Mercury downloads radiosounding data for a specified station at specified dates from the University of Wyoming1.
import mercury
mercury.mercury(station_id='YPDN', bg_date='20140201', end_date='20140228')
It will download and save all radiosounding data for the Darwin (Australia) station between 1-Feb-2014 and 28-Feb-2014.
If you want to know the list of available station and their id, just type:
mercury.station_list()