Observational Analysis of Tropical Cyclogenesis in the Western North Pacific. Part II: Budget Analysis

1989 ◽  
Vol 46 (16) ◽  
pp. 2599-2616 ◽  
Author(s):  
Cheng Shang Lee
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Tropical Cyclogenesis ◽  
Observational Analysis ◽  
Budget Analysis

scholarly journals Climatological Increased Precipitation from July to August in the Western North Pacific Region Simulated by CMIP6 Models

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 664
Author(s):  
Xiao Dong ◽  
Renping Lin
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Vertical Motion ◽  
Atmospheric Model ◽  
Coupled Models ◽  
Model Simulations ◽  
Observational Analysis ◽  
Budget Analysis ◽  
Circulation Change ◽  
Precipitation Increase

In this study, the climatological precipitation increase from July to August over the western North Pacific (WNP) region was investigated through observations and simulations in the Coupled Model Intercomparison Project Phase 6 (CMIP6), atmospheric model simulations and historical experiments. Firstly, observational analysis showed that the precipitation increase is associated with a decrease in the local sea surface temperature (SST), indicating that the precipitation increase is not driven by the change in SST. In addition, the pattern of precipitation increase is similar to the vertical motion change at 500-hPa, suggesting that the precipitation increase is related to the circulation change. Moisture budget analysis further confirmed this relation. In addition to the observational analysis, the outputs from 26 CMIP6 models were further evaluated. Compared with atmospheric model simulations, air–sea coupled models largely improve the simulation of the climatological precipitation increase from July to August. Furthermore, model simulations confirmed that the bias in the precipitation increase is intimately associated with the circulation change bias. Thus, two factors are responsible for the bias of the precipitation increase from July to August in climate models: air–sea coupling processes and the performance in vertical motion change.

Tropical Cyclogenesis Associated with Kelvin Waves and the Madden–Julian Oscillation

2011 ◽  
Vol 139 (9) ◽  
pp. 2723-2734 ◽  
Author(s):  
Carl J. Schreck ◽  
John Molinari
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
Diabatic Heating ◽  
Kelvin Waves ◽  
Tropical Cyclogenesis ◽  
Madden Julian Oscillation ◽  
Convective Envelope

The Madden–Julian oscillation (MJO) influences tropical cyclone formation around the globe. Convectively coupled Kelvin waves are often embedded within the MJO, but their role in tropical cyclogenesis remains uncertain. This case study identifies the influences of the MJO and a series of Kelvin waves on the formation of two tropical cyclones. Typhoons Rammasun and Chataan developed in the western North Pacific on 28 June 2002. Two weeks earlier, conditions had been unfavorable for tropical cyclogenesis because of uniform trade easterlies and a lack of organized convection. The easterlies gave way to equatorial westerlies as the convective envelope of the Madden–Julian oscillation moved into the region. A series of three Kelvin waves modulated the development of the westerlies. Cyclonic potential vorticity (PV) developed in a strip between the growing equatorial westerlies and the persistent trade easterlies farther poleward. Rammasun and Chataan emerged from the apparent breakdown of this strip. The cyclonic PV developed in association with diabatic heating from both the MJO and the Kelvin waves. The tropical cyclones also developed during the largest superposition of equatorial westerlies from the MJO and the Kelvin waves. This chain of events suggests that the MJO and the Kelvin waves each played a role in the development of Rammasun and Chataan.

scholarly journals Effects of monsoon trough interannual variation on tropical cyclogenesis over the western North Pacific

2014 ◽  
Vol 41 (12) ◽  
pp. 4332-4339 ◽  
Author(s):  
Xi Cao ◽  
Tim Li ◽  
Melinda Peng ◽  
Wen Chen ◽  
Guanghua Chen
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Interannual Variation ◽  
Monsoon Trough ◽  
Tropical Cyclogenesis

Multi-scale interactions of equatorial waves associated with tropical cyclogenesis over the western North Pacific

2018 ◽  
Vol 52 (5-6) ◽  
pp. 3023-3038 ◽  
Author(s):  
Haikun Zhao ◽  
Xianan Jiang ◽  
Liguang Wu ◽  
Philip J. Klotzbach
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Tropical Cyclogenesis ◽  
Equatorial Waves ◽  
Scale Interactions ◽  
Multi Scale

Does the Pacific meridional mode dominantly affect tropical cyclogenesis in the western North Pacific?

2020 ◽  
Vol 55 (11-12) ◽  
pp. 3469-3483
Author(s):  
Hongjie Zhang ◽  
Liang Wu ◽  
Ronghui Huang ◽  
Jau-Ming Chen ◽  
Tao Feng
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Tropical Cyclogenesis ◽  
The Pacific ◽  
Meridional Mode ◽  
Pacific Meridional Mode

scholarly journals An Examination of the Thermodynamic Impacts of Western North Pacific Tropical Cyclones on Their Tropical Tropospheric Environment

2015 ◽  
Vol 28 (19) ◽  
pp. 7529-7560 ◽  
Author(s):  
Benjamin A. Schenkel ◽  
Robert E. Hart
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Rossby Waves ◽  
Budget Analysis ◽  
Surface Latent Heat Flux ◽  
Static Energy ◽  
Thermodynamic Anomalies ◽  
Meridional Advection ◽  
Gas Effect ◽  
Sst Anomalies

Abstract The present study examines the tropospheric thermodynamic anomalies induced by western North Pacific tropical cyclone (TC) passage using storm-relative composites. Negative moist static energy (MSE) anomalies containing embedded westward-propagating anomalies generally occur only following larger TCs for two months following TC passage in a region extending from the domain center to ~3000 km to its west. Larger TCs force negative MSE anomalies likely because of feedbacks from stronger, broader TC-induced negative sea surface temperature (SST) anomalies and the excitation of TC-induced Rossby waves to the southeast of the TC. The negative MSE anomalies are composed of lower- and midtropospheric negative latent energy anomalies with smaller contributions from boundary layer and upper-tropospheric negative sensible heat anomalies. The lower- and midtropospheric negative MSE anomalies are forced by the TC, whereas the upper-tropospheric negative MSE anomalies are forced by the Madden–Julian oscillation. Vertically integrated MSE budgets at the domain center reveal negative MSE tendencies that are primarily forced by surface latent heat flux anomalies resulting from the TC-induced negative SST anomalies. Smaller negative MSE tendencies are due to 1) zonal and meridional advection of MSE anomalies by the Rossby waves and 2) enhanced top-of-the-atmosphere longwave radiative flux anomalies potentially associated with a reduction in the greenhouse gas effect of water vapor. The budget analysis in the west region is generally similar except that all terms are comparable in magnitude and relatively weaker. These results conservatively suggest that larger TCs can anomalously cool and dry their synoptic-scale environment for ~40 days following TC passage.

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