; ===============================================================================
function filename_3e,hem,year,version,revision,station_number,tag_preliminary
; ===============================================================================
    ; This function constructs the level 3e file name given the 
    ; following input:
    ;
    ;              hem    hemisphere ('north' or 'south')        string
    ;             year    year (e.g. '2009')                     string
    ;          version    CIPS data version # (e.g., '05.20')    string
    ;         revision    CIPS data revision # (e.g., '05')      string
    ;   station_number    Unique station index number           integer
    ; -----------------------------------------------------------------

    y1=strmid(strtrim(year,2),2,2)
    y2=strmid(strtrim(year+1,2),2,2)

    if(hem eq 'south') then season=hem+'_'+y1+y2 else season=hem+'_'+y1

    number_str=strtrim(station_number,2)
    if(station_number lt 10) then number_str='0'+number_str

    if (tag_preliminary) then $
      file='cips_3e_'+season+'_v'+version+'_r'+revision+'_station_'+number_str+'_prelim.preliminary.txt' $
    else $
      file='cips_3e_'+season+'_v'+version+'_r'+revision+'_station_'+number_str+'.txt'

    return,file
end