CDO calculate wind speed from U,V
Climate Data Operators (CDO) is a powerful software for climate data analysis. It can perform numerous operations on climate data sets. The following example lets you calculate wind speed from u, v components. uv.nc is the input data set which contains of u and v wind components. output wind speed will be written in ws.nc.
cdo chname,u,ws -sqrt -add -sqr -selname,u uv.nc -sqr -selname,v uv.nc ws.nc