Simulation of Synoptic- and Subsynoptic-Scale Phenomena Associated with the East Asian Summer Monsoon Using a High-Resolution GCM
- 1 January 2009
- journal article
- Published by American Meteorological Society in Monthly Weather Review
- Vol. 137 (1), 137-160
- https://doi.org/10.1175/2008mwr2511.1
Abstract
A 20-yr simulation using a global atmospheric general circulation model with a resolution of 0.5° latitude × 0.625° longitude is compared with observational findings. The primary goal of this survey is to assess the model performance in reproducing various summertime phenomena related to the continental-scale Asian monsoon in general, and the regional-scale East Asian monsoon in particular. In both model and observed atmospheres, the seasonal march of the precipitation centers associated with the Asian summer monsoon is characterized by onsets occurring earliest over the southeastern Bay of Bengal, followed by rapid northeastward advances over Indochina, the South China Sea–Philippine Sea and the western Pacific, northward evolution in the East Asian sector, as well as northwestward development over the Bay of Bengal, the Indian subcontinent, and the Arabian Sea. This onset sequence is accompanied by southwesterly low-level flows over the rainy regions, as well as northwestward migration of the 200-mb Tibetan anticyclone. Analysis of the heat sources and sinks in various regions illustrates the prominent role of condensational heating in the local energy budget during the mature phases of monsoon development. In accord with observations, the simulated monsoon rains in the East Asian sector are organized about zonally elongated “mei-yu–baiu” (plum rain) systems. These precipitation features advance to higher latitudes during the June–July period, in conjunction with displacements of the axis of the low-level anticyclone over the subtropical western Pacific. A detailed case study is performed on a prominent rainy episode in the simulation. The model is capable of reproducing the observed intense gradients in temperature, humidity, and moist static stability in the vicinity of the mei-yu–baiu front, as well as the spatial relationships between the rainband and the three-dimensional flow field. The axis of the mei-yu–baiu rainband in this event is aligned with the trajectory of a succession of mesoscale cyclonic vortices, which originate from southwestern China and travel northeastward over the Yangtze River basin.Keywords
This publication has 42 references indexed in Scilit:
- Recent trends in sea level pressure in the Indian Ocean regionGeophysical Research Letters, 2006
- GFDL's CM2 Global Coupled Climate Models. Part I: Formulation and Simulation CharacteristicsJournal of Climate, 2006
- The East Asian summer monsoon: an overviewArchiv für Meteorologie, Geophysik und Bioklimatologie Serie A, 2005
- East Asian MonsoonWorld Scientific Series on Asia-Pacific Weather and Climate, 2004
- SEASONAL MARCH OF THE EAST-ASIAN SUMMER MONSOONWorld Scientific Series on Asia-Pacific Weather and Climate, 2004
- RESEARCH ON THE PHENOMENA OF MEIYU DURING THE PAST QUARTER CENTURY: AN OVERVIEWWorld Scientific Series on Asia-Pacific Weather and Climate, 2004
- High-resolution simulations of global climate, part 1: present climateClimate Dynamics, 2003
- Impact of horizontal resolution on seasonal integrationsClimate Dynamics, 2001
- Summer Monsoon Rainfalls in ChinaJournal of the Meteorological Society of Japan. Ser. II, 1992
- Analysis of a Shallow Front during the Taiwan Area Mesoscale ExperimentMonthly Weather Review, 1990