Energetic Constraints on the Monthly Mean Position of the Intertropical Convergence Zone
HUANG Weichong
ZHAO Shuyun
MA Xinyu
WANG Wuke
DENG Qimin
Abstract：Recent studies suggest that the position of the intertropical convergence zone(ITCZ)and its meridional shift should be examined within the energy framework.The energy flux equator(EFE)is an index for tracking ITCZ position within this framework.It has been found that EFE and ITCZ have strong connection on the annual mean scale,their relationship on the monthly scale requires further investigation.This study analyzes monthly ITCZ and EFE positions from 1979 to 2021 and their relationship on the monthly scale using the fifth generation European Centre for Medium-Range Weather Forecasts(ECMWF)reanalysis dataset(ERA5).The research improved methods on determining ITCZ and EFE positions,complementing existing methods.The results show that ITCZ and EFE exhibit a strong correspondence in the Indian Ocean and Marine Continent regions,but a weaker correlation over the Pacific in the climatologically month-mean.The new algorithm could improve the matching situation over the Pacific to some extent.During classical years(super strong El Niño events),the ITCZ exhibited significant north-south position anomalies,which could be indicated by the EFE.Long-term correlation analysis of monthly ITCZ and EFE across different longitudes reveals significant linear correlation in specific regions and months.The strong correspondence between ITCZ and EFE in the Indian Ocean and Maritime Continent arises from the alignment of 850 hPa circulation convergence(ITCZ indicator)and energy flux divergence(EFE indicator),while their substantial separation in the Pacific Ocean explains the weak correlation.These findings suggest that monthly EFE can indicate ITCZ position and reflect its seasonal and interannual variations under certain conditions.The energy framework thus demonstrates utility in analyzing ITCZ position and meridional movement,with its applicability influenced by EFE algorithm selection,geographical region,and seasonal timing.
Keywords：intertropical convergence zonethe energy frameworkenergy flux equatormonthly scalesuper-strong El Niño
Publication Date：2025-06-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：15( 440-454 )