Hydrographic surveys and moored observations in Rhode Island Sound (RIS) in water depths of 30–50 m, off the southern New England coast, revealed a near-bottom intrusion of anomalously warm and saline water in late fall 2009. The properties of this water mass, with peak salinity of nearly 35, are typical of slope water that is normally found offshore of the shelfbreak front, located approximately 100 km to the south. The slope water intrusion, with a horizontal spatial scale of about 45 km, appears to have been brought onto the outer shelf during the interaction of a Gulf Stream warm core ring with the shelfbreak east (upshelf) of RIS. The along-shelf transport rate of the intrusion can be explained as due to advection by the mean outer-shelf along-isobath current, although the transit time of the intrusion is also consistent with the self-advection of a dense bolus on a sloping shelf. The mechanism responsible for the large onshore movement of the intrusion from the outer shelf is not entirely clear, although a wind-driven upwelling circulation appeared to be responsible for its final movement into the RIS region. Depth-averaged salinity at all RIS mooring sites increased by 0.5–1 over the 3–4 week intrusion period suggesting that the intrusion mixed irreversibly, at least partially, with the ambient shelf water. The mixing of the salty intrusion over the shelf indicates that net cross-isobath fluxes of salt and other water properties have occurred.
The southern New England coast of the United States is particularly vulnerable to land-falling hurricanes because of its east-west orientation. The impact of two major hurricanes on the city of Providence (Rhode Island, USA) during the middle decades of the 20th century spurred the construction of the Fox Point Hurricane Barrier (FPHB) to protect the city from storm surge flooding. Although the Rhode Island/Narragansett Bay area has not experienced a major hurricane for several decades, increased coastal development along with potentially increased hurricane activity associated with climate change motivates an assessment of the impacts of a major hurricane on the region. The ocean/estuary response to an extreme hurricane is simulated using a high-resolution implementation of the ADvanced CIRCulation (ADCIRC) model coupled to the Precipitation-Runoff Modeling System (PRMS). The storm surge response in ADCIRC is first verified with a simulation of a historical hurricane that made landfall in southern New England. The storm surge and the hydrological models are then forced with winds and rainfall from a hypothetical hurricane dubbed “Rhody”, which has many of the characteristics of historical storms that have impacted the region. Rhody makes landfall just west of Narragansett Bay, and after passing north of the Bay, executes a loop to the east and the south before making a second landfall. Results are presented for three versions of Rhody, varying in the maximum wind speed at landfall. The storm surge resulting from the strongest Rhody version (weak Saffir–Simpson category five) during the first landfall exceeds 7 m in height in Providence at the north end of the Bay. This exceeds the height of the FPHB, resulting in flooding in Providence. A simulation including river inflow computed from the runoff model indicates that if the Barrier remains closed and its pumps fail (for example, because of a power outage or equipment failure), severe flooding occurs north of the FPHB due to impoundment of the river inflow. These results show that northern Narragansett Bay could be particularly vulnerable to both storm surge and rainfall-driven flooding, especially if the FPHB suffers a power outage. They also demonstrate that, for wind-driven storm surge alone under present sea level conditions, the FPHB will protect Providence for hurricanes less intense than category five.
The potential of using ADvanced CIRCulation model (ADCIRC) to assess the time incremented progression of hazard impacts on individual critical facilities has long been recognized but is not well described. As ADCIRC is applied to create granular impact models, the lack of transparency in the methods is problematic. It becomes difficult to evaluate the entire system in situations where modeling integrates different types of data (e.g., hydrodynamic and existing geospatial point data) and involves multiple disciplines and stakeholders. When considering increased interest in combining hydrodynamic models, existing geospatial information, and advanced visualizations it is necessary to increase transparency and identify the pitfalls that arise out of this integration (e.g., the inadequacy of data to support the resolution of proposed outputs). This paper thus describes an all numerical method to accomplish this integration. It provides an overview of the generation of the hydrodynamic model, describes the all numerical method utilized to model hazard impacts, identifies pitfalls that arise from the integration of existing geospatial data with the hydrodynamic model, and describes an approach to developing a credible basis for determining impacts at a granular scale. The paper concludes by reflecting on the implementation of these methods as part of a Federal Emergency Management Agency (FEMA) Integrated Emergency Management Training Course (IEMC) and identifies the need to further study the effects of integrated models and visualizations on risk perception.
1 January 2006 in Communications of the Association for Information Systems
Mobile communication technologies are changing every aspect of the daily life, bringing new opportunities in many areas. Several converging mobile systems can potentially change organizations significantly by shifting the traditional boundaries of work-life and the workplace. Mobile telephony, combining satellite and terrestrial cellular systems, already transformed the way people work by allowing 'anytime/anywhere' telephone calling and text messaging. Broadband mobile telephony opens additional avenues to provide information conveniently as quickly and easily as possible, when needed and where needed. The evolution of wireless technologies (from Wireless Personal Area Networks to ubiquitous Third Generation/Universal Mobile Telecommunication System - UMTS) increased the number of services available to business organizations and mobile workers. Machine-to-machine, vertical applications, and mobile office applications are increasingly being deployed. Service providers and mobile operators are also changing the way they operate as a result of the increasing availability of mobile broadband communication services. IT departments need to change their systems, upgrade, and adapt their infrastructure and policies to support these mobile services. These changes are both positive and negative. With this progression, some fundamental questions related to privacy, security, and a new concept of work place and work space are raised. The implications for developing economies, such as China, and their potential for leapfrogging are future attention areas.