University of Rhode Island

About: University of Rhode Island is a education organization based out in Kingston, Rhode Island, United States. It is known for research contribution in the topics: Population & Bay. The organization has 11464 authors who have published 22770 publications receiving 841066 citations. The organization is also known as: URI & Rhode Island College of Agriculture and the Mechanic Arts.

Qualitative Research: The Evaluation of Its Credibility, Fittingness, and Auditability:

Abstract: The three criteria of credibility, fittingness, and auditability have been focused on in the hope of facilitating the critique of qualitative research. Once criteria that are appropriate to qualitative methodologies are developed, the scientific merit of these research studies can truly be appreciated. If traditional scientific criteria relevant to quantitative studies are used to critique qualitative methods, the development and acceptance of this paradigm-transcending research will be hindered.

Extreme climatic events shape arid and semiarid ecosystems

Abstract: 6 Climatic changes associated with the El Nino Southern Oscillation (ENSO) can have a dramatic impact on ter- restrial ecosystems worldwide, but especially on arid and semiarid systems, where productivity is strongly lim- ited by precipitation. Nearly two decades of research, including both short-term experiments and long-term studies conducted on three continents, reveal that the initial, extraordinary increases in primary productivity percolate up through entire food webs, attenuating the relative importance of top-down control by predators, providing key resources that are stored to fuel future production, and altering disturbance regimes for months or years after ENSO conditions have passed. Moreover, the ecological changes associated with ENSO events have important implications for agroecosystems, ecosystem restoration, wildlife conservation, and the spread of disease. Here we present the main ideas and results of a recent symposium on the effects of ENSO in dry ecosystems, which was convened as part of the First Alexander von Humboldt International Conference on the El Nino Phenomenon and its Global Impact (Guayaquil, Ecuador, 16-20 May 2005).

Routh-Hurwitz criterion in the examination of eigenvalues of a system of nonlinear ordinary differential equations.

Abstract: In stability analysis of nonlinear systems, the character of the eigenvalues of the Jacobian matrix (i.e., whether the real part is positive, negative, or zero) is needed, while the actual value of the eigenvalue is not required. We present a simple algebraic procedure, based on the Routh-Hurwitz criterion, for determining the character of the eigenvalues without the need for evaluating the eigenvalues explicitly. This procedure is illustrated for a system of nonlinear ordinary differential equations we have studied previously. This procedure is simple enough to be used in computer code, and, more importantly, makes the analysis possible even for those cases where the secular equation cannot be solved.

Real-Case Simulations of Hurricane-Ocean Interaction Using A High-Resolution Coupled Model: Effects on Hurricane Intensity

Abstract: In order to investigate the effect of tropical cyclone‐ocean interaction on the intensity of observed hurricanes, the GFDL movable triply nested mesh hurricane model was coupled with a high-resolution version of the Princeton Ocean Model. The ocean model had 1 /68 uniform resolution, which matched the horizontal resolution of the hurricane model in its innermost grid. Experiments were run with and without inclusion of the coupling for two cases of Hurricane Opal (1995) and one case of Hurricane Gilbert (1988) in the Gulf of Mexico and two cases each of Hurricanes Felix (1995) and Fran (1996) in the western Atlantic. The results confirmed the conclusions suggested by the earlier idealized studies that the cooling of the sea surface induced by the tropical cyclone will have a significant impact on the intensity of observed storms, particularly for slow moving storms where the SST decrease is greater. In each of the seven forecasts, the ocean coupling led to substantial improvements in the prediction of storm intensity measured by the storm’s minimum sea level pressure. Without the effect of coupling the GFDL model incorrectly forecasted 25-hPa deepening of Gilbert as it moved across the Gulf of Mexico. With the coupling included, the model storm deepened only 10 hPa, which was much closer to the observed amount of 4 hPa. Similarly, during the period that Opal moved very slowly in the southern Gulf of Mexico, the coupled model produced a large SST decrease northwest of the Yucatan and slow deepening consistent with the observations. The uncoupled model using the initial NCEP SSTs predicted rapid deepening of 58 hPa during the same period. Improved intensity prediction was achieved both for Hurricanes Felix and Fran in the western Atlantic. For the case of Hurricane Fran, the coarse resolution of the NCEP SST analysis could not resolve Hurricane Edouard’s wake, which was produced when Edouard moved in nearly an identical path to Fran four days earlier. As a result, the operational GFDL forecast using the operational SSTs and without coupling incorrectly forecasted 40-hPa deepening while Fran remained at nearly constant intensity as it crossed the wake. When the coupled model was run with Edouard’s cold wake generated by imposing hurricane wind forcing during the ocean initialization, the intensity prediction was significantly improved. The model also correctly predicted the rapid deepening that occurred as Fran began to move away from the cold wake. These results suggest the importance of an accurate initial SST analysis as well as the inclusion of the ocean coupling, for accurate hurricane intensity prediction with a dynamical model. Recently, the GFDL hurricane‐ocean coupled model used in these case studies was run on 163 forecasts during the 1995‐98 seasons. Improved intensity forecasts were again achieved with the mean absolute error in the forecast of central pressure reduced by about 26% compared to the operational GFDL model. During the 1998 season, when the system was run in near‐real time, the coupled model improved the intensity forecasts for all storms with central pressure higher than 940 hPa although the most significant improvement (;60%) occurred in the intensity range of 960‐970 hPa. These much larger sample sets confirmed the conclusion from the case studies, that the hurricane‐ocean interaction is an important physical mechanism in the intensity of observed tropical cyclones.