scholarly journals The 2020 Summer Floods and 2020/21 Winter Extreme Cold Surges in China and the 2020 Typhoon Season in the Western North Pacific

2021 ◽  
Author(s):  
Chunzai Wang ◽  
Yulong Yao ◽  
Haili Wang ◽  
Xiubao Sun ◽  
Jiayu Zheng
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Extreme Cold ◽  
Cold Surges ◽  
Typhoon Season

scholarly journals Contributions of SST Anomalies in the Indo-Pacific Ocean to the Interannual Variability of Tropical Cyclone Genesis Frequency over the Western North Pacific

2019 ◽  
Vol 32 (11) ◽  
pp. 3357-3372 ◽  
Author(s):  
Ruifen Zhan ◽  
Yuqing Wang ◽  
Jiuwei Zhao
Keyword(s):  
Pacific Ocean ◽  
Tropical Cyclone ◽  
Statistical Model ◽  
Interannual Variability ◽  
North Pacific ◽  
Western North Pacific ◽  
Southern Oscillation ◽  
Typhoon Season ◽  
Genesis Frequency ◽  
Sst Anomalies

Abstract This study attempts to evaluate quantitatively the contributions of sea surface temperature (SST) anomalies in the Indo-Pacific Ocean to the interannual variability of tropical cyclone (TC) genesis frequency (TCGF) over the western North Pacific (WNP). Three SST factors in the Indo-Pacific Ocean are found to play key roles in modulating the interannual variability of WNP TCGF. They are summer SST anomaly in the east Indian Ocean (EIO), the summer El Niño–Southern Oscillation Modoki index (EMI), and the spring SST gradient (SSTG) between the southwestern Pacific and the western Pacific warm pool. Results show that the three factors together can explain 72% of the total variance of WNP TCGF in the typhoon season for the period 1980–2015. Among them, the spring SSTG and the summer EIO contribute predominantly to the interannual variability of TCGF, followed by the summer EMI, with respective contributions being 39%, 38%, and 23%. Further analysis shows that the summer EMI was affected significantly by the spring SSTG and thus had a relatively lower contribution to the TCGF than the spring SSTG. In addition, a statistical model is constructed to predict the WNP TCGF in the typhoon season by a combination of the May EIO and the spring SSTG. The new model can reproduce well the observed WNP TCGF and shows an overall better skill than the ECMWF Seasonal Forecasting System 5 (SEAS5) hindcasts. This statistical model provides a good tool for seasonal prediction of WNP TCGF.

scholarly journals A Statistical Analysis of the Effects of Vertical Wind Shear on Tropical Cyclone Intensity Change over the Western North Pacific

2015 ◽  
Vol 143 (9) ◽  
pp. 3434-3453 ◽  
Author(s):  
Yuqing Wang ◽  
Yunjie Rao ◽  
Zhe-Min Tan ◽  
Daria Schönemann
Keyword(s):  
North Pacific ◽  
Wind Shear ◽  
Western North Pacific ◽  
Deep Layer ◽  
Vertical Wind Shear ◽  
Vertical Wind ◽  
Intensity Change ◽  
Low Level ◽  
Typhoon Season ◽  
Translational Speed

Abstract The effect of vertical wind shear (VWS) between different pressure levels on TC intensity change is statistically analyzed based on the best track data of tropical cyclones (TCs) in the western North Pacific (WNP) from the Joint Typhoon Warning Center (JTWC) and the ECMWF interim reanalysis (ERA-Interim) data during 1981–2013. Results show that the commonly used VWS measure between 200 and 850 hPa is less representative of the attenuating deep-layer shear effect than that between 300 and 1000 hPa. Moreover, the authors find that the low-level shear between 850 (or 700) and 1000 hPa is more negatively correlated with TC intensity change than any deep-layer shear during the active typhoon season, whereas deep-layer shear turns out to be more influential than low-level shear during the remaining less active seasons. Further analysis covering all seasons exhibits that a TC has a better chance to intensify than to decay when the deep-layer shear is lower than 7–9 m s−1 and the low-level shear is below 2.5 m s−1. The probability for TCs to intensify and undergo rapid intensification (RI) increases with decreasing VWS and increasing sea surface temperature (SST). TCs moving at slow translational speeds (less than 3 m s−1) intensify under relatively weaker VWS than TCs moving at intermediate translational speeds (3–8 m s−1). The probability of RI becomes lower than that of rapid decaying (RD) when the translational speed is larger than 8 m s−1. Most TCs tend to decay when the translational speed is larger than 12 m s−1 regardless of the shear condition.

Interpretation of Tropical Cyclone Forecast Sensitivity from the Singular Vector Perspective

2009 ◽  
Vol 66 (11) ◽  
pp. 3383-3400 ◽  
Author(s):  
Jan-Huey Chen ◽  
Melinda S. Peng ◽  
Carolyn A. Reynolds ◽  
Chun-Chieh Wu
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Flow Region ◽  
Synoptic Scale ◽  
Adjoint Systems ◽  
Dynamic Relationship ◽  
New Finding ◽  
Typhoon Season ◽  
The Relationship ◽  
Western North Pacific Typhoon

Abstract In this study, the leading singular vectors (SVs), which are the fastest-growing perturbations (in a linear sense) to a given forecast, are used to examine and classify the dynamic relationship between tropical cyclones (TCs) and synoptic-scale environmental features that influence their evolution. Based on the 72 two-day forecasts of the 18 western North Pacific TCs in 2006, the SVs are constructed to optimize perturbation energy within a 20° × 20° latitude–longitude box centered on the 48-h forecast position of the TCs using the Navy Operational Global Atmospheric Prediction System (NOGAPS) forecast and adjoint systems. Composite techniques are employed to explore these relationships and highlight how the dominant synoptic-scale features that impact TC forecasts evolve on seasonal time scales. The NOGAPS initial SVs show several different patterns that highlight the relationship between the TC forecast sensitivity and the environment during the western North Pacific typhoon season in 2006. In addition to the relation of the SV maximum to the inward flow region of the TC, there are three patterns identified where the local SV maxima collocate with low-radial-wind-speed regions. These regions are likely caused by the confluence of the flow associated with the TC itself and the flow from other synoptic systems, such as the subtropical high and the midlatitude jet. This is the new finding beyond the previous NOGAPS SV results on TCs. The subseasonal variations of these patterns corresponding to the dynamic characteristics are discussed. The SV total energy vertical structures for the different composites are used to demonstrate the contributions from kinetic and potential energy components of different vertical levels at initial and final times.

scholarly journals 2010 Western North Pacific Typhoon Season: Seasonal Overview and Forecast Using a Track-Pattern-Based Model

2012 ◽  
Vol 27 (3) ◽  
pp. 730-743 ◽  
Author(s):  
Joo-Hong Kim ◽  
Chang-Hoi Ho ◽  
Hyeong-Seog Kim ◽  
Woosuk Choi
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Track Density ◽  
Contributing Factors ◽  
Forecast System ◽  
The North ◽  
Rapid Transition ◽  
Typhoon Season ◽  
Track Pattern ◽  
Low Activity

Abstract Fourteen named tropical cyclones (TCs) formed in the western North Pacific (WNP) in 2010, representing the lowest count since 1951. Both low activity during the typhoon season (June–October) and quiescence during the pre- and posttyphoon seasons were major contributing factors. Despite overall low activity, TC activity along land boundaries was enhanced because the overall genesis locations of TCs shifted to the north and west and a majority of them affected the coastal countries in the WNP. These features are attributed to the expansion of the subtropical high and weakening of the monsoon trough associated with the rapid transition of the 2009/10 El Niño to the 2010/11 La Niña. The National Typhoon Center (NTC) in South Korea utilizes the recently developed track-pattern-based model of the hybrid statistical–dynamical type as the operational long-range TC forecast system. This model fairly forecast the anomalous spatial distribution of TC track density for the 2010 typhoon season. A higher-than-normal track density was successfully forecast near Korea and Japan. This is attributed to the overall skillful forecast of TC count for each pattern by the NTC model, though some deficiencies in forecasting extremes for some patterns are evident. The total seasonal genesis frequency integrated over the seven patterns is well below normal (about 16.4) close to the observations. The fair predictability in 2010 using the NTC model is attributed to the skillful forecast of the ENSO transition by the National Centers for Environmental Prediction’s Climate Forecast System, in addition to the validity of the NTC model itself.

Is there a quiescent typhoon season over the western North Pacific following a strong El Niño event?

2018 ◽  
Vol 39 (1) ◽  
pp. 61-73 ◽  
Author(s):  
Chao Wang ◽  
Liguang Wu ◽  
Haikun Zhao ◽  
Jian Cao ◽  
Wei Tian
Keyword(s):  
El Niño ◽  
North Pacific ◽  
Western North Pacific ◽  
El Nino ◽  
El Niño Event ◽  
Typhoon Season

scholarly journals Salient Differences in Tropical Cyclone Activity over the Western North Pacific between 1998 and 2016

2017 ◽  
Vol 30 (24) ◽  
pp. 9979-9997 ◽  
Author(s):  
Ruifen Zhan ◽  
Yuqing Wang ◽  
Qinyu Liu
Keyword(s):  
Tropical Cyclone ◽  
El Niño ◽  
North Pacific ◽  
Western North Pacific ◽  
El Nino ◽  
Western Pacific ◽  
The Pacific ◽  
El Niño Events ◽  
Typhoon Season ◽  
El Nino Events

Previous studies have suggested that tropical cyclone (TC) seasons over the western North Pacific (WNP) in the decaying years of El Niño events are generally less active than normal. The two strongest El Niño events on record were 1997/98 and 2015/16, but TC activities over the WNP displayed a sharp contrast between the decaying years of the two events. In 1998, consistent with previous studies, the WNP witnessed an extremely quiet season with no TC genesis in the preseason (January–June) and with only 10 named TCs observed in the typhoon season (July–October), making 1998 the most inactive season in the basin on record. In 2016, no TC formed in the preseason, similar to 1998; however, the basin became remarkably active in the typhoon season with above-normal named TCs observed. Further analyses indicate that the absence of TCs in the preseason in both 1998 and 2016 and the less active typhoon season in 1998 were attributed to the strong western Pacific anomalous anticyclone associated with the super El Niño events. However, the pattern of sea surface temperature anomalies (SSTAs) in the Pacific in 2016 showed features distinct from that in 1998. During July–August, the extremely positive phase of the Pacific meridional mode (PMM) triggered an anomalous cyclonic circulation and negative vertical wind shear over the WNP, favorable for TC geneses, while during September–October, the combined effect of the equatorial western Pacific warming and the weak La Niña event enhanced TC geneses over the WNP.

scholarly journals CFSv2-Based Statistical Prediction for Seasonal Accumulated Cyclone Energy (ACE) over the Western North Pacific

2016 ◽  
Vol 29 (2) ◽  
pp. 525-541 ◽  
Author(s):  
Ruifen Zhan ◽  
Yuqing Wang
Keyword(s):  
Statistical Model ◽  
Hybrid Model ◽  
North Pacific ◽  
Western North Pacific ◽  
Large Scale ◽  
Warm Pool ◽  
Statistical Prediction ◽  
Seasonal Forecasts ◽  
Typhoon Season ◽  
Using Data

Abstract A hybrid dynamical–statistical model is developed for predicting the accumulated cyclone energy (ACE)—a measure that can synthesize genesis number, mean life span, and intensity of tropical cyclones (TCs)—in the typhoon season (June–October) over the western North Pacific (WNP) using data from both observations and seasonal forecasts of the National Centers for Environmental Prediction’s (NCEP’s) Climate Forecast System, version 2 (CFSv2). The model is built on the relationships between the observed ACE and the large-scale variables for the period of 1982–2010. Four predictors are selected based on both previous work in the literature and statistical analyses in this study, including vertical zonal wind shear over the equatorial western North Pacific (Ushear), sea surface temperature (SST) gradient (SSTG) between the southwestern Pacific (SWP) and the western Pacific warm pool, Niño-3.4 SST, and SWP SST. Based on the cross validation, the hybrid model is finally constructed with the combination of the summer Niño-3.4 and SWP SST at the 4-to-2-month lead (January–March) and the summer Ushear and the April SSTG at the 1-to-0-month lead (April–May). The hybrid model is shown to be skillful in predicting WNP seasonal ACE starting from January, with the correlation coefficient ranging between 0.58 and 0.81 and the root-mean-square error ranging between 1.26 and 0.91 (scaled by 105 m2 s−2) initiated from January to May. The prediction experiments for 2011–13 using the hybrid dynamical–statistical model showed better skill and longer leads than that using the pure statistical models.

Physical processes controlling earlier and later onset of a typhoon season in the western North Pacific

2017 ◽  
Vol 51 (7-8) ◽  
pp. 2807-2823 ◽  
Author(s):  
Heng Zuo ◽  
Tim Li ◽  
Jia Liu ◽  
Melinda Peng
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Physical Processes ◽  
Typhoon Season

scholarly journals A new approach for location-specific seasonal outlooks of typhoon and super typhoon frequency across the Western North Pacific region

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrew D. Magee ◽  
Anthony S. Kiem ◽  
Johnny C. L. Chan
Keyword(s):  
North Pacific ◽  
Western North Pacific ◽  
Selection Procedure ◽  
The Philippines ◽  
Atmospheric Variability ◽  
Teleconnection Patterns ◽  
Super Typhoon ◽  
The North ◽  
Predictor Model ◽  
Typhoon Season

AbstractWith an average of 26 tropical cyclones (TCs) per year, the western North Pacific (WNP) is the most active TC basin in the world. Considerable exposure lies in the coastal regions of the WNP, which extends from Japan in the north to the Philippines in the south, amplifying TC related impacts, including loss of life and damage to property, infrastructure and environment. This study presents a new location-specific typhoon (TY) and super typhoon (STY) outlook for the WNP basin and subregions, including China, Hong Kong, Japan, Korea, Philippines, Thailand, and Vietnam. Using multivariate Poisson regression and considering up to nine modes of ocean-atmospheric variability and teleconnection patterns that influence WNP TC behaviour, thousands of possible predictor model combinations are compared using an automated variable selection procedure. For each location, skillful TY and STY outlooks are generated up to 6 months before the start of the typhoon season, with rolling monthly updates enabling refinement of predicted TY and STY frequency. This unparalleled lead time allows end-users to make more informed decisions before and during the typhoon season.

Sign in / Sign up

Export Citation Format

Share Document