caa a22 4500 605472971 CHVBK 20210128100340.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s00382-015-2513-5 doi (NATIONALLICENCE)springer-10.1007/s00382-015-2513-5 Propagation of the Madden-Julian Oscillation and scale interaction with the diurnal cycle in a high-resolution GCM [Elektronische Daten] [Simon Peatman, Adrian Matthews, David Stevens] The Madden-Julian Oscillation (MJO) is the chief source of tropical intra-seasonal variability, but is simulated poorly by most state-of-the-art GCMs. Common errors include a lack of eastward propagation at the correct frequency and zonal extent, and too small a ratio of eastward- to westward-propagating variability. Here it is shown that HiGEM, a high-resolution GCM, simulates a very realistic MJO with approximately the correct spatial and temporal scale. Many MJO studies in GCMs are limited to diagnostics which average over a latitude band around the equator, allowing an analysis of the MJO's structure in time and longitude only. In this study a wider range of diagnostics is applied. It is argued that such an approach is necessary for a comprehensive analysis of a model's MJO. The standard analysis of Wheeler and Hendon (Mon Wea Rev 132(8):1917-1932, 2004; WH04) is applied to produce composites, which show a realistic spatial structure in the MJO envelopes but for the timing of the peak precipitation in the inter-tropical convergence zone, which bifurcates the MJO signal. Further diagnostics are developed to analyse the MJO's episodic nature and the "MJO inertia” (the tendency to remain in the same WH04 phase from oneday to the next). HiGEM favours phases 2, 3, 6 and 7; has too much MJO inertia; and dies out too frequently in phase 3. Recent research has shown that a key feature of the MJO is its interaction with the diurnal cycle over the Maritime Continent. This interaction is present in HiGEM but is unrealistically weak. The Author(s), 2015 HiGEM nationallicence MJO nationallicence Maritime Continent nationallicence Diurnal cycle nationallicence Diagnostics nationallicence Peatman Simon Centre for Ocean and Atmospheric Sciences, School of Mathematics, University of East Anglia, NR4 7TJ, Norwich, UK aut Matthews Adrian Centre for Ocean and Atmospheric Sciences, School of Mathematics, University of East Anglia, NR4 7TJ, Norwich, UK aut Stevens David Centre for Ocean and Atmospheric Sciences, School of Mathematics, University of East Anglia, NR4 7TJ, Norwich, UK aut Climate Dynamics Springer Berlin Heidelberg 45/9-10(2015-11-01), 2901-2918 0930-7575 45:9-10<2901 2015 45 382 https://doi.org/10.1007/s00382-015-2513-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-015-2513-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Peatman Simon Centre for Ocean and Atmospheric Sciences, School of Mathematics, University of East Anglia, NR4 7TJ, Norwich, UK aut NATIONALLICENCE 700 1- Matthews Adrian Centre for Ocean and Atmospheric Sciences, School of Mathematics, University of East Anglia, NR4 7TJ, Norwich, UK aut NATIONALLICENCE 700 1- Stevens David Centre for Ocean and Atmospheric Sciences, School of Mathematics, University of East Anglia, NR4 7TJ, Norwich, UK aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 45/9-10(2015-11-01), 2901-2918 0930-7575 45:9-10<2901 2015 45 382