United States East Coast Storm Surge and Cyclone track Characteristics: Differences and Similarities for Extratropical Cyclones and Hurricanes

Author(s):  
James Booth ◽  
Harald Rieder

<p>Storm surge on the east coast of the United States can be generated by hurricanes or extratropical cyclones (ETCs). Understanding the differences in the impacts of these two phenomena is important for improving strategies to mitigate the damage created. As such, this work examines the magnitude, spatial footprint, and paths of hurricanes and ETCs that caused strong surge along the east coast of the US. Lagrangian cyclone track information, for hurricanes and ETCs, is used to associate surge events with individual storms. First, hurricane influence is examined using ranked surged events per site. The fraction of hurricanes among storms associated with surge decreases from 20-60% for the top 10 events to 10-30% for the top 50 events, and a clear latitudinal gradient of hurricane influence emerges for larger sets of events. Second, surge on larger spatial domains is examined by focusing on storms that cause exceedance of the probabilistic 1-year surge return level at multiple stations. Results show that if the strongest events, in terms of surge amplitude and spatial extent, are considered hurricanes are most likely to create the hazards. However, when slightly less strong events that still impact multiple areas during the storm life cycle are considered, the relative importance of hurricanes shrinks as that of ETCs grows.</p><p>Next we examine the details of the tracks of the storm events that cause strong surge events. We find that paths for ETCs causing multi-site surge at individual segments of the US east coast pass very close to the regions of impact. We find that the paths of hurricanes that cause the strongest multi-site surge are often influenced by nearby large-scale circulation patterns. We also examine the relationship between the storm surge time-evolution and the propagation speed of the low-pressure center of the storm events. For extratropical cyclones, slower moving events have weaker cyclonic winds which offsets the enhanced surge associated with the longer duration of the cyclone influence on surge. For hurricanes, there is less correlation between propagation speed and cyclonic wind motion, meaning slower moving events can still generate very strong winds. However, slow moving events still don’t cause the absolute largest events.</p><p> </p>

2021 ◽  
Author(s):  
Katherine L. Towey ◽  
James F. Booth ◽  
Alejandra Rodriguez Enriquez ◽  
Thomas Wahl

Abstract. To improve our understanding of the influence of tropical cyclones (TCs) on coastal flooding, the relationships between storm surge and TC characteristics are analyzed for the east coast of the United States. Using observational data, the statistical dependencies of storm surge on TCs are examined for these characteristics: distance from TC center, TC intensity, track path angle, and propagation speed. Statistically significant but weak linear correlations are found for nearly all sites. At each location, storm surge is influenced differently by these characteristics, with some locations more strongly influenced by TC intensity and others by the distance from the TC center. The correlation for individual and combined TC characteristics increases when conditional sorting is applied to isolate strong TCs close to a location, though the fraction of surge variance explained is never greater than 60 %. The probabilities of TCs generating surge exceeding specific return levels (RLs) are then analyzed for TCs that pass within 500 km of a location, where between 7 % and 26 % of TCs were found to cause surge exceeding the 0.5-yr RL. If only the closest and strongest TCs are considered, the percentage of TCs that generate surge exceeding the 0.5-yr RL is between 30 % and 50 % at sites north of Sewell’s Point, VA, and over 70 % at almost all sites south of Charleston, SC. Overall, this analysis demonstrates that no single TC characteristic dictates how much surge will be generated and offers a unique perspective on surge probabilities that is based on all TCs rather than focusing only on those that cause extreme surge.


Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 756
Author(s):  
Robert Mendelsohn

The National Atmospheric and Oceanic Administration (NOAA) calculates the surge probability distribution along the coast from their long-term tidal stations. This process is sufficient for predicting the surge from common storms but tends to underestimate large surges. Across 23 long-term tidal stations along the East Coast of the United States, 100-year surges were observed 49 times, although they should have occurred only 23 times. We hypothesize that these 100-year surges are not the tail outcome from common storms but are actually caused by major hurricanes. Matching these 100-year surges with major hurricanes revealed that major hurricanes caused 43 of the 49 surges. We consequently suggest a revised approach to estimating the surge probability distribution. We used tidal data to estimate the probability of common surges but analyzed major hurricane surges separately, using the return rate of major hurricanes and the observed surge from each major hurricane to predict hurricane surges. The revision reveals that expected coastal flooding damage is higher than we thought, especially in the southeast United States.


2019 ◽  
Vol 32 (7) ◽  
pp. 2131-2143 ◽  
Author(s):  
Arielle J. Catalano ◽  
Anthony J. Broccoli ◽  
Sarah B. Kapnick ◽  
Tyler P. Janoski

Abstract High-impact extratropical cyclones (ETCs) cause considerable damage along the northeast coast of the United States through strong winds and inundation, but these relatively rare events are difficult to analyze owing to limited historical records. Using a 1505-yr simulation from the GFDL FLOR coupled model, statistical analyses of extreme events are performed including exceedance probability computations to compare estimates from shorter segments to estimates that could be obtained from a record of considerable length. The most extreme events possess characteristics including exceptionally low central pressure, hurricane-force winds, and a large surge potential, which would greatly impact nearby regions. Return level estimates of metrics of ETC intensity using shorter, historical-length segments of the FLOR simulation are underestimated compared to levels determined using the full simulation. This indicates that if the underlying distributions of observed ETC metrics are similar to those of the 1505-yr FLOR distributions, the actual frequency of extreme ETC events could also be underestimated. Comparisons between FLOR and reanalysis products suggest that not all features of simulated high-impact ETCs are representative of observations. Spatial track densities are similar, but FLOR exhibits a negative bias in central pressure and a positive bias in wind speed, particularly for more intense events. Although the existence of these model biases precludes the quantitative use of model-derived return statistics as a substitute for those derived from shorter observational records, this work suggests that statistics from future models of higher fidelity could be used to better constrain the probability of extreme ETC events and their impacts.


1955 ◽  
Vol 36 (7) ◽  
pp. 318-324
Author(s):  
Emanuel M. Ballenzweig

The composite-map technique has been employed to construct some pictures of the average horizontal temperature distribution in the lower stratosphere over cyclones which do and cyclones which do not produce secondary Lows along the east coast of the United States. This study in comparative analysis verified that a characteristic anomaly exists in the 200-mb temperature field twelve hours prior to the development of the type of east-coastal secondary cyclones studied.


2018 ◽  
Vol 57 (1) ◽  
pp. 171-184 ◽  
Author(s):  
Arielle J. Catalano ◽  
Anthony J. Broccoli

AbstractExtratropical cyclones (ETCs) are responsible for most of the large storm-surge events in the northeastern United States. This study uses the ECMWF atmospheric reanalysis of the twentieth century (ERA-20C) and NOAA tide gauge data to examine the local, regional, and large-scale atmospheric circulation accompanying the 100 largest ETC-driven surge events at three locations along the northeastern coast of the United States: Sewells Point (Norfolk), Virginia; the Battery (New York City), New York; and Boston, Massachusetts. Results from a k-means cluster analysis indicate that the largest surges are generated when slowly propagating ETCs encounter a strong anticyclone, which produces a tighter pressure gradient and longer duration of onshore winds. The strength of the anticyclone is evident in the middle and upper troposphere where there are positive 500-hPa geopotential height anomalies overlying the surface anticyclone for the majority of clusters and nearly all of the five biggest surge events. Multiple clusters feature a slower-than-average storm and a strong anticyclone, indicating that various circulation scenarios can produce a large storm surge. This favorable environment for large surge events is influenced by well-known modes of climate variability including El Niño, the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), and the Pacific–North American (PNA) pattern. ETCs are more likely to produce a large surge during El Niño conditions, which have been shown to enhance the East Coast storm track. At Boston and the Battery, maximum surge occurs preferentially during the positive phase of PNA and the negative phases of AO/NAO.


Author(s):  
Steven Hurst

The United States, Iran and the Bomb provides the first comprehensive analysis of the US-Iranian nuclear relationship from its origins through to the signing of the Joint Comprehensive Plan of Action (JCPOA) in 2015. Starting with the Nixon administration in the 1970s, it analyses the policies of successive US administrations toward the Iranian nuclear programme. Emphasizing the centrality of domestic politics to decision-making on both sides, it offers both an explanation of the evolution of the relationship and a critique of successive US administrations' efforts to halt the Iranian nuclear programme, with neither coercive measures nor inducements effectively applied. The book further argues that factional politics inside Iran played a crucial role in Iranian nuclear decision-making and that American policy tended to reinforce the position of Iranian hardliners and undermine that of those who were prepared to compromise on the nuclear issue. In the final chapter it demonstrates how President Obama's alterations to American strategy, accompanied by shifts in Iranian domestic politics, finally brought about the signing of the JCPOA in 2015.


2014 ◽  
Vol 23 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Euan Hague ◽  
Alan Mackie

The United States media have given rather little attention to the question of the Scottish referendum despite important economic, political and military links between the US and the UK/Scotland. For some in the US a ‘no’ vote would be greeted with relief given these ties: for others, a ‘yes’ vote would be acclaimed as an underdog escaping England's imperium, a narrative clearly echoing America's own founding story. This article explores commentary in the US press and media as well as reporting evidence from on-going interviews with the Scottish diaspora in the US. It concludes that there is as complex a picture of the 2014 referendum in the United States as there is in Scotland.


2018 ◽  
Vol 47 (3) ◽  
pp. 130-134

This section, updated regularly on the blog Palestine Square, covers popular conversations related to the Palestinians and the Arab-Israeli conflict during the quarter 16 November 2017 to 15 February 2018: #JerusalemIstheCapitalofPalestine went viral after U.S. president Donald Trump recognized Jerusalem as the capital of Israel and announced his intention to move the U.S. embassy there from Tel Aviv. The arrest of Palestinian teenager Ahed Tamimi for slapping an Israeli soldier also prompted a viral campaign under the hashtag #FreeAhed. A smaller campaign protested the exclusion of Palestinian human rights from the agenda of the annual Creating Change conference organized by the US-based National LGBTQ Task Force in Washington. And, UNRWA publicized its emergency funding appeal, following the decision of the United States to slash funding to the organization, with the hashtag #DignityIsPriceless.


2019 ◽  
Vol 35 (2) ◽  
pp. 143-170
Author(s):  
Gerardo Gurza-Lavalle

This work analyses the diplomatic conflicts that slavery and the problem of runaway slaves provoked in relations between Mexico and the United States from 1821 to 1857. Slavery became a source of conflict after the colonization of Texas. Later, after the US-Mexico War, slaves ran away into Mexican territory, and therefore slaveholders and politicians in Texas wanted a treaty of extradition that included a stipulation for the return of fugitives. This article contests recent historiography that considers the South (as a region) and southern politicians as strongly influential in the design of foreign policy, putting into question the actual power not only of the South but also of the United States as a whole. The problem of slavery divided the United States and rendered the pursuit of a proslavery foreign policy increasingly difficult. In addition, the South never acted as a unified bloc; there were considerable differences between the upper South and the lower South. These differences are noticeable in the fact that southerners in Congress never sought with enough energy a treaty of extradition with Mexico. The article also argues that Mexico found the necessary leeway to defend its own interests, even with the stark differential of wealth and resources existing between the two countries. El presente trabajo analiza los conflictos diplomáticos entre México y Estados Unidos que fueron provocados por la esclavitud y el problema de los esclavos fugitivos entre 1821 y 1857. La esclavitud se convirtió en fuente de conflicto tras la colonización de Texas. Más tarde, después de la guerra Mexico-Estados Unidos, algunos esclavos se fugaron al territorio mexicano y por lo tanto dueños y políticos solicitaron un tratado de extradición que incluyera una estipulación para el retorno de los fugitivos. Este artículo disputa la idea de la historiografía reciente que considera al Sur (en cuanto región), así como a los políticos sureños, como grandes influencias en el diseño de la política exterior, y pone en tela de juicio el verdadero poder no sólo del Sur sino de Estados Unidos en su conjunto. El problema de la esclavitud dividió a Estados Unidos y dificultó cada vez más el impulso de una política exterior que favoreciera la esclavitud. Además, el Sur jamás operó como unidad: había diferencias marcadas entre el Alto Sur y el Bajo Sur. Estas diferencias se observan en el hecho de que los sureños en el Congreso jamás se esforzaron en buscar con suficiente energía un tratado de extradición con México. El artículo también sostiene que México halló el margen de maniobra necesario para defender sus propios intereses, pese a los fuertes contrastes de riqueza y recursos entre los dos países.


Author(s):  
Ana Elizabeth Rosas

In the 1940s, curbing undocumented Mexican immigrant entry into the United States became a US government priority because of an alleged immigration surge, which was blamed for the unemployment of an estimated 252,000 US domestic agricultural laborers. Publicly committed to asserting its control of undocumented Mexican immigrant entry, the US government used Operation Wetback, a binational INS border-enforcement operation, to strike a delicate balance between satisfying US growers’ unending demands for surplus Mexican immigrant labor and responding to the jobs lost by US domestic agricultural laborers. Yet Operation Wetback would also unintentionally and unexpectedly fuel a distinctly transnational pathway to legalization, marriage, and extended family formation for some Mexican immigrants.On July 12, 1951, US president Harry S. Truman’s signing of Public Law 78 initiated such a pathway for an estimated 125,000 undocumented Mexican immigrant laborers throughout the United States. This law was an extension the Bracero Program, a labor agreement between the Mexican and US governments that authorized the temporary contracting of braceros (male Mexican contract laborers) for labor in agricultural production and railroad maintenance. It was formative to undocumented Mexican immigrant laborers’ transnational pursuit of decisively personal goals in both Mexico and the United States.Section 501 of this law, which allowed employers to sponsor certain undocumented laborers, became a transnational pathway toward formalizing extended family relationships between braceros and Mexican American women. This article seeks to begin a discussion on how Operation Wetback unwittingly inspired a distinctly transnational approach to personal extended family relationships in Mexico and the United States among individuals of Mexican descent and varying legal statuses, a social matrix that remains relatively unexplored.


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