scholarly journals Intensified Mega-ENSO Has Increased the Proportion of Intense Tropical Cyclones Over the Western Northwest Pacific Since the Late 1970s

2017 ◽  
Vol 44 (23) ◽  
pp. 11,959-11,966 ◽  
Author(s):  
Ruifen Zhan ◽  
Yuqing Wang ◽  
Jiuwei Zhao
Keyword(s):  
Tropical Cyclones ◽  
Northwest Pacific

scholarly journals Vulnerability of the Maritime Network to Tropical Cyclones in the Northwest Pacific and the Northern Indian Ocean

2019 ◽  
Vol 11 (21) ◽  
pp. 6176
Author(s):  
Zhicheng Shen ◽  
Xinliang Xu ◽  
Jiaohao Li ◽  
Shikuan Wang
Keyword(s):  
Indian Ocean ◽  
Tropical Cyclones ◽  
Small World ◽  
The Philippines ◽  
Point Of View ◽  
Northwest Pacific ◽  
Power Law Distribution ◽  
Northern Indian Ocean ◽  
Maritime Networks ◽  
Port System

Maritime networks are one of the most important types of transportation networks in international logistics and it accounts for 90% of the global trade volume. However, the structure of maritime networks is severely impacted by tropical cyclones, especially the maritime network in the Northwest Pacific and the northern Indian Ocean. This paper investigates the vulnerability of the maritime network in the Northwest Pacific and the northern Indian Ocean to the influence of tropical cyclones through removing ports at high or very high tropical cyclones hazard levels and analyzing how the network structure characteristics change from a complex network point of view. From the results, we find that this maritime network is a small-world network and the degree distribution of ports follows a power law distribution. The ports in East Asia are impacted more severely by the tropical cyclones. Moreover, this maritime network exhibits some vulnerability to tropical cyclones. However, the interconnection of the survived ports is not severely impacted, when the network is attacked by tropical cyclones. The port system in the Philippines is most vulnerable to the influence of tropical cyclones, followed by the ports systems in Japan and China. The paper also shows that it is important for studies of maritime network vulnerability to identify the ports that are both important to the regional and cross-regional logistics and severely impacted by natural hazards. The findings provide a theoretical basis for optimizing the port layout and improving the ability of the network to resist damage caused by tropical cyclones.

Assessment on the wind hazard of tropical cyclones over the Northwest Pacific basin with parametric wind field model

2020 ◽  
Author(s):  
Cunmin Guo ◽  
Weihua Fang
Keyword(s):  
Tropical Cyclones ◽  
Parametric Models ◽  
Sea Surface ◽  
Northwest Pacific ◽  
Hazard Maps ◽  
Telecommunication System ◽  
China Meteorological Administration ◽  
Wind Speeds ◽  
Wind Hazard ◽  
Global Telecommunication System

<p>Strong winds over the sea surface induced by tropical cyclones (TCs) of Northwest Pacific (NWP) basin have been posing great threats to maritime activities, and quantitative assessment on its hazard intensity is of great importance. In the past, most studies focused on the modeling of winds over the land and areas of major island areas numerically or statistically. However, there is no systematic assessment of TC wind hazard over the NWP basin with long-term wind time series based on windfield modeling of historical TC events. In this study, the footprints of historical TC events during 1949~2019 were modeled based on the parametric models developed in previous studies, which simulate the winds of both gradient layer and planetary boundary layer. The historical TC track data were obtained from the China Meteorological Administration, and the wind records from the Global Telecommunication System (GTS) data were used for the calibration and validation of the models. The spatial resolution of the modeling output is 1km for winds over the sea surface. In order to reflect wind speed heterogeneity over the land of small islands, the wind speeds were modeled with 90-meter resolution by considering local terrain effects and roughness heights of islands, derived from 90m SRTM DEM data and 30m land-used data. Based on the simulated wind footprints of the 2384 TC events during 1949~2019, the relationships between wind intensity and frequency of each modeling pixel were analyzed and fitted with General Extreme Value (GEV) distribution. A series of wind hazard maps, including wind speeds for return periods of 5a, 10a, 20a, 50a and 100a, and the exceedance probabilities of wind scales from 10 to 17, etc were produced. These wind hazard maps are useful to the management of TC disaster risks in the NWP basin.</p>

scholarly journals Weak Tropical Cyclones Dominate the Poleward Migration of the Annual Mean Location of Lifetime Maximum Intensity of Northwest Pacific Tropical Cyclones since 1980

2017 ◽  
Vol 30 (17) ◽  
pp. 6873-6882 ◽  
Author(s):  
Ruifen Zhan ◽  
Yuqing Wang
Keyword(s):  
Tropical Cyclones ◽  
Large Scale ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Maximum Intensity ◽  
Sea Surface ◽  
Northwest Pacific ◽  
The Past ◽  
Increasing Trend ◽  
Sst Warming

The poleward migration of the annual mean location of tropical cyclone (TC) lifetime maximum intensity (LMI) has been identified in the major TC basins of the globe over the past 30 years, which is particularly robust over the western North Pacific (WNP). This study has revealed that this poleward migration consists mainly of weak TCs (with maximum sustained surface wind speed less than 33 m s−1) over the WNP. Results show that the location of LMI of weak TCs has migrated about 1° latitude poleward per decade since 1980, while such a trend is considerably smaller for intense TCs. This is found to be linked to a significant decreasing trend of TC genesis in the southern WNP and a significant increasing trend in the northwestern WNP over the past 30 years. It is shown that the greater sea surface temperature (SST) warming at higher latitudes associated with global warming and its associated changes in the large-scale circulation favor more TCs to form in the northern WNP and fewer but stronger TCs to form in the southern WNP.

scholarly journals PRECIPITATION AND LATENT HEATING PROPERTIES OF TROPICAL CYCLONE IN THE NORTHWEST PACIFIC MEASURED BY GPM DPR AND HIMAWARI-8

2019 ◽  
Vol XLII-3/W9 ◽  
pp. 77-82
Author(s):  
X. Hu ◽  
G. L. Li ◽  
C. Zhang ◽  
W. Yan
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Latent Heat ◽  
Mature Stage ◽  
Northwest Pacific ◽  
Latent Heating ◽  
Life Cycle Stages ◽  
Average Precipitation ◽  
Stratiform Precipitation ◽  
Statistical Results

Abstract. Using observations from the GPM Tropical Cyclone Overpass Dataset and Himawari-8, this study statistically analyses the tropical cyclones (above Typhoon categories) in the Northwest Pacific during the tropical cyclone (TC) frequent period (from May to October) of 2014–2018. Moreover, a case (Super Typhoon “Mangkhut”) was analysed in detail. This study uses a semi-manual method to identify three life cycle stages of tropical cyclones: developing stage, mature stage, and dissipating stage. The statistical results show that the distribution of precipitation and latent heat varies with positions and the tropical cyclone has the maximum precipitation (11.62 mm/h) at the mature stage along with the maximum convection ratio (22.97%) at the developing stage. It is most obvious that the release of latent heat in the upper cloud at developing stage and in the lower cloud at mature stage. The latent heat profile of convective precipitation presents a “bottom-heavy” structural, and the stratiform precipitation has a “top-heavy” latent heat profile. The proportion of stratiform precipitation to total precipitation (74.31%) is the largest, but the average precipitation of the stratiform (4.12 mm/h) is lower than the average precipitation of convective clouds (10.55 mm/h). The average particle radius of the stratiform precipitation is 1.13 mm, while the average precipitation particle radius of the convective cloud precipitation is 1.79 mm. Based on these statistical results, this paper briefly analyses the characteristics of cloud precipitation microphysical mechanisms in three life cycle stages. Besides, the latent heating profile distribution found in this study are related to the vertical variation of precipitation rate, which are different in terms of the type of precipitation cloud.

The Response and Feedback of Ocean Mesoscale Eddies to Four Sequential Typhoons in 2016 Based on Multiple Satellite Observations and Argo Floats

2021 ◽  
Vol 13 (19) ◽  
pp. 3805
Author(s):  
Jiagen Li ◽  
Han Zhang ◽  
Shanshan Liu ◽  
Xiuting Wang ◽  
Liang Sun
Keyword(s):  
Tropical Cyclones ◽  
Mesoscale Eddies ◽  
Reanalysis Data ◽  
Satellite Observations ◽  
Cyclonic Eddy ◽  
Secondary Response ◽  
Northwest Pacific ◽  
Northwest Pacific Ocean ◽  
Super Typhoon ◽  
Sst Cooling

Four sequential tropical cyclones generated and developed in the Northwest Pacific Ocean (NWP) in 2014, which had significant impacts on the oceanic environment and coastal regions. Based on a substantial dataset of multiple-satellite observations, Argo profiles, and reanalysis data, we comprehensively investigated the interactions between the oceanic environment and sequential tropical cyclones. Super typhoon Neoguri (2014) was the first typhoon-passing studied area, with the maximum sustained wind speed of 140 kts, causing strong cold wake along the track. The location of the strongest cold wake was consistent with the pre-existing cyclonic eddy (CE), in which the average sea surface temperature (SST) cooling exceeded −5 °C. Subsequently, three tropical cyclones passed the ocean environment left by Neoguri, namely, the category 2 typhoon Matmo (2014), the tropical cyclone Nakri (2014) and the category 5 typhoon Halong (2014), which caused completely different subsequent responses. In the CE, due to the fact that the ocean stratification was strongly destroyed by Neoguri and difficult to recover, even the weak Nakri could cause a secondary response, but the secondary SST cooling would be overridden by the first response and thus could cause no more serious ocean disasters. If the subsequent typhoon was super typhoon Halong, it could cause an extreme secondary SST cooling, exceeding −8 °C, due to the deep upwelling, exceeding 700 m, surpassing the record of the maximum cooling caused by the first typhoon. In the anti-cyclonic eddy (AE), since the first typhoon Neoguri caused strong seawater mixing, it was difficult for the subsequent weak typhoons to mix the deeper, colder and saltier water into the surface, thus inhibiting secondary SST cooling, and even the super typhoon Halong would only cause as much SST cooling as the first typhoon. Therefore, the ocean responses to sequential typhoons depended on not only TCs intensity, but also TCs track order and ocean mesoscale eddies. In turn, the cold wake caused by the first typhoon, Neoguri, induced different feedback effects on different subsequent typhoons.

A Dynamical Initialization Scheme for Binary Tropical Cyclones

2016 ◽  
Vol 144 (12) ◽  
pp. 4787-4803 ◽  
Author(s):  
Hao-Yan Liu ◽  
Zhe-Min Tan
Keyword(s):  
Tropical Cyclones ◽  
Initial Conditions ◽  
Environmental Flow ◽  
The Other ◽  
Northwest Pacific ◽  
Single Vortex ◽  
Direct Extension ◽  
Initialization Scheme ◽  
Better Than

Abstract This paper reports on a dynamical initialization scheme for binary vortices (BVDI) that was developed to improve the initial conditions supplied to the models used to forecast binary tropical cyclones (TCs). For binary TCs, one TC can be regarded as the environment for the other TC’s development. Based on the dynamical initialization scheme for a single vortex (SVDI), a specified multistep iteration of SVDI was introduced in the BVDI scheme to ensure that each TC develops under conditions of realistic binary vortices interaction during the 6-h cycle run. In the BVDI scheme, each TC is initialized twice within a continuously adjusted environmental flow. Four clusters of forecast simulations with different initial conditions were run for 11 pairs of binary TCs over the northwest Pacific. The forecasts of binary TCs by the BVDI scheme reduced the position and intensity errors associated with the forecast TCs by 35.2% and 56.6%, respectively, compared with those without initialization, and also performed better than the direct extension of the SVDI scheme to binary TCs. The representation of binary vortices interaction will need to be improved for initialization and future forecasts of binary TCs.

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