The role of surface roughness, albedo, and Bowen ratio on ecosystem energy balance in the Eastern United States

Land cover and land use influence surface climate through differences in biophysical surface properties, including partitioning of sensible and latent heat (e.g., Bowen ratio), surface roughness, and albedo. Clusters of closely spaced eddy covariance towers (e.g., \u3c10 \u3ekm) over a variety of land cover and land use types provide a unique opportunity to study the local effects of land cover and land use on surface temperature. We assess contributions albedo, energy redistribution due to differences in surface roughness and energy redistribution due to differences in the Bowen ratio using two eddy covariance tower clusters and the coupled (land-atmosphere) Variable-Resolution Community Earth System Model. Results suggest that surface roughness is the dominant biophysical factor contributing to differences in surface temperature between forested and deforested lands. Surface temperature of open land is cooler (−4.8 °C to −0.05 °C) than forest at night and warmer (+0.16 °C to +8.2 °C) during the day at northern and southern tower clusters throughout the year, consistent with modeled calculations. At annual timescales, the biophysical contributions of albedo and Bowen ratio have a negligible impact on surface temperature, however the higher albedo of snow-covered open land compared to forest leads to cooler winter surface temperatures over open lands (−0.4 °C to −0.8 °C). In both the models and observation, the difference in mid-day surface temperature calculated from the sum of the individual biophysical factors is greater than the difference in surface temperature calculated from radiative temperature and potential temperature. Differences in measured and modeled air temperature at the blending height, assumptions about independence of biophysical factors, and model biases in surface energy fluxes may contribute to daytime biases

Posicionamiento visual con resolución subpixel de objetos marcados que se desplazan en un plano: conceptos básicos y aplicaciones

Vision is a convenient tool for position measurements. In this paper, we present several applications in which a reference pattern can be defined on the target for a priori knowledge of image features and further optimization by software. Selecting pseudoperiodic patterns leads to high resolution in absolute phase measurements. This method is adapted to position encoding of live cell culture boxes. Our goal is to capture each biological image along with its absolute highly accurate position regarding the culture box itself. Thus, it becomes straightforward to find again an already observed region of interest when a culture box is brought back to the microscope stage from the cell incubator where it was temporarily placed for cell culture. In order to evaluate the performance of this method, we tested it during a wound healing assay of human liver tumor-derived cells. In this case, the procedure enabled more accurate measurements of the wound healing rate than the usual method. It was also applied to the characterization of the in-plane vibration amplitude from a tapered probe of a shear force microscope. The amplitude was interpolated by a quartz tuning fork with an attached pseudo-periodic pattern. Nanometer vibration amplitude resolution is achieved by processing the pattern images. Such pictures were recorded by using a common 20x magnification lens.La visión es una herramienta conveniente para mediciones de posición. En este artículo, presentamos aplicaciones en las que un patrón de referencia puede ser adherido al objeto de interés. Ésto permite tener un conocimiento a priori de las características de la imagen y así poder optimizar el software. Como patrón de referencia se usan patrones pseudo-periódicos, los cuales permiten una alta resolución en las mediciones de fase absoluta. El método es adaptado para codificar la posición de soportes de cultivos celulares, con el fin de documentar cada imagen biológica registrada con su posición absoluta. Por lo tanto, resulta sencillo encontrar de nuevo una región de interés, observada previamente, cuando una caja de cultivo es traída de nuevo al microscopio luego de estar en una incubadora. Para evaluar el método, éste se utilizó durante un ensayo de “cicatrización de herida” de un cultivo celular derivado de tumores hepáticos. En este caso, el método permite obtener mediciones más precisas de la tasa de “cicatrización”, comparado a los resultados obtenidos con el método usual. El método propuesto también se aplica a la caracterización de la amplitud de vibración en el plano de una sonda de un microscopio de fuerza atómica. La amplitud fue interpolada por medio de un diapasón de cuarzo al cual se la adhirió un patrón pseudo-periódico. A partir del procesamiento de las imágenes del patrón, se logra obtener resolución nanométrica en la medida de la amplitud de la vibración. Estas imágenes fueron obtenidas con un microscopio óptico con magnificación 20x

Posicionamiento visual con resolución subpixel de objetos marcados que se desplazan en un plano: conceptos básicos y aplicaciones

Vision is a convenient tool for position measurements. In this paper, we present several applications in which a reference pattern can be defined on the target for a priori knowledge of image features and further optimization by software. Selecting pseudoperiodic patterns leads to high resolution in absolute phase measurements. This method is adapted to position encoding of live cell culture boxes. Our goal is to capture each biological image along with its absolute highly accurate position regarding the culture box itself. Thus, it becomes straightforward to find again an already observed region of interest when a culture box is brought back to the microscope stage from the cell incubator where it was temporarily placed for cell culture. In order to evaluate the performance of this method, we tested it during a wound healing assay of human liver tumor-derived cells. In this case, the procedure enabled more accurate measurements of the wound healing rate than the usual method. It was also applied to the characterization of the in-plane vibration amplitude from a tapered probe of a shear force microscope. The amplitude was interpolated by a quartz tuning fork with an attached pseudo-periodic pattern. Nanometer vibration amplitude resolution is achieved by processing the pattern images. Such pictures were recorded by using a common 20x magnification lens.La visión es una herramienta conveniente para mediciones de posición. En este artículo, presentamos aplicaciones en las que un patrón de referencia puede ser adherido al objeto de interés. Ésto permite tener un conocimiento a priori de las características de la imagen y así poder optimizar el software. Como patrón de referencia se usan patrones pseudo-periódicos, los cuales permiten una alta resolución en las mediciones de fase absoluta. El método es adaptado para codificar la posición de soportes de cultivos celulares, con el fin de documentar cada imagen biológica registrada con su posición absoluta. Por lo tanto, resulta sencillo encontrar de nuevo una región de interés, observada previamente, cuando una caja de cultivo es traída de nuevo al microscopio luego de estar en una incubadora. Para evaluar el método, éste se utilizó durante un ensayo de “cicatrización de herida” de un cultivo celular derivado de tumores hepáticos. En este caso, el método permite obtener mediciones más precisas de la tasa de “cicatrización”, comparado a los resultados obtenidos con el método usual. El método propuesto también se aplica a la caracterización de la amplitud de vibración en el plano de una sonda de un microscopio de fuerza atómica. La amplitud fue interpolada por medio de un diapasón de cuarzo al cual se la adhirió un patrón pseudo-periódico. A partir del procesamiento de las imágenes del patrón, se logra obtener resolución nanométrica en la medida de la amplitud de la vibración. Estas imágenes fueron obtenidas con un microscopio óptico con magnificación 20x

Thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships

Doremus's model of viscosity assumes that viscous flow in amorphous materials is mediated by broken bonds (configurons). The resulting equation contains four coefficients, which are directly related to the entropies and enthalpies of formation and motion of the configurons. Thus by fitting this viscosity equation to experimental viscosity data these enthalpy and entropy terms can be obtained. The non-linear nature of the equation obtained means that the fitting process is non-trivial. A genetic algorithm based approach has been developed to fit the equation to experimental viscosity data for a number of glassy materials, including SiO2, GeO2, B2O3, anorthite, diopside, xNa2O–(1-x)SiO2, xPbO–(1-x)SiO2, soda-lime-silica glasses, salol, and α-phenyl-o-cresol. Excellent fits of the equation to the viscosity data were obtained over the entire temperature range. The fitting parameters were used to quantitatively determine the enthalpies and entropies of formation and motion of configurons in the analysed systems and the activation energies for flow at high and low temperatures as well as fragility ratios using the Doremus criterion for fragility. A direct anti-correlation between fragility ratio and configuron percolation threshold, which determines the glass transition temperature in the analysed materials, was found

Moist Static Energy Budget Analysis of Tropical Cyclone Intensification in High-Resolution Climate Models

Tropical cyclone intensification processes are explored in six high-resolution climate models. The analysis framework employs process-oriented diagnostics that focus on how convection, moisture, clouds, and related processes are coupled. These diagnostics include budgets of column moist static energy and the spatial variance of column moist static energy, where the column integral is performed between fixed pressure levels. The latter allows for the quantification of the different feedback processes responsible for the amplification of moist static energy anomalies associated with the organization of convection and cyclone spinup, including surface flux feedbacks and cloud-radiative feedbacks. Tropical cyclones (TCs) are tracked in the climate model simulations and the analysis is applied along the individual tracks and composited over many TCs. Two methods of compositing are employed: a composite over all TC snapshots in a given intensity range, and a composite over all TC snapshots at the same stage in the TC life cycle (same time relative to the time of lifetime maximum intensity for each storm). The radiative feedback contributes to TC development in all models, especially in storms of weaker intensity or earlier stages of development. Notably, the surface flux feedback is stronger in models that simulate more intense TCs. This indicates that the representation of the interaction between spatially varying surface fluxes and the developing TC is responsible for at least part of the intermodel spread in TC simulation