There is no existing program to take observational data for input to HYSPLIT. HYSPLIT requires gridded 4 dimensional fields (x,y,z,t) of the meteorological variables. Data interpolation can be a tricky process and we felt that most simple interpolation techniques due not properly address the problem. Others in your situation use a meteorological model, such as RAMS or MM5, to assimilate observational data into a gridded framework that is consistent with atmospheric dynamics.
Roland Draxler
02/2003