This dataset depends on the following independent variable (i.e, grid):
grid: /T (months since 1960-01-01) periodic [ (0000 1 Jan - 0000 11 Jan) (0000 11 Jan - 0000 21 Jan) (0000 21 Jan - 0000 11 Feb) (0000 11 Feb - 0000 21 Feb) (0000 21 Feb - 0000 1 Mar) (0000 1 Mar - 0000 11 Mar) (0000 11 Mar - 0000 21 Mar) (0000 21 Mar - 0000 1 Apr) (0000 1 Apr) (0000 1 Apr - 0000 11 Apr) (0000 11 Apr - 0000 21 Apr) (0000 21 Apr - 0000 11 May) (0000 11 May - 0000 21 May) (0000 21 May - 0000 1 Jun) (0000 1 Jun - 0000 11 Jun) (0000 11 Jun - 0000 21 Jun) (0000 21 Jun - 0000 1 Jul) (0000 1 Jul) (0000 1 Jul - 0000 11 Jul) (0000 11 Jul - 0000 21 Jul) (0000 21 Jul - 0000 11 Aug) (0000 11 Aug - 0000 21 Aug) (0000 21 Aug - 0000 1 Sep) (0000 1 Sep) (0000 1 Sep - 0000 11 Sep) (0000 11 Sep - 0000 1 Oct) (0000 1 Oct) (0000 1 Oct - 0000 11 Oct) (0000 11 Oct - 0000 21 Oct) (0000 21 Oct - 0000 11 Nov) (0000 11 Nov) (0000 11 Nov - 0000 21 Nov) (0000 21 Nov - 0000 11 Dec) (0000 11 Dec - 0000 21 Dec) (0000 21 Dec - 0000 1 Jan)] :grid
so there will be 35 links below for the different files.
You may want to get a utility like wget which can download sets of files. For example (all one line)
wget -r -l2 -nd --no-parent -e robots=off -v --relative 'http://digilib.icpac.net/SOURCES/.ENACTS/.version0/.dekadal/.rainfall/.rfe_merged_vs_meanrfe_merged/yearly-climatology/X+partial/T+partial/T+differences/%5BY+T+%5Ddetrend-bfl/downloadsarcinfo.html'
single quotes are necessary in unix to protect the url from expansion; probably necessary in other cases as well