Integration of models for storms and floods, damages and protections, should aid resilience plann... more Integration of models for storms and floods, damages and protections, should aid resilience planning and investments.
Tropical cyclones (TCs) have caused extensive power outages. The impacts of TC-caused blackouts m... more Tropical cyclones (TCs) have caused extensive power outages. The impacts of TC-caused blackouts may worsen in the future as TCs and heatwaves intensify. Here we couple TC and heatwave projections and power outage and recovery process analysis to investigate how TC-blackout-heatwave compound hazard risk may vary in a changing climate, with Harris County, Texas as an example. We find that, under the high-emissions scenario RCP8.5, long-duration heatwaves following strong TCs may increase sharply. The expected percentage of Harris residents experiencing at least one longer-than-5-day TC-blackout-heatwave compound hazard in a 20-year period could increase dramatically by a factor of 23 (from 0.8% to 18.2%) over the 21st century. We also reveal that a moderate enhancement of the power distribution network can significantly mitigate the compound hazard risk. Thus, climate adaptation actions, such as strategically undergrounding distribution network and developing distributed energy source...
Recent Hurricane Irma (2017) created the most extensive scale of evacuation in Florida's hist... more Recent Hurricane Irma (2017) created the most extensive scale of evacuation in Florida's history, involving about 6.5 million people on mandatory evacuation order and 4 million evacuation vehicles. To understand the hurricane evacuation process, the spatial and temporal evolution of the traffic flow is a critical piece of information, but it is usually not fully observed. Based on the game theory, this paper employs the available traffic observation on main highways (20 cameras; including parts of Route 1, 27 and I-75, 95, 4,10) during Irma to reconstruct the traffic flow in Florida during Irma. The model is validated with self-reported twitters. The traffic reconstruction estimates the traffic demand (about 4 million cars in total) and the temporal and spatial distribution of congestion during the evacuation. The results compare well with available information from news reports and Twitter records. The reconstructed data can be used to analyze hurricane evacuation decisions and...
Proceedings of the National Academy of Sciences of the United States of America, Oct 25, 2016
Coastal flood hazard varies in response to changes in storm surge climatology and the sea level. ... more Coastal flood hazard varies in response to changes in storm surge climatology and the sea level. Here we combine probabilistic projections of the sea level and storm surge climatology to estimate the temporal evolution of flood hazard. We find that New York City's flood hazard has increased significantly over the past two centuries and is very likely to increase more sharply over the 21st century. Due to the effect of sea level rise, the return period of Hurricane Sandy's flood height decreased by a factor of ∼3× from year 1800 to 2000 and is estimated to decrease by a further ∼4.4× from 2000 to 2100 under a moderate-emissions pathway. When potential storm climatology change over the 21st century is also accounted for, Sandy's return period is estimated to decrease by ∼3× to 17× from 2000 to 2100.
Two tropical cyclones (TCs) that make landfall close together can induce sequential hazards to co... more Two tropical cyclones (TCs) that make landfall close together can induce sequential hazards to coastal areas. Here we investigate the change in sequential TC hazards in the historical and future projected climates. We find that the chance of sequential TC hazards has been increasing over the past several decades at many US locations. Under the high (moderate) emission scenario, the chance of hazards from two TCs impacting the same location within 15 days may substantially increase, with the return period decreasing over the century from 10–92 years to ~1–2 (1–3) years along the US East and Gulf coasts, due to sea-level rise and storm climatology change. Climate change can also cause unprecedented compounding of extreme hazards at the regional level. A Katrina-like TC and a Harvey-like TC impacting the United States within 15 days of each other, which is non-existent in the control simulation for over 1,000 years, is projected to have an annual occurrence probability of more than 1% ...
A hidden Markov model is developed to simulate tropical cyclone intensity evolution dependent on ... more A hidden Markov model is developed to simulate tropical cyclone intensity evolution dependent on the surrounding large-scale environment. The model considers three unobserved (hidden) discrete states of storm intensity change and associates each state with a probability distribution of intensity change. The storm’s transit from one state to another is described as a Markov chain. Both the intensity change and state transit components of the model are dependent on environmental variables including potential intensity, vertical wind shear, relative humidity, and ocean feedback. This Markov Environment-Dependent Hurricane Intensity Model (MeHiM) is used to simulate the evolution of storm intensity along the storm track over the ocean, and a simple decay model is added to estimate the intensity change when the storm moves over land. Data for the North Atlantic (NA) basin from 1979 to 2014 (555 storms) are used for model development and evaluation. Probability distributions of 6- and 24-...
IABSE Congress, New York, New York 2019: The Evolving Metropolis
Tropical cyclones are multi‐hazard events capable of simultaneously affecting structures with win... more Tropical cyclones are multi‐hazard events capable of simultaneously affecting structures with wind, storm surge and rainfall. In practice, these concurrent hazards are typically treated independently using separate return level curves. Understanding this joint exposure, however, is critical for accurately assessing the structural vulnerability of buildings. We present such an analysis in study by investigating the joint and conditional return periods of two major cyclone hazards—wind and storm surge. To do so, a database of 566 synthetic cyclone events passing within 250 km of The Battery in New York City is first generated. Next, the Holland gradient wind profile and the ADvanced CIRCulation (ADCIRC) hydrodynamic model are used to simulate the maximum wind speed and peak storm tide for each synthetic event respectively. Finally, a bivariate copula is used to statistically estimate the joint and conditional return periods of the two hazards.
1 Supplemental Information for: Physically based Assessment of Hurricane Surge Threat under Clima... more 1 Supplemental Information for: Physically based Assessment of Hurricane Surge Threat under Climate Change Ning Lin, Kerry Emanuel, Michael Oppenheimer, Erik Vanmarcke Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA Department of Geosciences and the Woodrow Wilson School, Princeton University, Princeton, NJ 08544, USA Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA
The Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is the operational storm surge m... more The Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is the operational storm surge model of the National Hurricane Center (NHC). Previous studies have found that the SLOSH model estimates storm surges with an accuracy of ±20%. In this study, through hindcasts of historical storms, we assess the accuracy of the SLOSH model for four coastal regions in the Northeastern United States. We investigate the potential to improve this accuracy through modification of the wind field representation. We modify the surface background wind field, the parametric wind profile, and the maximum wind speed based on empirical, physical, and observational data. We find that on average the SLOSH model underestimates maximum storm surge heights by 22%. The modifications to the surface background wind field and the parametric wind profile have minor impacts; however, the effect of the modification to maximum wind speed is significant—it increases the variance in the SLOSH model estimates of max...
Integration of models for storms and floods, damages and protections, should aid resilience plann... more Integration of models for storms and floods, damages and protections, should aid resilience planning and investments.
Tropical cyclones (TCs) have caused extensive power outages. The impacts of TC-caused blackouts m... more Tropical cyclones (TCs) have caused extensive power outages. The impacts of TC-caused blackouts may worsen in the future as TCs and heatwaves intensify. Here we couple TC and heatwave projections and power outage and recovery process analysis to investigate how TC-blackout-heatwave compound hazard risk may vary in a changing climate, with Harris County, Texas as an example. We find that, under the high-emissions scenario RCP8.5, long-duration heatwaves following strong TCs may increase sharply. The expected percentage of Harris residents experiencing at least one longer-than-5-day TC-blackout-heatwave compound hazard in a 20-year period could increase dramatically by a factor of 23 (from 0.8% to 18.2%) over the 21st century. We also reveal that a moderate enhancement of the power distribution network can significantly mitigate the compound hazard risk. Thus, climate adaptation actions, such as strategically undergrounding distribution network and developing distributed energy source...
Recent Hurricane Irma (2017) created the most extensive scale of evacuation in Florida's hist... more Recent Hurricane Irma (2017) created the most extensive scale of evacuation in Florida's history, involving about 6.5 million people on mandatory evacuation order and 4 million evacuation vehicles. To understand the hurricane evacuation process, the spatial and temporal evolution of the traffic flow is a critical piece of information, but it is usually not fully observed. Based on the game theory, this paper employs the available traffic observation on main highways (20 cameras; including parts of Route 1, 27 and I-75, 95, 4,10) during Irma to reconstruct the traffic flow in Florida during Irma. The model is validated with self-reported twitters. The traffic reconstruction estimates the traffic demand (about 4 million cars in total) and the temporal and spatial distribution of congestion during the evacuation. The results compare well with available information from news reports and Twitter records. The reconstructed data can be used to analyze hurricane evacuation decisions and...
Proceedings of the National Academy of Sciences of the United States of America, Oct 25, 2016
Coastal flood hazard varies in response to changes in storm surge climatology and the sea level. ... more Coastal flood hazard varies in response to changes in storm surge climatology and the sea level. Here we combine probabilistic projections of the sea level and storm surge climatology to estimate the temporal evolution of flood hazard. We find that New York City's flood hazard has increased significantly over the past two centuries and is very likely to increase more sharply over the 21st century. Due to the effect of sea level rise, the return period of Hurricane Sandy's flood height decreased by a factor of ∼3× from year 1800 to 2000 and is estimated to decrease by a further ∼4.4× from 2000 to 2100 under a moderate-emissions pathway. When potential storm climatology change over the 21st century is also accounted for, Sandy's return period is estimated to decrease by ∼3× to 17× from 2000 to 2100.
Two tropical cyclones (TCs) that make landfall close together can induce sequential hazards to co... more Two tropical cyclones (TCs) that make landfall close together can induce sequential hazards to coastal areas. Here we investigate the change in sequential TC hazards in the historical and future projected climates. We find that the chance of sequential TC hazards has been increasing over the past several decades at many US locations. Under the high (moderate) emission scenario, the chance of hazards from two TCs impacting the same location within 15 days may substantially increase, with the return period decreasing over the century from 10–92 years to ~1–2 (1–3) years along the US East and Gulf coasts, due to sea-level rise and storm climatology change. Climate change can also cause unprecedented compounding of extreme hazards at the regional level. A Katrina-like TC and a Harvey-like TC impacting the United States within 15 days of each other, which is non-existent in the control simulation for over 1,000 years, is projected to have an annual occurrence probability of more than 1% ...
A hidden Markov model is developed to simulate tropical cyclone intensity evolution dependent on ... more A hidden Markov model is developed to simulate tropical cyclone intensity evolution dependent on the surrounding large-scale environment. The model considers three unobserved (hidden) discrete states of storm intensity change and associates each state with a probability distribution of intensity change. The storm’s transit from one state to another is described as a Markov chain. Both the intensity change and state transit components of the model are dependent on environmental variables including potential intensity, vertical wind shear, relative humidity, and ocean feedback. This Markov Environment-Dependent Hurricane Intensity Model (MeHiM) is used to simulate the evolution of storm intensity along the storm track over the ocean, and a simple decay model is added to estimate the intensity change when the storm moves over land. Data for the North Atlantic (NA) basin from 1979 to 2014 (555 storms) are used for model development and evaluation. Probability distributions of 6- and 24-...
IABSE Congress, New York, New York 2019: The Evolving Metropolis
Tropical cyclones are multi‐hazard events capable of simultaneously affecting structures with win... more Tropical cyclones are multi‐hazard events capable of simultaneously affecting structures with wind, storm surge and rainfall. In practice, these concurrent hazards are typically treated independently using separate return level curves. Understanding this joint exposure, however, is critical for accurately assessing the structural vulnerability of buildings. We present such an analysis in study by investigating the joint and conditional return periods of two major cyclone hazards—wind and storm surge. To do so, a database of 566 synthetic cyclone events passing within 250 km of The Battery in New York City is first generated. Next, the Holland gradient wind profile and the ADvanced CIRCulation (ADCIRC) hydrodynamic model are used to simulate the maximum wind speed and peak storm tide for each synthetic event respectively. Finally, a bivariate copula is used to statistically estimate the joint and conditional return periods of the two hazards.
1 Supplemental Information for: Physically based Assessment of Hurricane Surge Threat under Clima... more 1 Supplemental Information for: Physically based Assessment of Hurricane Surge Threat under Climate Change Ning Lin, Kerry Emanuel, Michael Oppenheimer, Erik Vanmarcke Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139-4307, USA Department of Geosciences and the Woodrow Wilson School, Princeton University, Princeton, NJ 08544, USA Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ 08544, USA
The Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is the operational storm surge m... more The Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model is the operational storm surge model of the National Hurricane Center (NHC). Previous studies have found that the SLOSH model estimates storm surges with an accuracy of ±20%. In this study, through hindcasts of historical storms, we assess the accuracy of the SLOSH model for four coastal regions in the Northeastern United States. We investigate the potential to improve this accuracy through modification of the wind field representation. We modify the surface background wind field, the parametric wind profile, and the maximum wind speed based on empirical, physical, and observational data. We find that on average the SLOSH model underestimates maximum storm surge heights by 22%. The modifications to the surface background wind field and the parametric wind profile have minor impacts; however, the effect of the modification to maximum wind speed is significant—it increases the variance in the SLOSH model estimates of max...
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