Description 
[curlz,cav] = curlm(lat,lon,U,V) computes the curl of U and V given their geographical coordinates lat and lon. lat, lon, U, and V must be m by n matrices of the same size. Coordinates given by lat and lon must be regular grids of latitudes and longitudesthat is, they must be separated as 120E, 121E, 123E, etc, not equally spaced in terms of kilometers of separation.
