Snow and Ice Physical Properties (SIPR)

Introduction

SIPR Define Grain size of snow ice particle in shallow layer derived mainly from SGLI 865nm band reflectance.
Unit μm
ATBD Ver.1 (Mar. 2016)
Ver.2 (May. 2020)

Update contents of Ver2

  • ・Improved algorithm for solving snow particle size
  • ・Update table of emissivity

Stored Physical quantity

Ver1,2 Description
SGSL Snow grain size of shallow layer
SIST Snow and ice surface temperature based on a model snow
QA_flag

QA_flag information

Ver.1 Ver.2 Ver.1(Sample Image) Ver.2(Sample Image)

Bit ver1 Description SGSL_L3_mask* SIST_L3_mask*
0 no input data 1 1
1 land/water flag 0 0
2 cloudy/clear flag 0 0
3 day/night(shadow) flag 0 0
4 snow over land or seaice 1 1
5 snow mixed w/t vegetation or bare ice 1 1
6 melting snow over land or seaice 1 1
7 stray light correction (VN) 0 0
8 stray light correction (SW) 0 0
9 stray light correction (IR) 0 0
10 radiance saturation 0 0
11 sun-glint area 0 0
12 missing channel(VN) 0 0
13 missing channel(SW) 0 0
14 missing channel(IR) 0 0
15 reserved - -

* Bits masked by statistical processing are indicated by 1.

Bit ver2 Description SGSL_L3_mask* SIST_L3_mask*
0 no input data 1 1
1 land/water flag 0 0
2 cloudy/clear flag 1 1
3 day/night(shadow) flag 1 1
4 snow over land or seaice 111 no snow 1 1
5 snow mixed w/t vegetation or bare ice 1 1
6 melting snow over land or seaice 1 1
7 stray light correction (VN) 0 0
8 stray light correction (SW) 0 0
9 stray light correction (IR) 0 0
10 radiance saturation 0 0
11 sun-glint area 0 0
12 missing channel(VN) 0 0
13 missing channel(SW) 0 0
14 missing channel(IR) 0 0
15 reserved - -

* Bits masked by statistical processing are indicated by 1.

*Download:QA_flag(Ver1) Sample Image
*Download:QA_flag(Ver2) Sample Image

Attribute information

Ver.1 Ver.2

Ver1 Attribute Remarks
Attribute of Image_data
Attribute of Image_data Number_of_lines 4800 250m: 4800
1km: 1200
Number_of_pixels 4800
Grid_interval 0.00208333 250m: 0.00208333
1km: 0.00833333
Grid_interval_unit deg
Image_projection L1B reference grid
Lower_left_latitude 40 Variable
Lower_left_longitude 130.541
Lower_right_latitude 40
Lower_right_longitude 143.595
Upper_left_latitude 50
Upper_left_longitude 155.572
Upper_right_latitude 50
Upper_right_longitude 171.13
SGSL
SGSL
16-bit unsigned integer		 Slope 0.08
Offset 20
Data_description Snow grain size of shallow layer (SGSL): SGSL = slope*DN + offset
Unit micrometer
Maximum_valid_DN 62250
Minimum_valid_DN 0
Error_DN 65535
No_retrieval_DN_(night) 65534
No_retrieval_DN_(no_main_VN_SW_channels) 65533
No_retrieval_DN_(no_main_IR_channels) 65532
No_retrieval_DN_(out_of_parameter_range) 65531
Mask_for_statistics 113 Detail: QA_flag_information(～L3_mask)
SIST
SIST
16-bit unsigned integer		 Slope 0.0005525
Offset 240
Data_description Snow and ice surface temperature based on a model snow (SIST): SIST = slope*DN + offset
Unit kelvin
Maximum_valid_DN 59999
Minimum_valid_DN 0
Error_DN 65535
No_retrieval_DN_(night) 65534
No_retrieval_DN_(no_main_VN_SW_channels) 65533
No_retrieval_DN_(no_main_IR_channels) 65532
No_retrieval_DN_(out_of_parameter_range) 65531
Mask_for_statistics 113 Detail: QA_flag_information(～L3_mask)
Ver2 Attribute Remarks
Attribute of Image_data
Attribute of Image_data Number_of_lines 4800 250m: 4800
1km: 1200
Number_of_pixels 4800
Grid_interval 0.00208333 250m: 0.00208333
1km: 0.00833333
Grid_interval_unit deg
Image_projection L1B reference grid
Lower_left_latitude 40 Variable
Lower_left_longitude 130.541
Lower_right_latitude 40
Lower_right_longitude 143.595
Upper_left_latitude 50
Upper_left_longitude 155.572
Upper_right_latitude 50
Upper_right_longitude 171.13
SGSL
SGSL
16-bit unsigned integer		 Slope 0.08
Offset 20
Data_description Snow grain size of shallow layer (SGSL): SGSL = slope*DN + offset
Unit micrometer
Maximum_valid_DN 62250
Minimum_valid_DN 0
Error_DN 65535
No_retrieval_DN_(night) 65534
No_retrieval_DN_(no_main_VN_SW_channels) 65533
No_retrieval_DN_(no_main_IR_channels) 65532
No_retrieval_DN_(out_of_parameter_range) 65531
Mask_for_statistics 125 Detail: QA_flag_information(～L3_mask)
SIST
SIST
16-bit unsigned integer		 Slope 0.0005525
Offset 240
Data_description Snow and ice surface temperature based on a model snow (SIST): SIST = slope*DN + offset
Unit kelvin
Maximum_valid_DN 59999
Minimum_valid_DN 0
Error_DN 65535
No_retrieval_DN_(night) 65534
No_retrieval_DN_(no_main_VN_SW_channels) 65533
No_retrieval_DN_(no_main_IR_channels) 65532
No_retrieval_DN_(out_of_parameter_range) 65531
Mask_for_statistics 125 Detail: QA_flag_information(～L3_mask)

How to use

  • ・Physical quantity＝DN*slope + offset
  • ・Valid values are during Minimum_valid_DN～Maximum_valid_DN

  • ・Snow and Ice Physical Properties (SIPR) algorithm has the following restrictions.(2020/07/28 Update)
    - In Snow grain size of shallow layer (SGSL) and Snow and ice surface temperature (SIST) products, the incorrect values are stored in QA flag of some tiles, and the incorrect values are stored in the statistical product.
    - Level2 SIPR,
    - Level2 Tile statistics SIPR (SGSL, SIST)
    - Level3 (SGSL, SIST)
    Product version: Ver.2 (2000)