data sets / data streams to consider adding

[gaelforget]

• earthdata, PODAAC access examples
• sea ice, GRACE
• reference indices such as ENSO, PDO, NAO, etc
• global mean surface temperature (not SST)
• more atmospheric variables (ERA5, MERRA2)
• data lakes in the cloud (AWS, Google, etc)
• STAC.jl examples

ps. if you are willing to get started on any of these, please feel free to open another issue to discuss more specifically (before sending a PR as much as possible), or just use this issue as a catch-all