NASA’s Earth Science Data Systems (ESDS) Program oversees the life cycle of NASA’s Earth science data—from acquisition through processing and distribution. Since 1994, Earth science data has been free and open to all users for any purpose, and since 2015, all data systems software developed through research and technology awards have been made available to the public as Open Source Software (OSS).
Users can browse data by topics including atmosphere, biosphere, cryosphere, human dimension, land surface, ocean, solid earth, sun-earth interactions, and terrestrial hydrosphere. Data is available in many formats including GIS raster and vector formats, excel or CSV, images such as jpeg and png, and many others. Each dataset has additional documentation, often including user guides. This instructional webinar from NASA may also be helpful.