In order to carry out the analysis of the rainfall
over the country as a whole has been expressed as
a linear combination of orthogonal functions. Let
P be a n  m matrix of monsoon rainfall over m
stations and a series of n years. In the present
study, n ˆ 41 years, and m ˆ 68 stations. Let P
represents the time and space variability of
rainfall. It has been de®ned that
P ˆ Q F;
…1†
where the matrix Q represents the time variation
and F represent the space variation of monsoon
rainfall. The element of the P matrix is given by
mX
qr;k …t† Â fks …x; y†;…2†Prs …x; y; t† ˆ
k ˆ1
where the element qrk …t† represents the time, and
fks …x; y† represents the space, respectively. The
matrix F is orthogonal matrix, hence the transpose
and product of this matrix should be represented
as a unique identity matrix. It has de®ne that
F FH ˆ I;