
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Step 3: Spatial Binning
3.1. The GAC pixels, converted to SST in Step 2, are then binned into an
equal-area integerized sinusoidal grid.
3.2. To reduce discontinuities along the date line, a data-day based on a
spatial data-day definition (Podestá, 1995) is used.
3.3. A land mask is applied to the data, identifying pixels that fall
on land. In Pathfinder Version 5, an improved mask based on a
1 km resolution Moderate Resolution Imaging Spectroradiometer
(MODIS) dataset (MOD12Q1) derived by the USGS Land Processes
Distributed Active Archive Center is used. 2 In earlier versions of
Pathfinder, the land mask was based on a Central Intelligence Agency
database of navigation hazards, but no citation or further information
is available.
Step 4: Temporal Binning
4.1. Step 4 begins by temporally binning the spatially binned pieces from
Step 3 into a single daytime and single nighttime file for each day. In
the case of overlapping satellite passes, only the highest quality pixels
available for each are used. If there is more than one contributing pixel
at the highest quality, these values are averaged. In Pathfinder Version
5, temporally binned files are also created for 5-, 7-, 8-day, monthly,
and yearly periods.
4.2. An internal Pathfinder reference check comparison is then made to
an internal 3-week Pathfinder comparison field. A sea ice mask based
on weekly SSM/I and sea ice information in the OISSTv2 is used to
exclude pixels from the computation of the internal reference field.
Note that sea ice information is not used in this way in the earlier
versions of Pathfinder.
4.3. The SST, quality, and related fields are reformatted from equalarea to equal-angle for distribution and archiving in HDF4-Scientific
Data Set format. Older Pathfinder versions were distributed in HDF4
Raster format.
Step 5: Quality Assurance, Archiving, and Distribution
5.1. Utilizing checksums to ensure file integrity, the HDF4-SDS files are
then acquired by NODC from the University of Miami and browse
graphics are generated.
2 See http://www-modis.bu.edu/landcover/userguidelc/lc.html for more info
283
Step 3: Spatial Binning
3.1. The GAC pixels, converted to SST in Step 2, are then binned into an
equal-area integerized sinusoidal grid.
3.2. To reduce discontinuities along the date line, a data-day based on a
spatial data-day definition (Podestá, 1995) is used.
3.3. A land mask is applied to the data, identifying pixels that fall
on land. In Pathfinder Version 5, an improved mask based on a
1 km resolution Moderate Resolution Imaging Spectroradiometer
(MODIS) dataset (MOD12Q1) derived by the USGS Land Processes
Distributed Active Archive Center is used. 2 In earlier versions of
Pathfinder, the land mask was based on a Central Intelligence Agency
database of navigation hazards, but no citation or further information
is available.
Step 4: Temporal Binning
4.1. Step 4 begins by temporally binning the spatially binned pieces from
Step 3 into a single daytime and single nighttime file for each day. In
the case of overlapping satellite passes, only the highest quality pixels
available for each are used. If there is more than one contributing pixel
at the highest quality, these values are averaged. In Pathfinder Version
5, temporally binned files are also created for 5-, 7-, 8-day, monthly,
and yearly periods.
4.2. An internal Pathfinder reference check comparison is then made to
an internal 3-week Pathfinder comparison field. A sea ice mask based
on weekly SSM/I and sea ice information in the OISSTv2 is used to
exclude pixels from the computation of the internal reference field.
Note that sea ice information is not used in this way in the earlier
versions of Pathfinder.
4.3. The SST, quality, and related fields are reformatted from equalarea to equal-angle for distribution and archiving in HDF4-Scientific
Data Set format. Older Pathfinder versions were distributed in HDF4
Raster format.
Step 5: Quality Assurance, Archiving, and Distribution
5.1. Utilizing checksums to ensure file integrity, the HDF4-SDS files are
then acquired by NODC from the University of Miami and browse
graphics are generated.
2 See http://www-modis.bu.edu/landcover/userguidelc/lc.html for more info