How well can inverse analyses of high-resolution satellite data resolve heterogeneous methane fluxes? Observing system simulation experiments with the GEOS-Chem adjoint model (v35)

We perform observing system simulation experiments (OSSEs) with the GEOS-Chem adjoint model to test how well methane emissions over North America can be resolved using measurements from the TROPOspheric Monitoring Instrument (TROPOMI) and similar high-resolution satellite sensors. We focus analysis on the impacts of (i) spatial errors in the prior emissions and (ii) model transport errors. Along with a standard scale factor (SF) optimization we conduct a set of inversions using alternative formalisms that aim to overcome limitations in the SF-based approach that arise for missing sources. We show that 4D-Var analysis of the TROPOMI data can improve monthly emission estimates at 25 km even with a spatially biased prior or model transport errors (42 %–93 % domain-wide bias reduction; R increases from 0.51 up to 0.73). However, when both errors are present, no single inversion framework can successfully improve both the overall bias and spatial distribution of fluxes relative to the prior on the 25 km model grid. In that case, the ensemble-mean optimized fluxes have a domain-wide bias of 77 Gg d−1 (comparable to that in the prior), with spurious source adjustments compensating for the transport errors. Increasing observational coverage through longer-timeframe inversions does not significantly change this picture. An inversion formalism that optimizes emission enhancements rather than scale factors exhibits the best performance for identifying missing sources, while an approach combining a uniform background emission with the prior inventory yields the best performance in terms of overall spatial fidelity – even in the presence of model transport errors. However, the standard SF optimization outperforms both of these for the magnitude of the domain-wide flux. For the common scenario in which prior errors are non-random, approximate posterior error reduction calculations (derived via gradient-based randomization) for the inversions reflect the sensitivity to observations but have no spatial correlation with the actual emission improvements. This demonstrates that such information content analysis can be used for general observing system characterization but does not describe the spatial accuracy of the posterior emissions or of the actual emission improvements. Findings here highlight the need for careful evaluation of potential missing sources in prior emission datasets and for robust accounting of model transport errors in inverse analyses of the methane budget.

Analysis of Structures’ Orientations in Archaeoastronomy

In the scope of archaeoastronomy, the analysis of a large number of structures through the frequency histograms for their azimuths and declinations can identify singular patterns of orientation. Conclusions often rely on qualitative assessments. Quantitative assessments have been proposed by using as null hypothesis a pure random distribution of azimuths over the 360º horizon. In some cases, such as orientation of Christian churches, the histograms or spectra are composite, with peaks overlapping a continuous and not uniform background. This paper presents a methodology for assessing the statistical significance of the net area of a peak in the histogram in relation to the local background level. The spectra use Normal kernel functions. The background contribution is estimated from the area of the trapezoidal polygon under the peak, and it is interpreted as the probability parameter for a Binomial distribution. The methodology is illustrated with a real case study which includes the azimuth and declination histograms for a set of churches from southern Spain dedicated to the Virgin of the Assumption. The method is more restrictive than previous approaches.

SCALING OF SENSATIONS DURING THE PERFORMANCE OF VISUAL TASKS IN RELATION TO HUMAN CENTRIC LIGHTING

Currently, programs for lighting calculation based on computer graphics (CG) allows us to move to a fundamentally new approach to a assessing the quality of lighting. A designing based on illuminance can be complement with designing based on synthetic images or on lighting design. Modern CG programs can calculate the spatial-angular distribution of luminance (SADL). However, to make the assessment of the quality of lighting using SADL a new criterion is needed. This paper considers constructing a physiological model of the visual perception scale based on experimental data and on neural network for simple scene as light source viewed on a uniform background with different luminance levels. Scale based on threshold contrasts of luminance for each sensation can be a fundament of new criterion. The article offers the method of construction the map for each sensation using the example of «discomfort» and «unpleasant» maps that can easily applied in programs.

Computer simulation of adapting the object image selection method to video surveillance conditions

The article deals with the issues of computer modeling of methods for selecting images of objects against a non-uniform background. A test video sequence with given background and object parameters is considered, which provides imitation of one of the special cases of video surveillance conditions, namely, the convergence of the video surveillance point and the object. The issues of adaptation of the compensation selection method to the specified conditions of video surveillance are discussed. Examples of test images and graphs of dependences of the probability of correct determination of coordinates depending on the value of the local contrast of the object in relation to the background, obtained by computer simulation are given.

Color Based Object Categorization Using Histograms of Oriented Hue and Saturation

In the last few years, there has been a lot of interest in making smart components, e.g. robots, able to simulate human capacity of object recognition and categorization. In this paper, we propose a new revolutionary approach for object categorization based on combining the HOG (Histograms of Oriented Gradients) descriptors with our two new descriptors, HOH (Histograms of Oriented Hue) and HOS (Histograms of Oriented Saturation), designed it in the HSL (Hue, Saturation and Luminance) color space and inspired by this famous HOG descriptor. By using the chrominance components, we have succeeded in making the proposed descriptor invariant to all lighting conditions changes. Moreover, the use of this oriented gradient makes our descriptor invariant to geometric condition changes including geometric and photometric transformation. Finally, the combination of color and gradient information increase the recognition rate of this descriptor and give it an exceptional performance compared to existing methods in the recognition of colored handmade objects with uniform background (98.92% for Columbia Object Image Library and 99.16% for the Amsterdam Library of Object Images). For the classification task, we propose the use of two strong and very used classifiers, SVM (Support Vector Machine) and KNN (k-nearest neighbors) classifiers.

Formation of the image of urban space in the visual arts as a means of pedagogical reception in architectural education

В городском пейзаже важной характеристикой является понятие «образ города» как проявление духовной сущности материального городского пространства, выражение общих черт и уникальных особенностей, отражение исторической и культурной памяти, этнокультурной идентичности, присущих городам. Изучение эволюции образа города в изобразительном искусстве позволяет выявить представления о ценностях, эстетических категориях, социальных нормах определенного исторического периода, тенденции в развитии городских пространств. При обсуждении конструкции города по типам элементов в общегородском масштабе выделяются: районы, границы, дороги, узлы, ориентиры. Однако "только во взаимосвязанности частей в единое целое пути могут раскрыть последовательность и характер районов и связать различные узлы; Узлы соединят и очертят пути, границы охватят районы, а ориентиры обозначат центры активности”. Полная проработка всех этих звеньев с помощью света способна связать их в целостный ночной образ, ибо ориентир обладает достаточной силой, если он виден с большого расстояния и в течение долгого времени; если, опираясь на него, можно установить собственную локализацию; узлы, как концептуальные опоры образа городов, которая может поддерживаться специфическим устойчивым освещением (применение ритмической световой инсталляции при визуальной организации узлов предоставляет такую специфическую особенность в ночное время, что делает его более четким); четкие пределы позволяют легче распознавать узлы; районы города как однородные по характеру территории лучше воспринимаются при организации однородного фонового освещения. In the urban landscape, an important characteristic is the concept of the "image of the city" as a manifestation of the spiritual essence of the material urban space, the expression of common features and unique features, the reflection of historical and cultural memory, ethno-cultural identity inherent in cities. The study of the evolution of the image of the city in the visual arts allows us to identify ideas about values, aesthetic categories, social norms of a certain historical period, trends in the development of urban spaces. When discussing the construction of a city by the types of elements on a citywide scale, the following are distinguished: districts, borders, roads, nodes, landmarks. However, " only in the interconnectedness of the parts into a single whole, the paths can reveal the sequence and character of the districts and connect various nodes; The nodes will connect and outline the paths, the boundaries will cover the districts, and the landmarks will indicate the centers of activity.” A complete study of all these links with the help of light is able to link them into a complete night image, because the landmark has sufficient strength if it is visible from a long distance and for a long time; if, relying on it, you can establish your own localization; nodes as conceptual supports of the image of cities, which can be supported by specific stable lighting (the use of a rhythmic light installation in the visual organization of nodes provides such a specific feature at night, which makes it clearer); clear limits make it easier to recognize nodes; city districts as homogeneous in the nature of the territory are better perceived when organizing uniform background lighting.

On interference between target and noise in visual stimuli

Visual stimuli in which a target is presented on a background of noise have been used widely in visionresearch. Adding a background of noise tends to reduce performance. Such reductions have typically beenattributed to factors in the visual system. The present analyses demonstrates how there may be interferencebetween target and noise. This interference takes place in the stimuli rather than in the visual system. Ittakes place even if the stimuli are not being seen. The interference causes the amplitudes in the combinedtarget and noise stimulus to be smaller than the amplitudes in the target plus the amplitudes in the noisewhen these are determined separately. Therefore, the full amplitudes of the target and those of the noisecannot all be contained in the amplitudes of the combined stimulus. As a consequence one cannot counton a target stimulus to have the same stimulus power when presented on a background of noise as whenpresented on a uniform background.

How well can inverse analyses of high-resolution satellite data resolve heterogeneous methane fluxes? Observation System Simulation Experiments with the GEOS-Chem adjoint model (v35)

We perform Observation System Simulation Experiments (OSSEs) with the GEOS-Chem adjoint model to test how well methane emissions over North America can be resolved using measurements from the TROPOspheric Monitoring Instrument (TROPOMI) and similar high-resolution satellite sensors. We focus analysis on the impacts of i) spatial errors in the prior emissions, and ii) model transport errors. Along with a standard scale-factor (SF) optimization we conduct a set of inversions using alternative formalisms that aim to overcome limitations in the SF-based approach that arise for missing sources. We show that 4D-Var analysis of the TROPOMI data can improve monthly emission estimates at 25 km even with a spatially biased prior or model transport errors (42–93 % domain-wide bias reduction; R increases from 0.51 up to 0.73). However, when both errors are present, no single inversion framework can successfully improve both the overall bias and spatial distribution of fluxes relative to the prior on the 25 km model grid. In that case, the ensemble-mean optimized fluxes have a domain-wide bias of 77 Gg/d (comparable to that in the prior), with spurious source adjustments compensating for the transport errors. Increasing observational coverage through longer-timeframe inversions does not significantly change this picture. An inversion formalism that optimizes emission enhancements rather than scale factors exhibits the best performance for identifying missing sources, while an approach combining a uniform background emission with the prior inventory yields the best performance in terms of overall spatial fidelity—even in the presence of model transport errors. However, the standard SF optimization outperforms both of these for the magnitude of the domain-wide flux. For the common scenario in which prior errors are non-random, approximate posterior error reduction calculations for the inversions reflect the sensitivity to observations but have no spatial correlation with the actual emission improvements. This demonstrates that such information content analysis can be used for general observing system characterization but does not describe the spatial accuracy of the posterior emissions or of the actual emission improvements. Findings here highlight the need for careful evaluation of potential missing sources in prior emission datasets and for robust accounting of model transport errors in inverse analyses of the methane budget.