RT Journal Article T1 Coupled interannual variability of the Hadley and Ferrel cells A1 Zurita Gotor, Pablo A1 Álvarez Zapatero, Pablo AB This work investigates the covariability in the strength of the Hadley and Ferrel cells on interannual time scales using reanalysis data. A significant correlation is found in both hemispheres only during boreal winter. For other seasons, only the outermost (subtropical) part of the Hadley cell is correlated with changes in the extratropical eddy momentum fluxes, as the eddies are unable to penetrate into the deep tropics. During boreal winter, the northern Hadley cell variability is driven by extratropical planetary momentum fluxes, but the mean meridional circulation response is primarily found below the level of maximum climatological outflow. Instead, at upper levels, changes in the zonal wind dominate the response to the anomalous eddy forcing. During austral winter, the southern Hadley cell is shielded from the extratropical eddy fluxes and its variability displays some of the characteristics of the angular momentum-conserving solution. PB American Meteorological Society. SN 0894-8755 YR 2018 FD 2018-06-15 LK https://hdl.handle.net/20.500.14352/12988 UL https://hdl.handle.net/20.500.14352/12988 LA eng NO ©2018 American Meteorological Society.We thank the three anonymous reviewers for their excellent reviews providing new insight and very detailed comments that improved the clarity of the manuscript. One of the reviewers alerted us to the important role played by the vertical eddy momentum divergence in the subtropics. NOAA-ERSST data was provided by the NOAA/OAR/ESRL PSD, Boulder, Colorado, from their website at http://www.esrl.noaa.gov/psd/. We thank NOAA for this data, and the European Centre for Medium-Range Weather Forecasts for the atmospheric reanalysis data. P. Z.-G. acknowledges financial support by Grant CGL2015-72259-EXP by the Ministry of Economy and Innovation of Spain. NO Ministerio de Economía y Competitividad (MINECO) DS Docta Complutense RD 9 may 2024