scholarly journals An Intraseasonal Prediction Model of Atlantic and East Pacific Tropical Cyclone Genesis

2013 ◽  
Vol 141 (6) ◽  
pp. 1925-1942 ◽  
Author(s):  
Stephanie A. Slade ◽  
Eric D. Maloney
Keyword(s):  
Logistic Regression ◽  
Tropical Cyclone ◽  
Southern Oscillation ◽  
Selection Procedure ◽  
Ocean Basin ◽  
Tropical Cyclogenesis ◽  
Tropical Cyclone Genesis ◽  
East Pacific ◽  
Skill Scores ◽  
Cyclone Genesis

Abstract A real-time statistical model based on the work of Leroy and Wheeler is developed via multiple logistic regression to predict weekly tropical cyclone activity over the Atlantic and east Pacific basins. The predictors used in the model include a climatology of tropical cyclone genesis for each ocean basin, an El Niño–Southern Oscillation (ENSO) index, and two indices representing the propagating Madden–Julian oscillation (MJO). The Atlantic model also includes a predictor representing the variability of sea surface temperature (SST) in the Main Development Region (MDR). These predictors are suggested as useful for the prediction of tropical cyclogenesis based on previous work in the literature and are further confirmed in this study using basic statistics. Univariate logistic regression models are generated for each predictor in each region to ensure the choice of prediction scheme. Using all predictors, cross-validated hindcasts are developed out to a seven-week forecast lead. A formal stepwise predictor selection procedure is implemented to select the predictors used in each region at each forecast lead. Brier skill scores and reliability diagrams are used to assess the skill and dependability of the models. Results show an increase in model skill over the time-varying climatology at predicting tropical cyclogenesis by the inclusion of the MJO out to a three-week forecast lead for the east Pacific and a two-week forecast lead for the Atlantic. The importance of ENSO and MDR SST for Atlantic genesis prediction is highlighted, and the uncertain effects of ENSO on east Pacific tropical cyclogenesis are revisited.

Asymmetric impact of CP ENSO on the significant reduction of tropical cyclone genesis frequency over the WNP since the late 1990s

2020 ◽  
Author(s):  
Han-Kyoung Kim ◽  
Sang-Wook Yeh ◽  
Nam-Young Kang ◽  
Byung-Kwon Moon
Keyword(s):  
Tropical Cyclone ◽  
Climate Model ◽  
Model Simulation ◽  
Southern Oscillation ◽  
Underlying Mechanism ◽  
Tropical Cyclone Genesis ◽  
Central Pacific ◽  
Asymmetric Impact ◽  
Cyclone Genesis ◽  
Genesis Frequency

<p>Tropical cyclone (TC) genesis frequency over the western North Pacific (WNP) is reduced significantly since the late 1990s, coinciding with a Pacific decadal oscillation (PDO) phase change from positive to negative. In this study, the underlying mechanism for this reduction is investigated through analysis of asymmetric central Pacific (CP) El Niño-Southern Oscillation (ENSO) properties induced by the negative PDO phase. Results suggest that the significant reduction is caused by asymmetric CP ENSO properties, in which the CP La Niña is more frequent than the CP El Niño during negative PDO phases; furthermore, stronger CP La Niña occurs during a negative PDO phase than during a positive PDO phase. CP La Niña (El Niño) events generate an anticyclonic (cyclonic) Rossby wave response over the eastern WNP, leading to a significant decrease (increase) in eastern WNP TC genesis. Therefore, more frequent CP La Niña events and the less frequent CP El Niño events reduce the eastern WNP mean TC genesis frequency during a negative PDO phase. In addition, stronger CP La Niña events during a negative PDO phase reinforce the reduction in eastern WNP TC genesis. The dependency of CP ENSO properties on the PDO phase is confirmed using a long-term climate model simulation, which supports our observational results. </p><p>Acknowledgements: This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT; No. 2019R1A2C1008549).</p>

scholarly journals Tropical cyclone genesis across palaeoclimates

2015 ◽  
Vol 11 (1) ◽  
pp. 181-220 ◽  
Author(s):  
J. H. Koh ◽  
C. M. Brierley
Keyword(s):  
Carbon Dioxide ◽  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Large Scale ◽  
Climate Models ◽  
Tropical Cyclogenesis ◽  
Tropical Cyclone Genesis ◽  
Inter Tropical Convergence Zone ◽  
Potential Index ◽  
Cyclone Genesis

Abstract. Tropical cyclone genesis is investigated for the Pliocene, Last Glacial Maximum (LGM) and the mid-Holocene through analysis of five climate models. The genesis potential index is used to estimate this from large scale atmospheric properties. The mid-Pliocene and LGM characterise periods where carbon dioxide levels were higher and lower than pre-industrial respectively, while the mid-Holocene differed primarily in its orbital configuration. The number of tropical cyclones formed each year is found to be fairly consistent across the various palaeoclimates. Although there is some model uncertainty in the change of global annual tropical cyclone frequency, there are coherent changes in the spatial patterns of tropical cyclogenesis. During the Pliocene and LGM, changes in carbon dioxide led to sea surface temperature changes throughout the tropics, yet the potential intensity of tropical cyclones appears relatively insensitive to these variations. Changes in tropical cyclone genesis during the mid-Holocene are observed to be asymmetric about the Equator: genesis is reduced in the Northern Hemisphere, but enhanced in the Southern Hemisphere. This is clearly driven by the altered seasonal insolation. Nonetheless, the enhanced seasonality may have driven localised effects on tropical cyclone genesis, through changes to the strength of monsoons and shifting of the inter-tropical convergence zone. Trends in future tropical cyclone genesis are neither consistent between the five models studied, nor with the palaeoclimate results. It is not clear why this should be the case.

scholarly journals Forecasting the Tropical Cyclone Genesis over the Northwest Pacific through Identifying the Causal Factors in Cyclone–Climate Interactions

2018 ◽  
Vol 35 (2) ◽  
pp. 247-259 ◽  
Author(s):  
Chengzu Bai ◽  
Ren Zhang ◽  
Senliang Bao ◽  
X. San Liang ◽  
Wenbo Guo
Keyword(s):  
Tropical Cyclone ◽  
Southern Oscillation ◽  
Causal Relation ◽  
Western Pacific Subtropical High ◽  
Tropical Cyclone Genesis ◽  
Climate Indices ◽  
Northwest Pacific ◽  
Causality Analysis ◽  
Climate Interactions ◽  
Cyclone Genesis

AbstractHow to extract the causal relations in climate–cyclone interactions is an important problem in atmospheric science. Traditionally, the most commonly used research methodology in this field is time-delayed correlation analysis. This may be not appropriate, since a correlation cannot imply causality, as it lacks the needed asymmetry or directedness between dynamical events. This study introduces a recently developed and very concise but rigorous formula—that is, a formula for information flow (IF)—to fulfill the purpose. A new way to normalize the IF is proposed and then the normalized IF (NIF) is used to detect the causal relation between the tropical cyclone (TC) genesis over the western North Pacific (WNP) and a variety of climate modes. It is shown that El Niño–Southern Oscillation and Pacific decadal oscillation are the dominant factors that modulate the WNP TC genesis. The western Pacific subtropical high and the monsoon trough are also playing important roles in affecting the TCs in the western and eastern regions of the WNP, respectively. With these selected climate indices as predictors, a method of fuzzy graph evolved from a nonparametric Bayesian process (BNP-FG), which is capable of handling situations with insufficient samples, is employed to perform a seasonal TC forecast. A forecast with the classic Poisson regression is also conducted for comparison. The BNP-FG model and the causality analysis are found to provide a satisfactory estimation of the number of TC genesis observed in recent years. Considering its generality, it is expected to be applicable in other climate-related predictions.

scholarly journals A Statistical Model of Tropical Cyclone Tracks in the Western North Pacific with ENSO-Dependent Cyclogenesis

2011 ◽  
Vol 50 (8) ◽  
pp. 1725-1739 ◽  
Author(s):  
Emmi Yonekura ◽  
Timothy M. Hall
Keyword(s):  
Tropical Cyclone ◽  
Statistical Model ◽  
North Pacific ◽  
Western North Pacific ◽  
Southern Oscillation ◽  
North Pacific Ocean ◽  
The Philippines ◽  
Tropical Cyclone Genesis ◽  
Cyclone Genesis ◽  
Index Value

AbstractA new statistical model for western North Pacific Ocean tropical cyclone genesis and tracks is developed and applied to estimate regionally resolved tropical cyclone landfall rates along the coasts of the Asian mainland, Japan, and the Philippines. The model is constructed on International Best Track Archive for Climate Stewardship (IBTrACS) 1945–2007 historical data for the western North Pacific. The model is evaluated in several ways, including comparing the stochastic spread in simulated landfall rates with historic landfall rates. Although certain biases have been detected, overall the model performs well on the diagnostic tests, for example, reproducing well the geographic distribution of landfall rates. Western North Pacific cyclogenesis is influenced by El Niño–Southern Oscillation (ENSO). This dependence is incorporated in the model’s genesis component to project the ENSO-genesis dependence onto landfall rates. There is a pronounced shift southeastward in cyclogenesis and a small but significant reduction in basinwide annual counts with increasing ENSO index value. On almost all regions of coast, landfall rates are significantly higher in a negative ENSO state (La Niña).

scholarly journals Investigate the relationship between Storm Formation and Tropical Cyclone Genesis Potential Index in the Vietnam East Sea

2019 ◽  
Vol 35 (2) ◽  
Author(s):  
Nguyen Manh Linh ◽  
Jack Katzfey ◽  
John McGregor ◽  
Nguyen Kim Chi ◽  
Pham Quang Nam ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
El Nino ◽  
East Sea ◽  
Tropical Cyclogenesis ◽  
Tropical Cyclone Genesis ◽  
Genesis Potential Index ◽  
American Meteorological Society ◽  
La Nina ◽  
Potential Index ◽  
Cyclone Genesis

Abstract: In this paper, the relationship between Tropical Cyclone (TC) Genesis Potential Index (GPI) and the number of TC (NTC) associated with ENSO over the Vietnam East Sea (VES) was investigated. Observed TC data of the Regional Specialized Meteorological Center (RSMC) Tokyo Typhoon Center and ERA Interim reanalysis data for the period 1985-2015 were used. The results show a good agreement between GPI and NTC over the VES with the correlation coefficient is 0.84. There were more TCs formed over the VES during La Nina years and less TCs during El Nino years. There were positive anomalies of GPI, environmental factors (relative humidity, sea surface temperature, absolute vorticity, potential intensity)over the region where the highest densityof TCs genesis locatedduring La Nina years while there were negative anomalies found during El Nino years. Relative humidity has the largest contribution to the positive difference GPI between La Nina years and El Nino years, the less contribution comes from the potential intensity, absolute vorticity, and wind shear. Keywords: GPI, Tropical Cyclone Genesis, ENSO, Vietnam East Sea. References: [1] K.A. Emanuel, D.S. Nolan, Tropical cyclone activity and global climate, Reprints, 26th Conference on hurricane and Tropical Meteorology, American meteorological Society: Miami, (2004) 240–241.[2] D.S. Nolan, E.D. Rappin, K.A. Emanuel., Tropical cyclogenesis sensitivity to environmental parameters in radiative-convective equilibrium, Quarterly Journal of the Royal Meteorological Society. 133 (2007) 2085–2107.[3] S.J. Camargo, K.A. Emanuel, A.H. Sobel, Use of the Genesis Potential Index to Diagnose ENSO effected on Tropical Cyclone Genesis, American Meteorological Society.20 (2007) 4819-4834[4] C.L. Bruyere, G.J. Holland, E. Towler, Investigating the Used of a Genesis Potential Index for Tropical Cyclones in the North Atlatic Basin, American Meteorological Society..25 (2012) 8611-8626[5] Song Yuan, Wang Lei, Lei Xiaoyan and Wang Xidong, Tropical cyclone genesis potential index over western north Pacific simulated by CMIP5 models, (2015).[6] Lei Wang, Diagnostic of the ENSO modulation of Tropical cyclogenesis over the southern South China Sea using a genesis potential index, Acta Oceanol. Sin., Vol. 31, No. 5 (2012) 54-68.[7] Xin Kieu-Thi, Hang Vu-Thanh, Truong Nguyen-Minh, Duc Le, Linh Nguyen-Manh, Izuru Takayabu, Hidetaka Sasaki, Akio Kito, Rainfall and tropical cyclone activity over Vietnam simulated and projected by the Non-Hydrostatic Regional Climate Model – NHRCM, Journal of the Meteorological Society of Japan. 94A (2016) 135-150.[8] https://www.jma.go.jp/jma/jma-eng/jma-center/ rsmc-hp-pub-eg/trackarchives.html[9] Trần Quang Đức, Xu thế biến động của một số đặc trưng ENSO, Tạp chí Khoa học Đại học Quốc gia Hà Nội, Khoa học Tự nhiên và Công nghệ. 1S (2011) 29-36.[10] https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php[11] E. Palmen, Formation and development of tropical cyclones, Proceedings of tropical cyclone Symposium, Brisbane, Australian Bur. Meteorol., Melbourne, (1956) 213-231[12] M. DeMaria, The effect of vertical wind shear on tropical cyclone intensity change, Jounal of Atmospheric Sicences. 53 (1996) 2076-2087.[13] S.J. Camargo, Diagnosis of the MJO modulation of Tropical cyclogenesis using an empirical index. American Meteorological Society. 66 (2009) 3061-3074.[14] S.J. Camargo, A.H. Sobel, Anthony G. Barnston, K.A. Emanuel, Tropical cyclone genesis potential index in climate models, Tellus A: Dynamic Meteorology and Ocenaography. 59:4 (2007) 428-443. doi: 10.1111/j.1600-0870.2007. 00238.

scholarly journals Understanding differences in tropical cyclone activity over the Arabian Sea and Bay of Bengal

MAUSAM ◽  
2021 ◽  
Vol 72 (1) ◽  
pp. 187-198
Author(s):  
IRIS C. LIU ◽  
SUZANA J. CAMARGO ◽  
ADAM H. SOBEL
Keyword(s):  
Tropical Cyclone ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Ocean Basin ◽  
North Indian Ocean ◽  
Tropical Cyclone Genesis ◽  
The North ◽  
The Difference ◽  
Cyclone Genesis ◽  
The Individual

Within the North Indian Ocean basin, tropical cyclone (TC) activity over the Bay of Bengal (BoB) is substantially greater than over the Arabian Sea (AS). The authors attempt to quantify the roles of specific environmental factors in order to understand the reasons for this difference between the two basins. Environmental variables are considered in the basin as a whole and in the immediate times and places at which cyclogenesis and storm intensification occur.The results for the two sub-basins are compared to determine  which environmental variablessignificantly between the sub-basins. A tropical cyclone genesis index (TCGI) is also examined to determine whether the AS- differedBased on that partial success, climatologies of the individual factors that comprise the index are examined to determine which ones are most important in the difference  

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