scholarly journals IMPACT OF THE PORT STRUCTURE IN THE SPATIO-TEMPORAL EVOLUTION OF THE SEDIMENTARY AND BATHYMETRIC CHARACTERISTICS OF A MOROCCAN ATLANTIC BAY, STUDY CASE BAY OF SAFI CITY

2022 ◽  
Vol XLVI-4/W3-2021 ◽  
pp. 215-221
Author(s):  
A. Minoubi ◽  
M. Bouchkara ◽  
K. El Khalidi ◽  
M. Chaibi ◽  
M. Ayt Ougougdal ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Temporal Evolution ◽  
Atlantic Coast ◽  
Sedimentary Facies ◽  
Hydrodynamic Conditions ◽  
Study Case ◽  
Spatio Temporal ◽  
The Impact ◽  
Port Construction

Abstract. This study focuses on morpho-sedimentary changes in the bay of Safi (Atlantic coast of Morocco), due to a progressive extension of the port. For this purpose, several bathymetric and sedimentary surveys carried out by the Hydrographic and Oceanographic Service of the Navy (SHOM) in 1892, 1906 and 1940 respectively, coupled with a bathymetric and sedimentary measurement mission in 2009, were analyzed to understand the impact of the port developments on the bottom of Safi Bay. This analysis consists of making maps of the evolution of (i) sedimentary facies (of different dates 1892, 1906, 1940 and 2009) and (ii) the shallow seabed of the three periods 1892–1906, 1906–1940 and 1940–2009. The sedimentary facies maps show that the facies appear unstable and evolve intermittently in response to environmental changes in the bay (port construction and expansion). In addition, the overlay of the bathymetric maps indicates that the bay has undergone changes (lowering, stability, and raising) controlled by hydrodynamic conditions before, during, and even after harbor construction. Analysis of the data showed that the expansion of the port often reshaped the morphology of the bay's seabed. The consequences of these evolutions are the appearance of the fattening or the erosion of the bank and the filling of small depressions of sediments. This evolution is reflected in the modification of the funds near the port and the beach of Safi.

scholarly journals THE IMPACT OF ENVIRONMENTAL CHANGES ON BLACK MARLIN, Makaira indica (Cuvier, 1832) ABUNDANCES IN THE EASTERN INDIAN OCEAN

2020 ◽  
Vol 26 (1) ◽  
pp. 41
Author(s):  
Bram Setyadji ◽  
Zulkarnaen Fahmi
Keyword(s):  
Indian Ocean ◽  
Fishery Management ◽  
Environmental Changes ◽  
Stock Assessment ◽  
Sea Surface ◽  
Main Driver ◽  
Spatio Temporal ◽  
Standardized Index ◽  
By Catch ◽  
The Impact

Black marlin (Makaira indica) is commonly caught as frozen by-catch from Indonesian tuna longline fleets. Its contribution estimated 18% (~2,500 tons) from total catch in Indian Ocean. Relative abundance indices as calculated based on commercial catches are the input data for several to run stock assessment analyses that provide models to gather information useful information for decision making and fishery management, however, little are known about the influence of environmental factors to its abundance. In this paper, the abundance was represented as standardized index in order to eliminate any bias on other factors which might influence it. Data were collected from August 2005 to December 2017 through scientific observer program (2005-2017) and national observer program (2016-2017). Most of the vessels monitored were based in Benoa Port, Bali. Overall, time trends of abundance was fluctuated, although, there was increasing trend since 2010 then dropped significantly into relatively similar figure in 2005. Even though, Sea Surface Temperature (SST) and Sea Surface Height (SSH) were statistically significant when incorporating into the models, but it allegedly wasn’t the main driver in determining the abundance of black marlin. Instead, it was more likely driven by spatio-temporal factors (year and area) effect rather than environmental changes.

scholarly journals Modelled land use and land cover change emissions – A spatio-temporal comparison of different approaches

2021 ◽  
Author(s):  
Wolfgang A. Obermeier ◽  
Julia E. M. S. Nabel ◽  
Tammas Loughran ◽  
Kerstin Hartung ◽  
Ana Bastos ◽  
...  
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Environmental Conditions ◽  
Agricultural Land ◽  
Environmental Changes ◽  
Land Cover Changes ◽  
Legacy Effects ◽  
Spatio Temporal ◽  
The Impact ◽  
Global Carbon

Abstract. Quantifying the net carbon flux from land use and land cover changes (fLULCC) is critical for understanding the global carbon cycle, and hence, to support climate change mitigation. However, large-scale fLULCC is not directly measurable, but has to be inferred from models instead, such as semi-empirical bookkeeping models, and process-based dynamic global vegetation models (DGVMs). By definition, fLULCC estimates are not directly comparable between these two different model types. As an example, DGVM-based fLULCC in the annual global carbon budgets is estimated under transient environmental forcing and includes the so-called Loss of Additional Sink Capacity (LASC). The LASC accounts for the impact of environmental changes on land carbon storage potential of managed land compared to potential vegetation which is not represented in bookkeeping models. In addition, fLULCC from transient DGVM simulations differs depending on the arbitrary chosen simulation time period and the historical timing of land use and land cover changes (including different accumulation periods for legacy effects). An approximation of fLULCC by DGVMs that is independent of the timing of land use and land cover changes and their legacy effects requires simulations assuming constant pre-industrial or present-day environmental forcings. Here, we analyze three DGVM-derived fLULCC estimations for twelve models within 18 regions and quantify their differences as well as climate- and CO2-induced components. The three estimations stem from the commonly performed simulation with transiently changing environmental conditions and two simulations that keep environmental conditions fixed, at pre-industrial and present-day conditions. Averaged across the models, we find a global fLULCC (under transient conditions) of 2.0 ± 0.6 PgC yr-1 for 2009–2018, of which ∼40 % are attributable to the LASC (0.8 ± 0.3 PgC yr-1). From 1850 onward, fLULCC accumulated to 189 ± 56 PgC with 40 ± 15 PgC from the LASC. Regional hotspots of high cumulative and annual LASC values are found in the USA, China, Brazil, Equatorial Africa and Southeast Asia, mainly due to deforestation for cropland. Distinct negative LASC estimates, in Europe (early reforestation) and from 2000 onward in the Ukraine (recultivation of post-Soviet abandoned agricultural land), indicate that fLULCC estimates in these regions are lower in transient DGVM- compared to bookkeeping-approaches. By unraveling spatio-temporal variability in three alternative DGVM-derived fLULCC estimates, our results call for a harmonized attribution of model-derived fLULCC. We propose an approach that bridges bookkeeping and DGVM approaches for fLULCC estimation by adopting a mean DGVM-ensemble LASC for a defined reference period.

scholarly journals Spatio-Temporal Evolution and Mechanism Analysis of China’s Regional Innovation Efficiency

2021 ◽  
Vol 13 (19) ◽  
pp. 11089
Author(s):  
Zhen Xu ◽  
Xiang Zhu ◽  
Guoen Wei ◽  
Xiao Ouyang
Keyword(s):  
Temporal Evolution ◽  
Spillover Effects ◽  
Essential Elements ◽  
Eastern Region ◽  
Mechanism Analysis ◽  
Regional Innovation ◽  
Evolution Pattern ◽  
Evolution Characteristics ◽  
Spatio Temporal ◽  
The Impact

Improving regional innovation efficiency is the key to developing an innovative country. Exploring the spatio-temporal evolution characteristics of regional innovation efficiency is crucial in the formulation of regional policies and the choice of innovation models. This study used the superdata envelopment analysis method with undesirable outputs in evaluating the innovation efficiency of Chinese provinces. To assess the spatial spillover effects of innovation factors, the spatial autocorrelation and spatial Durbin model were adopted to characterize the spatio-temporal evolution, spatial correlation, and mechanisms of innovation efficiency. The highlights of the results are as follows: (1) The time-series changes in innovation efficiency showed a general trend from declining to increasing. (2) There were pronounced regional differences in innovation efficiency. The innovation efficiencies at the provincial level evolved from being decentralized to concentrated. The innovation efficiency was relatively stable in the eastern region and increased significantly in the central and western regions. The east–center–west evolution pattern gradually weakened. (3) The innovative efficiency exhibited spatial dependence, and the spatial agglomeration continued to increase. The extent of hot spots expanded, while cold spots shrunk slightly. (4) The scientific research environment, entrepreneurial environment, labor quality, and market environment were the essential elements that improved innovation efficiency. The impact of the different factors on innovation efficiency at different periods exhibited significant spatial heterogeneity.

Spatio-temporal evolution of two-plasmon decay in homogeneous plasma

2009 ◽  
Vol 76 (5) ◽  
pp. 749-761
Author(s):  
D. R. DIMITRIJEVIĆ ◽  
A. A. MALUCKOV
Keyword(s):  
Temporal Evolution ◽  
Critical Density ◽  
Plasma Waves ◽  
Electron Plasma ◽  
Hot Electron ◽  
Plasma Parameters ◽  
Principal Mechanism ◽  
Homogeneous Plasma ◽  
Spatio Temporal ◽  
The Impact

AbstractA hydrodynamic model of two-plasmon decay in a homogeneous plasma slab near the quarter-critical density is utilized to study the spatio-temporal evolution of the daughter electron plasma waves in plasma in the course of the instability. The influence of laser and plasma parameters on the evolution of the amplitudes of the participating waves is discussed, assuming that the secondary coupling of two daughter electron plasma waves with an ion-acoustic wave is the principal mechanism of saturation of the instability. The impact of inherently non-resonant nature of this secondary coupling on the development of TPD is investigated for the first time and it is shown to significantly influence the electron plasma wave dynamics. Its inclusion leads to non-uniformity of the spatial profile of the instability and causes the burst-like pattern of the instability development, which should result in the burst-like hot-electron production in homogeneous plasma.

SPATIO-TEMPORAL CHAOS IN AN ECOLOGICAL COMMUNITY AS A RESPONSE TO UNFAVOURABLE ENVIRONMENTAL CHANGES

2001 ◽  
Vol 04 (02n03) ◽  
pp. 227-249 ◽  
Author(s):  
SERGEI V. PETROVSKII ◽  
HORST MALCHOW
Keyword(s):  
Population Dynamics ◽  
Chaotic Dynamics ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Ecological Community ◽  
Species Extinction ◽  
Population Extinction ◽  
Small Domain ◽  
Spatio Temporal ◽  
The Impact

The impact of ecological chaos on population dynamics has been an issue of intense discussion over the last decade. While many authors consider chaotic dynamics as a favourable factor facilitating species biodiversity, there is also a strong opinion that chaos may enhance population extinction. In this paper we show that chaotic spatio-temporal dynamics in an ecological community can arise as a response of the community to unfavourable environmental changes. Appearing in that way, chaos can prevent species extinction in a situation when it would be inevitable otherwise. We also show that an essential consequence of chaotic dynamics is that the issue of species extinction is subject to the size of the domain inhabited by the population, the extinction more likely happens in a small domain than in a large one.

Spatio-temporal relational evaluation of the Beijing water crisis and planning implementation from 1949 to 2013

Water Policy ◽  
2018 ◽  
Vol 20 (3) ◽  
pp. 490-509 ◽  
Author(s):  
Wei Fu ◽  
Kongjian Yu ◽  
Dihua Li
Keyword(s):  
Temporal Evolution ◽  
Water Security ◽  
Temporal Analysis ◽  
Water Shortage ◽  
Relational Model ◽  
Water Crisis ◽  
Water Planning ◽  
Planning Implementation ◽  
Spatio Temporal ◽  
The Impact

Abstract Due to a lack of evaluation of the implementation of water planning policies, based on long-term spatio-temporal analysis, this research uses Beijing as an empirical case study to bridge this gap. We analyze the spatio-temporal evolution of water problems and water planning implementations. Content analysis, cluster analysis, and spatial interpolation analysis are used to illustrate the spatio-temporal evolution of water planning implementation. In addition, a grey relational model is developed to determine the impact of the most relevant implementation objects on each water issue. The results indicate that the Beijing water crisis evolves from the center outwards in a planar expansion. However, the water plan implementation shows linear and point characteristics. The majority of implementation categories consist of single-function infrastructure. The implemented categories ‘which show a significant implementation peak’ influence more than one water issue. The categories ‘that were implemented at a steady rate’ have a high relational grade with both surface and underground water shortage problems. Different implementation types from different planning categories may have simultaneous effects on one kind of water problem. Thus, improving water governance is the key to water security in Beijing. This study may serve as a reference for future water planning in other cities.

scholarly journals eDNA metabarcoding reveals a core and secondary diets of the greater horseshoe bat with strong spatio-temporal plasticity

2020 ◽  
Author(s):  
Orianne Tournayre ◽  
Maxime Leuchtmann ◽  
Maxime Galan ◽  
Marine Trillat ◽  
Sylvain Piry ◽  
...  
Keyword(s):  
Environmental Changes ◽  
The Core ◽  
Molecular Approaches ◽  
Dietary Plasticity ◽  
Spatio Temporal ◽  
Elusive Species ◽  
Horseshoe Bat ◽  
Distinct Features ◽  
The Impact ◽  
Insect Phenology

AbstractDietary plasticity is an important issue for conservation biology as it may be essential for species to cope with environmental changes. However, this process still remains scarcely addressed in the literature, potentially because diet studies have long been constrained by methodological limits. The advent of molecular approaches now makes it possible to get a precise picture of diet and its plasticity, even for endangered and elusive species. Here we focused on the greater horseshoe bat (Rhinolophus ferrumequinum) in Western France, where this insectivorous species has been classified as ‘Vulnerable’ on the Regional Red List in 2016. We applied an eDNA metabarcoding approach on 1986 fecal samples collected in six maternity colonies at three sampling dates. We described its diet and investigated whether the landscape surrounding colonies and the different phases of the maternity cycle influenced the diversity and the composition of this diet. We showed that R. ferrumequinum feed on a highly more diverse spectrum of prey than expected from previous studies, therefore highlighting how eDNA metabarcoding can help improving diet knowledge of a flying elusive endangered species. Our approach also revealed that R. ferrumequinum diet is composed of two distinct features: the core diet consisting in a few preferred taxa shared by all the colonies (25% of the occurrences) and the secondary diet consisting in numerous rare prey that were highly different between colonies and sampling dates (75% of the occurrences). Energetic needs and constraints associated with the greater horseshoe bat life-cycle, as well as insect phenology and landscape features, strongly influenced the diversity and composition of both the core and whole diets. Further research should now explore the relationships between R. ferrumequinum dietary plasticity and fitness, to better assess the impact of core prey decline on R. ferrumequinum populations viability.

scholarly journals SPATIO-TEMPORAL DYNAMICS ALONG THE TERRAIN GRADIENT OF DIVERSE LANDSCAPE

2014 ◽  
Vol 22 (1) ◽  
pp. 50-63 ◽  
Author(s):  
T. V. Ramachandra ◽  
Settur Bharath ◽  
Aithal Bharath
Keyword(s):  
Land Cover ◽  
Environmental Changes ◽  
Temporal Dynamics ◽  
Demographic Data ◽  
Coastal Region ◽  
Data Sets ◽  
Lulc Change ◽  
Multi Temporal ◽  
Spatio Temporal ◽  
The Impact

Land use (LU) land cover (LC) information at a temporal scale illustrates the physical coverage of the Earth’s terrestrial surface according to its use and provides the intricate information for effective planning and management activities. LULC changes are stated as local and location specifc, collectively they act as drivers of global environmental changes. Understanding and predicting the impact of LULC change processes requires long term historical restorations and projecting into the future of land cover changes at regional to global scales. The present study aims at quantifying spatio temporal landscape dynamics along the gradient of varying terrains presented in the landscape by multi-data approach (MDA). MDA incorporates multi temporal satellite imagery with demographic data and other additional relevant data sets. The gradient covers three different types of topographic features, planes; hilly terrain and coastal region to account the signifcant role of elevation in land cover change. The seasonality is another aspect to be considered in the vegetation dominated landscapes; variations are accounted using multi seasonal data. Spatial patterns of the various patches are identifed and analysed using landscape metrics to understand the forest fragmentation. The prediction of likely changes in 2020 through scenario analysis has been done to account for the changes, considering the present growth rates and due to the proposed developmental projects. This work summarizes recent estimates on changes in cropland, agricultural intensifcation, deforestation, pasture expansion, and urbanization as the causal factors for LULC change.

scholarly journals Effects of meteorology and soil moisture on the spatio-temporal evolution of the depth hoar layer in the polar desert snowpack

2021 ◽  
pp. 1-16
Author(s):  
Gautier Davesne ◽  
Florent Domine ◽  
Daniel Fortier
Keyword(s):  
Soil Moisture ◽  
Environmental Changes ◽  
Temporal Evolution ◽  
High Arctic ◽  
Onset Date ◽  
Canadian High Arctic ◽  
Polar Desert ◽  
Resolute Bay ◽  
Spatio Temporal ◽  
Snowpack Properties

Abstract In polar deserts, depth hoar (hereinafter: DH) growth is not systematic unlike on tundra and this is critical for snowpack properties. Here, we address the spatio-temporal variability of the DH layer in the polar desert at two sites in the Canadian High Arctic: Ward Hunt Island (83° N) and Resolute Bay (75° N). Our data show that, over humid areas, DH represented a larger fraction of the snowpack and was characterized by lower density and coarser crystals than over dry gravelly areas. Increased soil moisture extends the zero-curtain period during freeze-up, leading to stronger temperature gradients in the snowpack and greater kinetic metamorphism. Our results also demonstrate that the large inter-annual variability in DH is primarily driven by wind conditions in the fall since this key variable controls the initial snow density and snow onset date. These strong controls exerted by soil moisture and meteorological conditions on DH growth in polar deserts highlight the possibility of major changes in polar snowpacks physical properties in response to the rapid climate and environmental changes currently affecting these regions.

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