File naming conventions:
[p][ft]_[by][ey][bm]-[em].dat
where:
[p] - parameter (s - salinity anomaly)
[ft] - file type (an,dd,sd,gp)
[by] - last two digits of beginning year
[ey] - last two digits of ending year
[bm] - two digits of beginning month
[em] - two digits of ending month
Note: year 2000 is presented as A0, 2001 is A1, etc.
year 2010 is presented as B0, 2011 is B1, etc.
year 2020 is presented as C0, 2021 is C1, etc.
