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Moisture recycling over the continents, which is known to increase with increasing spatial scale, increases both precipitation and sensible heat fluxes without increasing the overall latent heat flux, implying a reduction in evapotranspiration (ET) with increasing spatial scale. One may hypothesize that the architecture of plant/ecosystem root systems at the local scale may conform either to two‐dimensional (2D) or 3D fractal structure that is predicted by percolation theory. In this study, we test the hypothesis that only the 2D structure and associated fractal dimensionality are relevant for length scales commensurate with the continents. To test the hypothesis of a scale‐dependent ET, we compare the non‐parametric predictions of our recent theory, derived based on percolation theory and principle of optimality, for ET as a function of precipitation P and potential evapotranspiration potential evapotranspiration (PET) with multiple data sets from the literature for continental ET and P, and compatible estimations of PET. Within the limits set by the uncertainty in the data, most particularly in PET but also ET, the hypothesis that the 2D root structure model is relevant at the continental scales is confirmed. Certainly, at smaller length scales, both 2D and 3D results are observed. The resulting predicted and observed scale‐dependence of ET is consistent with the concept, magnitude, and spatial scale dependence of continental moisture recycling.

In the present investigation, by putting the isogeometric finite element methodology to use, the nonlinear flexural response of composite rectangular microplates having functionally graded (FG) porosity is predicted incorporating couple stress type of small scale effect. To accomplish this analysis, a non-uniform kind of rational B-spline functions are employed for an accurate geometrical description of cutouts with various shapes located at the center of microplates. The modified couple stress continuum elasticity is implemented within the framework of a new quasi-three-dimensional (quasi-3D) plate theory incorporating normal deflections with only four variables. By refining the power-law function, the porosity dependency in conjunction with the material gradient are taken into consideration in a simultaneous scheme. The couple stress-based nonlinear flexural curves are achieved numerically based upon a parametrical study. It is demonstrated that for a larger plate deflection, the role of couple stress type of small scale effect on the nonlinear bending curves of porous FG composite microplates is highlighted. It is seen that the gap between nonlinear flexural responses associated with different through-thickness porosity distribution schemes is somehow higher by taking the couple stress effect into account. Also, it is observed that the existence of a cutout at the center of composite microplates makes a change in the slope of their nonlinear flexural curve.

Very few studies exist in rationalizing comprehensively the relationship between market integration and green economic growth in China. This paper tries to answer the question whether and how market integration influences regional green economic growth in China. Based on the panel data of 285 city-level regions from year 2004 to 2018 in China, this paper develops explanatory mechanism and discusses the influence theoretically and empirically. To advance the analysis, we construct market integration indicator through relative price variance method based on commodity retail price index and employ the Malmquist–Luenberger (ML) productivity index and DEA-SBM (data envelopment analysis–slacks-based measure) model to evaluate green total factor productivity (GTFP) as indicator for green economic growth. Our empirical findings are: (1) Apparent regional imbalance exists in both the development of market integration and green growth and gaps are expanding from year 2004 to 2018. (2) Market integration promotes regional green growth significantly. (3) Mechanism analysis illustrates that market integration fosters green growth through economies of scale effect, composition effect and spillover effect, respectively. (4) Heterogeneous analysis suggests that the influence from market integration on green growth varies depending on region’s difference in traffic situation and in overall development level.

AIM: The global sprawl of marine hard infrastructure (e.g. breakwaters, sea walls and jetties) can extensively modify coastal seascapes, but the knowledge of such impacts remains limited to local scales. We examined the regional‐scale effects of marine artificial habitats on the distribution and abundance of assemblages of ascidians, a key group of ecosystem engineer species in benthic fouling systems. LOCATION: Five hundred kilometers of coastline in the North Adriatic Sea. METHODS: We sampled a variety of natural reefs, marine infrastructures and marinas, and tested hypotheses about the role of habitat type and location in influencing the relative distribution and abundance of both native and non‐indigenous species. RESULTS: Assemblages differed significantly between natural and artificial habitats and among different types of artificial habitats. Non‐indigenous species were 2–3 times more abundant on infrastructures built along sedimentary coastlines than on natural rocky reefs or infrastructures built close to rocky coastlines. Conversely, native species were twice as abundant on natural reefs than on nearby infrastructures and were scarce to virtually absent on infrastructures built along sedimentary coasts. The species composition of assemblages in artificial habitats was more similar to that of marinas than of natural reefs, independently of their location. MAIN CONCLUSIONS: Our results show that marine infrastructures along sandy shores disproportionally favour non‐indigenous over native hard bottom species, affecting their spread at regional scales. This is particularly concerning for coastal areas that have low natural densities of rocky reef habitats. We discuss design and management options to improve the quality as habitat of marine infrastructures and to favour their preferential use by native species over non‐indigenous ones.

Particle morphology is of great significance to the grain- and macro-scale behaviors of granular soils. Most existing traditional morphology descriptors have three perennial limitations, i.e., dissensus of definition, inter-scale effect, and surface roughness heterogeneity, which limit the accurate representation of particle morphology. The inter-scale effect refers to the inaccurate representation of the morphological features at the target relative length scale (RLS, i.e., length scale with respective to particle size) caused by the inclusion of additional morphological details existing at other RLS. To effectively eliminate the inter-scale effect and reflect surface roughness heterogeneity, a novel spherical harmonic-based multi-scale morphology descriptor Rinc is proposed to depict the incremental morphology variation (IMV) at different RLS. The following conclusions were drawn: (1) the IMV at each RLS decreases with decreasing RLS while the corresponding particle surface is, in general, getting rougher; (2) artificial neural network (ANN)-based mean impact values (MIVs) of Rinc at different RLS are calculated and the results prove the effective elimination of inter-scale effects by using Rinc; (3) Rinc shows a positive correlation with the rate of increase of surface area RSA at all RLS; (4) Rinc can be utilized to quantify the irregularity and roughness; (5) the surface morphology of a given particle shows different morphology variation in different sections, as well as different variation trends at different RLS. With the capability of eliminating the existing limitations of traditional morphology descriptors, the novel multi-scale descriptor proposed in this paper is very suitable for acting as a morphological gene to represent the multi-scale feature of particle morphology.

This paper sets out an approach to assessing shear strength of rock joints at project scale based on measurement and analysis rather than empiricism. The role of direct shear testing in this process is discussed in detail and the need for dilation measurement and correction emphasised. Dilation-corrected basic friction angles are presented for various rock types. The characterisation of first and second order roughness features and their contribution to shear strength at project scale are discussed with reference to possible scale effects. The paper is illustrated by a case example of a spillway slope for a dam in the Himalayas.

Topology optimization of structures and mechanisms with microstructural length-scale effect is investigated based on gradient elasticity theory. To meet the higher-order continuity requirement in gradient elasticity theory, Hermite finite elements are used in the finite element implementation. As an alternative to the gradient elasticity, the staggered gradient elasticity that requires C 0 -continuity, is also presented. The solid isotropic material with penalization (SIMP) like material interpolation schemes are adopted to connect the element density with the constitutive parameters of the gradient elastic solid. The effectiveness of the proposed formulations is demonstrated via numerical examples, where remarkable length-scale effects can be found in the optimized topologies of gradient elastic solids as compared with linear elastic solids.

Plant phenology is closely related to plant function, ecosystem services, and climate balance. Solar-induced chlorophyll fluorescence (SIF) offers new perspectives on plant phenology at regional and global scales. However, the effect of SIF products at different scales on phenology extraction is still unclear. Understanding of the mechanisms underlying phenological responses to environmental factors remains incomplete. Therefore, in this study, two phenological metrics for the Start of Growing Season (SOS) and the End of Growing Season (EOS) were extracted from the phenology of deciduous forests in the middle and high latitudes of the Northern Hemisphere, utilizing SIF products at scales of 1 km, 5 km, and 50 km, and applying the Savitzky-Golay filtering method along with the dynamic threshold method. Our results showed that the 1-km resolution SIF had a significant advantage over the 5-km and 50-km resolution SIFs in terms of consistency with the extracted phenology results from the Gross Primary Productivity (GPP) sites, with mean absolute errors (MAEs) of 4.48 and 15.49 days for SOS and EOS, respectively. For the 5-km resolution SIF, the MAEs for the same phenological metrics were 9.2 and 21.07 days. For the 50-km resolution SIF, the MAEs were 58.94 and 42.73 days. Meanwhile, this study analyzed the trends of phenology utilizing the three scales of SIF products and found a general trend of advancement. The coarser spatial resolution of the SIF data made the trend of advancement more obvious. Using SHapley Additive exPlanations (SHAP) analysis, we investigated the phenological responses to environmental factors at different scales. We found that SOS/EOS were mainly regulated by soil and air temperature, whereas the scale effect on this analysis’ results was not significant. This study has implications for optimizing the use of data, understanding ecosystem changes, predicting vegetation dynamics under global change, and developing adaptive management strategies.

Vegetation plays a crucial role in terrestrial ecosystems, and the FVC (Fractional Vegetation Coverage) is a key indicator reflecting the growth status of vegetation. The accurate quantification of FVC dynamics and underlying driving factors has become a hot topic. However, the scale effect on FVC changes and driving factors has received less attention in previous studies. In this study, the changes and driving factors of FVC at multiple scales were analyzed to reveal the spatial and temporal change in vegetation in the Henan section of the Yellow River basin. Firstly, based on the pixel dichotomy model, the FVC at different times and spatial scales was calculated using Landsat-8 data. Then, the characteristics of spatial and temporal FVC changes were analyzed using simple linear regression and CV (Coefficient of Variation). Finally, a GD (Geographic Detector) was used to quantitatively analyze the driving factors of FVC at different scales. The results of this study revealed that (1) FVC showed an upward trend at all spatial scales, increasing by an average of 0.55% yr−1 from 2014 to 2022. The areas with an increasing trend in FVC were 10.83% more than those with a decreasing trend. (2) As the spatial scale decreased, the explanatory power of the topography factors (aspect, elevation, and slope) for changes in FVC was gradually strengthened, while the explanatory power of climate factors (evapotranspiration, temperature, and rainfall) and anthropogenic activities (night light) for changes in FVC decreased. (3) The q value of evapotranspiration was always the highest across different scales, peaking notably at a spatial scale of 1000 m (q = 0.48).

The dynamic subsidence disaster caused by underground mining of coal resources is a complex spatiotemporal process, which is a common disaster in mining areas. The backfilling strip mining technology is a green and sustainable coal mining method, which has been commonly used to reduce the subsidence disaster of the overlying strata and protect surface buildings. The transient deformation is the main reason of surface buildings damage; therefore, in this study, the similar material model was used to research dynamic deformation characteristics of the overlying strata in backfilling strip mining at different time scales, and the optical image method was employed to monitor and obtain the movement data of the overlying strata automatically. The data analysis shows that there is a time-scale effect in mining subsidence. The deformation of the overlying strata increases instantaneously at a certain time under the monitoring of small time scale, and this phenomenon gradually disappears as time scales increase. According to the subsidence velocity of small time scale, the subsidence state of the overlying strata can be further divided into the abrupt subsidence state and the gentle subsidence state. This is really significant for promoting the development of the backfilling strip mining technology and preventing the damage of surface buildings.