Remote Sensing Systems publishes CCMP as a plain directory tree over HTTPS, one file per day. No account is needed for it: the registration RSS asks for covers their FTP service, and the HTTPS archive is open.
Value
a named list, one entry per version, each with root, pattern,
step_hours, start, resolution, and reference
Examples
names(ccmp_versions())
#> [1] "v03.1"
ccmp_versions()$v03.1$step_hours
#> [1] 6