High-resolution simulation of the boreal summer intra-seasonal oscillation in Met Office unified model

Fang, Y., Wu, P., Mizielinski, M. S., Roberts, M. J., Wu, T., Li, B., Vidale, P. L. ORCID: https://orcid.org/0000-0002-1800-8460, Demory, M.-E. and Schiemann, R. ORCID: https://orcid.org/0000-0003-3095-9856 (2017) High-resolution simulation of the boreal summer intra-seasonal oscillation in Met Office unified model. Quarterly Journal of the Royal Meteorological Society, 143 (702). pp. 362-373. ISSN 1477-870X doi: 10.1002/qj.2927

Abstract/Summary

The present study investigates the fidelity and resolution sensitivity of Met Office Unified Model Global Atmosphere 3.0 in simulating the intra-seasonal oscillation (ISO) of the East Asia and western North Pacific summer monsoon. Two sets of model simulations at horizontal resolutions of N216 (60km) and N96 (130km) forced by observed daily high-resolution sea surface temperature are examined and compared with the observations. Diagnostic results show that the model can well reproduce the gross spatio-temporal features of observed summer ISO over the East Asia and western North Pacific in terms of period, dominant REOF mode, variance, northward propagation, cycle evolution and vertical structure. The intra-seasonal change in intensity and position of western North Pacific Subtropical High and upper troposphere westerly jet associated with the northward propagating ISOs are also reasonably captured in the model. Moreover, increasing horizontal resolution improves most aspects of the ISO simulation, especially the intensity and northward propagation of the ISO-related convection and circulation systems. Further analysis indicates that the improvement as resolution increases is related to the weakening in background state of East Asian summer monsoon, which is due to the realistic simulation of land-sea thermal contrast at higher resolution model. This study suggests that enhanced model resolution can have some beneficial impacts on the ISO simulation.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/67290
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	Royal Meteorological Society
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