The Hadley cell is a large-scale thermally driven enclosed atmospheric circulation over the tropics, with warmer air rising around the equator and cooler air sinking over the subtropics of both hemispheres. This deep convection circulation is characterized by ascending motions of warm and moist air converging near the equator, followed by poleward flows in the upper troposphere in both hemispheres, which descend over the dry subtropics and return equatorward near the surface in the form of trade winds.
In this study, we used the historical data of NCEP/NCAR from the National Centers for Environmental Prediction and the National Center for Atmospheric Research, covering 1980 to 2025. We used the daily means of temperature, height, specific humidity, and the meridional wind component on eight pressure levels from 1000 to 300 hPa. First, the average moist static energy and the meridional circulation of this quantity were estimated, and then the role of the Hadley cell in the transfer of moist static energy was analyzed.
The results showed that part of the moist static energy that is transferred to different regions by the meridional mean circulation is limited to levels below 700 hPa in the cold and warm seasons of both hemispheres, and the values of the moist static energy flux by the Hadley cell in the cold months of the Northern and Southern Hemispheres in the northern and southern tropical regions are positive and negative, respectively, indicating poleward transfer in this part of both hemispheres.
During these months, when the solar declination angle is negative in the winter hemisphere and the Intertropical Convergence Zone (ITCZ) belt is located in the summer hemisphere, the transfer of moist static energy by the Hadley cell is from the equator of the summer hemisphere to the equator of the winter hemisphere.
In this process, in the Northern Hemisphere winter, the presence of southerly currents causes moist static energy to be transferred from the southern tropical regions to the northern tropical regions.