scholarly journals On the Mechanisms of the Active 2018 Tropical Cyclone Season in the North Pacific

2019 ◽  
Vol 46 (21) ◽  
pp. 12293-12302 ◽  
Author(s):  
Y. Qian ◽  
H. Murakami ◽  
M. Nakano ◽  
P.‐C. Hsu ◽  
T. L. Delworth ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
The North ◽  
Tropical Cyclone Season ◽  
The North Pacific

Satellite-Derived Tropical Cyclone Intensity in the North Pacific Ocean Using the Deviation-Angle Variance Technique

2014 ◽  
Vol 29 (3) ◽  
pp. 505-516 ◽  
Author(s):  
Elizabeth A. Ritchie ◽  
Kimberly M. Wood ◽  
Oscar G. Rodríguez-Herrera ◽  
Miguel F. Piñeros ◽  
J. Scott Tyo
Keyword(s):  
Tropical Cyclone ◽  
North Atlantic ◽  
North Pacific ◽  
Western North Pacific ◽  
North Pacific Ocean ◽  
Deviation Angle ◽  
Intensity Estimation ◽  
The North ◽  
The North Atlantic ◽  
The North Pacific

Abstract The deviation-angle variance technique (DAV-T), which was introduced in the North Atlantic basin for tropical cyclone (TC) intensity estimation, is adapted for use in the North Pacific Ocean using the “best-track center” application of the DAV. The adaptations include changes in preprocessing for different data sources [Geostationary Operational Environmental Satellite-East (GOES-E) in the Atlantic, stitched GOES-E–Geostationary Operational Environmental Satellite-West (GOES-W) in the eastern North Pacific, and the Multifunctional Transport Satellite (MTSAT) in the western North Pacific], and retraining the algorithm parameters for different basins. Over the 2007–11 period, DAV-T intensity estimation in the western North Pacific results in a root-mean-square intensity error (RMSE, as measured by the maximum sustained surface winds) of 14.3 kt (1 kt ≈ 0.51 m s−1) when compared to the Joint Typhoon Warning Center best track, utilizing all TCs to train and test the algorithm. The RMSE obtained when testing on an individual year and training with the remaining set lies between 12.9 and 15.1 kt. In the eastern North Pacific the DAV-T produces an RMSE of 13.4 kt utilizing all TCs in 2005–11 when compared with the National Hurricane Center best track. The RMSE for individual years lies between 9.4 and 16.9 kt. The complex environment in the western North Pacific led to an extension to the DAV-T that includes two different radii of computation, producing a parametric surface that relates TC axisymmetry to intensity. The overall RMSE is reduced by an average of 1.3 kt in the western North Pacific and 0.8 kt in the eastern North Pacific. These results for the North Pacific are comparable with previously reported results using the DAV for the North Atlantic basin.

scholarly journals Downstream Development of the Summertime Tropical Cyclone/Submonthly Wave Pattern in the Extratropical North Pacific

2010 ◽  
Vol 23 (8) ◽  
pp. 2223-2229 ◽  
Author(s):  
Ken-Chung Ko ◽  
Huang-Hsiung Hsu
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Wave Pattern ◽  
Wave Activity ◽  
Western North America ◽  
Energy Propagation ◽  
The North ◽  
The Impact ◽  
The North Pacific

Abstract The impact of tropical perturbation on the extratropical wave activity in the North Pacific in the submonthly time scale is demonstrated here. Previous studies identified a tropical cyclone (TC)/submonthly wave pattern, which propagated north-northwestward in the Philippine Sea and recurved in the oceanic region between Japan and Taiwan. This study found that, after the arrival of the TC/submonthly wave pattern at the recurving region, the eastward-propagating wave activity in the extratropical North Pacific was significantly enhanced. It is suggested that the TC/submonthly wave pattern, which is originated in the tropical western North Pacific, enhances the eastward energy propagation of Rossby wave–like perturbation in the extratropical North Pacific and may have an impact on the long-range weather predictability in the eastern North Pacific and western North America.

Influence of the North Pacific Victoria mode on western North Pacific tropical cyclone genesis

2018 ◽  
Vol 52 (1-2) ◽  
pp. 245-256 ◽  
Author(s):  
Xiushu Pu ◽  
Quanliang Chen ◽  
Quanjia Zhong ◽  
Ruiqiang Ding ◽  
Ting Liu
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Western North Pacific ◽  
Tropical Cyclone Genesis ◽  
The North ◽  
Cyclone Genesis ◽  
The North Pacific

scholarly journals Projection of North Pacific Tropical Upper-Tropospheric Trough in CMIP5 Models: Implications for Changes in Tropical Cyclone Formation Locations

2018 ◽  
Vol 31 (2) ◽  
pp. 761-774 ◽  
Author(s):  
Chao Wang ◽  
Liguang Wu
Keyword(s):  
Tropical Cyclone ◽  
North Pacific ◽  
Climate Models ◽  
Coupled Model ◽  
Atmospheric Composition ◽  
Cmip5 Models ◽  
The North ◽  
The Mean ◽  
The Impact ◽  
The North Pacific

The strong westerly shear to the south flank of the tropical upper-tropospheric trough (TUTT) limits the eastward extension of tropical cyclone (TC) formation over the western North Pacific (WNP) and thus the zonal shift of the TUTT in warming scenarios has an important implication for the mean formation location of TCs. The impact of global warming on the zonal shift of the TUTT is investigated by using output from phase 5 of the Coupled Model Intercomparison Project (CMIP5) of 36 climate models in this study. It is found that considerable spread exists in the zonal position, orientation, and intensity of the simulated-climatologic TUTT in the historical runs, which is forced by observed conditions such as changes in atmospheric composition, solar forcing, and aerosols. The large spread is closely related to the diversity in the simulated SST biases over the North Pacific. Based on the 15 models with relatively high skill in their historical runs, the near-term (2016–35) projection shows no significant change of the TUTT longitude, while the TUTT experiences an eastward shift of 1.9° and 3.2° longitude in the representative concentration pathway (RCP) 4.5 and 8.5 scenarios in the long-term (2081–2100) projection with considerable intermodel variability. Further examination indicates that the projected changes in the zonal location of the TUTT are also associated with the projected relative SST anomalies over the North Pacific. A stronger (weaker) relative SST warming over the North Pacific favors an eastward (westward) shift of the TUTT, suggesting that the spatial pattern of the future SST change is an important factor for the zonal shift of the mean formation location of TCs.

Downstream Development Associated with the Extratropical Transition of Tropical Cyclones over the Western North Pacific

2009 ◽  
Vol 137 (4) ◽  
pp. 1295-1319 ◽  
Author(s):  
Patrick A. Harr ◽  
Jonathan M. Dea
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
High Amplitude ◽  
Extratropical Transition ◽  
The North ◽  
The Impact ◽  
The North Pacific ◽  
Downstream Development

Abstract The movement of a tropical cyclone into the midlatitudes involves interactions among many complex physical processes over a variety of space and time scales. Furthermore, the extratropical transition (ET) of a tropical cyclone may also result in a high-amplitude Rossby wave response that can extend to near-hemispheric scales. After an ET event occurs over the western portion of a Northern Hemisphere ocean basin, the high-amplitude downstream response often forces anomalous midlatitude circulations for periods of days to a week. These circulations may then be related to high-impact weather events far downstream of the forcing by the ET event. In this study, downstream development following ET events over the western North Pacific Ocean is examined. Local eddy kinetic energy analyses are conducted on four cases of North Pacific tropical cyclones of varying characteristics during ET into varying midlatitude flow characteristics during 15 July–30 September 2005. The goal is to examine the impact of each case on downstream development across the North Pacific during a period in which these events might increase the midlatitude cyclogenesis across the North Pacific during a season in which cyclogenesis is typically weak. Four typhoon (TY) cases from the summer of 2005 are chosen to represent the wide spectrum of variability in ET. This includes a case (TY Nabi 14W) that directly resulted in an intense midlatitude cyclone, a case in which a weak midlatitude cyclone resulted (TY Banyan 07W), a case in which the decaying tropical cyclone was absorbed into the midlatitude flow (TY Guchol 12W), and a case (TY Saola 17W) in which the tropical cyclone decayed under the influence of strong vertical wind shear. The variability in downstream response to each ET case is related to specific physical characteristics associated with the evolution of the ET process and the phasing between the poleward-moving tropical cyclone and the midlatitude circulation into which it is moving. A case of downstream development that occurred during September 2005 without an ET event is compared with the four ET cases.

scholarly journals Impact of Strong ENSO on Regional Tropical Cyclone Activity in a High-Resolution Climate Model in the North Pacific and North Atlantic Oceans

2016 ◽  
Vol 29 (7) ◽  
pp. 2375-2394 ◽  
Author(s):  
Lakshmi Krishnamurthy ◽  
Gabriel A. Vecchi ◽  
Rym Msadek ◽  
Hiroyuki Murakami ◽  
Andrew Wittenberg ◽  
...  
Keyword(s):  
High Resolution ◽  
Tropical Cyclone ◽  
North Atlantic ◽  
El Niño ◽  
North Pacific ◽  
El Nino ◽  
Enso Events ◽  
The North ◽  
Strong Enso ◽  
The North Pacific

Abstract Tropical cyclone (TC) activity in the North Pacific and North Atlantic Oceans is known to be affected by the El Niño–Southern Oscillation (ENSO). This study uses the GFDL Forecast Oriented Low Ocean Resolution Model (FLOR), which has relatively high resolution in the atmosphere, as a tool to investigate the sensitivity of TC activity to the strength of ENSO events. This study shows that TCs exhibit a nonlinear response to the strength of ENSO in the tropical eastern North Pacific (ENP) but a quasi-linear response in the tropical western North Pacific (WNP) and tropical North Atlantic. Specifically, a stronger El Niño results in disproportionate inhibition of TCs in the ENP and North Atlantic, and leads to an eastward shift in the location of TCs in the southeast of the WNP. However, the character of the response of TCs in the Pacific is insensitive to the amplitude of La Niña events. The eastward shift of TCs in the southeast of the WNP in response to a strong El Niño is due to an eastward shift of the convection and of the associated environmental conditions favorable for TCs. The inhibition of TC activity in the ENP and Atlantic during El Niño is attributed to the increase in the number of days with strong vertical wind shear during stronger El Niño events. These results are further substantiated with coupled model experiments. Understanding of the impact of strong ENSO on TC activity is important for present and future climate as the frequency of occurrence of extreme ENSO events is projected to increase in the future.

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