scholarly journals Meandering Evolution and Width Variation, a Physics-Statistical Based Modeling Approach

10.29007/qvdj ◽  
2018 ◽  
Author(s):  
Sergio Lopez Dubon ◽  
Daniele Pietro Viero ◽  
Stefano Lanzoni
Keyword(s):  
Temporal Distribution ◽  
Channel Width ◽  
Erosion And Deposition ◽  
River Bank ◽  
Term Evolution ◽  
Stress Threshold ◽  
Spatio Temporal ◽  
Deposition Processes ◽  
The Stability

Many models have been proposed to simulate and understand the long-term evolution of meandering rivers. These models analyze the hydraulics of the in-channel flow and the river bank movement (erosion – accretion) process in different ways, but some gap still remain, e.g. the stability of long-term simulations when width variations are accounted for. Here we proposed a physics-statistical based approach to simulate the river bank evolution, that erosion and deposition processes act independently, with a specific shear stress threshold for each of them. In addition, we link the width evolution with a parametric probability distribution (PPD) based on a mean characteristic channel width. We are thus able to obtaining stable long-term simulations with realistic and reasonable spatio-temporal distribution of the along channel width.

scholarly journals CONSTRUCTION AND ANALYSIS OF LONG-TERM SURFACE TEMPERATURE DATASET IN FUJIAN PROVINCE

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 1223-1227 ◽  
Author(s):  
W. E. Li ◽  
X. Q. Wang ◽  
H. Su
Keyword(s):  
Time Series ◽  
Surface Temperature ◽  
Land Surface ◽  
Rapid Development ◽  
Temporal Distribution ◽  
Heat Fluxes ◽  
Urban Region ◽  
Fujian Province ◽  
Spatio Temporal

Land surface temperature (LST) is a key parameter of land surface physical processes on global and regional scales, linking the heat fluxes and interactions between the ground and atmosphere. Based on MODIS 8-day LST products (MOD11A2) from the split-window algorithms, we constructed and obtained the monthly and annual LST dataset of Fujian Province from 2000 to 2015. Then, we analyzed the monthly and yearly time series LST data and further investigated the LST distribution and its evolution features. The average LST of Fujian Province reached the highest in July, while the lowest in January. The monthly and annual LST time series present a significantly periodic features (annual and interannual) from 2000 to 2015. The spatial distribution showed that the LST in North and West was lower than South and East in Fujian Province. With the rapid development and urbanization of the coastal area in Fujian Province, the LST in coastal urban region was significantly higher than that in mountainous rural region. The LST distributions might affected by the climate, topography and land cover types. The spatio-temporal distribution characteristics of LST could provide good references for the agricultural layout and environment monitoring in Fujian Province.

The long‐term evolution of the Doruneh Fault region (Central Iran): A key to understanding the spatio‐temporal tectonic evolution in the hinterland of the Zagros convergence zone

2018 ◽  
Vol 54 (3) ◽  
pp. 1454-1479 ◽  
Author(s):  
Meisam Tadayon ◽  
Federico Rossetti ◽  
Massimiliano Zattin ◽  
Gabriele Calzolari ◽  
Reza Nozaem ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Long Term Evolution ◽  
Central Iran ◽  
Convergence Zone ◽  
Term Evolution ◽  
Spatio Temporal ◽  
Fault Region

Interfacial Interactions

2010 ◽  
pp. 128-177
Author(s):  
Wei Ge ◽  
Ning Yang ◽  
Wei Wang ◽  
Jinghai Li
Keyword(s):  
Temporal Distribution ◽  
Gravitational Potential Energy ◽  
Immersed Boundary ◽  
Immersed Boundary Methods ◽  
Additional Information ◽  
Mesoscale Structures ◽  
Computational Fluid Dynamics Cfd ◽  
Spatio Temporal ◽  
Drag Models ◽  
The Stability

The drag interaction between gas and solids not only acts as a driving force for solids in gas-solids flows but also plays as a major role in the dissipation of the energy due to drag losses. This leads to enormous complexities as these drag terms are highly non-linear and multiscale in nature because of the variations in solids spatio-temporal distribution. This chapter provides an overview of this important aspect of the hydrodynamic interactions between the gas and solids and the role of spatio-temporal heterogeneities on the quantification of this drag force. In particular, a model is presented which introduces a mesoscale description into two-fluid models for gas-solids flows. This description is formulated in terms of the stability of gas-solids suspension. The stability condition is, in turn, posed as a minimization problem where the competing factors are the energy consumption required to suspend and transport the solids and their gravitational potential energy. However, the lack of scale-separation leads to many uncertainties in quantifying mesoscale structures. The authors have incorporated this model into computational fluid dynamics (CFD) simulations which have shown improvements over traditional drag models. Fully resolved simulations, such as those mentioned in this chapter and the subject of a later chapter on Immersed Boundary Methods, can be used to obtain additional information about these mesoscale structures. This can be used to formulate better constitutive equations for continuum models.

scholarly journals Assessing the Spatial and Spatio-Temporal Distribution of Forest Species via Bayesian Hierarchical Modeling

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 573 ◽  
Author(s):  
Óscar Rodríguez de Rivera ◽  
Antonio López-Quílez ◽  
Marta Blangiardo
Keyword(s):  
Hierarchical Modeling ◽  
Temporal Distribution ◽  
Short Term ◽  
Distribution Models ◽  
Address Climate Change ◽  
Bayesian Hierarchical ◽  
Temporal Models ◽  
Spatio Temporal ◽  
The Relationship

Climatic change is expected to affect forest development in the short term, as well as the spatial distribution of species in the long term. Species distribution models are potentially useful tools for guiding species choices in reforestation and forest management prescriptions to address climate change. The aim of this study is to build spatial and spatio-temporal models to predict the distribution of four different species present in the Spanish Forest Inventory. We have compared the different models and showed how accounting for dependencies in space and time affect the relationship between species and environmental variables.

Research on Uplink Semi-Persistent Scheduling in LTE System

2013 ◽  
Vol 791-793 ◽  
pp. 1952-1956
Author(s):  
Ji Ke Gao ◽  
De Min Zhang ◽  
Fa Tang Chen
Keyword(s):  
Online Games ◽  
The Other ◽  
Collision Probability ◽  
Evolution System ◽  
Term Evolution ◽  
Collision Processes ◽  
The Stability ◽  
New Applications ◽  
The Relationship

In LTE(Long Term Evolution) system, scheduling plays an important role in the process of allocating resource. LTE system puts forward semi-persistent scheduling (SPS) for new applications such as VoIP(Voice on Internet Protocol) and online games. Considering the problem of resource collision in SPS HARQ(Hybrid Automatic Repeat reQuest) process, we explore the relationship between uplink semi-persistent scheduling period and the number of semi-persistent transmissions, and propose two novel solutions. One is choosing specific uplink semi-persistent period for different uplink/downlink (UL/DL) configurations and the number of transmissions. The other is delaying collision processes for the configuration of small uplink period. The analysis proves that the two solutions can reduce the collision probability and improve the stability of LTE system.

Analysis of methodological and physical bias on borehole temperature reconstructions from a pseudo-proxy approach.

2020 ◽  
Author(s):  
Camilo Melo Aguilar ◽  
Fidel González Rouco ◽  
Elena García Bustamante ◽  
Norman Steinert ◽  
Jorge Navarro ◽  
...  
Keyword(s):  
Grid Point ◽  
Ground Surface ◽  
Temporal Distribution ◽  
Surface Air Temperature ◽  
Internal Variability ◽  
Last Millennium ◽  
Subsurface Temperature ◽  
Borehole Logs ◽  
Spatio Temporal

<p>The analysis of subsurface temperature measurements from boreholes is a well established approach for reconstructing last millennium (LM) surface air temperature (SAT). It is based on the assumption that SAT variations are strongly coupled to ground surface temperature (GST) variations and transferred to the subsurface by thermal conduction. We have evaluated the long-term SAT-GST coupling over the LM using an ensemble of both full- and single-forcing simulations form the Community Earth System Model-Last Millennium Ensemble (CESM-LME). Such a premise is explored by investigating the evolution of the long-term SAT–GST relationship. The results indicate that SAT–GST coupling is strong at global and above multi-decadal timescales in CESM-LME. However, at local to regional scales this relationship experiences considerable long-term changes mostly after the end of the 19th century. Land use land cover (LULC) changes stand as the main driver for locally and regionally decoupling SAT and GST, due to the changes in the energy fluxes at the surface. Snow cover feedbacks due to the influence of GHG forcing are also important for corrupting the long-term SAT–GST coupling. These processes may represent a source of bias for SAT reconstructions from GST borehole profiles. In light of these findings, we subsequently assessed the potential effects on SAT reconstructions from the borehole method in pseudo-proxy experiments that make use of the same set of simulations from the CESM-LME. First, a heat-conduction forward model has been used to estimate subsurface temperature-anomaly profiles using simulated GST as boundary conditions. Subsequently, singular value decomposition inversion (SVD) has been applied to reconstruct LM GST variations from the simulated profiles. We implemented and ideal scenario in which it is assumed the existence of borehole logs at every model grid point. Further, this scenario considers that all boreholes are logged homogenously at the same time. In addition, we implemented a more realistic approach in which the real-world spatio-temporal distribution of the global borehole network is considered. Results show that the SVD inversion is able to retrieve the long-term GST variations over the LM when an appropriated coverture of borehole logs is available. However, due to the limited spatio-temporal distribution of the actual borehole network, there is a lost in the accuracy to retrieve the simulated GST 20th century trends, with the temporal logging of the BTPs as the main sampling issue. Furthermore, in the surrogate reality of the CESM-LME the SAT-GST decoupling, due to the influence of LULC and GHG forcings, leads to a slightly underestimation of SAT warming during the industrial period across the CESM-LME. The level of impact is, however, highly depended on the realization of internal variability.</p>

scholarly journals Trace Element Contamination in One of the Yangtze Tributaries (Hunan, China)—Source Review and Potential Release from Sediments

Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 271
Author(s):  
Cécile Grosbois ◽  
Marc Desmet ◽  
Mengxue Zhang ◽  
Nathalie Gassama ◽  
Qinghui Peng ◽  
...  
Keyword(s):  
Temporal Distribution ◽  
Pollution Level ◽  
Contamination Level ◽  
Experimental Protocol ◽  
Xiangjiang River ◽  
Aquatic Life ◽  
Spatio Temporal ◽  
Trace Element Contamination ◽  
The Stability ◽  
Aerobic And Anaerobic

Spatio-temporal distribution and leachability of some trace elements (TE) were investigated in sediments of the Xiangjiang River, tributary of the Yangtze River. Based on data collected during 2015–2017, a literature review and geoaccumulation indexes, the pollution level was the highest for Cd, Sb and Hg (Igeo > 3). Over the period reviewed, the TE contamination level displayed almost no temporal variation but an obvious spatial distribution. The most upstream contamination hotspot (Cd > Cr > As, Cu, Pb, Zn > Hg, Sb) was the Songbai section. This hotspot did not spread further downstream. The second hotspot identified was the Zhuzhou–Xiangtan section, impacted by Cd > Hg, Pb, Zn > Cu, with the Zhuzhou area being particularly highly impacted by Pb and Zn. A 30-day leaching experimental protocol under aerobic and anaerobic conditions was carried out to access TE mobility. Low percentages of TE released were calculated, showing that the TE fate mostly depends on the stability of bearing phases under specific physicochemical and microbial conditions. In this case, the studied sediments can be an important sink for these TE. However, some environmental issues have to be considered as some leachate concentrations of contaminants (As, Cr, Cu and U) released into water exceed freshwater aquatic life criteria.

scholarly journals Spatio-Temporal Analysis of Rainfall Variability and its Prediction in Al-Qassim Region Using (1987-2017): التحليل المكاني والزماني لتباين التهاطل المطري والتنبؤ به في منطقة القصيم (2017-1987)

2020 ◽  
Vol 4 (4) ◽  
Author(s):  
Aljazy Khalid Alturki, Ahmad Abdullah Aldughairi
Keyword(s):  
Urban Areas ◽  
Rainfall Variability ◽  
Temporal Distribution ◽  
Temporal Analysis ◽  
Seasonal Rainfall ◽  
Economic Activities ◽  
Systems Software ◽  
Distance Weighted ◽  
Spatio Temporal ◽  
The Stability

This study aimed to analyze the indicators of spatial and temporal distribution of daily, monthly, and seasonal rainfall measurements. It is looking for the possibility of the stability or change of precipitation properties by using the data of the present. Also, it is working with the most important factors that effects on the rainfall, Moreover, many of some statistical methods applied in this study. Using inverted distance weighted Inverse Distance Weighting (IDW) method to generates rain interpolation surface that is tool approves in geographic information systems software. Rain is an important element of many economic activities. Therefore, the importance of predicting the spatial distribution of precipitation that is important from water rain resources. This study presents an analysis of spatiotemporal variation of the daily, monthly and seasonal rainfall in Qassim region, based on data seven weather stations, that is including, Buraidah, Unaizah, Al Rasa, and the General Authority for Meteorology and Environmental Protection, also Prince Nayef Airport Station between (2017-1987) which period included 31 years for the accuracy of the results. The study reached to several recommendations that can be used in geographical fields, whether environmental or human, which are related to water resources and torrents, rainwater drainage projects and urban areas to avoid disasters.

scholarly journals Spatio-Temporal Distribution of Landslides in Java and the Triggering Factors

2017 ◽  
Vol 31 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Danang Sri Hadmoko ◽  
Franck Lavigne ◽  
Junun Sartohadi ◽  
Christopher Gomez ◽  
D Daryono
Keyword(s):  
Temporal Distribution ◽  
Rainfall Threshold ◽  
Short Term ◽  
Rainfall Events ◽  
Landslide Occurrence ◽  
Central Java ◽  
Causative Factors ◽  
Spatio Temporal ◽  
Gis Environment

Java Island, the most populated island of Indonesia, is prone to landslide disasters. Their occurrence and impact have increased mainly as the result of natural factors, aggravated by human imprint. This paper is intended to analyse: (1) the spatio-temporal variation of landslides in Java during short term and long-term periods, and (2) their causative factors such as rainfall, topography, geology, earthquakes, and land-use. The evaluation spatially and temporally of historical landslides and consequences were based on the landslide database covering the period of 1981 – 2007 in the GIS environment. Database showed that landslides distributed unevenly between West Java (67 %), Central Java (29 %) and East Java (4 %). Slope failures were most abundant on the very intensively weathered zone of old volcanic materials on slope angles of 30O – 40O. Rainfall threshold analysis showed that shallow landslides and deep-seated landslides were triggered by rainfall events of 300 – 600 mm and > 600 mm respectively of antecedent rainfall during 30 consecutive days, and many cases showed that the landslides were not always initiated by intense rainfall during the landslide day. Human interference plays an important role in landslide occurrence through land conversion from natural forest to dryland agriculture which was the host of most of landslides in Java. These results and methods can be used as valuable information on the spatio-temporal characteristics of landslides in Java and their relationship with causative factors, thereby providing a sound basis for landslide investigation in more detail.

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