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1991-04-15
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The TOMS program reads and displays the ozone data on this CD-ROM. It is
divided into three major parts:
Processing Daily Gridded Data:
-----------------------------
The following options are available:
a) Read the daily gridded data for a specific day. The user is prompted for
a date and the daily gridded data for that day is read into a gridded
array. The dimensions of the array are 180 rows by 288 columns. Each
grid cell in the array covers a 1.0 degree latitude by a 1.25 degree
longitude area, and therefore the array covers the entire world. The
latitudes range from -90.0 to 90.0 and the longitudes range from -180.0
to 180.0. Zero values in the array denote flagged data (bad or missing
data).
b) Display the current daily gridded data in table format using one of
three resolutions: full resolution (every value in the gridded array is
displayed), half resolution (every other value in the gridded array is
displayed), or quarter resolution (every fourth value in the gridded
array is displayed). The user can move through the table using the
movement keys (press F1 for help after this option has been chosen).
c) Calculate and display statistical values for the current day. The user
is prompted for the latitude range (and possibly the longitude range) of
the zone to be processed and the following values are displayed for this
zone: minimum ozone value and its location, maximum ozone value and its
location, the area weighted zonal mean (each one-degree latitude zone
within this zone has a different weight), the standard deviation, and
the percentage of valid (not flagged) data points present within this
zone (flagged points are points that were set to 0 in the data due to
bad or missing data). Only valid points are included in the calculation
of the zonal mean and the standard deviation.
d) Display the ozone value at a specific location for the current day. The
user is prompted for the latitude and longitude of the location to be
processed and the grid points are interpolated to produce the ozone
value at that location. If the grid points can not be interpolated due
to flagged data, the latitude and longitude of the grid cell
corresponding to the location are displayed instead of the latitude and
longitude entered by the user.
Processing Daily or Monthly Statistical Data:
--------------------------------------------
The user is prompted for the type of data to be processed (daily or
monthly) and for the date (day or month). Then, the pre-computed
statistical data for this day or month is read in and the following values
are displayed: global minimum ozone value, global maximum ozone value, and
the latitude range, minimum value, maximum value, area weighted zonal mean,
and standard deviation for each of the 18 ten-degree latitude zones (each
one-degree latitude zone within the ten-degree latitude zone has a
different weight). When these zonal means and standard deviations were
calculated, if there were not enough valid data points present within the
ten-degree latitude zone (85% or more) or enough valid (non-zero) daily
zonal means or standard deviations for the month (20 days or more), the
daily or monthly zonal means and standard deviations were set to 0.0.
Processing Time Series Data:
---------------------------
The following options are available:
a) Read and display daily or monthly pre-computed statistical data. The
user has the option to display all zonal statistics for a specific zone
for a range of days or months and a single year, or to display one
statistical value for a range of days or months and multiple years. The
user is prompted for the year(s) to be displayed, the type of statistics
to be displayed (if appropriate), the zone number (if appropriate --
these are 10-degree latitude zones), and the first and last days or
months of the period to be processed. If displaying a single year, the
following statistical values are displayed for one zone: the minimum
ozone value, the maximum ozone value, the area weighted zonal mean, and
the standard deviation. If displaying multiple years, one of the
following statistical values is displayed: global minimum ozone value,
global maximum ozone value, area weighted zonal mean for a specific
zone, standard deviation for a specific zone, minimum ozone value in a
specific zone, maximum ozone value in a specific zone.
b) Display the ozone values at a specific location for any range of days
(could include the entire database). The user is prompted for the
latitude and longitude of the location and for the first and last days
of the period to be processed. Due to the amount of time that it takes
to read the daily gridded data for one day, this part of the program
might take a VERY LONG time to execute if the user chooses to process
lots of days.
c) Display the mean for a specific zone for any range of days (could
include the entire database). The user is prompted for the latitude and
longitude ranges of the zone and for the first and last days of the
period to be processed. Due to the amount of time that it takes to read
the daily gridded data for one day, this part of the program might take
a VERY LONG time to execute if the user chooses to process lots of days.