MOPITT V4 Level 3 Data Quality Summary
The following information applies to MOPITT level 3 (L3) data,
Version 4 (V4; L3V2.0 or higher)
April 3, 2009
Further details on MOPITT Data Quality (and recommended analysis methods) can be found in the V4 User's Guide available at the MOPITT Publications webpage.
Gridded CO Retrievals
In
rare special situations, quality-control considerations prevent
inclusion of all the Level 2 data within a particular grid cell for
producing Level 3 gridded values. For example, for grid cells
overlapping coastline, Level 2 data within that grid cell will often
include more than one surface type. Averaging Level 2 data
characterized by significantly different averaging kernels, as would
occur in this case, should generally be avoided. Other special cases
are listed below, together with descriptions of the methods by which
such data are processed. If any single surface type constitutes at
least 75% of the Level 2 retrievals in a particular grid cell, only
retrievals with that surface type are used as the basis of the Level
3 gridded value. If no single surface type constitutes 75% of the
available Level 2 retrievals, all of the Level 2 data are retained in
the L3 gridded value, and the surface index is set to 2 ('Mixed'). If
the L2 retrievals in a particular L3 grid cell contain varying
numbers of valid levels (usually because of varying topography), it
is determined which case (i.e., number of valid levels) occurs most
frequently. Only this subset of L2 retrievals are retained as the
basis of the L3 gridded value. Methane (CH4) retrievals are not available in this data version.
Daily and Monthly Examples
Daily
Example (April 1, 2002)
Monthly
Example (April, 2002)CH4 Products