title: Vertical structure and physical processes of the Madden-Julian Oscillation: Biases and uncertainties at short range.
abstract: An analysis of diabatic heating and moistening processes from 12 to 36 h lead time forecasts from 12 Global Circulation Models are presented as part of the "Vertical structure and physical processes of the Madden-Julian Oscillation (MJO)" project. A lead time of 12-36 h is chosen to constrain the large-scale dynamics and thermodynamics to be close to observations while avoiding being too close to the initial spin-up of the models as they adjust to being driven from the Years of Tropical Convection (YOTC) analysis. A comparison of the vertical velocity and rainfall with the observations and YOTC analysis suggests that the phases of convection associated with the MJO are constrained in most models at this lead time although the rainfall in the suppressed phase is typically overestimated. Although the large-scale dynamics is reasonably constrained, moistening and heating profiles have large intermodel spread. In particular, there are large spreads in convective heating and moistening at midlevels during the transition to active convection. Radiative heating and cloud parameters have the largest relative spread across models at upper levels during the active phase. A detailed analysis of time step behavior shows that some models show strong intermittency in rainfall and differences in the precipitation and dynamics relationship between models. The wealth of model outputs archived during this project is a very valuable resource for model developers beyond the study of the MJO. In addition, the findings of this study can inform the design of process model experiments, and inform the priorities for field experiments and future observing systems.
authors.affiliation: Met Office Exeter UK.
authors.forename: Prince K
authors.initials: PK
authors.lastname: Xavier
authors.affiliation: Met Office Exeter UK.
authors.forename: Jon C
authors.initials: JC
authors.lastname: Petch
authors.affiliation: National Centre for Atmospheric Science-Climate University of Reading Reading UK.
authors.forename: Nicholas P
authors.identifier: 0000-0002-2927-9303
authors.initials: NP
authors.lastname: Klingaman
authors.affiliation: National Centre for Atmospheric Science-Climate University of Reading Reading UK.
authors.forename: Steve J
authors.initials: SJ
authors.lastname: Woolnough
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: Xianan
authors.initials: X
authors.lastname: Jiang
authors.affiliation: Jet Propulsion Laboratory California Institute of Technology Pasadena California USA.
authors.forename: Duane E
authors.initials: DE
authors.lastname: Waliser
authors.affiliation: Rossby Centre Swedish Meteorological and Hydrological Institute Norrköping Sweden.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Caian
authors.affiliation: Canadian Centre for Climate Modelling and Analysis Environment Canada Victoria British Columbia Canada.
authors.forename: Jason
authors.initials: J
authors.lastname: Cole
authors.affiliation: Pacific Northwest National Laboratory Richland Washington USA.
authors.forename: Samson M
authors.initials: SM
authors.lastname: Hagos
authors.affiliation: National Center for Atmospheric Research Boulder Colorado USA.
authors.forename: Cecile
authors.initials: C
authors.lastname: Hannay
authors.affiliation: Department of Atmospheric Sciences University of Washington Seattle Washington USA.
authors.forename: Daehyun
authors.initials: D
authors.lastname: Kim
authors.affiliation: Research Institute for Global Change Japan Agency for Marine-Earth Science and Technology Yokosuka Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Miyakawa
authors.affiliation: Department of Earth System Sciences University of California Irvine California USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Pritchard
authors.affiliation: CNRM-GAME, Météo-France and CNRS Toulouse France.
authors.forename: Romain
authors.initials: R
authors.lastname: Roehrig
authors.affiliation: Meteorological Research Institute Climate Research Department Ibaraki Japan.
authors.forename: Eiki
authors.initials: E
authors.lastname: Shindo
authors.affiliation: European Center for Medium-Range Weather Forecasts Reading UK.
authors.forename: Frederic
authors.initials: F
authors.lastname: Vitart
authors.affiliation: National Aeronautics and Space Administration Goddard Space Flight Center Greenbelt Maryland USA.
authors.forename: Hailan
authors.initials: H
authors.lastname: Wang
keywords: Madden‐Julian Oscillation; Year of Tropical convection; convection; diabatic processes; modeling; uncertainties