Hello everyone,

I am currently a beginner working on GOSAT TANSO-FTS data for CO₂ retrieval using machine learning (SWIR-based XCO₂ inversion). I am trying to build a dataset using Level-1B data, but I am confused about how to properly download the 1BOA product from the official sources.

📍 What I have already tried

I have accessed the GOSAT data portal and found multiple L1B products, including:

1BOA
1BOB
other L1B variants (depending on date/version)

However, I am not sure:

1.which exact product corresponds to SWIR full spectra (band1/band2)
2.whether 1BOA is required for SWIR-based CO₂ retrieval
3.how to ensure I download the complete and correct 1BOA dataset
❓ My questions
1.What is the correct procedure to download GOSAT L1B 1BOA data step by step?
2.Is 1BOA the recommended product for SWIR XCO₂ retrieval?
3.Are there differences in SWIR data availability between 1BOA and 1BOB?
4.On the data portal, some files seem incomplete or inconsistent — how can I verify I am downloading the correct 1BOA dataset?
5.Is there any official documentation or script for batch downloading 1BOA data?
🧠 My background
I am using Python (h5py, numpy, sklearn)
I am currently working on:
L1B spectrum extraction
L1–L2 matching
Random Forest XCO₂ retrieval
My goal is to build a reproducible SWIR-based CO₂ inversion model
📎 Example of my current issue

When I load L1B files, I can successfully extract TIR data using:

“/spectrum/TIR/band4_Finite_IFOV_Corr/observedSpectrum_Finite_IFOV_Corr”

But I cannot clearly find or extract SWIR band1/band2 data in some 1BOB files, which makes me suspect that I may be using the wrong product or missing the correct 1BOA dataset.

🙏 Request

I would really appreciate any guidance, including:

1.correct download link or workflow
2.official documentation
3.examples of downloaded 1BOA file structure
4.or any scripts used by the community

Thank you very much for your time and help!