Subsetting is a service provided by the Langley Atmospheric Science Data
Center(ASDC). This interface allows users to subset CERES data through the ASDC
Ordering Tool - Java version. Subsets are created by latitude and longitude
coordinates, by parameters, or by parameter criterion. The subset tool extracts
the data specified and generates another, smaller file in the same format as
the original file.
The following data sets are available for subsetting:
Clouds and Radiative Swath (CRS)
TOA/Surface Fluxes and Clouds (SSF)
ERBE-like TOA Estimates (ES-8)
Instructions
Subsets of CERES data are requested during the data ordering process at the
data set level. All files related to the specified data set for subsetting will
be a subset order. The CERES data may be subsetted by Area, Time, Criterion, and
Output Parameters. For reference, steps three through ten are numbered in the
example "Subset Criteria Selection Interface" image that follows.
Select the data granule(s) to be ordered in the ASDC Ordering Tool.
Select "CERES Subset" at the bottom of the web page to initiate
the subset interface. Note: If the dataset cannot be subset, then no
new window will be created.
In the new window,"Subset Criteria Selection Interface", select
the data set to be subset in the "Subsettable Data Set(s)"
section.
Subset by Parameters
In the "Subset type" section, select "Output
Parameters". The "Output Parameters" section, will list
all parameters in the selected data set that may be extracted from the
original data file. Select any number of these parameters. Default is all
parameters.
Subset by Latitude/Longitude
In the "Subset type" section, select "Area". In the
"Subset area" section, enter the South, North (-90,90) and
West, East (-180,180) coordinates. Default is the entire globe.
Subset by Time
In the "Subset type" section, select "Time". In the
"Subset Start Time" and/or "Subset End Time" section,
provide the times needed using the time format listed:
YYYY-MM-DD-hh:mm:ss.
Subset by Parameter Criterion
Criteria can be used to subset data based on the data
range available for the selected parameter. For example, if requesting daytime
data for SW radiances, select Solar Zenith Angle and change the limits to 0 and
90 degrees.
In the "Subset type" section, select "Criterion".
Select a parameter in the "Subset Parameters by Criterion"
section. The min/max values of the selected parameter will be propagated
in the "Criterion Value" area. Adjust the values as needed.
Select "Apply Criterion". A message in red will be printed
below to state the criterion was applied (eg. "Applied min/max value
for CERES Solar Zenith Angle").
Apply Subsetting to the Data Set
Select "Apply Subset". A message in red will be printed below
to state the subsetting of the dataset was applied (eg. "Saved
subset info for CER_CRS_TRMM-PFM-VIRS_Edition2C").
NOTE: For each additional dataset, repeat steps 3 thru 9.
To submit the order, select "Submit". After the orders
are completed, be sure to select the media type. Default is FTP.
Subset Criteria Selection Interface.
You will receive an e-mail notification when your order is ready.
