Aerosol Optical Thickness (100 KM) - AERO100

Data Usage Guidance/Restrictions

The operational data for this datatype is available to all registered CLASS users. Pre-operational data may be restricted to authorized users. To become an authorized user, send a request to the CLASS Help Desk.

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Output

User option for the format of the output file. The valid formats are:

  • Plotted image GIF
  • Generic ASCII file
  • Spreadsheet
  • Tab-delimited file
  • Comma-delimited file
  • NetCDF file

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Spatial

Refers to the geographic area of interest to the user. This section of the search page allows the user to define the geographic area of interest.

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Temporal

Refers to the time span of interest to the user. This section of the search page allows the user to define the range of dates/times of interest.

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Variables

User option for values in the output file. The valid values for each file are:

Optical Thickness - The latest Aerosol Optical Thickness calculated based on the previous analysis optical thickness, weighted according to its reliability, combined with a weighted average of current observations within a surrounding area which is determined according to the grid point's gradient.

Gradient in X- Direction - Change in optical thickness in the negative direction along the X axis.

Gradient in X+ Direction - Change in optical thickness between the grid point and neighbor points within the field in the positive direction along the X axis.

Gradient in Y- Direction - Change in optical thickness in the negative direction along the Y axis.

Gradient in Y+ Direction - Change in optical thickness in the positive direction along the Y axis.

Average Gradient - The average of the gradients in all four directions (N, S, E, W) from the grid intersection.

Climatological Temperature - The average sea surface temperature of a grid intersection for a particular month over a number of years, taken from the global climatology file.

Spatial Covariance X- - The distance in grid units from the grid intersection to the nearest land mass in the negative direction along the X axis.

Spatial Covariance X+ - The distance in grid units from the grid intersection to the nearest land mass in the positive direction along the X axis.

Spatial Covariance Y- - The distance in grid units from the grid intersection to the nearest land mass in the negative direction along the Y axis.

Spatial Covariance Y+ - The distance in grid units from the grid intersection to the nearest land mass in the positive direction along the Y axis.

Physiographic Descriptor - The land/sea tag indicating whether a grid intersection is a land or sea point.

Age of Most Recent Observation - The age, in hours from the time of last analysis, of the most recent observation used to determine the new optical thickness for a grid intersection.

Class 1 Temporal Coverage - Set of bits (0-15) of which bit 1 is set to 1 for each analysis which included observations with a reliability greater than or equal to a specific minimum reliability considered as class 1. Bit 0 always remains a 0, and all bits are shifted right during each analysis leaving bit 1 a 0 when no class 1 reliability observations are used for a grid intersection.

Number of Observations - The total number of current observations used in the analysis of the new optical thickness for the grid intersection.

Weight/ Reliability - New reliability associated with the new optical thickness, based on the previous reliability combined with the weighted reliability of all observations used in the last analysis.

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UTC

Coordinated Universal Time (UTC) is the international time standard. It is the current term for what was referred to as Greenwich Meridian Time (GMT). Zero (0) hours UTC is midnight in Greenwich England, which lies on the zero longitudinal meridian. Universal time is based on a 24 hour clock, therefore, afternoon hours such as 4 pm UTC are expressed as 16:00 UTC (sixteen hours, zero minutes).

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