On northern-hemisphere wave patterns associated with winter rainfall events in China

Stephan, C. C., Ng, Y. H. and Klingaman, N. P. ORCID: https://orcid.org/0000-0002-2927-9303 (2018) On northern-hemisphere wave patterns associated with winter rainfall events in China. Advances in Atmospheric Sciences, 35 (8). pp. 1021-1034. ISSN 1861-9533 doi: 10.1007/s00376-018-7267-7

Abstract/Summary

During extended winter (November-April) 43% of the intraseasonal rainfall variability in China is explained by three spatial patterns of temporally coherent rainfall. These patterns were identified with Empirical Orthogonal Teleconnection (EOT) analysis of observed 1982-2007 pentad rainfall anomalies and connected to midlatitude disturbances. However, examination of individual strong EOT events shows that there is substantial inter-event variability in their dynamical evolution, which implies that precursor patterns found in regressions cannot serve as useful predictors. To understand the physical nature and origins of the extratropical precursors, the EOT technique is applied to six simulations of the Met Office Unified Model at horizontal resolutions of 200--40 km and with and without air-sea coupling. All simulations reproduce the observed precursor patterns in regressions, indicating robust underlying dynamical processes. Further investigation into the dynamics associated with observed patterns shows that Rossby wave dynamics can explain the large inter-event variability. The results suggest that the apparently slowly evolving or quasi-stationary waves in regression analysis are a statistical amalgamation of more rapidly propagating waves with a variety of origins and properties.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/75509
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > NCAS Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Springer
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