CASTf90 (Circulation Analogue Simulation Tool in Fortran90) is a suite of shell script (sh) with ncks/nco and cdo commands, and a fortran90 program. CASTf90 first downloads fields from NCEP reanalysis ("surface" variables or variables on pressure levels, sea level pressure, slp, is the default) and then searches for a given simulation period the most similar cases within a given data base period according to a given distance (default is rms) measure. Finally it writes the N most similar days including the calculated distances for them to an output file.
The fortran program can run in parallel with shared memory using openMP. The purpose is the same as for "Analogue software", but it can do the calculations somewhat faster and comes with some options that allow for more flexibility in terms of time periods, variables and distances. For details see howto.pdf.
The programme is provided as is. It is free for academic use.
Please contact Pascal Yiou for a commercial use.