Record Search Query: [Service_Provider: Short_Name='NASA/GSFC/SED/ESD/GCDC/GESDISC']
map Time Anomaly for Giovanni-3
Entry ID: G3_mapTimeAnomaly
Abstract: The mapTimeAnomaly service for Giovanni-3 takes a series of grids as an input and
computes a series of anomaly grids as the output. The anomaly values are the
result of subtracting the mean of all of the input grids from each of the
individual input grids.
Anomalies of ... input data compared to mean for selected time-period
Same as input parameters
Input and output files are HDF4 format
* For map Time Average, if the input consists of 12 monthly data files, each
containing a global 1 degree x 1 degree grid of surface temperatures, then the
output will be a single 1 degree x 1 degree grid, where each pixel is the mean
of the corresponding pixel in each of the original 12 grids.
** Each anomaly grid has the same structure as the input and mean grids, but the
anomaly pixels contain the difference between the original pixel value for that
input grid, and the mean value for that pixel computed from all input grids.
*** If the input grids contain a third dimension, that dimension is interpreted as
multiple measurements of the same value, not a vertical dimension. In such
cases, the third dimension is collapsed by averaging all of its values to
produce a single value for the corresponding geographic pixel. No weighting is
performed in this collapsing computation, but fill values are masked out prior
to the computation. If a valid value cannot be computed for the pixel, the
pixel is set to the fill value.
If weighting by pixel counts is active, and the count grid for a single input
grid is three-dimensional, the grid of counts is collapsed to a two-dimensional
array by summing the count values in the third dimension, and using the sum in
the weighting operation.
NOTE: This document describes only the mathematical approach
used in the computation.
Quality Data quality is dependent on input data sets and processing.
Access Constraints There are no access constraints to data in Giovanni-3.
Use Constraints Use of the data and the Giovanni system should be acknowledged in published works and presentations.
Creation and Review Dates