Early Season Hurricane Risk Assessment: Climate-Conditioned HITS Simulation of North Atlantic Tropical Storm Tracks

2021 ◽  
Vol 60 (4) ◽  
pp. 559-575
Author(s):  
Jennifer Nakamura ◽  
Upmanu Lall ◽  
Yochanan Kushnir ◽  
Patrick A. Harr ◽  
Kyra McCreery
Keyword(s):  
Risk Assessment ◽  
North Atlantic ◽  
Large Scale ◽  
Assessment Model ◽  
Risk Modeling ◽  
Equatorial Pacific Ocean ◽  
Early Season ◽  
Main Development ◽  
Development Region ◽  
Hurricane Risk

AbstractWe present a hurricane risk assessment model that simulates North Atlantic Ocean tropical cyclone (TC) tracks and intensity, conditioned on the early season large-scale climate state. The model, Cluster-Based Climate-Conditioned Hurricane Intensity and Track Simulator (C3-HITS), extends a previous version of HITS. HITS is a nonparametric, spatial semi-Markov, stochastic model that generates TC tracks by conditionally simulating segments of randomly varying lengths from the TC tracks contained in NOAA’s Best Track Data, version 2, dataset. The distance to neighboring tracks, track direction, TC wind speed, and age are used as conditioning variables. C3-HITS adds conditioning on two early season, large-scale climate covariates to condition the track simulation: the Niño-3.4 index, representing the eastern equatorial Pacific Ocean sea surface temperature (SST) departure from climatology, and main development region, representing tropical North Atlantic SST departure from climatology in the North Atlantic TC main development region. A track clustering procedure is used to identify track families, and a Poisson regression model is used to model the probabilistic number of storms formed in each cluster, conditional on the two climate covariates. The HITS algorithm is then applied to evolve these tracks forward in time. The output of this two-step, climate-conditioned simulator is compared with an unconditional HITS application to illustrate its prognostic efficacy in simulating tracks during the subsequent season. As in the HITS model, each track retains information on velocity and other attributes that can be used for predictive coastal risk modeling for the upcoming TC season.

On Estimates of Historical North Atlantic Tropical Cyclone Activity*

2008 ◽  
Vol 21 (14) ◽  
pp. 3580-3600 ◽  
Author(s):  
Gabriel A. Vecchi ◽  
Thomas R. Knutson
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Linear Trend ◽  
Annual Number ◽  
Base Case ◽  
Expected Number ◽  
Storm Activity ◽  
Main Development ◽  
Development Region ◽  
The Relationship

Abstract In this study, an estimate of the expected number of Atlantic tropical cyclones (TCs) that were missed by the observing system in the presatellite era (between 1878 and 1965) is developed. The significance of trends in both number and duration since 1878 is assessed and these results are related to estimated changes in sea surface temperature (SST) over the “main development region” (“MDR”). The sensitivity of the estimate of missed TCs to underlying assumptions is examined. According to the base case adjustment used in this study, the annual number of TCs has exhibited multidecadal variability that has strongly covaried with multidecadal variations in MDR SST, as has been noted previously. However, the linear trend in TC counts (1878–2006) is notably smaller than the linear trend in MDR SST, when both time series are normalized to have the same variance in their 5-yr running mean series. Using the base case adjustment for missed TCs leads to an 1878–2006 trend in the number of TCs that is weakly positive, though not statistically significant, with p ∼ 0.2. The estimated trend for 1900–2006 is highly significant (+∼4.2 storms century−1) according to the results of this study. The 1900–2006 trend is strongly influenced by a minimum in 1910–30, perhaps artificially enhancing significance, whereas the 1878–2006 trend depends critically on high values in the late 1800s, where uncertainties are larger than during the 1900s. The trend in average TC duration (1878–2006) is negative and highly significant. Thus, the evidence for a significant increase in Atlantic storm activity over the most recent 125 yr is mixed, even though MDR SST has warmed significantly. The decreasing duration result is unexpected and merits additional exploration; duration statistics are more uncertain than those of storm counts. As TC formation, development, and track depend on a number of environmental factors, of which regional SST is only one, much work remains to be done to clarify the relationship between anthropogenic climate warming, the large-scale tropical environment, and Atlantic TC activity.

Technical Risk Assessment of Large-Scale Construction Project Based on Triangle Whitening Weight Function

2014 ◽  
Vol 989-994 ◽  
pp. 5294-5299
Author(s):  
Wei Ma
Keyword(s):  
Risk Assessment ◽  
Weight Function ◽  
Large Scale ◽  
Construction Project ◽  
Scale Construction ◽  
Assessment Model ◽  
Grey Theory ◽  
Risk Assessment Model ◽  
Technical Risk

Technical risk assessment model of large-scale construction project has been established by using triangle whitening weight function of grey theory against the problems of technical risk assessment of large-scale construction project. In the end, through example verification, this model is approved to be feasible and have certain value of reference and utilization in similar problems.

Study on Risk Assessment of Power Transformer Based on Life Cycle Quality Information

2014 ◽  
Vol 615 ◽  
pp. 88-92
Author(s):  
Tian Shu Bi ◽  
Jin Meng Chen
Keyword(s):  
Risk Assessment ◽  
Manufacturing Process ◽  
Large Scale ◽  
Control Method ◽  
Comprehensive Evaluation ◽  
Power Transformer ◽  
Fault Tree Analysis ◽  
Assessment Model ◽  
Fuzzy Synthetic Evaluation ◽  
Manufacture Process

It has significant impact on the safe operation of the power grid for large scale power transformer. The technique is complex, and the manufacture process is long. The users always take the manufacturing supervision on spot as the quality control method. The quality is determined during the manufacturing process. The quality defects may cause serious safe problems. It has important significance to strengthen the risk assessment and prevention. The quality defects of power transformer are classified based on the fault tree analysis theory. The quality defects of power transformer from the manufacturing supervision of State Grid Corporation of China (SGCC) in 2012 are analyzed as examples. The manufacturing process has multiple layers and factors. The index system for comprehensive evaluation of transformer is put forward. A risk assessment model for power transformer based on fuzzy synthetic evaluation is built. The example shows that the method can estimate the risk effectively. It can provide feasible decision basis for the risk management and maintenance.

scholarly journals Pedestrian Evacuation Risk Assessment of Subway Station under Large-Scale Sport Activity

2020 ◽  
Vol 17 (11) ◽  
pp. 3844 ◽  
Author(s):  
Zeyang Cheng ◽  
Jian Lu ◽  
Yi Zhao
Keyword(s):  
Risk Assessment ◽  
Large Scale ◽  
Sport Activity ◽  
Pedestrian Safety ◽  
Assessment Model ◽  
Subway Station ◽  
Force Model ◽  
Pedestrian Evacuation ◽  
Subway Stations ◽  
Evacuation Risk

Pedestrian evacuation risk of subway stations is an important concern in city management, as it not only endangers public safety but also affects the efficiency of urban subway transportation. Determination of how to effectively evaluate the pedestrian evacuation risk of subway stations is of great significance to improve pedestrian safety. Previous studies about the pedestrian evacuation of subway station were primarily focused on pedestrian moving behaviors and the evacuation modeling, and the evacuation scenario is the regular subway operation. There is a dearth of studies to quantify the pedestrian evacuation risk in the evacuation process, especially the pedestrian evacuation risk quantitative characterization of subway station in large-scale sport activity. The current study develops a quantitative pedestrian evacuation risk assessment model that integrates pedestrian stampede probability and pedestrian casualty. Then several different simulation scenarios based on the social force model (SFM) are simulated to evaluate the pedestrian evacuation risk of the “Olympic Park Station” in Beijing, China. The results demonstrate that the pedestrian evacuation method, pedestrian stampede location, and distance from the stampede location to the ticket gate have a large impact on pedestrian evacuation risk. Then, the pedestrian evacuation scenarios with the lowest and highest risk for the “Olympic Park Station” in large-scale sport activity are determined. The findings have potential applications in pedestrian safety protection of subway station during large-scale sports activity.

scholarly journals The ability of general circulation models to simulate tropical cyclones and their precursors over the North Atlantic main development region

2012 ◽  
Vol 39 (7-8) ◽  
pp. 1559-1576 ◽  
Author(s):  
Anne Sophie Daloz ◽  
Fabrice Chauvin ◽  
Kevin Walsh ◽  
Sally Lavender ◽  
Deborah Abbs ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
North Atlantic ◽  
General Circulation ◽  
General Circulation Models ◽  
The North ◽  
Main Development ◽  
Development Region ◽  
The North Atlantic

On vortices initiated over West Africa and their impact on North Atlantic tropical cyclones

2020 ◽  
Author(s):  
Jean Philippe Duvel
Keyword(s):  
West Africa ◽  
North Atlantic ◽  
The North ◽  
Potential Index ◽  
Main Development ◽  
Development Region ◽  
Vertical Development ◽  
Fouta Djallon ◽  
North And South ◽  
Seasonal And Interannual Variations

<p>Numerous low and mid-level vortices are initiated respectively north and south of 15°N in West Africa and enter the North Atlantic where they may trigger cyclogenesis. Applying an objective vortex tracking algorithm on 38 years of meteorological re-analysis, this work investigates the vortex origin and their role in cyclogenesis with an emphasis on: (i) orography, (ii) seasonal variations and, (iii) merge between low and mid-level vortex tracks. North path vortices are mostly initiated downstream of Hoggar Mountains (5°E, 24°N) and south path vortices are mostly initiated downstream of Fouta Djallon Mountains (15°W, 10°N). About 55% of cyclogeneses in the Main Development Region (MDR: east of 60°W; 5 to 20°N) is associated with vortices initiated on the continent east of 10°W. MDR cyclonic activity is governed by seasonal and interannual variations of the local Genesis Potential Index (maximal in August-September) and not by the number of vortices entering the Ocean. North path vortices, which are more numerous in July, are thus less cyclogenetic compared to south path vortices that are more numerous in August-September. Considering together vortices initiated on the continent and near the coast, about 20% of the cyclogeneses are associated with merge of north and south path vortices and about 14% with north path vortices only. The remaining part is mostly associated with south path vortices. In addition, south path vortices with greater intensity and vertical development between Greenwich and the coast are more cyclogenetic.</p>

scholarly journals FPSO Risk Assessment and Acceptance Criteria With Application to FPSO Mooring Systems

2009 ◽  
Author(s):  
Michael H. Faber ◽  
Daniel Straub ◽  
Roberto Montes-Iturrizaga ◽  
Ernesto Heredia-Zavoni
Keyword(s):  
Risk Assessment ◽  
Life Quality ◽  
Assessment Model ◽  
Structural Safety ◽  
Risk Modeling ◽  
Engineering Systems ◽  
Design Code ◽  
Mooring Lines ◽  
Industrial Project ◽  
Life Saving

Risk based design code safety format calibration for FPSO installations is addressed based on the results of a recent industrial project performed for IMP by the authors. Generic risk models for general engineering systems are introduced taking basis in recent work by the Joint Committee on Structural Safety (JCSS). Thereafter, the scenarios considered for the risk based calibration of a design code safety format for the design of FPSO facilities in the Gulf of Mexico are outlined in some detail. Furthermore, it is shown how these scenarios may be represented in a generic risk assessment model greatly enhanced by the utilization of hierarchical risk modeling procedures such as Bayesian Probabilistic Nets (BPN’s). A short outline of the Life Quality Index (LQI) principle is then introduced as a practically applicable means to determine how much should be invested into life saving activities. Finally, an example is given where the introduced concepts are used for the purpose of determining the target reliability index for individual mooring lines taking into account the direct and indirect consequences of failure of the mooring system for a considered generic FPSO installation.

Power System Cascading Failure Risk Assessment Model Based on Graph Theory

2014 ◽  
Vol 496-500 ◽  
pp. 2844-2847
Author(s):  
Fu Chao Zhang ◽  
Jia Dong Huang
Keyword(s):  
Risk Assessment ◽  
Power System ◽  
Large Scale ◽  
Social Impact ◽  
Assessment Model ◽  
Levels Of Analysis ◽  
Economic Losses ◽  
Cascading Failure ◽  
Risk Assessment Model ◽  
Failure Risk

In recent years, large-scale power blackouts occur frequently in power system, resulting in extremely serious economic losses and social impact [. Scholars from various countries have made various levels of analysis on the causes of widespread blackouts from different angles [2-.The results show that most of the fault are caused by the cascading failure, and the linkage and relevance between failures are typical of such events. Accordingly, to strengthen the analysis of cascading has important significances on preventing the occurrence of large-scale power blackouts.

scholarly journals On the Seasonal Cycles of Tropical Cyclone Potential Intensity

2017 ◽  
Vol 30 (16) ◽  
pp. 6085-6096 ◽  
Author(s):  
Daniel M. Gilford ◽  
Susan Solomon ◽  
Kerry A. Emanuel
Keyword(s):  
North Atlantic ◽  
Seasonal Cycle ◽  
Reanalysis Data ◽  
The Other ◽  
Thermodynamic Efficiency ◽  
Seasonal Cycles ◽  
Ambient Conditions ◽  
The North ◽  
Main Development ◽  
Development Region

Recent studies have investigated trends and interannual variability in the potential intensity (PI) of tropical cyclones (TCs), but relatively few have examined TC PI seasonality or its controlling factors. Potential intensity is a function of environmental conditions that influence thermodynamic atmosphere–ocean disequilibrium and the TC thermodynamic efficiency—primarily sea surface temperatures and the TC outflow temperatures—and therefore varies spatially across ocean basins with different ambient conditions. This study analyzes the seasonal cycles of TC PI in each main development region using reanalysis data from 1980 to 2013. TC outflow in the western North Pacific (WNP) region is found above the tropopause throughout the seasonal cycle. Consequently, WNP TC PI is strongly influenced by the seasonal cycle of lower-stratospheric temperatures, which act to damp its seasonal variability and thereby permit powerful TCs any time during the year. In contrast, the other main development regions (such as the North Atlantic) exhibit outflow levels in the troposphere through much of the year, except during their peak seasons. Mathematical decomposition of the TC PI metric shows that outflow temperatures damp WNP TC PI seasonality through thermodynamic efficiency by a quarter to a third, whereas disequilibrium between SSTs and the troposphere drives 72%–85% of the seasonal amplitude in the other ocean basins. Strong linkages between disequilibrium and TC PI seasonality in these basins result in thermodynamic support for powerful TCs only during their peak seasons. Decomposition also shows that the stratospheric influence on outflow temperatures in the WNP delays the peak month of TC PI by a month.

A Simulation Approach for Estimating Hurricane Risk over a 5-yr Horizon

2014 ◽  
Vol 6 (1) ◽  
pp. 77-90 ◽  
Author(s):  
A. Bonazzi ◽  
A. L. Dobbin ◽  
J. K. Turner ◽  
P. S. Wilson ◽  
C. Mitas ◽  
...  
Keyword(s):  
North Atlantic ◽  
Historical Record ◽  
Medium Term ◽  
The Past ◽  
Main Development ◽  
Development Region ◽  
Insurance Perspective ◽  
Hurricane Activity ◽  
Hurricane Track

Abstract We develop a stochastic North Atlantic hurricane track model whose climate inputs are Atlantic main development region (MDR) and Indo-Pacific (IP) sea surface temperatures and produce extremely long model simulations for 58 different climates, each one conditioned on 5 yr of observed SSTs from 1950 to 2011—hereafter referred as medium-term (MT) views. Stringent tests are then performed to prove that MT simulations are better predictors of hurricane landfalls than a long-term view conditioned on the entire SST time series from 1950 to 2011. In this analysis, the authors extrapolate beyond the historical record, but not in terms of a forecast of future conditions. Rather it is attempted to define—within the limitation of the modeling approach—the magnitude of extreme events that could have materialized in the past at fixed probability thresholds and what is the likelihood of observed landfalls given such estimates. Finally, a loss proxy is built and the value of the analysis results from a simplified property and casualty insurance perspective is shown. Medium-term simulations of hurricane activity are used to set the strategy of reinsurance coverage purchased by a hypothetical primary insurance, leading to improved solvency margins.

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