This program unfolds the velocity in a scanning 3-GHz netCDF data file. It operates on the v2 variable (the Doppler velocity calculated using both the H and V pulses, which folds at ±15 m s-1), and overwrites v1 with a new variable, v_unfolded. The original v2 is left unchanged except that it is renamed v. The v_unfolded parameter also has noise removed, and this is used as a mask to also clean up phi_dp, if present.
The algorithms to unfold and clean the data were written in Fortran by Danny Chapman, originally as `mex' functions for Matlab. The user should be aware that they sometimes unfold regions incorrectly, which is why the original folded data is left in the file. A few modifications to the algorithm by Robin Hogan have reduced the frequency that this occurs. The algorithm is in the libdan directory.
chilunfold [options] file1.dat [file2.dat ...]