FAQ
Q
About flag and mask processing
A
SHIKISAI products store information indicating quality (QA flag) for each pixel. QA flags are information that indicates missing data, the presence or absence of clouds, land and sea, etc., and can be masked to extract pixels depending on the purpose.
Mask values are also set in the physical quantity data. Specifically, L2 and L3 products are masked by statistical information, and L1B, LTOAQ, LTOAK, LTOAF, and LCLRF products have a stray light flag added to the upper bits of the physical quantity data.
The definition of QA flag differs depending on each products.
For details, please check the attributes of each products on JAXA / EORC HP and "SGLI Higher Level Product Format Description". For application of QA flag, please refer "Application of QA flag" in Material "SHIKISAI Product User's Guide (Introduction)" and the following the material. Also, please note that for the L3 statistical product SST, the QA flag is different for [1-day statistics] and [8-day statistics, 1-month statistics]. Please also have a look at the materials below.
In addition, the L1 product stores information such as Disturbance flag (stored in another array, Please see Q37 for details.), which indicates the status of satellites and sensors. Note that these flags are not assigned per pixel.Please see "SGLI Level1 Product Format Description".
Mask values are also set in the physical quantity data. Specifically, L2 and L3 products are masked by statistical information, and L1B, LTOAQ, LTOAK, LTOAF, and LCLRF products have a stray light flag added to the upper bits of the physical quantity data.
The definition of QA flag differs depending on each products.
For details, please check the attributes of each products on JAXA / EORC HP and "SGLI Higher Level Product Format Description". For application of QA flag, please refer "Application of QA flag" in Material "SHIKISAI Product User's Guide (Introduction)" and the following the material. Also, please note that for the L3 statistical product SST, the QA flag is different for [1-day statistics] and [8-day statistics, 1-month statistics]. Please also have a look at the materials below.
In addition, the L1 product stores information such as Disturbance flag (stored in another array, Please see Q37 for details.), which indicates the status of satellites and sensors. Note that these flags are not assigned per pixel.Please see "SGLI Level1 Product Format Description".
Last update: 2024/10/28