use Modern::Perl '2014';

my @data;
<DATA>;    # discard header line
while (<DATA>) {
    chomp;
    last if $_ eq 'END PARAMETERS';    # end of data marker, not necessary if reading from a file
    my ( $station, @fields ) = split /,/;
    $data[$station] = \@fields;
}
<DATA>;                                # discard header line
while (<DATA>) {
    chomp;
    my ( $station, $level ) = split /,/;
    say
"Station $station: salinity $level is $data[$station][$level-10] and temperature $level is $data[$station][$level-4]";
}

__DATA__
Station,S_10,S_11,S_12,S_13,S_14,S_15,T_10,T_11,T_12,T_13,T_14,T_15
1,31,29,29,31,29,29,15,14,23,15,14,23
2,33,28,23,33,28,23,17,15,23,17,15,23
3,23,27,33,23,27,33,18,16,23,18,16,23
4,25,26,28,25,26,28,23,14,15,23,14,15
5,26,26,27,26,26,27,23,18,17,23,18,17
6,27,33,31,27,33,31,14,17,18,14,17,18
7,33,29,29,33,29,29,12,18,23,12,18,23
END PARAMETERS
Station,Code
1,10
2,11
3,12
4,13
5,14

##</code><code>##

Station 1: salinity 10 is 31 and temperature 10 is 15
Station 2: salinity 11 is 28 and temperature 11 is 15
Station 3: salinity 12 is 33 and temperature 12 is 23
Station 4: salinity 13 is 25 and temperature 13 is 23
Station 5: salinity 14 is 26 and temperature 14 is 18