Level-3 25 km Brightness Temperature & Sea Ice Concentration Data Fields

The following notations are used throughout this document:

Int8 8-bit (1-byte) signed integer
Int16 16-bit (2-byte) signed integer
NT2 Enhanced NASA Team algorithm
ABA AMSR Basic Algorithm

North polar grids are 304 pixels by 448 pixels.
South polar grids are 316 pixels by 332 pixels.

North Polar Grids

Parameter

Data Type

Description

Scale Factor
SI_25km_NH_06V_ASC Int16

6.9 GHz vertical, daily average ascending Brightness Temperatures (Tbs)

Valid range: approximately 50 to 300 kelvin (K)

 Multiply data values by 0.1 to obtain units in kelvin (K)
SI_25km_NH_06V_DSC Int16

6.9 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_06V_DAY Int16

6.9 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_06H_ASC Int16

6.9 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_06H_DSC Int16

6.9 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_06H_DAY Int16

6.9 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_10V_ASC Int16

10.7 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_10V_DSC Int16

10.7 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_10V_DAY Int16

10.7 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_10H_ASC Int16

10.7 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_10H_DSC Int16

10.7 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_10H_DAY Int16

10.7 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_18V_ASC Int16

18.7 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_18V_DSC Int16

18.7 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_18V_DAY Int16

18.7 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_18H_ASC Int16

18.7 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_18H_DSC Int16

18.7 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_18H_DAY Int16

18.7 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_23V_ASC Int16

23.8 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_23V_DSC Int16

23.8 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_23V_DAY Int16

23.8 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_23H_ASC Int16

23.8 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_23H_DSC Int16

23.8 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_23H_DAY Int16

23.8 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_36V_ASC Int16

36.5 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_36V_DSC Int16

36.5 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_36V_DAY Int16

36.5 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_36H_ASC Int16

36.5 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_36H_DSC Int16

36.5 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_36H_DAY Int16

36.5 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_89V_ASC Int16

89.0 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_89V_DSC Int16

89.0 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_89V_DAY Int16

89.0 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_89H_ASC Int16

89.0 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_89H_DSC Int16

89.0 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_89H_DAY Int16

89.0 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_NH_ICECON_ASC Int16 Sea ice concentration, daily ascending average

Value

Description
0 Open Water
1 to 100 Percent Ice Concentration
120 Land Mask
N/A
SI_25km_NH_ICECON_DSC Int16 Sea ice concentration daily descending average

Value

Description
0 Open Water
1 to 100 Percent Ice Concentration
120 Land Mask
N/A
SI_25km_NH_ICECON_DAY Int16 Sea ice concentration daily average

Value

Description
0 Open Water
1 to 100 Percent Ice Concentration
120 Land Mask
N/A
SI_25km_NH_ICEDIFF_ASC Int16 Sea ice concentration daily ascending average, using the difference between ABA and NT2 algorithms

Value

Description
0 Open Water
1 to 100 or -1 to -100 Percent Difference Between Algorithms*
120 Land Mask
200 to 300 Missing NT2 value (200+ABA)**
-200 to -300 Missing ABA value (-200-NT2)**
N/A
SI_25km_NH_ICEDIFF_DSC Int16 Sea ice concentration daily descending average, using the difference between ABA and NT2 algorithms

Value

Description
0 Open Water
1 to 100 or -1 to -100 Percent Difference Between Algorithms*
120 Land Mask
200 to 300 Missing NT2 value (200+ABA)**
-200 to -300 Missing ABA value (-200-NT2)**
N/A
SI_25km_NH_ICEDIFF_DAY Int16 Sea ice concentration daily average, using the difference between ABA and NT2 algorithms

Value

Description
0 Open Water
1 to 100 or -1 to -100 Percent Difference Between Algorithms*
120 Land Mask
200 to 300 Missing NT2 value (200+ABA)**
-200 to -300 Missing ABA value (-200-NT2)**
N/A

* Positive values 1 to 100% represent the difference in concentration where NT2 is greater than BBA and negative values -1 to -100% represent the difference in concentration where BBA is greater than NT2.

**The difference values need input from both the NT2 and ABA sea ice concentration algorithms. These new values indicate when one of these is missing. If there is a valid ABA value and missing NT2, it takes on the value 200+ABA. Like wise, a valid NT2 and missing ABA takes on the value -200-NT2. A difference value of 200 means the ABA was open water and the NT2 was missing; a value of 225 means the ABA was 25% and the NT2 was missing. So I guess a value of 300 means ABA was 100 and NT2 was missing. The normal range of difference values is -100 to 100.

South Polar Grids

Parameter

Data Type

Description

Scale Factor
SI_25km_SH_06V_ASC Int16

6.9 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 kelvin (K)

 Multiply data values by 0.1 to obtain units in kelvin (K)
SI_25km_SH_06V_DSC Int16

6.9 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_06V_DAY Int16

6.9 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_06H_ASC Int16

6.9 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_06H_DSC Int16

6.9 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_06H_DAY Int16

6.9 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_10V_ASC Int16

10.7 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_10V_DSC Int16

10.7 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_10V_DAY Int16

10.7 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_10H_ASC Int16

10.7 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_10H_DSC Int16

10.7 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_10H_DAY Int16

10.7 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_18V_ASC Int16

18.7 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_18V_DSC Int16

18.7 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_18V_DAY Int16

18.7 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_18H_ASC Int16

18.7 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_18H_DSC Int16

18.7 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_18H_DAY Int16

18.7 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_23V_ASC Int16

23.8 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_23V_DSC Int16

23.8 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_23V_DAY Int16

23.8 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_23H_ASC Int16

23.8 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_23H_DSC Int16

23.8 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_23H_DAY Int16

23.8 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_36V_ASC Int16

36.5 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_36V_DSC Int16

36.5 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_36V_DAY Int16

36.5 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_36H_ASC Int16

36.5 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_36H_DSC Int16

36.5 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_36H_DAY Int16

36.5 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_89V_ASC Int16

89.0 GHz vertical, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_89V_DSC Int16

89.0 GHz vertical, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_89V_DAY Int16

89.0 GHz vertical, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_89H_ASC Int16

89.0 GHz horizontal, daily average ascending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_89H_DSC Int16

89.0 GHz horizontal, daily average descending Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_89H_DAY Int16

89.0 GHz horizontal, daily average Tbs

Valid range: approximately 50 to 300 K

 Multiply data values by 0.1 to obtain units in K
SI_25km_SH_ICECON_ASC Int16 Sea ice concentration, daily ascending average

Value

Description
0 Open Water
1 to 100 Percent Ice Concentration
110 Not Calculated
120 Land Mask
N/A
SI_25km_SH_ICECON_DSC Int16 Sea ice concentration daily descending average

Value

Description
0 Open Water
1 to 100 Percent Ice Concentration
110 Not Calculated
120 Land Mask
N/A
SI_25km_SH_ICECON_DAY Int16 Sea ice concentration daily average 

Value

Description
0 Open Water
1 to 100 Percent Ice Concentration
110 Not Calculated
120 Land Mask
N/A
SI_25km_SH_ICEDIFF_ASC Int16 Sea ice concentration daily ascending average, using the difference between ABA and NT2 algorithms

Value

Description
0 Open Water
1 to 100 or -1 to -100 Percent Difference Between Algorithms*
110 Not Calculated
120 Land Mask
200 to 300 Missing NT2 value (200+ABA)**
-200 to -300 Missing ABA value (-200-NT2)**
N/A
SI_25km_SH_ICEDIFF_DSC Int16 Sea ice concentration daily descending average, using the difference between ABA and NT2 algorithms

Value

Description
0 Open Water
1 to 100 or -1 to -100 Percent Difference Between Algorithms*
110 Not Calculated
120 Land Mask
200 to 300 Missing NT2 value (200+ABA)**
-200 to -300 Missing ABA value (-200-NT2)**
N/A
SI_25km_SH_ICEDIFF_DAY Int16 Sea ice concentration daily average, using the difference between ABA and NT2 algorithms

Value

Description
0 Open Water
1 to 100 or -1 to -100 Percent Difference Between Algorithms*
110 Not Calculated
120 Land Mask
200 to 300 Missing NT2 value (200+ABA)**
-200 to -300 Missing ABA value (-200-NT2)**
N/A

* Positive values 1 to 100% represent the difference in concentration where NT2 is greater than BBA and negative values -1 to -100% represent the difference in concentration where BBA is greter than NT2.

**The difference values need input from both the NT2 and ABA sea ice concentration algorithms. These new values indicate when one of these is missing. If there is a valid ABA value and missing NT2, it takes on the value 200+ABA. Like wise, a valid NT2 and missing ABA takes on the value -200-NT2. A difference value of 200 means the ABA was open water and the NT2 was missing; a value of 225 means the ABA was 25% and the NT2 was missing. So I guess a value of 300 means ABA was 100 and NT2 was missing. The normal range of difference values is -100 to 100.