Linking Irrigation to Landslides in Franklin County, Washington

Landslides occur when a slope is unstable and collapses with different contributing and mediating factors to slope instability, including human activity. This study evaluates the association between the occurrence of landslides and irrigation in Franklin County, Washington. The study sought to evaluate whether irrigation can be linked to an increase in the occurrence of landslide events within Franklin County. The study area was divided into a ‘treatment site’ and several ‘control sites.’ The treatment site is located in Franklin County where irrigation has occurred near the cliff, while the control sites are sloped and non-irrigated areas outside of Franklin County. Control and treatment areas share the same characteristics in terms of underlying geology and slope. Therefore, the likelihood for landslide events is comparable for both types of areas, except for the presence or absence of irrigation. The study spans 20 years; from 2000 to 2019. For each year, landslide events were extracted using the Digital Elevation Model (DEM) differencing method and verified with visual analysis of false color composites. Results show that eight landslides were identified in irrigated areas while two landslides were detected in non-irrigated areas, for a total of 729 pixels. I used a Generalized Linear Model (GLM), specifically the Binomial specification/Logistic Regression to determine the importance of irrigation on the occurrence of landslides identified. Pixels located within irrigated areas were found to be 32.5 to 36.3 times more likely to have landslides occur than if no irrigation occurred. Several different versions of the GLM were explored, and the rate at which irrigation effects landslides changes depending on which variables were included. The results of this study can be used to advocate for more environmental regulations where irrigation occurs on slopes. Limitations of this research include data restraints and study area restrictions. Future work can further investigate the study area or develop additional methods

Influence of the three-dimensional effects on the simulation of landscapes in thermal infrared

International audienceThe paper deals with the modelling of landscapes for the simulation of very high spatial resolution images in the thermal infrared range, from 3 to 14 μm. It focuses on the influence of the 3-D effects on the simulation. The major relevant physical processes are described. Examples are made, comparing simulations obtained with 2-D and 3-D representation of the landscape. They help in classifying the relative influence of each process. The necessity to take into account a 3-D landscape representation for the simulation of very high spatial resolution images in the infrared range is also demonstrated

Specifications and conceptual architecture of a thermal infrared simulator of landscapes

International audienceThis paper deals with the simulation of very high spatial resolution images in the thermal infrared range, from 3 to 14 m. It focuses on the conceptual architecture of a simulator of 3-D landscapes; its specifications are described and discussed. A new methodology is proposed for the simulation to best reproduce the properties of the infrared imagery. Particularly, this methodology enables a very accurate simulation of the signal coming from each object constituting the landscape. The interactions between the radiations and objects and between objects themselves are considered. Their changes in time, and the recent past of the temperature and the humidity for each object, are taken into account. To reproduce these physical phenomena, the computation is performed on elements, which are defined as homogeneous entities with respect to the physical processes. This concept of element leads to a new methodology in design and realization of simulators. It permits to reproduce efficiently the behavior of the landscape in this spectral range at very high spatial resolution

Outdoor Scene Synthesis in the Infrared Range for Remote Sensing Applications

International audienceThis paper deals with a method of representation of landscape for the simulation of the behavior of an outdoor scene in the thermal infrared range, from 3 to 14 μm. The scene and objects are modeled in 3-D at very high spatial resolution of half a meter or so. The mesh is adapted to reproduce all the physical phenomena and their variations, according to their relative importance. The classical facet is no longer appropriate. A new quantity is introduced: the element. The element is defined as a part of an object. It is homogeneous with respect to material constitution and energy flux balance at a given instant. The mesh representing the scene is made of the union of the elements for the period of simulation of the temperature. All computations of fluxes and temperature are made on this mesh. Sufficient accuracy can be achieved by considering the most important physical phenomena to generate the elements. Shadow effect is the most important one. Influences of other phenomena are modeled by the mean of texture synthesis. In this paper, the method to define and generate elements is exposed, and an example is given, showing the efficiency of such a method to predict surface temperature, and afterward the irradiance of the scene

Simulation d'images dans l'infrarouge thermique par une approche synthétique : spécifications et architecture fonctionnelle

International audienceon présente les spécifications et l'architecture fonctionnelle d'un simulateur de scènes dans l'infrarouge thermique pour des longueurs d'onde variant de 3 14 micron. Ce simulateur doit être capable de générer des scènes avec une trés haute résolution spatiale et de gérer l'ensemble des interactions entre les objets composant le paysage. Les phénomènes physiques sont brièvement rappelés ; une méthodologie originale de simulation basée sur la gestion d'entités homogènes spatialement et temporellement vis à vis des processus physiques est proposée. Elle permet de traduire efficacement l'histoire récente de la scène, toujours nécessaire la simulation d'une image infrarouge

OSIrIS: a physically based simulation tool to improve training in thermal infrared remote sensing over urban areas at high spatial resolution

International audienceThis paper describes an infrared image simulator for remote sensing applications, called OSIrIS (outdoor scene and infrared image simulation). It has been developed partly for training and reproduces with great details the physical phenomena that play a major role in complex urban environment. OSIrIS performs a synthesis of scene based on a 3-D description of the landscape with a high spatial resolution (0.5 – 10 m). The physical processes are briefly described and their importance with respect to the objectives are discussed. Thermal emission depends on temperature and generally dominates the signal. Temperature is governed by heat equation and is solved by the means of boundary conditions such as in-depth temperature and flux balance at surface. Main parameters are solar and atmospheric radiations, wind, heat conduction and changes in humidity. An innovative approach was developed to take into account variations in time of the interactions between the landscape and the physical processes. OSIrIS aims at simulating situations that are encountered in reality. It enables users self-formation, helping them understanding changes in image radiance as a function of the input parameters and their own simulation requirements. Examples are given that illustrate specific aspects of infrared images

Le mosaïquage d'images satellitales optiques à haute résolution spatiale

Cette communication propose une réflexion sur les performances et les traitements nécessaires à un système d'observation spatiale à haute résolution optique - métrique et sub-métrique - mettant en oeuvre des techniques de mosaïquage spécifiques pour la production d'images à large fauchée - supérieure à 50 km - à partir d'instruments à faible champ (inférieur à 20 km)

A simulator of images in the infrared spectral band for training users

International audienceThis paper deals with the description and the applications of SPIRou, SPIRou synthesize realistic radiance images at ground level of outdoor scenes in infrared spectral band. SPIRou method make use of physical models to simulate the energy balance at the surface of natural and artificial objects, of mathematical model to predict surface temperature and of physical models to estimate radiance in the spectral band of the radiometer. Various physical parameters can be changed, which e.g. simulate changes in meteorological conditions. Such a simulator are useful to train users to the analysis or the interpretation of infrared images

S.P.I.Rou.: a landscape synthesis tool in the infrared spectral band

International audienceThis paper deals with a method to synthesize realistic outdoor scenes in infrared spectral band. This method makes use of physical models to simulate the energy balance at the surface of natural and artificial objects, for given meteorological conditions and landscape to be sensed, of mathematical model to predict surface temperature and of physical models to estimate radiance in the spectral band of the radiometer. The whole approach is described and infrared images are synthesized. The limits of the physical models are analyzed and their impact upon the resulting images are assessed