Very cool! Random weird suggestion: you could get very substantial further space savings (2x-16x) by storing the data in a compressed texture format such as ASTC HDR. What makes compressed textures different from other compressed image formats is that they are designed for random access of the compressed data, with fixed size blocks. Compression is lossy but you can choose the compression level to match your data. I expect that weather data is very suitable for compression so you should be able to get a large benefit with few artifacts.