scholarly journals The Climatological Analysis of Typhoon Tracks, Steering Flow, and the Pacific Subtropical High in the Vicinity of Taiwan and the Western North Pacific

Atmosphere ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 543
Author(s):  
Chih-wen Hung ◽  
Ming-Fu Shih ◽  
Te-Yuan Lin
Keyword(s):  
Tropical Cyclones ◽  
Large Scale ◽  
Subtropical High ◽  
Boreal Summer ◽  
The South ◽  
The West ◽  
Steering Flow ◽  
The Pacific ◽  
Typhoon Season ◽  
Typhoon Tracks

Taiwan frequently suffers from typhoon hits in the boreal summer and fall. The location of Taiwan makes it vulnerable to the pathways of typhoons mainly determined by the position of the Pacific subtropical high. In order to clarify the linkage between typhoon invasion and associated large-scale environments from a climatological perspective, this study counts the historical typhoon invasion days for each month in the typhoon season to establish analyzed cases and then categorizes them with statistical thresholds. Besides, the categorized cases with less typhoon invasion are further sorted to distinguish different movements of tropical cyclones. Therefore, corresponding composites are applied for each category. The results reveal that when the subtropical high retreats eastward, the accompanying steering flow guides typhoons to make an early recurvature toward Japan and South Korea. While the subtropical high further extends its property to the west covering Taiwan, the steering flow on the south transfers typhoons moving westward to the South China Sea. However, when the subtropical high lies in areas between the above two scenarios, the steering flow along the periphery of the subtropical high continuously sends typhoons toward Taiwan and the vicinity, which greatly increases the threat to the island.

scholarly journals Sudden Track Changes of Tropical Cyclones in Monsoon Gyres: Full-Physics, Idealized Numerical Experiments*

2015 ◽  
Vol 72 (4) ◽  
pp. 1307-1322 ◽  
Author(s):  
Jia Liang ◽  
Liguang Wu
Keyword(s):  
Tropical Cyclones ◽  
Numerical Experiments ◽  
Large Scale ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Coalescence Process ◽  
The West ◽  
Steering Flow ◽  
Sharp Turn ◽  
Wind Profiles

Abstract Tropical cyclones (TCs) in the eastern semicircle of large-scale monsoon gyres (MGs) were observed to take either a northward (sudden northward and northward without a sharp turn) or a westward TC turn, but only the northward turn was previously simulated in a barotropic model. To understand what controls TC track types in MGs, idealized numerical experiments are performed using the full-physics Weather Research and Forecasting (WRF) Model. These experiments indicate that TCs initially located in the eastern semicircle of MGs can generally take three types of tracks: a sudden northward track, a westward track, and a northward track without a sharp turn. The track types depend upon the TC movement relative to the MG center. In agreement with barotropic simulations, the WRF simulation confirms that approaching and being collocated with the MG center is crucial to the occurrence of sudden northward TC track changes and that sudden northward track changes can be generally accounted for by changes in the steering flow. TCs that take westward tracks and northward tracks without a sharp turn do not experience such a coalescence process. Westward TCs move faster than MGs and are then located to the west of the MG center, while TCs move more slowly than MGs and then take a northward track without a sharp turn. This study reveals that the specific TC track in the eastern semicircle of an MG is sensitive to the initial wind profiles of both MGs and TCs, suggesting that improvement in the observation of TC and MG structures is very important for predicting TC track types in MGs.

scholarly journals Interannual and interdecadal impact of Western North Pacific Subtropical High on tropical cyclone activity

2020 ◽  
Vol 54 (3-4) ◽  
pp. 2237-2248 ◽  
Author(s):  
Qiong Wu ◽  
Xiaochun Wang ◽  
Li Tao
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Southern Oscillation ◽  
Subtropical High ◽  
Interdecadal Change ◽  
Steering Flow ◽  
The Pacific ◽  
Sea Surface Temperature Anomalies ◽  
Peak Phase

AbstractIn this study, we analyzed the impacts of Western North Pacific Subtropical High (WNPSH) on tropical cyclone (TC) activity on both interannual and interdecadal timescales. Based on a clustering analysis method, we grouped TCs in the Western North Pacific into three clusters according to their track patterns. We mainly focus on Cluster 1 (C1) TCs in this work, which is characterized by forming north of 15° N and moving northward. On interannual timescale, the number of C1 TCs is influenced by the intensity variability of the WNPSH, which is represented by the first Empirical Orthogonal Function (EOF) of 850 hPa geopotential height of the region. The WNPSH itself is modulated by the El Niño–Southern Oscillation at its peak phase in the previous winter, as well as Indian and Atlantic Ocean sea surface temperature anomalies in following seasons. The second EOF mode shows the interdecadal change of WNPSH intensity. The interdecadal variability of WNPSH intensity related to the Pacific climate regime shift could cause anomalies of the steering flow, and lead to the longitudinal shift of C1 TC track. Negative phases of interdecadal Pacific oscillation are associated with easterly anomaly of steering flow, westward shift of C1 TC track, and large TC impact on the East Asia coastal area.

scholarly journals Coastal Wave Extremes around the Pacific and Their Remote Seasonal Connection to Climate Modes

Climate ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 168
Author(s):  
Julien Boucharel ◽  
Loane Santiago ◽  
Rafael Almar ◽  
Elodie Kestenare
Keyword(s):  
Large Scale ◽  
Wind Wave ◽  
Boreal Summer ◽  
Opposite Hemisphere ◽  
Ocean Surface Waves ◽  
First Order ◽  
Coastal Waves ◽  
The Pacific ◽  
Wide Range ◽  
The Tropics

At first order, wind-generated ocean surface waves represent the dominant forcing of open-coast morpho-dynamics and associated vulnerability over a wide range of time scales. It is therefore paramount to improve our understanding of the regional coastal wave variability, particularly the occurrence of extremes, and to evaluate how they are connected to large-scale atmospheric regimes. Here, we propose a new “2-ways wave tracking algorithm” to evaluate and quantify the open-ocean origins and associated atmospheric forcing patterns of coastal wave extremes all around the Pacific basin for the 1979–2020 period. Interestingly, the results showed that while extreme coastal events tend to originate mostly from their closest wind-forcing regime, the combined influence from all other remote atmospheric drivers is similar (55% local vs. 45% remote) with, in particular, ~22% coming from waves generated remotely in the opposite hemisphere. We found a strong interconnection between the tropical and extratropical regions with around 30% of coastal extremes in the tropics originating at higher latitudes and vice-versa. This occurs mostly in the boreal summer through the increased seasonal activity of the southern jet-stream and the northern tropical cyclone basins. At interannual timescales, we evidenced alternatingly increased coastal wave extremes between the western and eastern Pacific that emerge from the distinct seasonal influence of ENSO in the Northern and SAM in the Southern Hemisphere on their respective paired wind-wave regimes. Together these results pave the way for a better understanding of the climate connection to wave extremes, which represents the preliminary step toward better regional projections and forecasts of coastal waves.

Three new ameirid harpacticoids from Korea and first record of Proameira simplex (Crustacea: Copepoda: Ameiridae)

Zootaxa ◽  
2012 ◽  
Vol 3368 (1) ◽  
pp. 91 ◽  
Author(s):  
TOMISLAV KARANOVIC ◽  
JOO-LAE CHO
Keyword(s):  
Species Complex ◽  
Alternative Hypothesis ◽  
First Record ◽  
The South ◽  
The West ◽  
The Pacific ◽  
The World ◽  
South Sea ◽  
First Time ◽  
Caudal Rami

Ameiridae Monard, 1927 was previously known from Korea only after one endemic and four cosmopolitan species of the genus Nitokra Boeck, 1865, and a single widely distributed species of the genus Ameira Boeck, 1865, all from brackish enviroments. After a survey of 22 sampling sites and close to 3,500 harpacticoid specimens from various marine enviroments, we report on two new endemic species of Ameira, A. zahaae sp. nov. and A. kimchi sp. nov., from the West Sea and the South Sea respectively. They are both relatively closely related to the previously recorded cosmopolitan A. parvula (Claus, 1866), but show many novel morphological structures in the caudal rami shape and ornamentation. The identity of the cosmopolitan A. parvula in Korea is questioned, and an alternative hypothesis of a species-complex proposed. The fine ornamentation of body somites (especially the pores/sensilla pattern) is studied in detail, and proves to be a very useful new morphological tool in distinguishing closely related spacies in this genus. The genus Pseudameira Sars, 1911 is reported for the first time in Korea, after four females of P. mago sp. nov. from the South Sea. A single damaged female of Proameira cf. simplex (Norman & Scott, 1905) represents the first record of the genus Proameira Lang, 1944 in Korea, Asia, and anywhere in the Pacific. A key to Korean ameirids is also provided, and their apparent rarity in this part of the world noticed.

‘Burn it down!’: Materialising intersectional solidarities in the architecture of the South African Embassy during the London Poll Tax Riot, March 1990

2019 ◽  
Vol 38 (2) ◽  
pp. 233-250 ◽  
Author(s):  
Gavin Brown
Keyword(s):  
South Africa ◽  
Working Class ◽  
South African ◽  
Large Scale ◽  
The South ◽  
The West ◽  
England And Wales ◽  
Metropolitan Police ◽  
Trafalgar Square ◽  
Poll Tax

This paper offers a new way of conceptualising how intersectional solidarities are actualised. It recounts and theorises an outbreak of radical internationalism, when working class struggles in Britain and South Africa were unexpectedly linked. It examines how intersectional solidarity was materialised through a process of coming together against the architectural fabric of the South African Embassy and considers the interwoven temporalities that enabled this action to occur. On 31 March 1990, nearly a quarter of a million people demonstrated in London against the Poll Tax that was due to take effect in England and Wales the following day. On the day, the Metropolitan Police lost control of an already enraged crowd and provoked a large scale riot that engulfed the West End of London for several hours. In the midst of the riot, during a short retreat by the police, protesters took the opportunity to attack the South African Embassy in Trafalgar Square – many windows were broken and an attempt was made to set the building alight. Drawing on interviews with former anti-apartheid protesters who were present on that day (and who had concluded a four-year long Non-Stop Picket of the embassy a month earlier), this paper explores and analyses their memories of that unexpected moment when their previously symbolic call to ‘burn it down’ was (almost) materialised. In doing so, it contributes new ways of conceptualising the spatiality and temporality of intersectional solidarity.

scholarly journals Internal Intraseasonal Variability of the West African Monsoon in WRF

2017 ◽  
Vol 30 (15) ◽  
pp. 5815-5833 ◽  
Author(s):  
Ghassan J. Alaka ◽  
Eric D. Maloney
Keyword(s):  
East Africa ◽  
Large Scale ◽  
Intraseasonal Variability ◽  
West African Monsoon ◽  
West African ◽  
Boreal Summer ◽  
Kelvin Wave ◽  
The West ◽  
African Monsoon ◽  
External Influences

The West African monsoon (WAM) and its landmark features, which include African easterly waves (AEWs) and the African easterly jet (AEJ), exhibit significant intraseasonal variability in boreal summer. However, the degree to which this variability is modulated by external large-scale phenomena, such as the Madden–Julian oscillation (MJO), remains unclear. The Weather Research and Forecasting (WRF) Model is employed to diagnose the importance of the MJO and other external influences for the intraseasonal variability of the WAM and associated AEW energetics by removing 30–90-day signals from initial and lateral boundary conditions in sensitivity tests. The WAM produces similar intraseasonal variability in the absence of external influences, indicating that the MJO is not critical to produce WAM variability. In control and sensitivity experiments, AEW precursor signals are similar near the AEJ entrance in East Africa. For example, an eastward extension of the AEJ increases barotropic and baroclinic energy conversions in East Africa prior to a 30–90-day maximum of perturbation kinetic energy in West Africa. The WAM appears to prefer a faster oscillation when MJO forcing is removed, suggesting that the MJO may serve as a pacemaker for intraseasonal oscillations in the WAM. WRF results show that eastward propagating intraseasonal signals (e.g., Kelvin wave fronts) are responsible for this pacing, while the role of westward propagating intraseasonal signals (e.g., MJO-induced Rossby waves) appears to be limited. Mean state biases across the simulations complicate the interpretation of results.

scholarly journals Interaction of Typhoon Shanshan (2006) with the Midlatitude Trough from both Adjoint-Derived Sensitivity Steering Vector and Potential Vorticity Perspectives

2009 ◽  
Vol 137 (3) ◽  
pp. 852-862 ◽  
Author(s):  
Chun-Chieh Wu ◽  
Shin-Gan Chen ◽  
Jan-Huey Chen ◽  
Kun-Hsuan Chou ◽  
Po-Hsiung Lin
Keyword(s):  
Potential Vorticity ◽  
Large Scale ◽  
Mesoscale Model ◽  
High Sensitivity ◽  
Forecast Model ◽  
Central China ◽  
Subtropical High ◽  
Steering Vector ◽  
Steering Flow ◽  
Targeted Observation

Abstract Targeted observation is one of the most important research and forecasting issues for improving tropical cyclone predictability. A new parameter [i.e., the adjoint-derived sensitivity steering vector (ADSSV)] has been proposed and adopted as one of the targeted observing strategies in the Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR). The ADSSV identifies the sensitive areas at the observing time to the steering flow at the verifying time through the adjoint calculation. In this study, the ADSSV is calculated from the nonlinear forecast model of the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) and its adjoint to interpret the dynamical processes in the interaction between Typhoon Shanshan (2006) and the midlatitude trough. The ADSSV results imply that high-sensitivity regions affecting the motion of Typhoon Shanshan are located at the edge of the subtropical high and the 500-hPa midlatitude trough over northern central China. These ADSSV signals are in very good agreement with the quantitative evaluation based on the potential vorticity (PV) diagnosis. The vertical structure of the ADSSV is also shown for more physical insights into the typhoon–trough interaction. The maximum ADSSV occurs at 800–500 hPa to the southeast of Shanshan (associated with the subtropical high), while distinct ADSSV signals are located upstream of the storm center at about 500–300 hPa (associated with the mid- to upper-tropospheric midlatitude trough). Overall, it is demonstrated that the ADSSV features can well capture the signal of the large-scale trough feature affecting the motion of Shanshan, which can also be well validated from the PV analysis.

scholarly journals The state of mental health in the Philippines

2004 ◽  
Vol 1 (6) ◽  
pp. 8-11 ◽  
Author(s):  
Udgardo Juan L. Tolentino
Keyword(s):  
Mental Health ◽  
South China Sea ◽  
South China ◽  
The Philippines ◽  
Land Area ◽  
The South ◽  
The West ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean

The Philippines, known as the Pearl of the Orient, is an archipelago of 7107 islands, bounded on the west by the South China Sea, on the east by the Pacific Ocean, on the south by the Sulu and Celebes Sea, and on the north by the Bashi Channel. The northernmost islands are about 240 km south of Taiwan and the southernmost islands approximately 24 km from Borneo. The country has a total land area of some 300 000 km2. It is divided into three geographical areas: Luzon, Visayas and Mindanao. It has 17 regions, 79 provinces, 115 cities, 1495 municipalities and 41 956 barangays (the smallest geographic and political unit). It has over 100 ethnic groups and a myriad of foreign influences (including Malay, Chinese, Spanish and American).

scholarly journals The South Atlantic Subtropical High: Climatology and Interannual Variability

2017 ◽  
Vol 30 (9) ◽  
pp. 3279-3296 ◽  
Author(s):  
Xiaoming Sun ◽  
Kerry H. Cook ◽  
Edward K. Vizy
Keyword(s):  
Interannual Variability ◽  
Annual Cycle ◽  
Large Scale ◽  
Austral Summer ◽  
Southern Annular Mode ◽  
South Atlantic ◽  
Subtropical High ◽  
Interannual Variations ◽  
The South ◽  
The North

ERA-Interim and JRA-55 reanalysis products are analyzed to document the annual cycle of the South Atlantic subtropical high (SASH) and examine how its interannual variability relates to regional and large-scale climate variability. The annual cycle of the SASH is found to have two peaks in both intensity and size. The SASH is strongest and largest during the solstitial months when its center is either closest to the equator and on the western side of the South Atlantic basin during austral winter or farthest poleward and in the center of the basin in late austral summer. Although interannual variations in the SASH’s position are larger in the zonal direction, the intensity of the high decreases when it is positioned to the north. This relationship is statistically significant in every month. Seasonal composites and EOF analysis indicate that meridional changes in the position of the SASH dominate interannual variations in austral summer. In particular, the anticyclone tends to be displaced poleward in La Niña years when the southern annular mode (SAM) is in its positive phase and vice versa. Wave activity flux vectors suggest that ENSO-related convective anomalies located in the central-eastern tropical Pacific act as a remote forcing for the meridional variability of the summertime SASH. In southern winter, multiple processes operate in concert to induce interannual variability, and none of them appears to dominate like ENSO does during the summer.

Fujita, Tsuguharu (藤田嗣治) (1886–1968)

2018 ◽  
Author(s):  
John Szostak
Keyword(s):  
Cultural Landscape ◽  
Large Scale ◽  
Pacific War ◽  
The West ◽  
White Pigment ◽  
The Pacific ◽  
Japanese Military ◽  
Post War ◽  
Contemporary Painting ◽  
French Citizen

Fujita Tsuguharu was a Japanese oil painter who spent most of his career in France. He is known in the West for female nudes and portraits painted in the 1920s with a distinctive pearl-white pigment, executed in a style that melds French modernism with the linear aesthetics of traditional Japanese prints. These paintings, which frequently featured cats, won him both critical and popular acclaim, earned him membership in the Salon d’Automne, and made him a mainstay of the Montparnasse artist community. He is the sole Japanese painter associated with the École de Paris. Fujita returned to Japan in 1933, where he exerted substantial influence on contemporary painting as a member of the Second Section Society (Nikakai). During the Pacific War, Fujita created many large-scale works for the Japanese military as an official war artist, activities that continue to affect his reputation in Japan today. Difficulties adjusting to the post-war cultural landscape of Japan led Fujita to return to France in 1950, where he revitalized his career. He became a French citizen in 1955, and was awarded the Legion of Honour in 1957.

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