The programme is a suite of scripts in shell script (sh) with ncks/nco and cdo commands, and an R script. The programme downloads and concatenates NCEP reanalysis SLP for the North Atlantic region, then computes the analogues for various distance/metrics (rms, correlations...). It runs on linux or macosX computers. It is more comfortable to have a powerful multicore computer to do the job.
By default, the analogues are computed by minimizing an rms (or Euclidean) distance. 20 "best" analogues are computed for each day between 1st Jan. 1948 and the current day. The analogues are taken from a different year than the "target" day, and are separated by at most 30 calendar days.
The R code can run in parallel on multicore computers (with the "parallel" package). It has been tested on our computing cluster with n=12 processors.
The programme is provided as is. It is free for academic use. Please contact Pascal Yiou for a commercial use. The suite of programmes is available here.
Yiou, P., T. Salameh, P. Drobinski, L. Menut, R. Vautard, and M. Vrac, 2013 : Ensemble reconstruction of the atmospheric column from surface pressure using analogues. Clim. Dyn., 41, 1419-1437. [.pdf]
A web processing service (WPS) that allows you to compute analogues, weather regimes, and much more, on reanalyses or model simulations has been developed for the A2C2 project. This WPS is called flyingpidgeon. It is compatible with a wider ecosystem of WPS (the birdhouse).
We also developed an analogue viewer, for a quick visualisation of the computation of analogues. Its experimental form can be obtained at:
Web Processing Service "blackswan"
The analogues can also be computed "online" from the "blackswan" WPS that is available on github.