Changes In Energy Fluxes Research Articles

Numerical simulation of [formula omitted] drift effects on fueling pellet ablation and transport in EAST

The pellet injection technique is considered a primary method for fueling future fusion devices. The inclusion of the E×B particle drift effect is essential in the simulation to reproduce the actual particle transport of injected pellets and the changes in energy flux in the divertor region. In this study, the dynamic neutral gas shield model is coupled with the edge plasma code SOLPS-ITER, utilizing initial data referencing from EAST experiments. The investigation focuses on the effects of the E×B drift on the ablation of injected fuel pellets, particle transport, and heat flux in the divertor region. The simulation results show that the poloidal component of the E×B drift velocity causes the dispersion of ions and electrons produced by the ionization of ablated atoms from the pellet, which would accumulate around the pellet if the E×B drift is not considered. Under unfavorable toroidal magnetic field conditions, a significant accumulation of ions ▪ produced by the ionization of D atoms introduced by the injected pellet is observed near the outer target. Moreover, both the change and duration of energy flux variations in the outer target region are higher when compared with the case without E×B drift.

Sustainable Land Use Strengthens Microbial and Herbivore Controls in Soil Food Webs in Current and Future Climates.

Climate change and land-use intensification are threatening soil communities and ecosystem functions. Understanding the combined effects of climate change and land use is crucial for predicting future impacts on soil biodiversity and ecosystem functioning in agroecosystems. Here, we used a field experiment to quantify the combined effects of climate change (warming and altered precipitation patterns) and land use (agricultural type and management intensity) on soil food webs across nematodes, micro-, and macroarthropods. Specifically, we investigated two types of agricultural systems-croplands and grasslands-under both high- and low-intensity management. We focused on assessing the functioning of soil food webs by investigating changes in energy flux to consumers in the main trophic groups: decomposers, microbivores, herbivores, and predators. While the total energy flux and detritivory, herbivory and predation in the soil food web remained unchanged across treatments, low-intensity land use-compared to high intensity-led to higher microbivory and microbial control under future climate conditions (i.e., warming and summer drought) in croplands and grasslands. At the same time, microbial and herbivore control were higher under low-intensity land use in croplands and grasslands. Overall, our results underscore the potential benefits of less intensive, more sustainable management practices for soil food-web functioning under current and future climate scenarios.

Nonlinear changes in urban heat island intensity, urban breeze intensity, and urban air pollutant concentration with roof albedo

This study systematically examines how the urban heat island (UHI) and urban breeze circulation (UBC) respond to an increase in roof albedo (αr) and its influence on urban air pollutant dispersion. For this, idealized ensemble simulations are performed using the Weather Research and Forecasting (WRF) model. The increase in αr from 0.20 to 0.65 decreases the UHI intensity, UBC intensity, and urban planetary boundary layer (PBL) height in the daytime (from 1200 to 1700 LST) by 47%, 36%, and 6%, respectively. As both UBC intensity and urban PBL height decrease, the daytime urban near-surface passive tracer concentration increases by 115%. The daytime UHI intensity, UBC intensity, and urban tracer concentration nonlinearly change with αr: For 0.10 ≤ αr < 0.80, the rates of changes in the UHI intensity, UBC intensity, and urban tracer concentration with αr overall increase as αr increases. For αr ≥ 0.80, the daytime roof surface temperature is notably lower than the daytime urban near-surface air temperature, the UHI intensity, UBC intensity, and urban tracer concentration very slightly changing with αr. This study provides insights into the associations between changes in roof surface temperature and roof surface energy fluxes with αr and those in UHI intensity.

Critical dimension for hydrodynamic turbulence.

Hydrodynamic turbulence exhibits nonequilibrium behavior with k^{-5/3} energy spectrum, and equilibrium behavior with k^{d-1} energy spectrum and zero viscosity, where d is the space dimension. Using recursive renormalization group in Craya-Herring basis, we show that the nonequilibrium solution is valid only for d<6, whereas equilibrium solution with zero viscosity is the only solution for d>6. Thus, d=6 is the critical dimension for hydrodynamic turbulence. In addition, we show that the energy flux changes sign from positive to negative near d=2.15. We also compute the energy flux and Kolmogorov's constants for various d's, and observe that our results are in good agreement with past numerical results.

An Invasive Predator Substantially Alters Energy Flux Without Changing Food Web Functional State or Stability

ABSTRACTUnderstanding how invasive species affect the stability and function of ecosystems is critical for conservation. Here, we quantified the effect of an actively suppressed invasive species on the Yellowstone Lake ecosystem using a food web energetics approach. We compared energy flux, functional state, and stability of four food web states: a pre‐invasion network and three post‐invasion networks undergoing active invasive species suppression, namely, initial invasion, expansion, and decline. Invasion caused ≥ 25% change (±) in energy flux for most consumers, and total flux increased twofold post‐invasion. Flux to the species of conservation concern, Yellowstone cutthroat trout (Oncorhynchus virginalis bouvieri), was 2.8 times less post‐invasion versus pre‐invasion, whereas invasive lake trout (Salvelinus namaycush) flux was up to 17.3 times higher compared to the initial invasion network. The dominant functional state and food web stability did not change post‐invasion, likely due to introduction of a generalist predator and the stabilizing effect of suppression. Lake trout invasion in Yellowstone Lake caused large changes to energy flux, shifting dominant fluxes away from the species of conservation concern, despite not changing functional state or stability. We demonstrate that changes in energy flux may signal invasions in ecosystems, but functional state or stability may not necessarily reflect the magnitude of invasion influences. For invaded fish communities, a better understanding of how the invasive species control the food web beyond just the direct influence on prey can be achieved by investigating energy flux, functional state, and food web stability. Furthermore, evaluating the effect of suppression beyond the invasive species can demonstrate the far‐reaching value of suppression management actions for conservation.

A Multi‐Scale Particle‐In‐Cell Simulation of Plasma Dynamics From Magnetotail Reconnection to the Inner Magnetosphere

AbstractDuring magnetospheric substorms, plasma from magnetic reconnection in the magnetotail is thought to reach the inner magnetosphere and form a partial ring current. We simulate this process using a fully kinetic 3D particle‐in‐cell (PIC) numerical code along with a global magnetohydrodynamics (MHD) model. The PIC simulation extends from the solar wind outside the bow shock to beyond the reconnection region in the tail, while the MHD code extends much further and is run for nominal solar wind parameters and a southward interplanetary magnetic field. By the end of the PIC calculation, ions and electrons from the tail reconnection reach the inner magnetosphere and form a partial ring current and diamagnetic current. The primary source of particles to the inner magnetosphere is bursty bulk flows (BBFs) that originate from a complex pattern of reconnection in the near‐Earth magnetotail at to . Most ion acceleration occurs in this region, gaining from 10 to 50 keV as they traverse the sites of active reconnection. Electrons jet away from the reconnection region much faster than the ions, setting up an ambipolar electric field allowing the ions to catch up after approximately 10 ion inertial lengths. The initial energy flux in the BBFs is mainly kinetic energy flux from the ions, but as they move earthward, the energy flux changes to enthalpy flux at the ring current. The power delivered from the tail reconnection in the simulation to the inner magnetosphere is W, which is consistent with observations.

Global tropical and extra-tropical tropospheric ozone trends and radiative forcing deduced from satellite and ozonesonde measurements for the period 2005–2020

Tropospheric ozone (TPO) is considered as a "near-term climate forcer”, whose impact on climate depends on its radiative forcing (RF), which is a change in the Earth's energy flux. Here, we use the ground-based and satellite measurements during the period 2005–2020 to deduce the trends of TPO, which is significantly positive in the tropical and extra-tropical northern hemisphere (0.2–0.5 DU/yr) and southern extra-tropics (0.1–0.2 DU/yr). Furthermore, the trends derived using a multiple linear regression model (MLR) also confirm these estimates, which are about 0.05–0.1 DU/yr and the regions with higher trends (>0.06 DU/yr) are statistically significant. We also use a standalone Rapid Radiative Transfer Model coupled with a convective model (Radiative-Convective Model; RCM) to assess the climate forcing of ozone using its vertical profiles from the Modern Era Retrospective Reanalysis (MERRA)-2 reanalysis. The estimated temperature rise due to the radiative forcing of ozone in the tropical troposphere (1000–100 hPa) is about 0.2–0.3 °C for the study period. In brief, there is a positive trend in the tropospheric ozone in the tropics and extra-tropics, which is a great concern for regional warming, public health and ecosystem dynamics.

Nitrogen addition and precipitation reduction alter ecosystem multifunctionality and decrease soil nematode abundance and trophic energy fluxes in a temperate forest

Soil biota and energy flow within their food webs have a profound impact on various ecosystem functions. However, there are still significant gaps in our understanding of how climate change factors, such as nitrogen deposition and reduced precipitation, impact ecosystem functioning, particularly in temperate forest ecosystems. In this study, we evaluated the response of ecosystems to long-term nitrogen deposition and/or reduced precipitation due to climate change. We assessed these responses by examining nematode community energy fluxes and their associated ecosystem multifunctionality. Field experiments were conducted in a temperate forest to simulate nitrogen deposition (5.0 kg N·ha−1·yr−1) using NH4NO3 application and to reduce precipitation (to 70 % of a normal year) using rain shelters. Our findings showed that nitrogen addition and/or precipitation reduction treatments altered soil nematode composition. Nitrogen addition alone reduced the abundance and energy fluxes of high trophic groups such as omnivore-predators, which served as proxies for total abundance and energy fluxes. In contrast, precipitation reduction did not exhibit significant effects on overall abundance and energy fluxes. Environmental factors influencing changes in soil nematode abundance and energy fluxes included soil pH, NH4+-N, and total nitrogen in the soil. Nitrogen addition increased ecosystem multifunctionality by promoting nutrient cycling, while precipitation reduction promoted plant productivity and inhibited carbon cycling, without changing ecosystem multifunctionality. Regression analysis showed that soil nematode energy fluxes were negatively correlated with ecosystem multifunctionality. The effects of these two factors on soil nematode food webs showed temporal variation, as well as indicators related to multiple functions of the ecosystem. Our study suggests that soil nematode energy fluxes are more sensitive than nematode abundance for quantifying the relationship between biodiversity and ecosystem multifunctionality.

Distinguishability of binary extreme-mass-ratio inspirals in low frequency band

The inspiral of compact stellar objects into massive black holes are one of the main astrophysical sources for the Laser Interferometer Space Antenna (LISA) and Taiji. These extreme-mass-ratio inspirals (EMRIs) have great potential for cosmology and fundamental physics. A binary extreme-mass-ratio inspiral (b-EMRI) describes the case where binary black holes (BBHs) are captured by a supermassive black hole. The b-EMRIs serve as multi-band gravitational wave sources and provide insights into the dynamics of nuclei and tests of general relativity. However, if the b-EMRIs can be distinguished from the normal EMRIs or not is still not clear. In this work, with a few of assumptions, and using the Teukolsky equation, we calculate the approximate gravitational waves of b-EMRIs and assess their detectability by space-based detectors. We also decouple the secondary object information from the Teukolsky equation, enabling us to calculate the energy fluxes and generate the waveforms more conveniently. Variations in the quadrupole of the binary result in small but non-negligible changes in energy fluxes and waveforms, making it possible to distinguish b-EMRI signals with data analysis. This opens up the potential of using b-EMRIs to test gravity theories and for further astrophysical studies.

Rainforest transformation reallocates energy from green to brown food webs

Terrestrial animal biodiversity is increasingly being lost because of land-use change1,2. However, functional and energetic consequences aboveground and belowground and across trophic levels in megadiverse tropical ecosystems remain largely unknown. To fill this gap, we assessed changes in energy fluxes across ‘green’ aboveground (canopy arthropods and birds) and ‘brown’ belowground (soil arthropods and earthworms) animal food webs in tropical rainforests and plantations in Sumatra, Indonesia. Our results showed that most of the energy in rainforests is channelled to the belowground animal food web. Oil palm and rubber plantations had similar or, in the case of rubber agroforest, higher total animal energy fluxes compared to rainforest but the key energetic nodes were distinctly different: in rainforest more than 90% of the total animal energy flux was channelled by arthropods in soil and canopy, whereas in plantations more than 50% of the energy was allocated to annelids (earthworms). Land-use change led to a consistent decline in multitrophic energy flux aboveground, whereas belowground food webs responded with reduced energy flux to higher trophic levels, down to −90%, and with shifts from slow (fungal) to fast (bacterial) energy channels and from faeces production towards consumption of soil organic matter. This coincides with previously reported soil carbon stock depletion3. Here we show that well-documented animal biodiversity declines with tropical land-use change4–6 are associated with vast energetic and functional restructuring in food webs across aboveground and belowground ecosystem compartments.

Global impacts of vegetation clumping on regulating land surface heat fluxes

The clumping index (CI) quantifies the non-random distribution of vegetation across space, which regulates the canopy radiative transfer processes and land surface carbon, water, and energy cycles. However, its impact on global surface energy budget, particularly sensible heat fluxes and surface temperature, is not well understood. Additionally, while there have been studies showing significant seasonal variations in CI, the impacts of these variations on surface energy fluxes remain unclear. In this study, we incorporated satellite-derived spatially and temporally explicit CI data into the Community Land Model version 5 (CLM5) to evaluate the effects of CI on global land energy fluxes. Our results showed that including CI increased the global mean sensible heat flux dissipated from ground by 3.9 W m−2 (∼18%), while decreasing the global mean vegetation sensible heat flux by 4.9 W m−2 (∼65%), resulting in a total sensible heat decrease of 1.0 W m−2 (∼3%). In contrast, CI increased the global mean latent heat flux by 0.8 W m−2 (∼2%), primarily due to increased evapotranspiration (up to 11 W m−2) in tropical regions. We also found considerable impacts of seasonal variations in CI, particularly on sensible heat fluxes from ground and vegetation in evergreen needleleaf forests and deciduous needleleaf forests. Using constant CI rather than considering seasonal variations resulted in significant overestimation and underestimation of the sensible heat fluxes from vegetation and ground, respectively, in boreal summer. These changes in surface energy fluxes caused by CI and its seasonal variations led to up to 1.7 and 0.5 K differences in simulated mean ground temperature. These findings highlight the importance of including CI and considering its seasonal variations in modeling land surface energy fluxes.

Design and development study of gradient composite shielding material for nuclear radiation

In this manuscript, the design process and genetic algorithm coupled with the SuperMC to design the gradient composite radiation shielding material are described. As nuclear radiation penetrates the shielding materials, its energy spectrum and flux change gradually with depth as a result of interaction with material, so composition of materials should also change accordingly for effective shielding that gives the idea of gradient shielding materials. To design the gradient shielding material, the changed leaked source is determined and analyzed at smaller steps along the depth. At each step the composition is adjusted according to changed leaked source that makes the gradation of gradient shielding material. As the step size is smaller, so there are hundreds of input files to be executed, to handle this long computational work, a genetic algorithm was developed that automatically generates the required composition according to leaked source, write the inputs files and execute them on the SuperMC, analyze the outputs, and extract the data to design the whole gradient shielding material. This genetic algorithm coupled with SuperMC takes the base materials, source, mesh size and total thickness as input parameters. As an example, a gradient material based on Polyethylene (C2H4), Tungsten (W) and Boron carbide (B4C) was developed using this algorithm and compared its performance to that of homogenized material and potential layered shielding structures having the same total contents of base materials as that of gradient material. At a thickness of 150 cm, the total dose through the gradient material is about 1250% lower than the total dose through the homogenized material, which shows the better shielding performance of the gradient shielding material. So the gradient composite shielding materials would be particularly important for shielding in mobile compact nuclear applications.

Modelling water/heat transfer and crop growth under film mulching condition in a seed–maize field

Film mulching has been widely applied in arid and semi–arid areas around the world. Current models simulating the process of water, heat, and crop growth generally neglect or simplify the role of film mulching in energy balance and water/heat exchange. In this study, CropSMPAC model was established based on previously developed model (CropSPAC, the soil water/heat transfer and crop growth model), by incorporating the influence of film mulching on energy budget and partition, sensible and latent heat fluxes of the soil surface, precipitation interception, and crop growth. The CropSMPAC model was calibrated and validated using experimental data from a seed–maize field located in arid Northwest China for the years 2017, 2018, and 2019. The experimental setup included two mulching treatments, i.e., full film mulching (M1) and no mulching (M0) along with three irrigation treatments, i.e., full irrigation (WF), medium irrigation (WM, 70%WF), low irrigation (WL, 40%WF). The results demonstrated that the model performed well in simulating the dynamics of field water, heat, and crop growth under various film mulching and irrigation conditions. The Nash-Sutcliffe efficiency coefficients for net radiation, soil heat flux, soil water storage (SWS), soil temperature (ST), leaf area index (LAI), aboveground dry biomass (ADB) were 0.57, 0.37, 0.79, 0.76, 0.95, 0.95, respectively. The relative errors for seed-maize yield, crop evapotranspiration (ET) were 9.38%, 9.10%, respectively. Furthermore, the model accurately reflected the differences in SWS and ST due to different mulching conditions (M1 and M0). The observed differences in SWS between M1 and M0 ranged from –30.6 to 32.9 mm, while the simulated differences ranged from –30.5 to 30.2 mm under various irrigation treatments. Similarly, the observed differences in ST between M1 and M0 were 1.8, 1.7, 1.0 and 1.4 °C at 10, 20, 40 and 80 cm soil depths, respectively, while the simulated differences were 2.3, 2.1, 1.7 and 0.8 °C under WF treatment. Additionally, the model effectively simulated the effects of film mulching on advancing the crop growth period and promoting LAI, ADB and yield. Overall, the model accurately captured the changes in energy fluxes, soil water, heat and crop growth caused by plastic film mulching, demonstrating that it is a useful tool for irrigation water management and crop production in crop land with film mulching.

Regional tropical rainfall shifts under global warming: an energetic perspective

Future climate simulations feature pronounced spatial shifts in the structure of tropical rainfall. We apply a novel atmospheric energy flux analysis to diagnose late 21st century tropical rainfall shifts in a large ensemble of simulations of 21st century climate. The method reconstructs 2D spatial changes in rainfall based on horizontal shifts in the lines of zero meridional and zonal divergent energy flux, called the energy flux equator (EFE) and energy flux prime meridian (EFPM), respectively. Two main sources of future atmospheric energy flux changes, and hence rainfall shifts, are identified by the analysis: the high-latitude North Atlantic due to a weakened Atlantic Meridional Overturning Circulation that shifts tropical rainfall southwards over the greater Tropical Atlantic sector and eastern Pacific; and the eastern tropical Pacific due to a permanent El-Niño-like response that produces zonal shifts over the Maritime Continent and South America. To first order, the shifts in the EFE and EFPM mirror gross distributional changes in tropical precipitation, with a southward shift in rainfall over the tropical Atlantic, West Africa, and eastern tropical Pacific and an eastward shift over the Maritime Continent and western Pacific. When used to reconstruct future rainfall shifts in the tropical Atlantic and Sahel, the method reasonably represents the simulated meridional structure of rainfall shifts but does not do so for the zonal structures.

Correlations between energy flux and thin film modifications in an atmospheric pressure direct current microplasma

A custom-built atmospheric pressure direct current microplasma discharge was designed utilizing Au coated Si3N4 transmission electron microscopy (TEM) grids as electrodes to enable a direct imaging of the plasma treated anode and cathode surfaces. Significant differences between the anode and the cathode, as well as between Ar or He operation of the microplasma, respectively, were observed already by examination of the electrode surfaces by light microscopy. Scanning electron microscopy as well as TEM imaging revealed details such as grain growth and changes in surface morphology. The energy fluxes from plasma towards the anode and cathode were determined and correlated with the surface modifications. As expected from structure zone diagrams higher energy fluxes result in higher degree of crystallinity even at atmospheric pressure. Furthermore, ions and their respective energy contributions were identified to play a major role for the surface modification, despite their low kinetic energy due to the large number of collisions. Depending on the working gas, Ar or He, the identified energetic contributions of the total ion energy flux change and, subsequently, result in visible differences in the plasma treated Au films.

Refraction of the M2 internal tides by mesoscale eddies in the South China Sea

Mesoscale eddies (MEs) are active in the northern South China Sea, yet it is hard to separate their impacts on the internal tides (ITs) from those of other subtidal circulation. This study examines the role of an anticyclonic eddy and a cyclonic eddy in modulating the M2 ITs based on numerical simulations. In idealized experiments, MEs that differ only in polarity are located on the main beam of the M2 ITs in the northern South China Sea. Results show that the anticyclonic eddy and cyclonic eddy cause northward and southward refractions of the M2 ITs, respectively, which echoes the realistic simulation. The most dramatic changes in the M2 IT energy fluxes occur on the continental slope to the west of the MEs. Theoretical analysis based on the ray-tracing model and the empirical model for estimating wave front locations reveals that the MEs cause refraction of the M2 ITs by changing the phase speeds. Further investigation shows that the currents related to the MEs make a greater contribution to the IT refraction than the ME-associated stratification. These results have important implications for investigation of spatial and temporal variations in the magnitude and direction of the M2 IT energy fluxes.

An analytical approximation of urban heat and dry islands and their impact on convection triggering

It is well known that cities increase air and surface temperatures compared to their rural surroundings, the so-called urban heat island (UHI) effect. However, the associated changes in atmospheric humidity (also known as urban dry island, UDI) and convection triggering remain largely unexplored and it is still unclear how urban modifications of the surface energy budget influence the diurnal evolution of temperature and humidity in the Atmospheric Boundary Layer (ABL) and ultimately control the initiation of convective clouds.Here we quantify the impact of different urban settings and free atmospheric conditions on UHI, UDI, and convection triggers by means of a zero-order model of the ABL. Specifically, we derive an approximate solution for urban-rural changes in surface energy fluxes and ABL potential temperature and humidity and we investigate the crossing between the ABL height and the lifting condensation level (LCL) which is a proxy for the triggering of convective clouds. We show that urban areas are generally warmer and drier, thus causing an increase in both ABL and LCL heights. However, the response of the ABL-LCL crossing to surface conditions is non-linear and there exists a range of free atmosphere conditions for which changes in imperviousness can impact convective clouds.

Changes in Poleward Atmospheric Energy Transport over a Wide Range of Climates: Energetic and Diffusive Perspectives and A Priori Theories

Abstract The midlatitude poleward atmospheric energy transport increases in radiatively forced simulations of warmed climates across a range of models from comprehensive coupled general circulation models (GCMs) to idealized aquaplanet moist GCMs to diffusive moist energy balance models. These increases have been rationalized from two perspectives. The energetic (or radiative) perspective takes the atmospheric energy budget and decomposes energy flux changes (radiative forcing, feedbacks, or surface fluxes) to determine the energy transport changes required by the budget. The diffusive perspective takes the net effect of atmospheric macroturbulence to be a diffusive energy transport down-gradient, so transport changes can arise from changes in mean energy gradients or turbulent diffusivity. Here, we compare these perspectives in idealized moist, gray-radiation GCM simulations over a wide range of climates. The energetic perspective has a dominant role for radiative forcing in this GCM, with cancellation between the temperature feedback components that account for the GCM’s nonmonotonic energy transport changes in response to warming. Comprehensive CMIP5 simulations have similarities in the Northern Hemisphere to the idealized GCM, although a comprehensive GCM over several CO2 doublings has a distinctly different feedback evolution structure. The diffusive perspective requires a non-constant diffusivity to account for the idealized GCM-simulated changes, with important roles for the eddy velocity, dry static stability, and horizontal energy gradients. Beyond diagnostic analysis, GCM-independent a priori theories for components of the temperature feedback are presented that account for changes without knowledge of a perturbed climate state, suggesting that the energetic perspective is the more parsimonious one.

Understanding interactive processes: a review of CO2 flux, evapotranspiration, and energy partitioning under stressful conditions in dry forest and agricultural environments.

Arid and semiarid environments are characterized by low water availability (e.g., in soil and atmosphere), high air temperature, and irregularity in the spatio-temporal distribution of rainfall. In addition to the economic and environmental consequences, drought also causes physiological damage to crops and compromises their survival in ecosystems. The removal of vegetation is responsible for altering the energy exchange of heat and water in natural ecosystems and agricultural areas. The fluxes of CO2 are also changed, and environments with characteristics of sinks, which can be sources of CO2 after anthropic disturbances. These changes can be measured through methods such as sap flow, eddy covariance, remote sensing, and energy balance. Despite the relevance of each method mentioned above, there are limitations in their applications that must be respected. Thus, this review aims to quantify the processes and changes of energy fluxes, CO2, and their interactions with the surfaces of terrestrial ecosystems in dry environments. Studies report that the use of methods that integrate data from climate monitoring towers and remote sensing products helps to improve the accuracy of the determination of energy fluxes on a global scale, also helping to reduce the dissimilarity of results obtained individually. Through the collection of works in the literature, it is reported that several areas of the Brazilian Caatinga biome, which is a Seasonally Dry Tropical Forest have been suffering from changes in land use and land cover. Similar fluxes of sensible heat in areas with cacti and Caatinga can be observed in studies. On the other hand, one of the variables influenced mainly by air temperature is net radiation. In dry forest areas, woody species can store large amounts of carbon in their biomass above and belowground. The use of cacti can modify the local carbon budget when using tree crops together. Therefore, the study highlights the complexity and severity of land degradation and changes in CO2, water, and energy fluxes in dry environments with areas of forest, grassland, and cacti. Vegetation energy balance is also a critical factor, as these simulations are helpful for use in forecasting weather or climate change. We also highlight the need for more studies that address environmental conservation techniques and cactus in the conservation of degraded areas.

Comparison of the shape of focal spots in terms of intensity and energy flux for a high-aperture zone plate and a spiral zone plate

Using a finite-difference time-domain method, it has been shown that focal spots generated when tightly focusing a linearly polarized Gaussian beam by a Fresnel zone plate (FZP) and when focusing a Gaussian beam with an embedded optical vortex by a spiral zone plate (SZP) have different patterns of the intensity and energy flux. The most significant differences are observed when the value of the topological charge (TC) is equal to three. The energy flux has an annular distribution when the Gaussian beam is focused by the FZP, while the SZP produces a field whose patterns of intensity and energy flux have three local maxima. The number of local maxima corresponds to the order of the SZP. At a certain distance from the focus, the petal structure of the intensity (and energy flux) changes to a ring distribution.