Phil - downloaded the 3hourly Ap and Kp from

ftp://ftp.ngdc.noaa.gov/STP/GEOMAGNETIC_DATA/INDICES/KP_AP/

Need to then use Excel to strip out the required columns which are the
year, month, day, 3 hourly and daily Ap values. Store in files with
name a####.txt (#### = year) using tab delimited format. Then run apfile.m
followed by apmsis4.m.