A vertical cross section along 05N is shown, depicting the winds and isotherms of potential temperature in degrees K at an interval of 2 degrees.  A circulation is evident aloft above 500 hPa, and along 40W/43W.  Evaluation of the horizontal temperature gradient shows a gradual decrease in temperature towards the axis of the circulation as we near 42W/43W.  This suggests that the circulation has cold core characteristics.