scholarly journals Sensitivity of Western North Pacific Summertime Tropical Synoptic-Scale Disturbances to Extratropical Forcing – A Regional Climate Model Study

2022 ◽  
Author(s):  
Ying Lung LIU ◽  
Chi-Yung TAM ◽  
Andie Yee Man AU-YEUNG
Keyword(s):  
Regional Climate Model ◽  
North Pacific ◽  
Western North Pacific ◽  
Climate Model ◽  
Regional Climate ◽  
Synoptic Scale ◽  
Model Study ◽  
Extratropical Forcing

scholarly journals Sensitivity of western north Pacific summertime tropical synoptic- scale disturbances to extratropical forcing – A regional climate model study

2021 ◽  
Author(s):  
Ying Lung Liu ◽  
Chi-Yung Tam ◽  
Andie Yee Man Au-Yeung
Keyword(s):  
Regional Climate Model ◽  
North Pacific ◽  
Western North Pacific ◽  
Climate Model ◽  
Regional Climate ◽  
Wave Activity ◽  
Synoptic Scale ◽  
Low Level ◽  
Zonal Wavenumber ◽  
Extratropical Forcing

Abstract The role of extratropical forcing on the summertime tropical synoptic-scale disturbances (TSDs) in the western north Pacific has been investigated, by conducting parallel integrations of the Regional Climate Model (RegCM). The suite of experiments consists of a control run (CTRL) with European Centre for Medium Range Forecasts (ECMWF) Reanalysis data as boundary conditions, and an experimental run (EXPT) with the same setting, except that signals with zonal wavenumber > 6 were suppressed at the northern boundary (located at 42°N) of the model domain. Comparison between CTRL and EXPT showed that, without extratropical forcing, there is weaker TSD activity in the June-to-August season, with reduced precipitation over the TSD pathway. Associated with suppressed TSD, southeastward-directed wave activity is also reduced, leading to less active mixed Rossby gravity (MRG) waves in the equatorial western Pacific area. Further analysis revealed that extratropical forcing and associated circulation changes can modulate the TSD wavetrain and its coherence structure, in relation to low-level vorticity in far western north Pacific. In CTRL, west of about 140°E, TSD-related circulation tends to be stronger; in EXPT, vorticity signals and vertical motions are found to be slightly more coherent in the more eastern portion of the TSD wavetrain. The latter enhanced coherency of TSD east of 140°E, from the EXPT simulations, might be due to changes in wave activity transport channelled by modulated upper-level mid-latitude westerlies in EXPT. Energetics indicate that changes in low-level background circulation itself can also influence TSD characteristics. Our results serve to quantify how extratropical forcing and related general circulation features influence western north Pacific summertime TSD activities. Implications on understanding the initiation of TSD, as well as their variability on longer time scales, are discussed.

scholarly journals IMPACTS OF LAND COVER AND GREENHOUSE GAS (GHG) CONCENTRATION CHANGES ON THE HYDROLOGICAL CYCLE IN AMAZON BASIN: A REGIONAL CLIMATE MODEL STUDY

2015 ◽  
Vol 15 ◽  
Author(s):  
Vinícius Machado Rocha ◽  
Francis Wagner Silva Correia ◽  
Prakki Satyamurty ◽  
Saulo Ribeiro De Freitas ◽  
Demerval Soares Moreira ◽  
...  
Keyword(s):  
Land Cover ◽  
Regional Climate Model ◽  
Greenhouse Gas ◽  
Amazon Basin ◽  
Climate Model ◽  
Hydrological Cycle ◽  
Regional Climate ◽  
Model Study ◽  
Concentration Changes

scholarly journals Boreal Summer Synoptic-Scale Waves over the Western North Pacific in Multimodel Simulations

2016 ◽  
Vol 29 (12) ◽  
pp. 4487-4508 ◽  
Author(s):  
Haikun Zhao ◽  
Xianan Jiang ◽  
Liguang Wu
Keyword(s):  
Spatial Pattern ◽  
North Pacific ◽  
General Circulation ◽  
Western North Pacific ◽  
Climate Model ◽  
Climate Modeling ◽  
Active Role ◽  
General Circulation Models ◽  
Boreal Summer ◽  
Synoptic Scale

During boreal summer, vigorous synoptic-scale wave (SSW) activity, often evident as southeast–northwest-oriented wave trains, prevails over the western North Pacific (WNP). In spite of their active role for regional weather and climate, modeling studies on SSWs are rather limited. In this study, a comprehensive survey on climate model capability in representing the WNP SSWs is conducted by analyzing simulations from 27 recent general circulation models (GCMs). Results suggest that it is challenging for GCMs to realistically represent the observed SSWs. Only 2 models out of the 27 GCMs generally well simulate both the intensity and spatial pattern of the observed SSW mode. Plausible key processes for realistic simulations of SSW activity are further explored. It is illustrated that GCM skill in representing the spatial pattern of the SSW is highly correlated to its skill in simulating the summer mean patterns of the low-level convergence associated with the WNP monsoon trough and conversion from eddy available potential energy (EAPE) to eddy kinetic energy (EKE). Meanwhile, simulated SSW intensity is found to be significantly correlated to the amplitude of 850-hPa vorticity, divergence, and conversion from EAPE to EKE over the WNP. The observed modulations of SSW activity by the Madden–Julian oscillation are able to be captured in several model simulations.

scholarly journals A regional climate model study of how biomass burning aerosol impacts land-atmosphere interactions over the Amazon

2008 ◽  
Vol 113 (D14) ◽  
Author(s):  
Yan Zhang ◽  
Rong Fu ◽  
Hongbin Yu ◽  
Robert E. Dickinson ◽  
Robinson Negron Juarez ◽  
...  
Keyword(s):  
Regional Climate Model ◽  
Biomass Burning ◽  
Climate Model ◽  
Regional Climate ◽  
Model Study ◽  
Biomass Burning Aerosol

A Regional Climate Model Study of the Scale Dependence of Cloud-Radiation Interactions

1996 ◽  
Vol 9 (6) ◽  
pp. 1221-1234 ◽  
Author(s):  
Michael P. Dudek ◽  
Xin-Zhong Liang ◽  
Wei-Chyung Wang
Keyword(s):  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Scale Dependence ◽  
Model Study
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