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The geocoordinate and pixel-area tools described here provide the same functionality for all polar stereographic passive microwave data sets at NSIDC. They include Fortran routines for determining latitude and longitude from i,j coordinates and a pixel-area grid.
The geocoordinate tools allow the user to obtain latitude/longitude coordinates from (i,j) coordinates and vice versa. The geocoordinate tools that are availabe are the following; click on the links for more information about that tool:
| Tool Name | psn06lats_v2.dat and pss06lats_v2.dat |
|---|---|
| Applicable Data Sets | AMSR-E/Aqua Daily L3 6.25 km 89 GHz Brightness Temperature Polar Grids |
| Description | Grids that determine the latitude of a given
pixel for the 6.25 km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). These latitude
grids are in binary format and are stored as 4-byte
integers (little endian) scaled by 100,000 (divide the stored
value by 100,000 to get decimal degrees). Each array location
(i, j) contains the latitude value at the center of the corresponding
data grid cells. psn06lats_v2.dat: 1216 columns x 1792 rows, range = [31.0967, 89.8363] pss06lats_v2.dat: 1264 columns x 1328 rows, range = [-39.3649, -89.8368] |
| Access | FTP |
| Tool Name | psn06lons_v2.dat and pss06lons_v2.dat |
|---|---|
| Applicable Data Sets | AMSR-E/Aqua Daily L3 6.25 km 89 GHz Brightness Temperature Polar Grids |
| Description | Grids that determine the longitude of a given
pixel for the 6.25 km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemispere). These longitude
grids are in binary format and are stored as 4-byte
integers (little endian) scaled by 100,000 (divide the stored
value by 100,000 to get decimal degrees). Each array location
(i, j) contains the longitude value at the center of the corresponding
data grid cells. An East-longitude convention is used; therefore, positive longitude values are to the east of Greenwich, England. psn06lons_v2.dat: 1216 columns x 1792 rows, range = [-180.0000, 179.8140] pss06lons_v2.dat: 1264 columns x 1328 rows, range = [-179.8181, 179.8181] |
| Access | FTP |
| Tool Name | psn12lats_v2.dat and pss12lats_v2.dat |
|---|---|
| Applicable Data Sets | DMSP SSM/I Daily Polar Gridded Brightness Temperatures
Near Real-Time DMSP SSM/I Daily Polar Gridded Brightness Temperatures AMSR-E/Aqua Daily L3 12.5 km Brightness Temperature, Sea Ice Concentration, & Snow Depth Polar Grids |
| Description | Grids that determine the latitude of a given
pixel for the 12.5 km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). These latitude
grids are in binary format and are stored as 4-byte
integers (little endian) scaled by 100,000 (divide the stored
value by 100,000 to get decimal degrees). Each array location
(i, j) contains the latitude value at the center of the corresponding
data grid cells. psn12lats_v2.dat: 608 columns x 896 rows, range = [31.0967, 89.8363] pss12lats_v2.dat: 632 columns x 664 rows, range = [-39.3649, -89.8368] |
| Access | Brightness Temperature Data Sets:
FTP Sea Ice Data Sets: FTP |
| Tool Name | psn12lons_v2.dat and pss12lons_v2.dat |
|---|---|
| Applicable Data Sets | DMSP SSM/I Daily Polar Gridded Brightness Temperatures
Near Real-Time DMSP SSM/I Daily Polar Gridded Brightness Temperatures AMSR-E/Aqua Daily L3 12.5 km Brightness Temperature, Sea Ice Concentration, & Snow Depth Polar Grids |
| Description | Grids that determine the longitude of a given
pixel for the 12.5 km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). These longitude
grids are in binary format and are stored as 4-byte
integers (little endian) scaled by 100,000 (divide the stored
value by 100,000 to get decimal degrees). Each array location
(i, j) contains the longitude value at the center of the corresponding
data grid cells. An East-longitude convention is used; therefore, positive longitude values are to the east of Greenwich, England. psn12lons_v2.dat: 608 columns x 896 rows, range = [-180.0000, 179.8140] pss12lons_v2.dat: 632 columns x 664 rows, range = [-179.8181, 179.8181] |
| Access | Brightness Temperature Data Sets:
FTP Sea Ice Data Sets: FTP |
| Tool Name | psn25lats_v2.dat and pss25lats_v2.dat |
|---|---|
| Applicable Data Sets | DMSP SSM/I Daily Polar Gridded Brightness Temperatures DMSP SSM/I Daily and Monthly Polar Gridded Sea Ice Concentrations Nimbus-5 ESMR Polar Gridded Sea Ice Concentrations Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data Nimbus-5 ESMR Polar Gridded Brightness Temperatures Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Near Real-Time DMSP SSM/I Daily Polar Gridded Brightness Temperatures Near Real-Time DMSP SSM/I Daily Polar Gridded Sea Ice Concentrations Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I Brightness Temperatures AMSR-E/Aqua Daily L3 25 km Brightness Temperature & Sea Ice Concentration Polar Grids |
| Description | Grids that determine the latitude of a given
pixel for the 25 km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). These latitude
grids are in binary format and are stored as 4-byte
integers (little endian) scaled by 100,000 (divide the stored
value by 100,000 to get decimal degrees). Each array location
(i, j) contains the latitude value at the center of the corresponding
data grid cells. psn25lats_v2.dat: 304 columns x 448 rows, range = [31.0967, 89.8363] pss25lats_v2.dat: 316 columns x 332 rows, range = [-39.3649, -89.8368] |
| Access | Brightness Temperature Data Sets:
FTP Sea Ice Data Sets: FTP |
| Tool Name | psn25lons_v2.dat and pss25lons_v2.dat |
|---|---|
| Applicable Data Sets | DMSP SSM/I Daily Polar Gridded Brightness Temperatures DMSP SSM/I Daily and Monthly Polar Gridded Sea Ice Concentrations Nimbus-5 ESMR Polar Gridded Sea Ice Concentrations Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Passive Microwave Data Nimbus-5 ESMR Polar Gridded Brightness Temperatures Bootstrap Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I Near Real-Time DMSP SSM/I Daily Polar Gridded Brightness Temperatures Near Real-Time DMSP SSM/I Daily Polar Gridded Sea Ice Concentrations Snow Melt Onset Over Arctic Sea Ice from SMMR and SSM/I Brightness Temperatures AMSR-E/Aqua Daily L3 25 km Brightness Temperature & Sea Ice Concentration Polar Grids |
| Description | Grids that determine the longitude of a given
pixel for the 25 km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). These longitude
grids are in binary format and are stored as 4-byte
integers (little endian) scaled by 100,000 (divide the stored
value by 100,000 to get decimal degrees). Each array location
(i, j) contains the longitude value at the center of the corresponding
data grid cells. An East-longitude convention is used; therefore, positive longitude values are to the east of Greenwich, England. psn25lons_v2.dat: 304 columns x 448 rows, range = [-180.0000, 179.8140] pss25lons_v2.dat: 316 columns x 332 rows, range = [-179.8181, 179.8181] |
| Access | Brightness Temperature Data Sets:
FTP Sea Ice Data Sets: FTP |
The pixel-area tools that are availabe are the following:
Please note that the data ranges given here are latitude and longitude values for the center of each grid cell. The range covered by the full grid extends to the pole (90 degrees latitude) and all longitudes (0 to 360 degrees longitude). Also note that corrected grids for the northern hemisphere were created June 22, 1999 and should replace the three psn25*.dat files that were distributed prior to this date.
To determine the lat/lon values of corresponding (i,j) data grid cells:
| Tool Name | psn06area_v2.dat and pss06area_v2.dat |
|---|---|
| Applicable Data Sets | AMSR-E/Aqua Daily L3 6.25 km 89 GHz Brightness Temperature Polar Grids |
| Description | Grids that determine the area of a given pixel for the 6.25
km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). The arrays are in binary format
and are stored as 4-byte integers scaled by 1000 (divide by 1000 to get square km).
psn06lons_v2.dat: 1216 columns x 1792 rows pss06lons_v2.dat: 1264 columns x 1328 rows |
| Access | FTP |
| Tool Name | psn12area_v2.dat and pss12area_v2.dat |
|---|---|
| Applicable Data Sets | DMSP SSM/I Daily Polar Gridded Brightness Temperatures
Near Real-Time DMSP SSM/I Daily Polar Gridded Brightness Temperatures AMSR-E/Aqua Daily L3 12.5 km Brightness Temperature, Sea Ice Concentration, & Snow Depth Polar Grids |
| Description | Grids that determine the area of a given pixel for the 12.5
km grids for either hemisphere (psn for the Northern Hemisphere and pss for the Southern Hemisphere). The arrays are in binary format
and are stored as 4-byte integers scaled by 1000 (divide by 1000 to get square km).
psn12area_v2.dat: 608 columns x 896 rows pss12area_v2.dat: 632 columns x 664 rows |
| Access | Brightness Temperature Data Sets:
FTP Sea Ice Data Sets: FTP |
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