This dataset depends on the following independent variable (i.e, grid):
grid: /P (mb) ordered [ (1000) (925) (850) (700) (600) (500) (400) (300) (250) (200) (150) (100)] :grid
grid: /T (months since 01-Jan) periodic (16 Jan - 15 Feb) to (16 Dec - 15 Jan) by 1.0 N= 12 pts :grid
so there will be 144 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://maproom.meteorwanda.gov.rw/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.MONTHLY/.Intrinsic/.PressureLevel/.CBTW/decompress/yearly-climatology/%5BT%5Ddifferences/%5BP+%5Ddetrend-bfl/downloadsarcinfo.html'
single quotes are necessary in unix to protect the url from expansion; probably necessary in other cases as well