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Q1) Please tell me the difference between sunshine (daytime) and shade (nighttime), ascending and descending.

 [Sunshine/Shade]

Sunshine areas are sunshine, and shade areas are vice versa.

 [Ascending/Descending]

The definition of the satellite orbit (orbit) refers to the half orbit from the northernmost point to the southernmost point.
①Ascending: Southernmost to northernmost (satellite is moving northward)
②Descending: Northernmost point to southernmost point (satellite is moving southward)
In the ascending orbit, the path number changes with the equator crossing as the starting point.

Q2) Please tell me the relationship between D and N in L1B and shade/sunshine.

"D" and "N" of L1B are as follows.
D: This data has VNR observation data
N: This data has no VNR observation data See here for satellite observation mode transitions.

Q3) Are D and N of L1B Orbit_direction and Granule_ID the same?

D and N of L1B Orbit_direction and Granule_ID are different.
The stored value of Orbit_direction changes depending on the scene number.
"Descending" in Scenes 07-18
"Ascending" in Scenes 01-06, 19-24
The sunshine/shade identifier of Granule_ID is determined by the presence or absence of observation data.

Ex: GC1SG1_202207180125Q05406_1BSG_VNRDK_2006.h5
→ The observation trajectory (Orbit_direction) is "Ascending", but since there is observation data, the sunshine/shade discrimination of Granule_ID is "D".

Q4) What is the difference between SSTD and SSTN?

"SSTD" and "SSTN" change depending on the input of L1B (VNR) used for processing.
SSTD: one with VNR in input
SSTN: Inputs that do not contain VNR

Q5) What is the difference between A/D of the tile product and D/N of the scene product?

The A/D of the tile product is defined by the half orbit explained in above 1). Therefore, it differs from the scene D/N (sunshine/shade) explained in above 2).

Last update: 2022/08/05