Recent Hadley Circulation Strengthening: A Trend or Multidecadal Variability?

Abstract This study explores the possible drivers of recent Hadley circulation strengthening in modern reanalyses. Predominantly, two generations reanalyses provided by European Centre for Medium-Range Weather Forecasts are used: fifth-generation atmospheric reanalysis (ERA5) and interim (ERA-Interim). Some results also evaluated against other long-term To assess origins cell (HC) strength variability, we employ Kuo–Eliassen (KE) equation. ERA5 shows that both HCs were prior to 2000s, but they have been weakening or remained steady afterward. Most variability is explained meridional gradient diabatic (latent) heating, which related precipitation gradients. However, larger than expected from observed zonal-mean [estimated Global Precipitation Climatology Project (GPCP)]. suggests HC trends decades can be partly as an artifact misrepresentation latent heating through (physical) variability. show latter true, analyze preliminary data 1950–78 period, (e.g., twentieth century) reanalyses, sea surface temperature observational data. reveals changes a consequence Atlantic multidecadal oscillation (AMO) frictional processes, turn drive global work has implications further understanding circulation.