Search results for "SCALE"
showing 10 items of 5180 documents
Testing the “physical model concept” by soil loss data measured in Sicily
2012
The best possible model to predict the erosion from an area of land has been suggested to be a physical model of the area that has similar soil type, land use, size, shape, slope and erosive inputs. Therefore, a replicated plot has to be considered the best possible, unbiased, real world model. In this paper the physical model concept was tested by using soil loss data collected on plots of different length at the experimental station of Sparacia, in Sicily (South Italy). This investigation supported the conclusions that i) a coefficient of determination between measured and predicted soil loss values of 0.77 has to be considered as the best-case prediction scenario and ii) an uncalibrated …
Comparing data mining and deterministic pedology to assess the frequency of WRB reference soil groups in the legend of small scale maps
2015
Abstract The assessment of class frequency in soil map legends is affected by uncertainty, especially at small scales where generalization is greater. The aim of this study was to test the hypothesis that data mining techniques provide better estimation of class frequency than traditional deterministic pedology in a national soil map. In the 1:5,000,000 map of Italian soil regions, the soil classes are the WRB reference soil groups (RSGs). Different data mining techniques, namely neural networks, random forests, boosted tree, classification and regression tree, and supported vector machine (SVM), were tested and the last one gave the best RSG predictions using selected auxiliary variables a…
SENTINEL-1 for wheat mapping and soil moisture retrieval
2015
The main objective of this study is to assess the use of Sentinel-1 (S-1) data for surface soil moisture (SSM) retrieval and wheat mapping (WM) at high spatial resolution (e.g. 100–500m), which constitute valuable information for improving crop yield forecast at large scale. A knowledge based classification method and a SSM retrieval algorithm, developed in view of the European Space Agency Sentinel-1 mission, have been applied to a time series of S-1A data collected from October 2014 to April 2015 over a well-documented agricultural site in southern Italy. In particular, observations of SSM content recorded by a network of ground stations deployed in an experimental farm have been used to …
Factors Influencing Point Measurement of Near-surface Saturated Soil Hydraulic Conductivity in a Small Sicilian Basin
2017
Hydraulic conductivity of saturated soil, Ks, controls many hydrological processes. Parameterization of basin hydrological models in terms of Ks is complicated and uncertain owing to the very high spatial variability of this soil property. A small Sicilian basin was intensively sampled by the simplified falling head technique to obtain spatially distributed Ks data, and an attempt to explain their spatial variability on the basis of soil physical characteristics, digital elevation model-derived topographic attributes and land cover was carried out. High Ks values were obtained when clay content was low and both elevation and mean slope were high. Moreover, differences in Ks among land cover…
A simplified approach to estimate water retention for Sicilian soils by the Arya-Paris model
2014
Application of the Arya and Paris (AP) model to estimate the soil water retention curve requires a detailed description of the particle-size distribution (PSD) because the scale factor a, relating the pore length of an ideal soil to that of the natural one, depends on the particle size distribution parameters. For a dataset of 140 Sicilian soils that were grouped in five texture groups, the logistic and linear models were applied to evaluate a, and the water retention values predicted by the AP model were compared with the measured ones. Using the parameters proposed by Arya et al. (1999), the two models yielded similar unsystematic root mean error of estimate (RMSEu). Therefore, their pote…
Measurement Invariance of the Multidimensional Scale of Perceived Social Support Among Chinese and South Asian Ethnic Minority Adolescents in Hong Ko…
2020
Seven hundred adolescents (Chinese = 50%; South Asian ethnic minority = 50%) with mean age of 15.3 years (SD = 1.53). Multigroup confirmatory factor analysis was performed to assess measurement invariance of the MSPSS scale across Chinese and South Asian ethnic minority samples. Results show that the original three-factor structure of the MSPSS was supported in both samples. Measurement invariance was supported in terms of configural, metric, and partial scalar invariance. Given partial scalar invariance was achieved, the latent mean differences were compared across samples. Chinese adolescents had higher levels of all three types of social support when compared with their South Asian ethni…
VALIDACIÓN ESPAÑOLA DEL CUESTIONARIO DE LOCUS DE CONTROL EN DEPORTE INFANTIL // SPANISH VALIDATION OF THE LOCUS OF CONTROL QUESTIONNAIRE IN SPORT FOR…
2018
RESUMEN El locus de control ha sido estudiado en el deporte, sin embargo no existia un instrumento valido para evaluarlo en deporte infantil. Este estudio lleva a cabo la validacion espanola del Children´s Sport Locus of Control Scale (CSLCS) que desarrollaron Tsai y Hsieh (2015). La adaptacion presenta dos fases: una primera exploratoria con 248 ninos entre 7 y 16 anos para observar el comportamiento cualitativo de los items; y una segunda con 221 deportistas entre 8 y 22 anos en la que se modifico el cuestionario para ajustarlo a los resultados obtenidos. Se obtiene una escala final de 10 items, con 5 items por dimension (interna y externa), que presenta un ajuste adecuado. Los resultados…
Effects of distance and scale dependence in geographical models of cities and territories
2019
International audience; This third chapter questions the essential role of distance and scale dependence in models to analyzing the spatial configuration of human settlements and activities, as well as the processes that lead to their evolution, with reference to urban or regional study areas. The subject of study therefore concerns both the form of human settlements and the actions of people (individuals, groups) in their territory (or territories). A human settlement consists of the materialization in space-the physical inscription-of one or more human activities. It is characterized by a certain degree of sustainability. It can be a group of a few buildings or a larger group of thousands…
Land Surface Temperature
2019
Abstract An introduction to the chapter on Land Surface Temperature (LST). The basic thermal infrared theory is presented with example algorithms for the retrieval of LST and emissivity data are described in the later section. Various methods to validate satellite Land Surface Temperature (LST) products exist, but the most accurate and conclusive method is the direct comparison against in situ LST obtained from spatially representative radiance measurements over homogeneous sites. Some validation results and insights found in the literature are provided and the determination of in situ emissivity and LST with thermal infrared field radiometers is explained. The chapter concludes with an exa…
Changes in Onset of Vegetation Growth on Svalbard, 2000–2020
2022
The global temperature is increasing, and this is affecting the vegetation phenology in many parts of the world. The most prominent changes occur at northern latitudes such as our study area, which is Svalbard, located between 76°30′N and 80°50′N. A cloud-free time series of MODIS-NDVI data was processed. The dataset was interpolated to daily data during the 2000–2020 period with a 231.65 m pixel resolution. The onset of vegetation growth was mapped with a NDVI threshold method which corresponds well with a recent Sentinel-2 NDVI-based mapping of the onset of vegetation growth, which was in turn validated by a network of in-situ phenological data from time lapse cameras. The results show th…