Determination of the spatial variability of temperature and moisture near a tropical Pacific island with MTI satellite images

2002 ◽  
Author(s):  
Robert J. Kurzeja ◽  
Byron L. O'Steen ◽  
Malcolm M. Pendergast
Author(s):  
Guglielmo Federico Antonio Brunetti ◽  
Samuele De Bartolo ◽  
Carmine Fallico ◽  
Ferdinando Frega ◽  
Maria Fernanda Rivera Velásquez ◽  
...  

AbstractThe spatial variability of the aquifers' hydraulic properties can be satisfactorily described by means of scaling laws. The latter enable one to relate the small (typically laboratory) scale to the larger (typically formation/regional) ones, therefore leading de facto to an upscaling procedure. In the present study, we are concerned with the spatial variability of the hydraulic conductivity K into a strongly heterogeneous porous formation. A strategy, allowing one to identify correctly the single/multiple scaling of K, is applied for the first time to a large caisson, where the medium was packed. In particular, we show how to identify the various scaling ranges with special emphasis on the determination of the related cut-off limits. Finally, we illustrate how the heterogeneity enhances with the increasing scale of observation, by identifying the proper law accounting for the transition from the laboratory to the field scale. Results of the present study are of paramount utility for the proper design of pumping tests in formations where the degree of spatial variability of the hydraulic conductivity does not allow regarding them as “weakly heterogeneous”, as well as for the study of dispersion mechanisms.


2012 ◽  
Vol 10 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Fernanda Bruno ◽  
Paola Barreto ◽  
Milena Szafir

This on line curatorship presents a selection of 11 works by Latin American artists who incorporate in their creations technologies traditionally linked to surveillance and control processes. By Surveillance Aesthetics we understand a compound of artistic practices, which include the appropriation of dispositifs such as closed circuit video, webcams, satellite images, algorithms and computer vision among others, placing them within new visibility, attention and experience regimes. The term referred to in the title of this exhibition is intended more as a vector of research rather than the determination of a field, as pointed by Arlindo Machado under the term “surveillance culture”. (Machado 1991) In this sense, a Latin America Surveillance Aesthetics exhibition is a way to propose, starting from the works presented here, a myriad of questions. How and to what extent do the destinies of surveillance devices reverberate or are subverted by market, security and media logics in our societies? If, in Europe and in the USA, surveillance is a subject related to the war against terror and border control, what can be said about Latin America? What forces and conflicts are involved? How have artistic practices been creating and acting in relation to these forces and conflicts? Successful panoramas of so called Surveillance Art already take place in Europe and North America for at least three decades, the exhibition “Surveillance”, at the Los Angeles Contemporary Exhibitions being one of the first initiatives in this domain. In Latin America however, art produced in the context of surveillance devices and processes is still seen as an isolated event. Our intention is to assemble a selection of works indicating the existence of a wider base of production, which cannot be considered eventual.The online exhibition can be accessed here.http://www.pec.ufrj.br/surveillanceaestheticslatina/


2020 ◽  
pp. 3445-3455
Author(s):  
Heba Khudhair Abbas ◽  
Farah Faris ◽  
Sale Sami ◽  
Al Zahraa Fadel

Mathematical integration techniques rely on mathematical relationships such as addition, subtraction, division, and subtraction to merge images with different resolutions to achieve the best effect of the merger. In this study, a simulation is adopted to correct the geometric and radiometric distortion of satellite images based on mathematical integration techniques, including Brovey Transform (BT), Color Normalization Transform (CNT), and Multiplicative Model (MM). Also, interpolation methods, namely the nearest neighborhood, Bi-linear, and Bi-cubic were adapted to the images captured by an optical camera. The evaluation of images resulting from the integration process was performed using several types of measures; the first type depends on the determination of quality in the regions of the edges using a contrast measure as well as the number of edges and threshold. The second type is the global one that is based on the parameters of the image region, including the Mean (µ), Standard Deviation (SD), and Signal to Noise Ratio (SNR). The parameters also included the Amount of Information Added (AIA) to the original image, such as those for the total (AIAt) , edges (AIAe), and homogenous (AIAh) regions. The results showed the efficiency of the integration process in the image fusion with different resolutions in one image integrated resolution. The quality measures used were also capable in evaluating the most efficient techniques and determining the accurate information of the resulting image.


2021 ◽  
Vol 11 (1) ◽  
pp. 45-66
Author(s):  
Mete Durlu ◽  
Ozan Eski ◽  
Emre Sumer

In many geospatial applications, automated detection of buildings has become a key concern in recent years. Determination of building locations provides great benefits for numerous geospatial applications such as urban planning, disaster management, infrastructure planning, environmental monitoring. The study  aims to present a practical technique for extracting the buildings from high-resolution satellite images using color image segmentation and binary morphological image processing. The proposed method is implemented on satellite images of 4 different selected study areas of the city of Batikent, Ankara.  According to experiments conducted on the study areas, overall accuracy, sensitivity, and F1 values were computed to be on average, respectively. After applying morphological operations, the same metrics are calculated . The results show that the determination of urban buildings can be done more successfully with the suitable combination of morphological operations using rectangular structuring element. Keywords: Building Extraction; Colour Image Processing;Colour space conversion; Image Morphology; Remote Sensing        


Author(s):  
Benjamin Holt ◽  
D. Andrew Rothrock ◽  
Ronald Kwok
Keyword(s):  
Sea Ice ◽  

2012 ◽  
Vol 16 (3) ◽  
pp. 1001-1015 ◽  
Author(s):  
K. X. Soulis ◽  
J. D. Valiantzas

Abstract. The Soil Conservation Service Curve Number (SCS-CN) approach is widely used as a simple method for predicting direct runoff volume for a given rainfall event. The CN parameter values corresponding to various soil, land cover, and land management conditions can be selected from tables, but it is preferable to estimate the CN value from measured rainfall-runoff data if available. However, previous researchers indicated that the CN values calculated from measured rainfall-runoff data vary systematically with the rainfall depth. Hence, they suggested the determination of a single asymptotic CN value observed for very high rainfall depths to characterize the watersheds' runoff response. In this paper, the hypothesis that the observed correlation between the calculated CN value and the rainfall depth in a watershed reflects the effect of soils and land cover spatial variability on its hydrologic response is being tested. Based on this hypothesis, the simplified concept of a two-CN heterogeneous system is introduced to model the observed CN-rainfall variation by reducing the CN spatial variability into two classes. The behaviour of the CN-rainfall function produced by the simplified two-CN system is approached theoretically, it is analysed systematically, and it is found to be similar to the variation observed in natural watersheds. Synthetic data tests, natural watersheds examples, and detailed study of two natural experimental watersheds with known spatial heterogeneity characteristics were used to evaluate the method. The results indicate that the determination of CN values from rainfall runoff data using the proposed two-CN system approach provides reasonable accuracy and it over performs the previous methods based on the determination of a single asymptotic CN value. Although the suggested method increases the number of unknown parameters to three (instead of one), a clear physical reasoning for them is presented.


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