The Impact of Weather on Influenza and Pneumonia Mortality in New York City, 1975–2002: A Retrospective Study

The substantial winter influenza peak in temperate climates has lead to the hypothesis that cold and/or dry air is a causal factor in influenza variability. We examined the relationship between cold and/or dry air and daily influenza and pneumonia mortality in the cold season in the New York metropolitan area from 1975–2002. We conducted a retrospective study relating daily pneumonia and influenza mortality for New York City and surroundings from 1975–2002 to daily air temperature, dew point temperature (a measure of atmospheric humidity), and daily air mass type. We identified high mortality days and periods and employed temporal smoothers and lags to account for the latency period and the time between infection and death. Unpaired t-tests were used to compare high mortality events to non-events and nonparametric bootstrapped regression analysis was used to examine the characteristics of longer mortality episodes. We found a statistically significant (p = 0.003) association between periods of low dew point temperature and above normal pneumonia and influenza mortality 17 days later. The duration (r = −0.61) and severity (r = −0.56) of high mortality episodes was inversely correlated with morning dew point temperature prior to and during the episodes. Weeks in which moist polar air masses were common (air masses characterized by low dew point temperatures) were likewise followed by above normal mortality 17 days later (p = 0.019). This research supports the contention that cold, dry air may be related to influenza mortality and suggests that warning systems could provide enough lead time to be effective in mitigating the effects

Spring 1968

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The response of the coastal ocean to strong offshore winds: With application to circulations in the Gulfs of Tehuantepec and Papagayo

Two ocean models are used to investigate the response of the coastal ocean to strong offshore winds: a linear 1½-layer model, and a nonlinear 1½-layer model that allows entrainment of cool water into the surface layer. The models are forced by wind stress fields similar in structure to the intense winter-time, mountain-pass jets (∼20 dyne/cm2) that appear in the Gulfs of Tehuantepec and Papagayo for periods of 3–10 days. Solutions are arranged in a hierarchy of increasing dynamical complexity, in order to illustrate the important physical processes. They compare favorably with observations in several ways. Some properties of solutions are the following. While the wind strengthens there is an ageostrophic current (not Ekman drift) that is directed offshore. This offshore drift forces coastal upwelling, thereby lowering the local sea level and sea surface temperature (SST). Although the drop in sea level at the coast can be large and rapid (of the order of 20 cm at the peak of a wind event), none of this signal propagates poleward as a coastally trapped wave. While the wind weakens the ageostrophic current is directed onshore, and consequently the coastal ocean readjusts toward its initial state. Throughout the wind event, cyclonic and anticyclonic gyres spin up offshore on either side of the jet axis due to Ekman pumping. Entrainment cools SST offshore, on and to the right (looking onshore) of the jet axis, and virtually eliminates the cyclonic gyre. The advection terms intensify the anticyclonic gyre and give it a more circular shape. After a wind event, the anticyclonic gyre propagates westward due to β. Its propagation speed is enhanced over that of a linear Rossby wave due to the nonlinear terms associated with the increased layer thickness at the center of the gyre and with the divergence of momentum flux

Prediction of hazardous Columbia River bar conditions

In this study methods were developed for the prediction of wave conditions that are hazardous to navigation at river entrances, with emphasis on applicability to the Columbia River. There are two basic components to the prediction system: (1) a semi-automated spectral method for forecasting the significant height and average period of waves in deep water, and (2) an index of navigation hazard at river entrances that depends on the significant height and average period in deep water and on the mean current and water depth at the entrance. The computerized, deep water forecast method is a hybrid scheme that combines the spectral principles of the Pierson-Neumann-James method with the graphical input techniques of Wilson and the fetch limited spectrum of Liu. The significant heights generated by the method are well verified by winter wave measurements at Newport, Oregon. The hazard index is based on the probability of wave-breaking in water of arbitrary depth and current. The breaking probability is derived under the assumption that wave heights and squared periods are statistically independent and distributed according to a Rayleigh probability density function. The breaking-wave probability and the hazard index depend on the wave steepness in deep slack water and on the depth (relative to the wave period squared) and current (relative to the period) at the river entrance. The dependence on depth and current is achieved in two ways: (1) the limiting steepness (breaking index) k found as a function of relative depth and relative current, and (2) the wave spectrum in water of arbitrary depth and current is found by transformation of the spectrum in deep slack water. The transformation is performed by requiring that the rate of wave energy propagation remain constant. The hazard index is closely related to the probability of breaking swell. At water depths that are typical of river entrances, the hazard index depends strongly on the significant wave height, mean current and depth, but only weakly on the mean wave period (since the breaking height of swell at such depths is only weakly dependent on period). Hindcasts of deep water significant wave heights and hazard indices compared reasonably well with measured heights and Columbia River bar closure periods. Forecasts based on accurate prognostic weather charts should provide similar results

The development of forecast techniques for wave and surf conditions over the bars in the Columbia River Mouth and at the entrance to Yaquina Bay : final report

This investigation has been carried out primarily to define the Columbia River bar crossing problem, to determine the physical factors involved in hazardous transit developments, and to develop a method for predicting hazardous bar transit conditions sufficiently in advance to allow proper safety precautions to be effected. Actual records of periods of bar closure for the years 1963 - 1969, as determined by the Columbia River Bar Pilots Association, provide a firm foundation for the entry into this study. Meteorological and oceanographic conditions leading to the closures, as well as those occurring during periods of closure, are being analyzed to identify the more immediate causes for such situations and also to determine the nature of their temporal and spatial evolution. Much of the background material necessary for this study has been compiled, and case histories on conditions leading to closure circumstances are being prepared to determine the various types of situation development

In Defense of the Epistemic Imperative

Sample (2015) argues that scientists ought not to believe that their theories are true because they cannot fulfill the epistemic obligation to take the diachronic perspective on their theories. I reply that Sample’s argument imposes an inordinately heavy epistemic obligation on scientists, and that it spells doom not only for scientific theories but also for observational beliefs and philosophical ideas that Samples endorses. I also delineate what I take to be a reasonable epistemic obligation for scientists. In sum, philosophers ought to impose on scientists only an epistemic standard that they are willing to impose on themselves

Discrete Rainfall Predictability Using El Niño/Southern Oscillation Interaction

The objective of the study was to determine the probability of occurrence of wet or dry season events, based on the phase of El Niño/Southern Oscillation (ENSO) phenomenon using multinomial logit regression models. The study used monthly time series of the Pacific equatorial sea surface temperature (SST), a sea level pressure index (SOI) and rainfall anomalies over a 2.5x2.5 degrees grid along the west coast of Central and South America, for latitudes starting at 25N, through 45S, since 1951 to 2011. We defined an ENSO index (NSO) as predictor and rainfall as response. Data was categorized into terciles to construct non symmetrical three way contingency table. As results, we generated latitudinal profiles of the predictability (association), for the West Coast of Central and South America, using ENSO as predictor.Universidad de Costa Rica/[805-A7-002]/UCR/Costa RicaUniversidad de Costa Rica/[808-A9-180]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Natural variability of surface oceanographic conditions in the offshore Gulf of Mexico

AbstractThis work characterizes patterns of temporal variability in surface waters of the central Gulf of Mexico. We examine remote-sensing based observations of sea surface temperature (SST), wind speed, sea surface height anomaly (SSHA), chlorophyll-a concentration (Chl-a) and Net Primary Production (NPP), along with model predictions of mixed layer depth (MLD), to determine seasonal changes and long-term trends in the central Gulf of Mexico between the early 1980s and 2012. Specifically, we examine variability in four quadrants of the Gulf of Mexico (water depth >1000m). All variables show strong seasonality. Chl-a and NPP show positive anomalies in response to short-term increases in wind speed and to cold temperature events. The depth of the mixed layer (MLD) directly and significantly affects primary productivity throughout the region. This relationship is sufficiently robust to enable real-time estimates of MLD based on satellite-based estimates of NPP. Over the past 15–20years, SST, wind speed, and SSHA show a statistically significant, gradual increase. However, Chl-a and NPP show no significant trends over this period. There has also been no trend in the MLD in the Gulf of Mexico interior. The positive long-term trend in wind speed and SST anomalies is consistent with the warming phase of the Atlantic Multidecadal Oscillation (AMO) that started in the mid-90s. This also coincides with a negative trend in the El Niño/Southern Oscillation Multivariate ENSO Index (MEI) related to an increase in the frequency of cooler ENSO events since 1999–2000. The results suggest that over decadal scales, increasing temperature, wind speed, and mesoscale ocean activity have offsetting effects on the MLD. The lack of a trend in MLD anomalies over the past 20years explains the lack of long-term changes in chlorophyll concentration and productivity over this period in the Gulf. Understanding the background of seasonal and long-term variability in these ocean characteristics is important to interpret changes in ocean health due to episodic natural and anthropogenic events and long term climate changes or development activities. With this analysis we provide a baseline against which such changes can be measured

A compilation of observations from moored current meters. Vol. 12. Wind currents and temperature over the continental shelf and slope off Peru during JOINT II, March 1976-May 1977

Oregon State University installed and recovered moorings along the coast of Peru during the period late March 1976 through mid-May 1977. A mid-shelf mooring near 15°S (MILA) was maintained for the full duration of the experiment, through five successive installations. This site was complemented by six other moorings in the first half of 1976 and by nine in the March-April-May 1977 period. These simultaneous moorings were arranged in onshore-offshore arrays near 15°S and in alongshore arrays at midshelf from 10°S to 15°30'S. The data described in this report consists of the hourly processed and filtered values of wind and current velocity, air and water temperature, and pressure from the 1976-1977 Peru installations. We describe the data through installation summaries, statistics tables, progressive vector diagrams, speed and direction histograms, rotary spectra and time series plots

Discrete analysis for the America west coast rainfall predictability using El Niño/Southern Oscillation relationships

poster -- Universidad de Costa Rica. Centro de Investigaciones Geofísicas, 2013. Sugerencia para referencias: - Cid, L., S. Ramírez, E. Alfaro & D. Enfield, 2013. Discrete analysis for the America west coast rainfall predictability using El Niño/Southern Oscillation relationships. Memorias del 3er Congreso de Oceanografía Física, Meteorología y Clima del Pacífico Suroriental. Sesión de Variabilidad Climática (poster VC.P3). Santiago, Chile. 16-18 de octubre de 2013.The objective of the study was to determine the probability of occurrence of wet or dry season events, based on the phase of El Niño/Southern Oscillation (ENSO) phenomenon using multinomial response logit and logit regression models. The study used monthly time series of the Pacific equatorial sea surface temperature (SST), a sea level pressure index (SOI) and rainfall anomalies over a 2.5x2.5 degrees grid along the west coast of Central and South America, for latitudes starting at 25°N, through 45°S, since 1951 to 2011. An ENSO index (NSO) was defined as predictor and rainfall as response. Series were first transformed into trimesters, replacing data by the three months average of the seasons DJF – MAM –JJA - SON. Data was categorized into terciles to construct non symmetrical three way contingency tables, including a time lagged categorization of the predictor variable (NSO). Two types of latitudinal profiles of the predictability (association), for the West Coast of Central and South America, using ENSO as predictor were generated as results. One using the categorized NSO index, using a multinomial response logit model to estimate the probabilities at the corners, of the contingency tables, representing the chances of extreme events of rainfall, given the El Niño and La Niña events and a second using multinomial response logit regression models, to estimate the same rainfall events, but using the NSO as a continuous predictor in which the NSO index was used as continuous predictor. The analysis was performed for all the contingency tables, particularly for the “corner cells” and the results were plotted as latitudinal profiles.Universidad de Costa Rica, IPGH, IAI, FI&FUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI