4 research outputs found
Evaluating four remote sensing based models to estimate latent heat flux in semi-arid climate for heterogeneous surface coverage of western Algeria
No full textOptimal estimation of water balance components at the local and regional scales is essential for many applications such as integrated water resources management, hydrogeological modelling and irrigation scheduling. Evapotranspiration is a very important component of the hydrological cycle at the soil surface, particularly in arid and semi-arid lands. Mapping evapotranspiration at high resolution with internalised calibration (METRIC), trapezoid interpolation model (TIM), two-source energy balance (TSEB), and soil-plant-atmosphere and remote sensing evapotranspiration (SPARSE) models were applied using Landsat 8 images for four dates during 2014-2015 and meteorological data. Surface energy maps were then generated. Latent heat flux estimated by four models was then compared and evaluated with those measured by applying the method of Bowen ratio for the various days. In warm periods with high water stress differences and with important surface temperature differences, METRIC proves to be the most robust with the root-mean-square error (RMSE) less than 40 W∙m-2. However, during the periods with no significant surface temperature and soil humidity differences, SPARSE model is superior with the RMSE of 35 W∙m-2. The results of TIM are close to METRIC, since both models are sensitive to the difference in surface temperature. However, SPARSE remains reliable with the RMSE of 55 W∙m-2 unlike TSEB, which has a large deviation from the other models. On the other hand, during the days when the temperature difference is small, SPARSE and TSEB are superior, with a clear advantage of SPARSE serial version, where temperature differences are less important
Evaluation of seismic hazard using tectonic fault data: case of Beni-Chougrane Mountains (Western Algeria)
No full textIn the world, people are increasingly exposed to natural hazards such as earthquakes. To this end, seismic risk mapping remains an essential topic of study in order to minimize their destructive effects. These maps are needed for both seismic risk management and for the design of infrastructure. The challenge is to take into account local information provided by seismic sources (historical seismicity) as well as information related to active tectonic faults. In this article, we calculated the seismic risk in the Mascara Mountains (western Algeria) using the geometric characteristic of known faults. This study is based on an important collection of a tectonic database of these faults (Nature, geometry and geological context). This information is relevant for their seismic potential. Indeed, by including these formations we tried to compute the seismic risk this region characterized by weak seismicity. Our results show more or less alarming facts. Indeed, the magnitude values calculated are between 4.85 and 7.25, whereas the magnitudes obtained by experimental seismicity do not exceed 6 on the Richter scale. The values of the maximum ground acceleration (PGA) are between 0.03 and 0.28 g. These results were compared with assessments made on the basis of historical seismicity; the maximum values obtained do not exceed 0.2 g. The higher values of magnitude calculated from the active faults is due to: (i) the nature of the faults (inverse, normal and strike slip), (ii) the geometry (length and depth) and (iii) that some of these faults may have an aseismic character
