雪氷特性 (SIPR)

概要

SIPR 定義 波長865nmの反射率をもとに抽出する積雪の浅い層に存在する氷結晶の粒径
単位 μm
ATBD Ver.1 (Mar. 2016)
Ver.2 (May. 2020)

Ver2での変更点

  • ・積雪粒径求解アルゴリズム改良
  • ・射出率テーブル更新

格納物理量

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情報

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 - -

* 1は統計処理時にマスクされるBitを意味します。

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 - -

* 1は統計処理時にマスクされるBitを意味します。

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

Attribute情報

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 詳細: QA_flag情報(~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 詳細: QA_flag情報(~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 詳細: QA_flag情報(~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 詳細: QA_flag情報(~L3_mask)

使い方

  • ・物理量=DN*slope+offset
  • ・有効値はMinimum_valid_DN~Maximum_valid_DN

  • ・雪氷特性 (SIPR)アルゴリズムに以下の制約があります。(2020年7月28日追記)
    雪氷特性 (SIPR)の一部タイルのQAフラグに不正な値が入り、L2統計・L3マッププロダクトに意図しない値が格納される。
    [影響範囲]
    対象プロダクト:L2 SIPR, L2タイル時間統計SIPR(SGSL, SIST), L3(SGSL,SIST)
    プロダクトバージョン:Ver.2(2000)