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This is a
quickandeasy exercise that shows what can be done in about 30 minutes.
Wimsoft (http://wimsoft.com) software is
applied to monthly composited and mapped global images at 9 km resolution
of the OCTS (1996/11 1997/06) and SeaWiFS (1997/09 2004/12) and 4km
resolution images of AquaMODIS (2005/01 2005/02). For more information
please see a related article at http://spg.ucsd.edu/Satellite_Projects/Monthly_global_time_series/Monthly_global_time_series.htm.
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The
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An animated GIF
using monthly images is shown below. Using monthly data makes the transitions from
one month to another too sharp. A better but more time consuming way would be using
8day data with interpolation.
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The
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A time series
of the chlorophylla concentration was constructed for the
·
The time series
image is based on a table in the following form:
Image 
SYear 
EYear 
SDay 
EDay 
Mask 
Nin 
Nout 
Min 
Max 
Mean 
StDev 
Median 













This table is the
standard output from a wam_statist. The
meaning of the table columns is the following:
Image
image file name
SYear, SDay start year and day, respectively
EYear, EDay end year and day, respectively
Mask
mask number (could be up to 255), only one mask used here
Nin, Nout the number of valid (in) and
invalid (out) pixels used
Min, Max, Mean,
StDev, Median the statistics parameters of the valid pixels
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To see the full
table of statistics click on the time series image or here.
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Another way of
looking at the monthly dynamics is to look at the monthly anomalies. Monthly
anomalies are derived by first creating the monthly means for each of the
twelve months using all available data (19862005) and then expressing each
month as a ratio to the mean or as a difference from the mean. For chlorophyll
we the ratio of the actual month values to the mean month values whereas for
SST we subtract the mean month from the actual month. The calculation of
monthly means and all the anomalies is done with a single command of a WAM
script wam_anomaly. An animated GIF
of the monthly anomaly images is shown below. Areas shown in red are
significantly above the corresponding monthly mean whereas areas shown in blue
are significantly below the corresponding monthly mean. A time series plot
shown above for the median chlorophyll values in the Santa Barbara Basin could
also be made for the anomal;ies.