Pattern Of Patches Research Articles

Taylor Expansion and Matrix-Based Interval Analysis of Linear Arrays With Patch Element Pattern Tolerance

In this study, a novel interval analysis (IA) approach for linear arrays with element pattern tolerance is proposed. This study differentiates itself from the classic interval analysis (CIA) method because it focuses on the effects of the array element (e.g., patch) pattern tolerance on the antenna array pattern; the tolerance may be caused by fabrication errors in the element. The closed-form pattern expressions of the element (e.g., patch) and array are deduced by the interval arithmetic method. To mitigate the interval extension (also referred to as the overestimation problem) caused by the dependency problem, Taylor expansion and matrix-based interval analysis (TMIA) methods are proposed and implemented in this study. A set of numerical examples is reported and analyzed to indicate the effectiveness of the proposed TMIA approach with the results of Monte Carlo (MC) and CIA methods, as well as to indicate its potential capabilities and advantages in the actual application of industrial antenna arrays.

A new species of Egglestonichthys (Teleostei, Gobiiformes, Gobiidae) from Okinawa Island, Japan.

Egglestonichthys fulmensp. nov. (Teleostei: Gobiidae) is described on the basis of a single specimen (21.7 mm in standard length) collected from 250 m depth off Okinawa Island, Ryukyu Islands, Japan. The new species is characterized by the following combination of characters: anal-fin rays I, 9; pectoral-fin rays 17, lower rays not free from membrane; longitudinal scale series 25; transverse scales 8; pre-dorsal-fin scale rows 8; cheek and opercle naked; pelvic frenum absent; caudal fin lanceolate, its length 32.2% of SL; interorbital width very narrow, 1.2% of HL (much narrower than pupil diameter); no spicules or odontoid processes on outer surface of gill arches; and body whitish, upper half with broken zigzag pattern of bright yellow patches and associated scattered black melanophores in fresh specimens (melanophores retained in preserved specimens). Several characters, including pectoral-fin ray count, interorbital width, and coloration uniquely distinguish the new species from congeners.

Effects of Patchiness on Surface Soil Moisture of Alpine Meadow on the Northeastern Qinghai-Tibetan Plateau: Implications for Grassland Restoration

Surface soil moisture (SSM) is a key limiting factor for vegetation growth in alpine meadow on the Qinghai-Tibetan Plateau (QTP). Patches with various sizes and types may cause the redistribution of SSM by changing soil hydrological processes, and then trigger or accelerate alpine grassland degradation. Therefore, it is vital to understand the effects of patchiness on SSM at multi-scales to provide a reference for alpine grassland restoration. However, there is a lack of direct observational evidence concerning the role of the size and type of patches on SSM, and little is known about the effects of patches pattern on SSM at plot scale. Here, we first measured SSM of typical patches with different sizes and types at patch scale and investigated their patterns and SSM spatial distribution through unmanned aerial vehicle (UAV)-mounted multi-type cameras at plot scale. We then analyzed the role of the size and type of patchiness on SSM at both patch and plot scales. Results showed that: (1) in situ measured SSM of typical patches was significantly different (P < 0.01), original vegetation patch (OV) had the highest SSM, followed by isolate vegetation patch (IV), small bare patch (SP), medium bare patch (MP) and large bare patch (LP); (2) the proposed method based on UAV images was able to estimate SSM (0–40 cm) with a satisfactory accuracy (R2 = 0.89, P < 0.001); (3) all landscape indices of OV, with the exception of patch density, were positively correlated with SSM at plot scale, while most of the landscape indices of LP and IV showed negative correlations (P < 0.05). Our results indicated that patchiness intensified the spatial heterogeneity of SSM and potentially accelerated the alpine meadow degradation. Preventing the development of OV into IV and the expansion of LP is a critical task for alpine meadow management and restoration.

Experimental Study of the Guided Wave Directivity Patterns of Thin Removable Magnetostrictive Patches.

The characteristics of removable magnetostrictive thin patches are investigated for the generation of guided waves in plates. The directivity patterns of SH, S0 and A0 modes have been measured in a thin metallic plate for different combinations of static and dynamic magnetic field directions. This used different coil geometries such as racetrack and spiral coils to generate the dynamic magnetic field, as well as separate biasing static magnetic fields from permanent magnets. This arrangement generated signals via both Lorentz and magnetostrictive forces, and the resultant emitted guided waves were studied for different dynamic and static magnetic field directions and magnitudes. It is demonstrated that different guided wave modes can be produced by controlling these parameters.

Stand-scale responses of forest-floor small mammal populations to varying size, number, and location of retention tree patches

Retention forestry, the practice of maintaining stand legacies in harvested forests, is used to create more complex forest structure and positive biodiversity outcomes in managed forests. However, the relative effectiveness of different retention strategies at increasing forest structural complexity and populations of dependent wildlife species is not well understood. We used an experimental study to evaluate changes in the population density of three small mammal species in response to different size and location (riparian or upland) of retention tree patches within harvested forests in the Pacific Northwest, USA. We further assessed whether small mammal density varied in relation to differences in structural complexity within retention patches among experimental retention stands. Within stands, deer mice (Peromyscus spp.) population density did not differ between retention and harvested areas (β = −0.05, SE = 0.06), Townsend’s chipmunk (Neotamias townsendii) density was higher in retention compared to clearcut areas (β = 1.61, SE = 0.10), and creeping vole (Microtus oregoni) density was highest in clearcut areas (β = −0.68, SE = 0.10). At the stand-scale, deer mouse density and chipmunk density were lowest in stands with large upland patches of retention (mean = 83, SD = 28 trees) and highest in stands with multiple small patches of upland retention (mean = 8, SD = 2 trees). Creeping vole density followed the opposite pattern, highest in stands with large upland patches and lowest in stands with multiple small patches. Densities of each species were intermediate in stands where at least a portion of the retention trees were connected to forested riparian buffers. Relating the density of each species to structural complexity within stands revealed that Townsend’s chipmunk density increased with increasing retention tree blowdown (β = 0.39, SE = 0.08), a proxy for downed wood resources, whereas creeping vole density decreased (β = −0.51, SE = 0.12), and deer mice density did not change consistently (β = 0.00, SE = 0.08). Furthermore, retention tree mortality was highest in the experimental treatment with several small patches and lowest in the treatment with a single large patch. Our results demonstrate that adopting dispersed retention patch patterns increases the abundance of small mammals in managed, early-seral forests in the Pacific Northwest. This relationship is at least partly mediated through higher levels of structural complexity within small retention patches caused by increased retention tree blowdown compared to larger patches.

Study on Landscape Patches Influencing Hillslope Erosion Processes and Flow Hydrodynamics in the Loess Plateau of Western Shanxi Province, China

Although vegetation restoration plays an important role in the management of surface runoff and soil erosion, the large-scale restoration of vegetation can increase water consumption and reduce surface water resources, thus affecting the health of river ecosystems. Therefore, vegetation restoration should aim to achieve a vegetation landscape pattern that optimizes protection of soil resources while limiting water consumption. This study established field runoff plots with different landscape patch types, including bare land, S-road patches, strip patches, grid patches, and random patches, as well as different quantities patches of 5, 10, 15, and 20. An artificial rainfall experiment was conducted to determine the effect of different vegetation patches in reducing runoff and sediment, and the relationship between the types and number of vegetation patches and hydrodynamic parameters. The results showed that the runoff yields of the four vegetation patch types decreased by 16.1–48.7% compared with that of bare land, whereas sediment yields decreased by 42.1–86.5%. In addition, the resistance coefficients of the poorly connected patch patterns, including strip patches, grid patches, and random patches, ranged between 0.2–1.17 times higher than that of the well-connected S-road patch pattern, and the stream power decreased by 33.3–50.7%. Under a set vegetation coverage rate, an increase in the number of vegetation patches resulted in a significant reduction in runoff velocity, runoff yield, and sediment yield, increases in surface roughness and flow resistance, and reductions in runoff shear force and stream power. Besides, the sensitivity of soil to erosion decreased with an increasing number of the patch in the vegetation landscape, whereas the sensitivities of patch combinations with poor connectivity were lower than those with good connectivity. The results of this study highlight the importance of vegetation patch type and quantity for control of soil erosion.

Patch Pattern and Ecological Risk Assessment of Alpine Grassland in the Source Region of the Yellow River

The source region of the Yellow River (SRYR) is an important water conservation and animal husbandry resource in China. It is of great significance to understand the patch pattern and ecological risk of alpine grassland in the SRYR for ecological environment management. This study first used 12 unmanned aerial vehicle (UAV) aerial images and eight moderate resolution imaging spectroradiometer (MODIS) vegetation index product MOD13Q1 images from July to August in 2019 to extract alpine grassland patch patterns in the SRYR, then constructed an ecological risk model based on the landscape vulnerability index and landscape disturbance index, and finally combined spatial self-reliance correlation and semi-variance analysis methods to explore the spatial distribution of ecological risks. The results showed that the patch fragmentation degree (Pi), area weighted shape index (AWMSI), and separation degree (Si) of the four grassland types in the SRYR are ordered as follows: alpine steppe > degraded meadow > alpine meadow > swamp meadow. Moreover, the greater the fractional vegetation cover (FVC), the greater the landscape dominance index (DOi), and the better the ecosystem stability. The spatial difference of ecological risk in the SRYR shows a situation of low risk in the east (ERImin=1.5355) and high risk in the west (ERImax = 70.6429). High FVC was found in low and mild low risk areas where the vegetation types are mainly swamp meadow and shrub, while low FVC was found in high and mild high-risk areas where the vegetation types are mainly alpine steppe and degraded meadow. The spatial distribution of ecological risk of the SRYR has obvious positive spatial correlation (Moran's I = 0.863), the spatial aggregation distribution is distinct, and the local space has significant high-high aggregation and low–low aggregation phenomena. The results of this study reveal that patch characteristics have good indicative significance for alpine grassland ecological protection and should be considered in future studies. In addition, the ecological risk in the SRYR is relatively high, especially in the western region, which should be taken seriously in future ecological management and governance.

Spatial features of geomagnetic cutoff rigidity secular variation using analytical approaches

The secular variation spatial pattern of geomagnetic cutoff rigidity, Rc, is analyzed considering analytical expressions. Störmer analytic Rc equation in terms of geomagnetic latitude is used considering a pure dipolar field for the centered and eccentric dipole coordinates, together with a dipole-quadrupole superposition simplified equation. Linear Rc time trend for the period 1900–2020 in a 5 ° × 15 ° latitude-longitude grid is assessed in each case and a comparative analysis is made with trends based on trajectory based Rc estimations. Common features with some analytic approaches are the two patches of Rc positive and negative trends in the western hemisphere, even though maximum and minimum trend values are underestimated in all analytical cases. Global mean values are almost coincident, except for the dipole-quadrupole superposition case. The salient patches pattern may be due mainly to the dipole axis rotation, more than to its center displacement, its decreasing momentum or the increasing quadrupolar component role. Even though with the advent of better computational tools the trajectory based estimation would be a natural choice to analyze Rc variations, we still consider that an appropriately modified Störmer equation, with its natural advantages of its analytical form and extremely fast way of computation, is sufficient for many applications.

Lichens Bite the Dust - A Bioweathering Scenario in the Atacama Desert.

SummaryBioweathering mediated by microorganisms plays a significant role in biogeochemical cycles on global scales over geological timescales. Single processes induced by specific taxa have been described but could rarely be demonstrated for complex communities that dominate whole landscapes. The recently discovered grit crust of the coastal Atacama Desert, which is a transitional community between a cryptogamic ground cover and a rock-bound lithic assemblage, offers the unique chance to elucidate various bioweathering processes that occur simultaneously. Here, we present a bioweathering scenario of this biocenosis including processes such as penetration of the lithomatrix, microbial responses to wet-dry cycles, alkalinolysis, enzyme activity, and mineral re-localization. Frequently occurring fog, for example, led to a volume increase of microorganisms and the lithomatrix. This, together with pH shifts and dust accumulation, consequently results in biophysical breakdown and the formation of a terrestrial protopedon, an initial stage of pedogenesis fueled by the grit crust.

Tracking dispersal across a patchy landscape reveals a dynamic interaction between genotype and habitat structure

Theoretical and empirical studies often show that within populations, individuals vary in their propensity to disperse. We aspired to understand how this behavioural variation is impacted by the distribution and pattern of food patches across a landscape. In a series of experiments we examined how inter‐patch distance and the distribution of food patches influenced dispersal in wild‐type strains of Drosophila melanogaster with natural allelic variants of the foraging (for) gene known to influence dispersal in this species. The ‘rover' strain was homozygous for the forR allele (more dispersive) whereas the ‘sitter' strain was homozygous for fors (less dispersive). We also assessed an outbred population of flies with an unknown dispersal propensity. Dispersal was assayed in a multi‐patch lab arena (25 cells, 5 × 5 array). In the inter‐patch distance trials, landscapes of two different sizes (small versus large) were used, both with food in all 25 cells. Dispersal was reduced in the large landscape relative to the small landscape for all three fly strains. Sitter dispersal was lowest relative to both rovers and the outbred flies, whose dispersal tendencies were similar. In the patch distribution trials, flies were assayed in landscapes with varying distribution and number of cells containing food. Dispersal generally increased as the number of patches with food increased, however, rovers and sitters adopted similar dispersal strategies when food was fixed and limited. Conversely, their strategies differed when the total amount of food increased with the number of patches. We find that both the inter‐patch distance and distribution can influence dispersal. However, the effect of inter‐patch distance and distribution on dispersals depends on genotype × environment interaction. Our findings highlight the importance of considering G × E when assessing how dispersal strategies and landscape dynamics influence the distribution of animal communities.

Lateral confinement of high‐impedance surface‐waves through reinforcement learning

The authors present a model-free policy-based reinforcement learning model that introduces perturbations on the pattern of a metasurface. The objective is to learn a policy that changes the size of the patches, and therefore the impedance in the sides of an artificially structured material. The proposed iterative model assigns the highest reward when the patch sizes allow the transmission along a constrained path and penalties when the patch sizes make the surface wave radiate to the sides of the metamaterial. After convergence, the proposed model learns an optimal patch pattern that achieves lateral confinement along the metasurface. Simulation results show that the proposed learned-pattern can effectively guide the electromagnetic wave through a metasurface, maintaining its instantaneous eigenstate when the homogeneity is perturbed. Moreover, the pattern learned to prevent reflections by changing the patch sizes adiabatically. The reflection coefficient shows that most of the power gets transferred from the source to the destination with the proposed design.

Landscape composition is the strongest determinant of bird occupancy patterns in tropical forest patches

Biodiversity in tropical region has declined in the last decades, mainly due to forest conversion into agricultural areas. Consequently, species occupancy in these landscapes is strongly governed by environmental changes acting at multiple spatial scales. We investigated which environmental predictors best determines the occupancy probability of 68 bird species exhibiting different ecological traits in forest patches. We conducted point-count bird surveys in 40 forest sites of the Brazilian Atlantic forest. Using six variables related to landscape composition and configuration and local vegetation structure, we predicted the occupancy probability of each species accounting for imperfect detections. Landscape composition, especially forest cover, best predicted bird occupancy probability. Specifically, most bird species showed greater occupancy probability in sites inserted in more forested landscapes, while some species presented higher occurrence in patches surrounded by low-quality matrices. Conversely, only three species showed greater occupancy in landscapes with higher number of patches and dominated by forest edges. Also, several species exhibited greater occupancy in sites harbouring either larger trees or lower number of understory plants. Of uttermost importance, our study revealed that a minimum of 54% of forest cover is required to ensure high (> 60%) occupancy probability of forest species. We highlighted that maintaining only 20% of native vegetation in private property according to Brazilian environmental law is insufficient to guarantee a greater occupancy for most bird species. We recommend that policy actions should safeguard existing forest remnants, expand restoration projects, and curb human-induced disturbances to minimise degradation within forest patches.

Comparison of methods to model species habitat networks for decision-making in nature conservation: The case of the wildcat in southern Belgium

Facing the loss of biodiversity caused by landscape fragmentation, implementation of ecological networks to connect habitats is an important biodiversity conservation issue. It is necessary to develop easily reproducible methods to identify and prioritize actions to maintain or restore ecological corridors. To date, several competing methods are used with recurrent debate on which is best and if expert-based approaches can replace data-driven models. We compared three methods: knowledge-driven (expert based), data-driven (based on species distribution model), and a mixed approach. We quantified their differences in habitat and corridor mapping, and prioritizations of landscape elements in terms of importance for connectivity. Key parameters generating these differences were identified. To put this into practice, the case study of the wildcat (Felis silvestris Schreber, 1777) was chosen. The results highlighted differences and similarities between approaches used. The data-driven approach was more successful in identifying the suitable habitat with regard to wildcat ecology, while the knowledge-driven approach was better able to account for obstacles to wildcat movements in the landscape matrix. However, these two methods converged for the identification of patterns of habitat patches and corridors that are important for global landscape connectivity. For both methods, we identified adjustments that can improve the outcome. The mixed approach largely differed in that it required more inputs to be performed. In the end, conservation actions were identified and could guide nature conservation practitioners in their efforts to restore landscape connectivity.

Study on the Spatial Layout Features of Linpan in Western Sichuan with the Aid of GIS: A Case Study in Deyuan Town

This paper principally focuses on the spatial layout features of Linpan in Deyuan Town of Chengdu City in China. The spatial shape analysis and spatial fractal analysis in studied areas was carried out by using analysis methods of Fractal Analysis, Zonal Geometry as Table, Field Calculator. The results demonstrated that densely shaped Linpan (resembling square or circle type) with starlike scattered distribution, and loosely shaped Linpan (slender type) distributed along roads or water strips, both of which are concentrated along water systems or roads and stay away from major exterior roads. It is found that Linpan in the studied area is in the state of random motion similar to the Brownian motion. The spatial pattern of the residential patch is complex and in the most unstable state. Quantitative research on the spatial layout features of Linpan is conducive to strengthening the scientific and rational understanding of Linpan. The research findings could be used as the scientific foundation for guiding the selection of rural centers, surrounding village construction, township land planning and remediation.

Investigation of the flow characteristics with one-line emergent canopy patches in open channel

Experiments are performed on channels with emergent one-line porous canopy patches distributed along the channel sidewalls in which flow dynamics and turbulent structures are analyzed. The evolution of the transverse distribution of the mean streamwise velocity and Reynolds stress profiles in specific transverse sections with downstream distance suggests that a fully equilibrated zone is reached beyond an adjustment distance, and the adjustment distance needed for vegetation with high solid volume fractions is short. The flow field can be divided into three main different regions based on the transverse distribution of the mean streamwise velocity and Reynolds stress in the equilibrium zone: a boundary-affected region, an analog mixing layer, and a uniform region in a non-vegetated area. The analog mixing layer exhibits a two-layer structure governed by local coherent vortices. The dominant frequencies of the vortices at the interface are determined through spectral analysis and proven to correspond to a patch scale. The development of the shear layer, the analysis of the frequencies and scales of the vortices, and the experiment on flow visualization indicate that von-Karman vortices continue to form downstream despite the interference of the sidewall and the special one-line distribution pattern of patches. Quadrant analysis is adopted to illustrate the lateral momentum exchange caused by different motions. Results show that ejections and sweeps are the main contributions to Reynolds stress in the analog mixing layer. Different signs of Reynolds stress in the boundary-affected region and the analog mixing layer can also be explained through quadrant analysis.

Denoising framework based on external prior guided rotational clustering

The image denoising model based on non-local self-similarity prior (NSS) has received extensive attention in recent years because of the repeated structure of natural image patches. Similar patches collected by exploiting NSS prior are sparse, which can be used to estimate potential lowrank subspace. Meanwhile, the modelling of natural images, such as Gaussian mixture models (GMMs), has been successful in all aspects of computer vision by reducing the patterns of image patches. However, the version of its geometric transformation (e.g. rotational transformation) cannot be matched directly by using distance. How to further reduce the patterns of the patches by geometric prior and accelerate rotational matching through parallel calculation is an issue that needs to be solved. In this study, an external guided rotational matching denoising framework is proposed. The proposed framework combines non-local, sparse and low-rank image priors and we design a parallel computing scheme. They demonstrate the performance improvement of the proposed algorithm on images with strong rotational properties and the comparison with traditional state-of-the-art denoising methods. The scalability and effectiveness of the new framework are verified by simulation experiments in public and real datasets.

Deforestation dynamics in Brazil's Amazonian settlements: Effects of land-tenure concentration

Brazil's Amazon deforestation is a major global and national environmental concern, and the ability to model and project both its course and the effect of different policy options depends on understanding how this process occurs at present and how it might change in the future. The present paper addresses one key factor in Amazon deforestation: land-tenure concentration in settlements. Brazil's policies for establishing and regulating settlement projects represent critical government decisions shaping the landscape in the 5 × 106 km2 Legal Amazonia region. We used remote-sensing data and information provided by the National Institute for Colonization and Agrarian Reform (INCRA) to evaluate the effect of land-tenure concentration in a settlement project (Projeto de Assentamento) located in a frontier area where cattle-ranching is expanding. We identified the actors and their deforestation patterns in the Matupi settlement in the southern part of Brazil's state of Amazonas. We spatially identified actors who concentrated “lots” (the parcels of land distributed to individual settlers) in 2011 and assessed whether the concentration was done by individual landholders or by “families” (where members merged their lots and the clearing was done together). Deforestation rates (1995–2011) were estimated for each type of actor and the trajectory of deforestation in the settlement (cumulative deforestation to 1994 and annual deforestation 1995–2016) was also analyzed. Concentrators occupied 28% (9653 ha) of the settlement and 29% of the lots (152 lots) analyzed; the numbers of lots concentrated ranged from two to ten. Concentrators of two lots and non-concentrators were the predominant actor types in the settlement. The mean annual clearing per landholding for concentrators of two lots (families: 4.1 ± 2.8 ha (mean ± SD); individuals: 5.1 ± 4.6 ha) was greater than for non-concentrators (1.7 ± 1.2 ha), despite their having similar patterns of small clearings. Concentrators of three or more lots had mean annual clearing per landholding between 6.2 ± 12.2 ha and 23.9 ± 38.7 ha and, the pattern of patches cleared per year >34 ha in area was predominant. The deforestation rate per lot was higher among concentrators as compared to non-concentrators, showing that lot concentration speeds deforestation. Analysis of deforestation patterns helps to better understand the process of lot concentration by spatially identifying the predominant patterns of each type of actor. The approach used in our study could assist authorities in identifying and monitoring land-tenure concentration in settlements. Agrarian-reform policymakers need to monitor this process, since it speeds deforestation in Amazonian settlement projects, as well as undermining the social objectives of the agrarian-reform program.

Principles of Intrinsic Motor Cortex Connectivity in Primates.

The forelimb representation in motor cortex (M1) is an important model system in contemporary neuroscience. Efforts to understand the organization of the M1 forelimb representation in monkeys have focused on inputs and outputs. In contrast, intrinsic M1 connections remain mostly unexplored, which is surprising given that intra-areal connections universally outnumber extrinsic connections. To address this knowledge gap, we first mapped the M1 forelimb representation with intracortical microstimulation (ICMS) in male squirrel monkeys. Next, we determined the connectivity of individual M1 sites with ICMS + intrinsic signal optical imaging (ISOI). Every stimulation site activated a distinctive pattern of patches (∼0.25 to 1.0 mm radius) that we quantified in relation to the motor map. Arm sites activated patches that were mostly in arm zones. Hand sites followed the same principle, but to a lesser extent. The results collectively indicate that preferential connectivity between functionally matched patches is a prominent organizational principle in M1. Connectivity patterns for a given site were conserved across a range of current amplitudes, train durations, pulse frequencies, and microelectrode depths. In addition, we found close correspondence in somatosensory cortex between connectivity that we revealed with ICMS+ISOI and connections known from tracers. ICMS+ISOI is therefore an effective tool for mapping cortical connectivity and is particularly advantageous for sampling large numbers of sites. This feature was instrumental in revealing the spatial specificity of intrinsic M1 connections, which appear to be woven into the somatotopic organization of the forelimb representation. Such a framework invokes the modular organization well-established for sensory cortical areas.SIGNIFICANCE STATEMENT Intrinsic connections are fundamental to the operations of any cortical area. Surprisingly little is known about the organization of intrinsic connections in motor cortex (M1). We addressed this knowledge gap using intracortical microstimulation (ICMS) concurrently with intrinsic signal optical imaging (ISOI). Quantifying the activation patterns from dozens of M1 sites allowed us to uncover a fundamental principle of M1 organization: M1 patches are preferentially connected with functionally matched patches. Relationship between intrinsic connections and neurophysiological map is well-established for sensory cortical areas, but our study is the first to extend this framework to M1. Microstimulation+imaging opened a unique possibility for investigating the connectivity of dozens of tightly spaced M1 sites, which was the linchpin for uncovering organizational principles.

Landsat-8 and Sentinel-2 based Forest fire burn area mapping using machine learning algorithms on GEE cloud platform over Uttarakhand, Western Himalaya

The accurate quantitative and qualitative estimation of burn-area are crucial to analyze the impact of fire on forest. The medium resolution optical-satellite imagery of Landsat-8 and Sentinel-2 are employed covering the period 2016 to 2019 for forest fire patches identification on Google Earth Engine (GEE). The most indispensable season of Forest Fire (FF) is pre-monsoon in Uttarakhand, western Himalaya, India. Bi-temporal (pre and post fire) reflectance contrast of burn-sensitive spectral bands was used to compute differential spectral indices, namely, Normalized Burn Ratio (dNBR), Normalized Difference Vegetation Index (dNDVI), Normalized Difference Water Index (dNDWI), and Short-Wave Infrared (dSWIR). The differential spectral-indices composite is further used as an input to unsupervised Weka clustering algorithms for capturing the shape and pattern of fire patches. Sample training-data of burn and unburn classes were collected with reference to thermal and optical spectral principle. Classification Regression Tree (CART), Random Forest (RF), and Support Vector Machine (SVM) algorithms have been employed to identify FF. The key findings revealed that CART and RF algorithms displayed similar forest fire patches with an overall accuracy of 97–100%. The classification accuracy is slightly lower in SVM and its underestimating forest fire patches detections. Landsat-8 OLI derived burn area was fitted better with fire product of Climate Change Initiative (Fire-CCI of ESA) and MCD64A1 of MODIS burn area product with R-square of 0.71–0.93 and 0.62–0.91, respectively which attributed to better spectral bands of Landsat-8 than the Sentinel-2. However, Sentinel-2 bands have the potential to capture fire patches during post-fire events. This study has demonstrated the potential utilities of combined effort of unsupervised and supervised algorithms on Landsat-8 and Sentinel-2 on GEE to identify fire patches.

Incorporating fish habitat requirements of the complete life cycle into ecological flow regime estimation of rivers

AbstractMaintenance of ecological flow regime for aquatic biota is essential to river ecosystem health. To estimate ecological flow, habitat simulation methods have been widely applied because of their combination of hydrological regime and species hydraulic preference. However, few methods are available to provide a flow regime that varies over time due to time‐specific habitat requirements from different target species or from one target species at its different life stages. This paper described a novel approach for evaluating the ecological flow regime that was a time series of discharge considering different life stages of target species. First, an ecohydraulic model that combined multivariable habitat suitability curve of target species with a hydraulic module was developed to establish the relationship between habitat status and hydrological conditions. Then, the habitat connectivity index was adopted to assess the spatial patterns of habitat patches. Finally, the ecological flow regime considering the complete life cycle of target species was derived. The developed approach was applied to the middle reach of Huaihe River, where the flow is highly regulated by dams and sluices. The Chinese bream (Parabramis pekinensis) was chosen as the target species for ecological flow calculation. The ecological flow regime in the Lutaizi was provided for the river management. The study provided a promising method to support ecological friendly operations of hydraulic structures for river ecosystem restoration and management.