scholarly journals Climatological Characteristics and Seasonal Forecasting of Tropical Cyclones Making Landfall along the South China Coast

2003 ◽  
Vol 131 (8) ◽  
pp. 1650-1662 ◽  
Author(s):  
K. S. Liu ◽  
Johnny C. L. Chan
Keyword(s):  
Tropical Cyclones ◽  
South China ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
The South ◽  
La Nina ◽  
South China Coast ◽  
China Coast

Abstract This paper presents the important climatological features of the tropical cyclones making landfall along the South China coast and proposes a statistical scheme for the prediction of the annual number of such tropical cyclones. This number is found to have a large variation, which is mainly due to the occurrence or nonoccurrence of the El Niño–Southern Oscillation (ENSO) phenomenon. A strong El Niño event is found to reduce the number of landfalling tropical cyclones whereas more tropical cyclones tend to make landfall in years associated with La Niña events. Such variations are more prominent in some seasons. The late season (October–November) activity is generally suppressed (enhanced) in El Niño (La Niña) years whereas the chance of a tropical cyclone striking the South China coast increases (decreases) significantly in the early season (May and June) after the mature phase of a La Niña (El Niño) event. These anomalous activities are apparently linked to the ENSO-induced anomalies in the low- and midlevel large-scale circulation. Based on the ENSO-related indices such as the Niño-3.4 sea surface temperature anomaly and the equatorial Southern Oscillation index, a statistical prediction scheme for the annual number of such landfalling tropical cyclones by 1 April is developed using the projection–pursuit regression technique. This scheme provides a 40% skill improvement in root-mean-square error with respect to climatology. A real-time prediction made in 2001 gave reasonable results.

scholarly journals Diversity of Marine Heatwaves in the South China Sea regulated by the ENSO phase

2021 ◽  
pp. 1-51
Author(s):  
Kai Liu ◽  
Kang Xu ◽  
Congwen Zhu ◽  
Boqi Liu
Keyword(s):  
South China Sea ◽  
Latent Heat ◽  
South China ◽  
El Niño ◽  
El Nino ◽  
The South China Sea ◽  
La Niña ◽  
The South ◽  
China Sea ◽  
La Nina

Abstract Marine heatwaves (MHWs) in the South China Sea (SCS) have dramatic impacts on local ecosystems, fisheries, and aquacultures. Our results show that SCS MHWs were strongly regulated by El Niño-Southern Oscillation (ENSO) with a distinct life cycle during 1982–2018. Based on the ENSO-associated sea surface temperature anomaly (SSTA) warming peaks in the SCS, we can classify SCS MHWs into three categories, namely, El Niño-P1 during the first warming peak of El Niño from September to the following February, El Niño-P2 during the second warming peak of El Niño from the following June to September, and La Niña-P1 during the single warming peak of La Niña from the following February to May. The three types of SCS MHWs are all affected by the lower-level enhanced anticyclone over the western North Pacific (WNP), but their physical mechanisms are quite different. In El Niño-P1, SCS MHWs are mostly induced by enhanced net downward shortwave radiation and reduced latent heat flux loss over the southwestern and northern SCS, respectively. In El Niño-P2, SCS MHWs are primarily attributed to weaker entrainment cooling caused by a local enhanced anticyclone and stronger Ekman downwelling in the central-northern SCS. However, in La Niña-P1, SCS MHWs are mainly contributed by the reduced latent heat loss due to the weaker WNP anticyclone centered east of the Philippines on the pentad timescale. The distinct spatial distributions of MHWs show phase locking with ENSO-associated SCS SSTA warming, which provides a potential seasonal forecast of SCS MHWs according to the ENSO phase.

scholarly journals Major Floods and Tropical Cyclones over Bangladesh: Clustering from ENSO Timescales

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 692
Author(s):  
Md Wahiduzzaman
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Flood Events ◽  
Post Monsoon ◽  
La Nina ◽  
Synoptic Conditions ◽  
Major Floods

The present study analyzed major floods and tropical cyclones (TCs) over Bangladesh on El Niño-Southern Oscillation (ENSO) timescales. The geographical location, low and almost flat topography have introduced Bangladesh as one of the most vulnerable countries of the world. Bangladesh is highly vulnerable to the extreme hazard events like floods and cyclones which are impacted by ENSO. ENSO is mainly a tropical event, but its impact is global. El Niño (La Niña) represents the warm (cold) phase of the ENSO cycle. Rainfall and cyclonic disturbances data have been used for the period of 70 years (1948–2017) and compared with the corresponding observations of the Southern Oscillation Index. Result shows that major flood events occurred during the monsoon period, and most of them are during the La Niña condition, consistent with the historical archives of flood events in Bangladesh. Synoptic conditions of these events are well matched during La Niña condition. On the other hand, the major TC cases are in the period of either pre-monsoon or post-monsoon season. The pre-monsoon cases are under neutral (developing La Niña) or El Niño and the post-monsoon cases are under La Niña, consistent with climatology studies that La Niña is favorable to have more intense TCs over the Bay of Bengal.

scholarly journals Changes in Western Pacific Tropical Cyclones Associated with the El Niño–Southern Oscillation Cycle

2012 ◽  
Vol 25 (17) ◽  
pp. 5864-5878 ◽  
Author(s):  
Richard C. Y. Li ◽  
Wen Zhou
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
Wind Shear ◽  
El Nino ◽  
Southern Oscillation ◽  
Vertical Wind Shear ◽  
Vertical Wind ◽  
La Niña ◽  
El Nino Southern Oscillation ◽  
La Nina

Abstract This study examines the interannual variability of three groups of tropical cyclones (TCs)—super typhoons (STYs), typhoons (TYs), and tropical storms and tropical depressions (TSTDs)—and their relationship with the El Niño–Southern Oscillation (ENSO). Both wavelet analysis and correlation studies of upper-ocean heat content reveal significant differences for the three types of TCs. In particular, an increase (decrease) in the frequency of STYs is usually associated with the mature phase of El Niño (La Niña) events, while the converse is true for TSTDs. In contrast, the frequency of TYs increases (decreases) during the transition period from La Niña to El Niño (El Niño to La Niña) events. The results suggest that the timing with which ENSO impacts STYs, TYs, and TSTDs varies and that their corresponding changes in frequency closely follow the evolution of the ENSO cycle. Empirical orthogonal function analysis is also conducted to investigate the impact of different environmental factors influenced by ENSO on TCs. The vertical wind shear and moist static energy associated with ENSO are identified as the dominant factors that control the frequency of STYs. In comparison, the frequency of TYs is found to be closely related to the relative vorticity and vertical wind shear associated with both the transition phase of ENSO and with other types of climate variability.

Asymmetric response of the South China Sea SST to El Niño and La Niña

2013 ◽  
Vol 12 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Zhuo Huang ◽  
Yan Du ◽  
Yanling Wu ◽  
Haiming Xu
Keyword(s):  
South China Sea ◽  
South China ◽  
El Niño ◽  
El Nino ◽  
The South China Sea ◽  
La Niña ◽  
The South ◽  
China Sea ◽  
La Nina ◽  
Asymmetric Response

Rendimento de grãos de soja e de milho, no Rio Grande do Sul, não difere entre eventos El Niño Oscilação Sul

Agrometeoros ◽  
2018 ◽  
Vol 26 (1) ◽  
Author(s):  
Ronaldo Matzenauer ◽  
Bernadete Radin ◽  
Alberto Cargnelutti Filho
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Rio Grande ◽  
La Niña ◽  
Rio Grande Do Sul ◽  
La Nina ◽  
Significant Difference ◽  
Income Data ◽  
The Relationship

O objetivo deste trabalho foi avaliar a relação entre o fenômeno El Niño Oscilação Sul - ENOS e o rendimento de grãos de soja e de milho no Rio Grande do Sul e verificar a hipótese de que os eventos El Niño são favoráveis e os eventos La Niña são prejudiciais ao rendimento de grãos das culturas. Foram utilizados dados de rendimento de grãos dos anos agrícolas de 1974/75 a 2016/17, e relacionados com as ocorrências de eventos ENOS. Foram analisados os dados de rendimento observados na colheita e os dados estimados com a remoção da tendência tecnológica. Os resultados mostraram que não houve diferença significativa do rendimento médio de grãos de soja e de milho na comparação entre os eventos ENOS. Palavras-chave: El Niño, La Niña, safras agrícolas. Abstract – The objective of this work was to evaluate the relationship between the El Niño Southern Oscillation (ENSO) phenomenon with the grain yield of soybean and maize in Rio Grande do Sul state, Brazil and to verify the hypothesis that the El Niño events are favorable and the La Niña events are harmful to the culture’s grain yields. Were used data from the agricultural years of 1974/75 to 2016/17, and related to the occurrence of ENOS events. We analyzed income data observed at harvest and estimated data with technological tendency was removed. The results showed that there was no significant difference in the average yield of soybeans and corn in the comparison between events.

scholarly journals El Niño, La Niña, and the Forecastability of the Realized Variance of Heating Oil Price Movements

2021 ◽  
Vol 13 (14) ◽  
pp. 7987
Author(s):  
Mehmet Balcilar ◽  
Elie Bouri ◽  
Rangan Gupta ◽  
Christian Pierdzioch
Keyword(s):  
El Niño ◽  
Predictive Value ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
Realized Variance ◽  
La Nina ◽  
Out Of Sample ◽  
Heating Oil ◽  
Price Movements

We use the heterogenous autoregressive (HAR) model to compute out-of-sample forecasts of the monthly realized variance (RV) of movements of the spot and futures price of heating oil. We extend the HAR–RV model to include the role of El Niño and La Niña episodes, as captured by the Equatorial Southern Oscillation Index (EQSOI). Using data from June 1986 to April 2021, we show evidence for several model configurations that both El Niño and La Niña phases contain information useful for forecasting subsequent to the realized variance of price movements beyond the predictive value already captured by the HAR–RV model. The predictive value of La Niña phases, however, seems to be somewhat stronger than the predictive value of El Niño phases. Our results have important implications for investors, as well as from the perspective of sustainable decisions involving the environment.

scholarly journals Role of the Indo-Pacific Interbasin Coupling in Predicting Asymmetric ENSO Transition and Duration

2012 ◽  
Vol 25 (9) ◽  
pp. 3321-3335 ◽  
Author(s):  
Masamichi Ohba ◽  
Masahiro Watanabe
Keyword(s):  
El Niño ◽  
General Circulation ◽  
El Nino ◽  
Southern Oscillation ◽  
La Niña ◽  
La Nina ◽  
The Pacific ◽  
Enso Asymmetry ◽  
Sst Anomalies

Warm and cold phases of El Niño–Southern Oscillation (ENSO) exhibit a significant asymmetry in their transition/duration such that El Niño tends to shift rapidly to La Niña after the mature phase, whereas La Niña tends to persist for up to 2 yr. The possible role of sea surface temperature (SST) anomalies in the Indian Ocean (IO) in this ENSO asymmetry is investigated using a coupled general circulation model (CGCM). Decoupled-IO experiments are conducted to assess asymmetric IO feedbacks to the ongoing ENSO evolution in the Pacific. Identical-twin forecast experiments show that a coupling of the IO extends the skillful prediction of the ENSO warm phase by about one year, which was about 8 months in the absence of the IO coupling, in which a significant drop of the prediction skill around the boreal spring (known as the spring prediction barrier) is found. The effect of IO coupling on the predictability of the Pacific SST is significantly weaker in the decay phase of La Niña. Warm IO SST anomalies associated with El Niño enhance surface easterlies over the equatorial western Pacific and hence facilitate the El Niño decay. However, this mechanism cannot be applied to cold IO SST anomalies during La Niña. The result of these CGCM experiments estimates that approximately one-half of the ENSO asymmetry arises from the phase-dependent nature of the Indo-Pacific interbasin coupling.

scholarly journals The roles of ENSO on the occurrence of abruptly recurving tropical cyclones over the Western North Pacific Ocean Basin

2006 ◽  
Vol 6 ◽  
pp. 139-148 ◽  
Author(s):  
N. K. W. Cheung
Keyword(s):  
Tropical Cyclones ◽  
El Niño ◽  
North Pacific ◽  
Western North Pacific ◽  
Pressure Field ◽  
El Nino ◽  
North Pacific Ocean ◽  
Ocean Basin ◽  
La Niña ◽  
La Nina

Abstract. The abruptly recurving tropical cyclones over the Western North Pacific Ocean Basin during El Niño and La Niña events are studied. Temporal and spatial variations of these anomalous tracks under different phases of ENSO are shown. The anomalies of the pressure field in relation to ENSO circulation for the occurrence of the abruptly recurving cyclone tracks are investigated using fuzzy method. These are supplemented by wind field analyses. It is found that the occurrence of recurving-left (RL) and recurving-right (RR) tropical cyclones under the modification of the steering currents, including the re-adjustment of the westerly trough, the expansion or contraction of the sub-tropical high pressure, the intensifying easterly flow and the strengthening of the cross-equatorial flow, can be in El Niño or La Niña events. Evidently, there is a higher chance of occurrence of anomalous tropical cyclone trajectories in El Niño rather than La Niña events, but there is not any pronounced spatial pattern of anomalous tropical cyclone tracks. By analyzing the pressure-field, it is seen RL (RR) tropical cyclones tend to occur when the subtropical high pressure is weak (strong) in El Niño and La Niña events. More importantly, how the internal force of tropical cyclones changed by the steering current, which relies upon the relative location of tropical cyclones to the re-adjustment of the weather systems, shows when and where RL and RR tropical cyclones occur in El Niño and La Niña events.

scholarly journals The Impact of Obliquity Change on El Niño Southern Oscillation (ENSO) and La Niña Climate Episodes

2022 ◽  
Author(s):  
Paul C. Rivera
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Global Climate Model ◽  
La Niña ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
La Nina ◽  
The Impact

An alternative physical mechanism is proposed to describe the occurrence of the episodic El Nino Southern Oscillation (ENSO) and La Nina climatic phenomena. This is based on the earthquake-perturbed obliquity change (EPOCH) model previously discovered as a major cause of the global climate change problem. Massive quakes impart a very strong oceanic force that can move the moon which in turn pulls the earth’s axis and change the planetary obliquity. Analysis of the annual geomagnetic north-pole shift and global seismic data revealed this previously undiscovered force. Using a higher obliquity in the global climate model EdGCM and constant greenhouse gas forcing showed that the seismic-induced polar motion and associated enhanced obliquity could be the major mechanism governing the mysterious climate anomalies attributed to El Nino and La Nina cycles.

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