Operational Forecasting of Wind-Generated Waves by Hurricane Isabel at NCEP*

2005 ◽  
Vol 20 (4) ◽  
pp. 544-557 ◽  
Author(s):  
Hendrik L. Tolman ◽  
Jose-Henrique G. M. Alves ◽  
Yung Y. Chao
Keyword(s):  
North Atlantic ◽  
Wave Model ◽  
The United States ◽  
Wind Fields ◽  
The North ◽  
Operational Forecasting ◽  
Model Improvement ◽  
Hurricane Isabel ◽  
Wave Models ◽  
Environmental Prediction

Abstract The accuracy of the operational wave models at the National Centers for Environmental Prediction (NCEP) for sea states generated by Hurricane Isabel is assessed. The western North Atlantic (WNA) and the North Atlantic hurricane (NAH) wave models are validated using analyzed wind fields, and wave observations from the Jason-1 altimeter and from 15 moored buoys. Both models provided excellent guidance for Isabel in the days preceding landfall of the hurricane along the east coast of the United States. However, the NAH model outperforms the WNA model in the initial stages of Isabel, when she was a category 5 hurricane. The NAH model was also more accurate in providing guidance for the swell systems arriving at the U.S. coast well before landfall of Isabel. Although major model deficiencies can be attributed to shortcomings in the driving wind fields, several areas of potential wave model improvement have been identified.

An Operational System for Predicting Hurricane-Generated Wind Waves in the North Atlantic Ocean*

2005 ◽  
Vol 20 (4) ◽  
pp. 652-671 ◽  
Author(s):  
Yung Y. Chao ◽  
Jose-Henrique G. M. Alves ◽  
Hendrik L. Tolman
Keyword(s):  
Prediction Model ◽  
North Atlantic ◽  
North Atlantic Ocean ◽  
Wind Waves ◽  
Wave Model ◽  
Atlantic Hurricane ◽  
The North ◽  
Hurricane Season ◽  
The North Atlantic ◽  
Environmental Prediction

Abstract A new wind–wave prediction model, referred to as the North Atlantic hurricane (NAH) wave model, has been developed at the National Centers for Environmental Prediction (NCEP) to produce forecasts of hurricane-generated waves during the Atlantic hurricane season. A detailed description of this model and a comparison of its performance against the operational western North Atlantic (WNA) wave model during Hurricanes Isidore and Lili, in 2002, are presented. The NAH and WNA models are identical in their physics and numerics. The NAH model uses a wind field obtained by blending data from NCEP’s operational Global Forecast System (GFS) with those from a higher-resolution hurricane prediction model, whereas the WNA wave model uses winds provided exclusively by the GFS. Relative biases of the order of 10% in the prediction of maximum wave heights up to 48 h in advance, indicate that the use of higher-resolution winds in the NAH model provides a successful framework for predicting extreme sea states generated by a hurricane. Consequently, the NAH model has been made operational at NCEP for use during the Atlantic hurricane season.

Comparison Between Two Forecast Systems Implemented With WAM and WaveWatch 3 for the North Atlantic

2016 ◽  
Author(s):  
A. Rute Bento ◽  
Marta Gonçalves ◽  
Ricardo Campos ◽  
C. Guedes Soares
Keyword(s):  
North Atlantic ◽  
Wave Spectrum ◽  
Wind Fields ◽  
Fine Grid ◽  
Warm Up ◽  
The North ◽  
Operational Forecasting ◽  
The North Atlantic ◽  
North Atlantic Area

The performance of two operational forecasting systems implemented for the North Atlantic area is compared. One forecast system runs the WAM model and the other using the WaveWatchIII model, both driven by GFS wind fields and with the same resolutions for time and space. The GFS wind fields used to drive the models have a spatial resolution of 0.5° by 0.5° and a time resolution of 3h. Regarding the geographical grids implemented, they cover the North Atlantic from the longitude of 90° West to 33° East and from the latitude of 80° North to 2° South, with a fine grid resolution of 0.5 by 0.5 degrees. The wave spectrum is discretized using 30 frequencies, being the lowest frequency equal to 0.0418 Hz, and 36 directions. A 4-days warm up was implemented and a 4-days forecast was calculated. In general both models performed well, as forecasting systems, presenting the same behavior and magnitude of values, when compared to the in-situ measurements.

scholarly journals Performance of NCEP Regional Wave Models in Predicting Peak Sea States during the 2005 North Atlantic Hurricane Season*

2010 ◽  
Vol 25 (5) ◽  
pp. 1543-1567 ◽  
Author(s):  
Yung Y. Chao ◽  
Hendrik L. Tolman
Keyword(s):  
Wave Height ◽  
North Atlantic ◽  
Wave Model ◽  
Wind Forcing ◽  
Random Errors ◽  
Atlantic Hurricane ◽  
The North ◽  
Hurricane Wind ◽  
The North Atlantic ◽  
Wave Models

Abstract Unprecedented numbers of tropical cyclones occurred in the North Atlantic Ocean and the Gulf of Mexico in 2005. This provides a unique opportunity to evaluate the performance of two operational regional wave forecasting models at the National Centers for Environmental Prediction (NCEP). This study validates model predictions of the tropical cyclone–generated maximum significant wave height, simultaneous spectral peak wave period, and the time of occurrence against available buoy measurements from the National Data Buoy Center (NDBC). The models used are third-generation operational wave models: the Western North Atlantic wave model (WNA) and the North Atlantic Hurricane wave model (NAH). These two models have identical model physics, spatial resolutions, and domains, with the latter model using specialized hurricane wind forcing. Both models provided consistent estimates of the maximum wave height and period, with random errors of typically less than 25%, and timing errors of typically less than 5 h. Compared to these random errors, systematic model biases are negligible, with a typical negative model bias of 5%. It appears that higher wave model resolutions are needed to fully utilize the specialized hurricane wind forcing, and it is shown that present routine wave observations are inadequate to accurately validate hurricane wave models.

Allied High Commission for Germany

1951 ◽  
Vol 5 (4) ◽  
pp. 825-832
Keyword(s):  
United States ◽  
North Atlantic ◽  
Foreign Minister ◽  
The United States ◽  
Scrap Metal ◽  
German Federal Republic ◽  
The North ◽  
The United Kingdom ◽  
The North Atlantic ◽  
Contractual Agreements

With the development of certain administrative frictions (concerning coal quotas, occupation costs, and the scrap metal treaty) between the western occupying powers and the German Federal Republic, early indications were that if the talk of “contractual agreements” did materialize it would reserve, for the occupying powers, wide controls over important areas of west Germany's internal and external affairs. In Washington, however, a general modification of approach was noted during the September discussions between the United States Secretary of State (Acheson), the United Kingdom Foreign Secretary (Morrison), and the French Foreign Minister (Schuman), preparatory to the Ottawa meetings of the North Atlantic Council.

Why Is There So Much Christianity in the United States? A Reply to Sommerville

2002 ◽  
Vol 71 (4) ◽  
pp. 858-864 ◽  
Author(s):  
David A. Hollinger
Keyword(s):  
United States ◽  
North Atlantic ◽  
Religious Affiliation ◽  
The United States ◽  
Church History ◽  
Voluntary Organizations ◽  
Secular Culture ◽  
The North ◽  
The Individual ◽  
The Church

If we are going to explain the slow pace of de-Christianization for the United States relative to other industrialized societies in the North Atlantic West, we might well begin with the church-state relationship. The absence of an established church in the United States has enabled religious affiliation to function, like other voluntary organizations in “civil society,” as mediators between the individual and the nation. I conimented on this rather old idea in a book C. John Sommerville is kind enough to cite in another connection, Science, Jews, and Secular Culture, but since he does not take up this point, I will develop it a bit further here, before reacting to Sommerville's other concerns as expressed in his refreshingly fair-minded rejoinder to my essay in the March 2001 issue of Church History.

North Atlantic Treaty Organization

1961 ◽  
Vol 15 (2) ◽  
pp. 326-329 ◽  
Keyword(s):  
United States ◽  
North Atlantic ◽  
Foreign Minister ◽  
North Atlantic Treaty Organization ◽  
The United States ◽  
Ballistic Missile ◽  
The North ◽  
The Press ◽  
Ballistic Missiles ◽  
Medium Range

The Ministerial Council of the North Atlantic Treaty Organization (NATO) held its eleventh annual ministerial review at NATO headquarters in Paris from December 16 to 18, 1960. The main topic of discussion at the meeting was the announcement by United States Secretary of State Christian Herter of what he reportedly termed a new concept for the operation of medium-range ballistic missiles. The United States plan included: 1) a proposal that NATO discuss a multilateral system for the political control of the weapons; 2) an offer to place five ballistic missile submarines armed with 80 Polaris missiles under the command of the Supreme Allied Commander, Europe (SACEUR), by the end of 1963; and 3) a suggestion that the other members of the alliance contribute approximately 100 more medium-range ballistic missiles by purchasing them in the United States. The press reported that Lord Home, Foreign Secretary of the United Kingdom, welcomed the United States proposal and said that NATO should examine the possibility of a medium-range ballistic missile force under multilateral control, a suggestion in which M. Couve de Murville, the French Foreign Minister, concurred. The West German Defense Minister, Franz Joseph Strauss, told the Ministers, the press announced, that concrete decisions on the United States proposal should be taken in the near future, and that plans for NATO control of the Polaris missile force should be pushed through by military and political authorities early in the spring of 1961. The Council of Ministers decided to pass on to its Permanent Comand other related materials, according to the press.

Strategy and the Atlantic Alliance

1963 ◽  
Vol 17 (3) ◽  
pp. 709-732 ◽  
Author(s):  
Robert R. Bowie
Keyword(s):  
United States ◽  
North Atlantic ◽  
North Atlantic Treaty Organization ◽  
The United States ◽  
The North ◽  
Nuclear Control ◽  
The North Atlantic ◽  
The Military

The debate over strategy, forces, and nuclear control, which now divides the North Atlantic Treaty Organization (NATO), is framed largely in military terms: what is the best way to protect the NATO area and its members from aggression? The military aspects are complex in themselves, but the import of these issues extends far beyond defense. Their handling will greatly affect prospects for a partnership between the United States and a strong, united Europe

scholarly journals The Role of Nuclear Weapons in NATO’s Early Cold War Strategies (1949–1957)

2015 ◽  
Vol 14 (1) ◽  
pp. 107-120
Author(s):  
Petra Kiss
Keyword(s):  
Cold War ◽  
International Relations ◽  
North Atlantic ◽  
Nuclear Weapons ◽  
The United States ◽  
Strategic Thinking ◽  
Atomic Weapons ◽  
The North ◽  
Significant Factors

Since August 1945 atomic weapons have become significant factors in international relations, every state with great ambitions has aspired to get atomic secrets. The primary goal of the North Atlantic Treaty Organization (NATO) created in 1949 was – possessing the United States’, a nuclear power’s, security guarantee – to deter the Soviet agression. The first strategic documents of the Alliance were written with this very purpose. However, in the 1950s there was a shift in the allied nations’ policies, which influenced NATO’s strategic thinking as well, so in 1957 a real different strategic concept was adopted. Gaining technological superiority became the most important goal, which led to development and intense production of nuclear weapons. This article examines the emerging role of nuclear weapons and the changing strategy of the Alliance between 1949 and 1957.

Shaping the postwar balance of power: multilateralism in NATO

1992 ◽  
Vol 46 (3) ◽  
pp. 633-680 ◽  
Author(s):  
Steve Weber
Keyword(s):  
United States ◽  
Soviet Union ◽  
North Atlantic ◽  
Balance Of Power ◽  
The United States ◽  
The North ◽  
The Soviet Union ◽  
The North Atlantic ◽  
Multilateral Organization ◽  
John Ruggie

At the end of the 1940s, the United States and several West European states allied to defend themselves against invasion by the Soviet Union. Balance-ofpower theory predicts the recurrent formation of such balances among states. But it says little about the precise nature of the balance, the principles on which it will be constructed, or its institutional manifestations. The North Atlantic Treaty Organization (NATO) has been a peculiar mix. As a formal institution, NATO has through most of its history been distinctly nonmultilateral, with the United States commanding most decision-making power and responsibility. At the same time, NATO provided security to its member states in a way that strongly reflected multilateral principles. Within NATO, security was indivisible. It was based on a general organizing principle, the principle that the external boundaries of alliance territory were completely inviolable and that an attack on any border was an attack on all. Diffuse reciprocity was the norm. In the terms set out by John Ruggie, NATO has generally scored low as a multilateral organization but high as an institution of multilateralism.

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