A vertical cross section along 05N is shown, depicting the winds, negative relative vorticity contoured in red and positive relative vorticity contoured in blue, and isotherms of potential temperature in degrees K contoured in cyan at an interval of 2 degrees..  The negative vorticity is increasing with height along the axis of circulation between 400-200 hPa.  This is the same area where the isotherms of potential temperature suggest that the circulation might have cold core characteristics.  Thus in this case, the negative vorticity along the circulation axis might correlate with cyclonic vorticity rather than anticyclonic vorticity as one might expect from a northern hemisphere system.