Simulation model of Ulva rigida growth in shallow water of the lagoon of Venice.

The model presented here points out the possibility of simulating with a mathematical description the life cycle of Ulva rigida C. Ag. in the Lagoon of Venice. Model simulations allow the assessment of the relative importance of factors like light, temperature and nutrient availability on U. rigida growth. Particularly, phosphorus internal quota is shown to be always close to its maximum and thus it is never limiting while nitrogen limitation is weak and occurs only in the warm months. The influence of environmental disturbance, here represented by water movement and sediment resuspension induced by climatic events, is introduced in the model to simulate the observed sharp decline of biomass. Macroalgae biomass accumulation is not described in the model and its lack is claimed to justify some failure of the model when reproducing the biomass peak in the growing season. More knowledge is needed in this direction to understand better the influence that such factors could have on growth and distribution of U. rigida in shallow water areas of the Lagoon of Venice. The model has been implemented by following the object oriented paradig

Simulation model of Ulva rigida growth in shallow water of the lagoon of Venice.

The model presented here points out the possibility of simulating with a mathematical description the life cycle of Ulva rigida C. Ag. in the Lagoon of Venice. Model simulations allow the assessment of the relative importance of factors like light, temperature and nutrient availability on U. rigida growth. Particularly, phosphorus internal quota is shown to be always close to its maximum and thus it is never limiting while nitrogen limitation is weak and occurs only in the warm months. The influence of environmental disturbance, here represented by water movement and sediment resuspension induced by climatic events, is introduced in the model to simulate the observed sharp decline of biomass. Macroalgae biomass accumulation is not described in the model and its lack is claimed to justify some failure of the model when reproducing the biomass peak in the growing season. More knowledge is needed in this direction to understand better the influence that such factors could have on growth and distribution of U. rigida in shallow water areas of the Lagoon of Venice. The model has been implemented by following the object oriented paradig

Un modello di qualit\ue0\ua0 dell'acqua dei rii in Laguna di Venezia

Il volume, che costituisce il primo studio sitematico sui rii di Venenzia, si compone di due sezioni: nella prima i rii, vie d'acqua e "sistema arterioso" della citt\ue0 di Venezia, vengono descritti e analizzati dal punto di vista storico e scientifico, considerandone le caratteristiche chimiche, idrodinamiche, e logistico-urbanistiche in una serie di saggi firmati dai pi\uf9 importanti esperti del settore (W. Dorigo, G. Caniato e S. Piasentini per la parte storica; V. Giannotti, F. Carrera, F. Fiorin, G. Coffaro, L. Bottazzo, P. Gardin e I. Turlon per la parte scientifica)

Simulation model of Ulva rigida growth in shallow water of the Lagoon of Venice

Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Post-Image Acquisition Processing Approaches For Coherent Backscatter Validation

Utilizing a retro-reflector from a target point, the reflected irradiance of a laser beam traveling back toward the transmitting point contains a peak point of intensity known as the enhanced backscatter (EBS) phenomenon. EBS is dependent on the strength regime of turbulence currently occurring within the atmosphere as the beam propagates across and back. In order to capture and analyze this phenomenon so that it may be compared to theory, an imaging system is integrated into the optical set up. With proper imaging established, we are able to implement various post-image acquisition techniques to help determine detection and positioning of EBS which can then be validated with theory by inspection of certain dependent meteorological parameters such as the refractive index structure parameter, Cn2and wind speed

Scintillation Fluctuations Of Optical Communication Lasers In Atmospheric Turbulence

The purpose of this research is to evaluate scintillation fluctuations on optical communication lasers and evaluate potential system improvements to reduce scintillation effects. This research attempts to experimentally verify mathematical models developed by Andrews and Phillips [1] for scintillation fluctuations in atmospheric turbulence using two different transmitting wavelengths. Propagation range lengths and detector quantities were varied to confirm the theoretical scintillation curve. In order to confirm the range and wavelength dependent scintillation curve, intensity measurements were taken from a 904nm and 1550nm laser source for an assortment of path distances along the 1km laser range at the Townes Laser Institute. The refractive index structure parameter (Cn2) data was also taken at various ranges using two commercial scintillometers. This parameter is used to characterize the strength of atmospheric turbulence, which induces scintillation effects on the laser beam, and is a vital input parameter to the mathematical model. Data was taken and analyzed using a 4-detector board array. The material presented in this paper outlines the verification and validation of the theoretical scintillation model, and steps to improve the scintillation fluctuation effects on the laser beam through additional detectors and a longer transmitting wavelength. Experimental data was post processed and analyzed for scintillation fluctuations of the two transmitting wavelengths. The results demonstrate the benefit of additional detectors and validate a mathematical model that can be scaled for use in a variety of communications or defense applications. Scintillation is a problem faced by every free space laser communication system and the verification of an accurate mathematical model to simulate these effects has strong application across the industry. © 2014 SPIE

Extended Bkb Model Utilizing Regional Weather Data For Cn\u3csup\u3e2\u3c/sup\u3eMeasurement

The alternative Bendersky, Kopeika, and Blaunstein (BKB) model of measuring the refractive structure index parameter, Cn2has proven to be a reliable, well-used means of quantifying and characterizing the atmospheric turbulence in a given environment. This model relies on various meteorological parameters such as temperature, wind speed, relative humidity, and time of day in order to procure the resulting Cn2quantity. Using experimentally confirmed results from a desert environment, the utility of this model may be extended to other climates by adapting temporal hour weights used within the model. The adaptation of these weighted parameters are shown to have a relationship with the unique weather conditions of a given region which are demonstrated by data points collected from two testing ranges located in Florida in addition to archived weather data. The resulting extended model is then compared to commercial scintillometer data for validation