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You are here: GES DISC Home Giovanni - Interactive Visualization and Analysis Giovanni-3 Operation Technical Summary: Time Averaging

Giovanni-3 Operation Technical Summary: Time Averaging

Time Averaging

The Time Averaging operation is employed in Giovanni-3 so that the time dimension for a time-dependent parameter can be collapsed by averaging, leaving the other dimensions intact. In most cases, it is a straight forward geometric average, skipping over any fill or missing values:

Geometric mean equation for time averaging

where v(x,y,z,…t) are not fill or missing values.

The Time Averaging operation can support weighted averages as well.  The weighting factor must be available for each time step.  In this case, the above equation is then,

Weighted geometric mean for time averaging

where v(x,y,z,…t) are not fill or missing values.

Currently, there is one such case: the MODIS Aerosol Small Mode Fraction is weighted along the time axis, by the Aerosol Optical Depth for MODIS MOD08_D3, MOD08_M3, MYD08_D3 and MYD08_M3 products. For more information, see the Parameter Weighted Average operation.

This Technical Summary page a draft version -- for information on this operation while
the document is being refined, please send a message to GES DISC Help.

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Last updated: Apr 06, 2016 04:17 PM ET
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