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Acta Oceanologica Sinica 2016年第12期35卷 110-118页

作者： WANG Cao LI Quanwang PANG Long ZOU Aming ZHANG Long Department of Civil Engineering Tsinghua University CCCC Highway Consultants CO. Ltd.

Natural hazards such as hurricanes may cause extensive economic losses and social disruption for civil structures and infrastructures in coastal areas, implying the importance of understanding the construction performance subjected to hurricanes and assessing the hurricane damages properly. The intensity and frequency of hurricanes have been reported to change with time due to the potential impact of climate change.In this paper, a probability-based model of hurricane damage assessment for coastal constructions is proposed taking into account the non-stationarity in hurricane intensity and frequency. The nonhomogeneous Poisson process is employed to model the non-stationarity in hurricane occurrence while the non-stationarity in hurricane intensity is reflected by the time-variant statistical parameters(e.g., mean value and/or standard deviation), with which the mean value and variation of the cumulative hurricane damage are evaluated explicitly. The Miami-Dade County, Florida, USA, is chosen to illustrate the hurricane damage assessment method proposed in this paper. The role of non-stationarity in hurricane intensity and occurrence rate due to climate change in hurricane damage is investigated using some representative changing patterns of hurricane parameters.

关键词： hurricane damage assessment intensity frequency non-stationarity climate change

Landform type mediates compositional change in a hurricane-disturbed subtropical forest

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Ecological Processes 2020年第1期9卷 292-304页

作者： Robert L.Spicer Ariel ELugo Nathan Ruhl Department of Biological Science Rowan UniversityGlassboroNJ 08028USA International Institute of Tropical Forestry United States Department of Agriculture Forest ServiceJardín Botánico SurRío PiedrasPRUSA

Background:Categorization of topographical features into landform type is a long-standing method for understanding physiographic patterns in the environment.Differences in forest composition between landform types are driven primarily by concurrent differences in soil composition and moisture,but also disturbance regime.Many studies have focused on the interaction between fire disturbance,succession,and landforms,but the effects of hurricane disturbance on compositional differences between landforms are poorly understood.In the study presented here,we assess compositional and structural differences between landform types in the tree community of a young sub-tropical forest that is frequently subjected to hurricanes.Specifically,we ask whether the tree community(1)changed structurally over the study period,(2)experienced compositional change over the study period,(3)is compositionally different between landform types,and(4)exhibits compositional change mediated by landform type.Results:The tree community experienced significant structural change over the course of our study,but compositional change was only significant for some landforms.Conclusion:Despite large-scale,intense,and frequent hurricane disturbance to our study system,compositional change in the tree community was localized and only significant for some landform types.

关键词： hurricane Forest Community Composition Change Succession Landform

Identifying disaster-related tweets and their semantic,spatial and temporal context using deep learning,natural language processing and spatial analysis:a case study of hurricane Irma

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International Journal of Digital Earth 2019年第11期12卷 1205-1229页

作者： Muhammed Ali Sit Caglar Koylu Ibrahim Demir Department of Computer Science University of IowaIowa CityIAUSA Department of Geographical and Sustainability Sciences University of IowaIowa CityIAUSA Department of Civil and Environmental Engineering University of IowaIowa CityIAUSA

We introduce an analytical framework for analyzing tweets to(1)identify and categorize fine-grained details about a disaster such as affected individuals,damaged infrastructure and disrupted services;(2)distinguish impact areas and time periods,and relative prominence of each category of disaster-related information across space and time.We first identify disaster-related tweets by generating a human-labeled training dataset and experimenting a series of deep learning and machine learning methods for a binary classification of disasterrelatedness.We employ LSTM(Long Short-Term Memory)networks for the classification task because LSTM networks outperform other methods by considering the whole text structure using long-term semantic word and feature dependencies.Second,we employ an unsupervised multi-label classification of tweets using Latent Dirichlet Allocation(LDA),and identify latent categories of tweets such as affected individuals and disrupted services.Third,we employ spatiallyadaptive kernel smoothing and density-based spatial clustering to identify the relative prominence and impact areas for each information category,respectively.Using hurricane Irma as a case study,we analyze over 500 million keyword-based and geo-located collection of tweets before,during and after the disaster.Our results highlight potential areas with high density of affected individuals and infrastructure damage throughout the temporal progression of the disaster.

关键词： Social sensing Twitter deep learning natural language processing spatial analysis hurricane

Assessment of the effectiveness of wood pole repair using FRP considering the impact of climate change on decay and hurricane risk

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Advances in Climate Change Research 2020年第4期11卷 332-348页

作者： Eric MERSCHMAN Abdullahi M.SALMAN Emilio BASTIDAS-ARTEAGA Yue LI Department of Civil&Environmental Engineering The University of Alabama in HuntsvilleHuntsvilleAL 35899USA Universitede Nantes GeMInstitute for Research in Civil and Mechanical EngineeringNantesCNRS UMR 6183France Department of Civil Engineering Case Western Reserve UniversityClevelandOH 44106USA

Electric power distribution systems are vulnerable to disruption due to severe weather events,especially hurricanes.Such vulnerability is expected to increase over time due to the impact of climate change on hurricanes and the decay of wood poles that support the distribution lines.This study investigates the effectiveness of using fiber-reinforced polymer(FRP)sleeve to reinforce wood poles subjected to decay and hurricane hazard to restore their lost strength and extend their effective service life.The potential impact of climate change on the pole decay rate and the intensity and frequency of hurricanes is also considered.The optimal FRP repair time based on the structural reliability of the poles is also determined.Three locations with varying climates are chosen to evaluate and compare the results:Miami,Charleston,and New York City.The results show that in all three locations,the application of the FRP sleeve can more than double the service life of the pole depending on the time of the repair.The results also show that climate change significantly increases the vulnerability of the pole.The probability of failure of the pole at the end of the 21st century under RCP8.5 emission scenario in Miami,Charleston,and New York City increase by about 30%,70%,and 73%,respectively,compared to a no climate change scenario.If climate change is only assumed to affect the decay of the pole,i.e.,no change in hurricane hazard intensity,the corresponding increases in failure probability are 5%,22%,and 20% in Miami,Charleston,and New York City,respectively.This implies that most of the impact of climate change on pole failure risk is due to the increase in hurricane intensity.The impact of climate change on decay is found to be comparatively small.It increases with time as variation in temperature and precipitation becomes more prominent towards the end of the 21st century.The optimization results show that the optimal FRP repair time depends on how the FRP affects the pole's decay rate.If the FRP can significantly slow down th

关键词： Wood poles FRP repair hurricane Wood decay Climate change adaptation

Effect of stratification on current hydrodynamics over Louisiana shelf during hurricane Katrina

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Water Science and Engineering 2017年第2期10卷 154-165页

作者： Mohammad Nabi Allahdadi Chunyan Li Department of Oceanography and Coastal Sciences College of the Coast and Environment Louisiana State University Baton Rouge 70803 USA

Numerical experiments were conducted using the finite volume community ocean model(FVCOM) to study the impact of the initial density stratification on simulated currents over the Louisiana shelf during hurricane Katrina. Model results for two simulation scenarios, including an initially stratified shelf and an initially non-stratified shelf, were examined. Comparison of two simulations for two-dimensional(2D) currents,the time series of current speed, and variations of cross-shore currents across different sections showed that the smallest differences between simulated currents for these two scenarios occurred over highly mixed regions within 1 radius of maximum wind(RMW) under the hurricane.For areas farther from the mixed zone, differences increased, reaching the maximum values off Terrebonne Bay. These large discrepancies correspond to significant differences between calculated vertical eddy viscosities for the two scenarios. The differences were addressed based on the contradictory behavior of turbulence in a stratified fluid, as compared to a non-stratified fluid. Incorporation of this behavior in the MellorYamada turbulent closure model established a Richardson number-based stability function that was used for estimation of the vertical eddy viscosity from the turbulent energy and macroscale. The results of this study demonstrate the necessity for inclusion of shelf stratification when circulation modeling is conducted using three-dimensional(3D) baroclinic models. To achieve high-accuracy currents, the parameters associated with the turbulence closures should be calibrated with field measurements of currents at different depths.

关键词： hurricane Katrina Louisiana shelf Hydrodynamics Baroclinic and barotropic models Stratification

Mapping floods due to hurricane Sandy using NPP VIIRS and ATMS data and geotagged Flickr imagery

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International Journal of Digital Earth 2016年第5期9卷 427-441页

作者： Donglian Sun Sanmei Li Wei Zheng Arie Croitoru Anthony Stefanidis Mitchell Goldberg Department of Geography and Geoinformation Science George Mason UniversityFairfaxVAUSA NOAA JPSS Program Office LanhamMDUSA

In this study,we present an approach to estimate the extent of large-scale coastal floods caused by hurricane Sandy using passive optical and microwave remote sensing data.The approach estimates the water fraction from coarse-resolution VIIRS and ATMS data through mixed-pixel linear decomposition.Based on the water fraction difference,using the physical characteristics of water inundation in a basin,the flood map derived from the coarse-resolution VIIRS and ATMS measurements was extrapolated to a higher spatial resolution of 30 m using topographic information.It is found that flood map derived from VIIRS shows less inundated area than the Federal Emergency Management Agency(FEMA)flood map and the ground observations.The bias was mainly caused by the time difference in observations.This is because VIIRS can only detect flood under clear conditions,while we can only find some clear-sky data around the New York area on 4 November 2012,when most flooding water already receded.Meanwhile,microwave measurements can penetrate through clouds and sense surface water bodies under clear-or-cloudy conditions.We therefore developed a new method to derive flood maps from passive microwave ATMS observations.To evaluate the flood mapping method,the corresponding ground observations and the FEMA storm surge flooding(SSF)products are used.The results show there was good agreement between our ATMS and the FEMA SSF flood areas,with a correlation of 0.95.Furthermore,we compared our results to geotagged Flickr contributions reporting flooding,and found that 95%of these Flickr reports were distributed within the ATMS-derived flood area,supporting the argument that such crowd-generated content can be valuable for remote sensing operations.Overall,the methodology presented in this paper was able to produce high-quality and high-resolution flood maps over largescale coastal areas.

关键词： coastal flood hurricane water fraction high-resolution flood mapping VIIRS ATMS

Assimilating Best Track Minimum Sea Level Pressure Data Together with Doppler Radar Data Using an Ensemble Kalman Filter for hurricane Ike (2008) at a Cloud-Resolving Resolution

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Acta meteorologica Sinica 2013年第3期27卷 379-399页

作者：薛明董继立 Center for Analysis and Prediction of Storms University of Oklahoma School of Meteorology University of Oklahoma Key Laboratory for Mesoscale Severe Weather/Ministry of Education and School of Atmospheric ScienceNanjing University

Extending an earlier study, the best track minimum sea level pressure （MSLP） data are assimilated for landfalling hurricane Ike （2008） using an ensemble Kalman filter （EnKF）, in addition to data from two coastal ground-based Doppler radars, at a 4-km grid spacing. Treated as a sea level pressure observation, the MSLP assimilation by the EnKF enhances the hurricane warm core structure and results in a stronger and deeper analyzed vortex than that in the GFS （Global Forecast System） analysis; it also improves the subsequent 18-h hurricane intensity and track forecasts. With a 2-h total assimilation window length, the assimilation of MSLP data interpolated to 10-min intervals results in more balanced analyses with smaller subsequent forecast error growth and better intensity and track forecasts than when the data are assimilated every 60 minutes. Radar data are always assimilated at 10-min intervals. For both intensity and track forecasts, assimilating MSLP only outperforms assimilating radar reflectivity （Z） only. For intensity forecast, assimilating MSLP at 10-min intervals outperforms radar radial wind （Vr） data （assimilated at 10-min intervals）, but assimilating MSLP at 60-rain intervals fails to beat Vr data. For track forecast, MSLP assimilation has a slightly （noticeably） larger positive impact than Vr （Z） data. When V~ or Z is combined with MSLP, both intensity and track forecasts are improved more than the assimilation of individual observation type. When the total assimilation window length is reduced to 1 h or less, the assimilation of MSLP alone even at 10-min intervals produces poorer 18-h intensity forecasts than assimilating Vr only, indicating that many assimilation cycles are needed to establish balanced analyses when MSLP data alone are assimilated; this is due to the very limited pieces of information that MSLP data provide.

关键词： hurricane data assimilation ensemble Kalman filter best track

Quantifying Environmental Impacts of Temporary Housing at the Urban Scale: Intersection of Vulnerability and Posthurricane Relief in New Orleans

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International Journal of Disaster Risk Science 2019年第4期10卷 478-492页

作者： Claire McConnell Chiara Bertolin Department of Architecture and Technology Norwegian University of Science and Technology(NTNU)7491 TrondheimNorway Department of Mechanical and Industrial Engineering Norwegian University of Science and Technology(NTNU)7491 TrondheimNorway

The increasing risk and exposure of people and assets to natural hazards and disasters suggests an increasing need for temporary housing following disasters.Resilience to natural hazards is dependent on the resources available to families or communities to prepare for and mitigate risk,influenced by social vulnerability.This study seeks to quantify the total environmental impact of temporary housing deployment in New Orleans,using the catastrophic impact of hurricane Katrina in southern Louisiana in August 2005 as a case example.We employ a novel approach to estimate displacement period and take into account social vulnerability across New Orleans neighborhoods to better understand the scale of post-disaster relief and its global warming potential.The methodology implemented in this study comprises three steps:a risk assessment,a life cycle assessment,and a resulting total impact assessment.We demonstrate the considerable risk of greenhouse gas emissions and energy impacts from temporary housing deployment linked to hurricane hazard.Furthermore,we show that environmental impact is highly sensitive to displacement period and find the current methodology of anticipating temporary housing use by hazard alone to be inadequate.Additionally,the approach presented in this article provides tools to politicians and disaster risk professionals that allow for resource investment planning to decrease social vulnerability,thus enhancing resilience and adaptive capacity in a more homogeneous way at the urban scale.

关键词： Disaster risk Global warming potential hurricane Katrina Life cycle assessment New Orleans Social vulnerability Temporary housing

Observation of ocean current response to 1998 hurricane Georges in the Gulf of Mexico

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Acta Oceanologica Sinica 2006年第1期25卷 1-14页

作者： ZHENG Quanan LAI Ronald J HUANG Nortlen E PAN Jiayi LIU W Timothy Department of Atmospheric and Oceanic Science University of Maryland College Park Maryland 20742 USA Minerals Management Service U S Department of the Interior Hemdon Virginia 20170 USA Ocean and Ice Branch NASA Goddard Space Flight Center Greenbelt Maryland 20771 USA Department of Environmental and Biomolecular Systems Oregon Graduate Institute Beaverton Oregon 97006 USA Jet Propulsion Laboratory California Institute of Technology Pasadena California 91109 USA

The ocean current response to a hurricane on the shelf-break is examined. The study area is the DeSoto Canyon in the northeast Gulf of Mexico, and the event is the passage of 1998 hurricane Georges with a maximum wind speed of 49 m/s. The data sets used for analysis consist of the mooring data taken by the Field Program of the DeSoto Canyon Eddy Intrusion Study, and simultaneous winds observed by NOAA （National Oceanic and Atmospheric Administration） Moored Buoy 42040. Time-depth ocean current energy density images derived from the observed data show that the ocean currents respond almost immediately to the hurricane with important differences on and offthe shelf. On the shelf, in the shallow water of 100 m, the disturbance penetrates rapidly downward to the bottom and forms two energy peaks, the major peak is located in the mixed layer and the secondary one in the lower layer. The response dissipates quickly after external forcing disappears. Offthe shelf, in the deep water, the major disturbance energy seems to be trapped in the mixed layer with a trailing oscillation; although the disturbance signals may still be observed at the depths of 500 and 1 290 m. Vertical dispersion analysis reveals that the near-initial wave packet generated offthe shelf consists of two modes. One is a barotropic wave mode characterized by a fast decay rate of velocity amplitude of 0.020 s^-, and the other is baroclinic wave mode characterized by a slow decay rate of 0.006 9 s^-1. The band-pass-filtering and empirical function techniques are employed to the frequency analysis. The results indicate that ialf frequencies shift above the local inertial frequency. On the shelf, the average frequency is 1.04fin the mixed layer, close to the diagnosed frequency of the first baroclinic mode, and the average frequency increases to 1.07fin the thermocline. Offthe shelf, all frequencies are a little smaller than the diagnosed frequency of the first mode. The average frequency decreases from 1.035fin the mixed layer to 1.02fin the thermocline,

关键词： shelf dynamics hurricane ocean current air-sea interaction

Effects of hurricane forward speed and approach angle on storm surges: an idealized numerical experiment

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Acta Oceanologica Sinica 2019年第7期38卷 48-56页

作者： Chenguang Zhang Chunyan Li Department of Oceanography and Coastal Sciences Louisiana State University

The effects of hurricane forward speed(V)and approach angle(θ)on storm surge are important and a systematic investigation covering possible and continuous ranges of these parameters has not been done before.Here we present such a study with a numerical experiment using the Finite Volume Community Ocean Model(FVCOM).The hurricane track is simplified as a straight line,such that V andθfully define the motion of the hurricane.The maximum surge is contributed by both free waves and a forced storm surge wave moving with the hurricane.Among the free waves,Kelvin-type waves can only propagate in the down-coast direction.Simulations show that those waves can only have a significant positive storm surge when the hurricane velocity has a down-coast component.The optimal values of V andθthat maximize the storm surge in an idealized semi-circular ocean basin are functions of the bathymetry.For a constant bathymetry,the maximum surge occurs when the hurricane approaches the coast from the normal direction when the free wave generation is minimal;for a stepped bathymetry,the maximum surge occurs at a certain acute approach angle which maximizes the duration of persistent wind forcing;a step-like bathymetry with a sloped shelf is similar to the stepped bathymetry,with the added possibility of landfall resonance when the free and forced waves are moving at about the same velocity.For other cases,the storm surge is smaller,given other parameters(hurricane size,maximum wind speed,etc.)unchanged.

关键词： storm surge experiments FVCOM hurricane forward speed approach angle Kelvin waves forced and free surge interactions