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

Giovanni-3 Operation Technical Summary: Dimension Averaging

Dimension Averaging

The Dimension Averaging operation can perform one of two average types:

1) spatial area average, weighted by cosine latitude; or

2) the mathematical mean (average) along one or more dimensions (without weighting). Averaging is done for all user selected geophysical parameters or data arrays contained in a set of input files representing a time series.  The dimension-averaged data are then constructed into a time series and saved to a single output HDF file for further operations.

The input to this operation is a set of input HDF files representing a time series. The input files contain the user selected parameters as n-dimensional data arrays.

The output is an HDF file containing the dimension-averaged data as a time series.

Each dimension is averaged separately, except for area average where all values are averaged within the spatial region.  Missing data points are filled with fill values during processing and are not included in the calculation. All other valid data points are averaged using the mathematical mean, which can be an weighted area average using the cosine latitude as the weight.

Mean value computation:

mean value equation

Weighted mean value computation (w is the weighting factor, in this case the cosine latitude):

weighted mean value equation


This Technical Summary page is 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: Nov 10, 2011 01:08 PM ET