The mass stream function of mean meridional circulation is calculated from the ECMWF and NCEP/NCAR reanalysis data sets using a superposition computation scheme. The comparison of results shows that the common ascending leg of the Hadley cell calculated from the ECMWF data is strong and narrow, and averagely lies more north of the equator in comparison with its counterpart from the NCEP/NCAR data, and furthermore the Hadley cell from the ECMWF data shows an obvious double-layer structure. Therefore, there are obvious differences between Hadley cells displayed by the two objective analysis data sets.
