Hasil untuk "Physical geography"

G. Nellhaus

M. Gachkivskyi, M. Gachkivskyi, U. Karstens et al.

<p>Atmospheric measurements of the short-lived radioactive noble gas radon-222 (<span class="inline-formula">²²²Rn</span>) have many applications. Its concentrations are driven by atmospheric mixing as well as seasonal variations, which follow the seasonality of <span class="inline-formula">²²²Rn</span> exhalation from continental soils, with lower values during the wet winter and spring months compared to more dry summer conditions. Hence, it can be used as a tracer to distinguish marine from continental air masses or for transport model validation. The Heidelberg Radon Monitor (HRM) is a static filter detector measuring atmospheric <span class="inline-formula">²¹⁴po</span>lonium (<span class="inline-formula">²¹⁴Po</span>), which is a progeny of <span class="inline-formula">²²²Rn</span>. These measurements can be used to infer atmospheric <span class="inline-formula">²²²Rn</span> activity concentrations if the radioactive disequilibrium between <span class="inline-formula">²¹⁴Po</span> and <span class="inline-formula">²²²Rn</span> at the measurement site is known. In this study, <span class="inline-formula">²¹⁴Po</span> activity concentrations measured with the HRM at eight stations in the Integrated Carbon Observation System (ICOS) Germany network are presented, along with guidelines for evaluating these data to estimate atmospheric <span class="inline-formula">²²²Rn</span> activity concentrations. In addition to the established line loss and disequilibrium corrections applied when sampling through long tubing or from air intake heights close to the ground, respectively, an upper limit for relative humidity (RH) is suggested, where secular equilibrium can still be assumed. At higher RH, aerosol scavenging effects can cause disequilibrium between <span class="inline-formula">²¹⁴Po</span> and <span class="inline-formula">²²²Rn</span>. Using comparison with the model this threshold is determined to be at about 98 <span class="inline-formula">%</span> RH and was applied uniformly at all measurement sites. A clear diurnal cycle of <span class="inline-formula">²²²Rn</span> is observed at all German tower stations during the summer and autumn months as is a seasonal cycle with a maximum during summer and autumn months. Overall, our results demonstrate that the <span class="inline-formula">²¹⁴Po</span>-based <span class="inline-formula">²²²Rn</span> measurements with the HRM are reliable if the equilibrium conditions between <span class="inline-formula">²¹⁴Po</span> and <span class="inline-formula">²²²Rn</span> can be ensured, i.e., for air intake heights above 80–90 <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M19" display="inline" overflow="scroll" dspmath="mathml"><mrow class="unit"><mi mathvariant="normal">m</mi><mspace width="0.125em" linebreak="nobreak"/><mi mathvariant="normal">a</mi><mo>.</mo><mi mathvariant="normal">g</mi><mo>.</mo><mi mathvariant="normal">l</mi><mo>.</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="36pt" height="12pt" class="svg-formula" dspmath="mathimg" md5hash="8e966d80b90499d50817f03759d7e713"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-17-6173-2025-ie00001.svg" width="36pt" height="12pt" src="essd-17-6173-2025-ie00001.png"/></svg:svg></span></span> during conditions with <span class="inline-formula">RH&lt;98</span> <span class="inline-formula">%</span>. The corrected and ready-to-use dataset of 10-<span class="inline-formula">year</span> radon activity concentrations from the eight ICOS stations is published alongside this paper (<a href="https://doi.org/10.18160/Q2M8-B1HJ">https://doi.org/10.18160/Q2M8-B1HJ</a>, <span class="cit" id="xref_altparen.1"><a href="#bib1.bibx16">Fischer et al.</a>, <a href="#bib1.bibx16">2024</a></span>).</p>

Jianyong Ma, Peter Anthoni, Stefan Olin et al.

Abstract Cover crops (CCs) can improve soil nutrient retention and crop production while providing climate change mitigation co‐benefits. However, quantifying these ecosystem services across global agricultural lands remains inadequate. Here, we assess how the use of herbaceous CCs with and without biological nitrogen (N) fixation affects agricultural soil carbon stocks, N leaching, and crop yields, using the dynamic global vegetation model LPJ‐GUESS. The model performance is evaluated with observations from worldwide field trials and modeled output further compared against previously published large‐scale estimates. LPJ‐GUESS broadly captures the enhanced soil carbon, reduced N leaching, and yield changes that are observed in the field. Globally, we found that combining N‐fixing CCs with no‐tillage technique could potentially increase soil carbon levels by 7% (+0.32 Pg C yr−1 in global croplands) while reducing N leaching loss by 41% (−7.3 Tg N yr−1) compared with fallow controls after 36 years of simulation since 2015. This integrated practice is accompanied by a 2% of increase in total crop production (+37 million tonnes yr−1 including wheat, maize, rice, and soybean) in the last decade of the simulation. The identified effects of CCs on crop productivity vary widely among main crop types and N fertilizer applications, with small yield changes found in soybean systems and highly fertilized agricultural soils. Our results demonstrate the possibility of conservation agriculture when targeting long‐term environmental sustainability without compromising crop production in global croplands.

Zekeriya Konurhan, Erkin Başaran

In today’s world, searching for an alternative energy source instead of fossil fuels has become highly popular. Renewable energy sources such as solar panels and wind power plants are the alternatives to fossil fuels. Wind power plants (WPPs) are actively used in several regions of the world, both at sea and on land. In Turkey, WPPs have been used, especially since the early 2000s, with the Aegean and Marmara regions being their prime locations. However, there is no WPP in Tunceli. Thus, the main objective of this study is to recommend suitable WPP areas for Tunceli. In this context, the best-worst method (BWM) was integrated into the geographical information system (GIS) and used in the study. The BWM method is a multi-criteria decision making (MCDM) method based on pairwise comparison. In the study, 16 criteria were determined under four main criteria “topography”, “socio-economic”, “technical,” and “location” by using the BWM model. Experts from different disciplines evaluated each criterion as a questionnaire and used it for appropriate site selection. For the 16 criteria, separate maps were created, explanations of the criteria were established, and these maps were cumulatively used in the resulting map. The criteria weights determined using the BWM model were integrated into the GIS, and suitable WPP installation areas for Tunceli were determined. Accordingly, some areas around Pertek and Mazgirt in the southeast of Tunceli, north of Pülümür, and around Çemişgezek, which provide suitable conditions in terms of physical geography, are suitable for WPP installation.

J. Hirshleifer

THE field variously called population biology, sociobiology, or ecology is concerned to explain the observed interrelations among the various forms of life--organisms, species, and broader groupings and communities-and between forms of life and their external environments. The subject includes both material aspects of these interrelations (the geographical distributions of species in relation to one another, their respective numbers, physical properties like size differences between the sexes) and behavioral aspects (why some species are territorial while others flock, why some are monogamous and others polygamous, why some are aggressive and others

Aurélien Costes, Quentin Rodier, Valéry Masson et al.

Abstract Coupled atmosphere‐fire modeling is recognized as a relevant approach for the representation of the interaction between a wildland fire and local meteorology at landscape scales. The atmospheric model component used in the coupled system is based on several approximations, which are adopted for computational efficiency or physical processes representation, including the widely used anelastic approximation. The validity domain of the anelastic approximation may be questioned in the context of high‐resolution wildland fire modeling due to the large fire‐induced heat releases near the surface. This study aims to study this question with the MesoNH anelastic model coupled with the Blaze fire model. A compressible version of the MesoNH‐Blaze coupled model has been developed for comparison with the anelastic system. The FireFlux I experimental fire is used for this comparative study conducted at a 10‐m and a 25‐m horizontal atmospheric resolution. Results show significant anelastic/compressible differences at a 10‐m resolution on the physical processes occurring near the fire with higher horizontal velocities and the presence of gravity waves downstream of the fire. This is in addition to the fire plume with realistic larger vertical velocities. Differences at a 25‐m resolution are much smaller in all evaluated processes. The compressible system only enriches the physics underlying fire‐atmosphere interactions at a very high resolution, which means that the anelastic approximation remains relevant for large‐scale coupled atmosphere‐fire simulations, considering the significant economy concerning numerical costs.

Qiaofeng Tan, Yunze Mao, Xin Wen et al.

Multivariate flood frequency analysis has been widely used in the design and risk assessment of hydraulic structures. However, analytical solutions are often obtained based on an idealized linear reservoir model in which a linear routing process is assumed, and consequently, the flood risk is likely to be over- or underestimated. The present study proposes a nonlinear reservoir model in which the relationships of reservoir water level with reservoir volume and discharge are assumed to be nonlinear in order to more accurately describe the routing process as it takes into consideration the interactions between hydrological loading and different discharge structures. The structure return period is calculated based on the copula function and compared with that based on the linear reservoir model and the bivariate return period based on the Kendall distribution function. The results show that the structure return period based on the linear model leads to an underestimation of the flood risk under the conditions of high reservoir water level. For the same reservoir, linear and nonlinear reservoir models give quite different reservoir volume-water level and discharge-water level curves; therefore, they differ substantially in the sensitivity to flood events with different combinations of flood peak and volume. We also analyze the effects of the parameters involved in the reservoir volume-water level and discharge-water level relationships on the maximum water level at different return periods in order to better understand the applicability and effectiveness of the proposed method for different hydraulic projects. HIGHLIGHTS The structure return period is calculated based on the nonlinear reservoir model.; Nonlinear relationships of water level with volume and discharge are assumed.; Interactions between hydrological loading and different structures are analyzed.; Effects of different storage and discharge capacity parameters are discussed.;

Everaldo Batista da Costa, Delfina Trinca Fighera, Ilia Alvarado Sizzo et al.

El editorial del vol. 4, núm. 8 de PatryTer – Revista Latinoamericana y Caribeña de Geografía y Humanidades cumple dos objetivos. Al igual que el editorial anterior, este está dedicado a la memoria de las personas fallecidas a causa del COVID-19 y a sus familiares; además, destacar, objetivamente, como esta crisis afecta las dinámicas del trabajo en nuestros países latinoamericanos. También se desea enfatizar la importancia del pensamiento del geógrafo brasileño Milton Santos en el contexto actual, bien sea para una crítica necesaria a la forma como estados y gobiernos conducen las políticas nacionales, o para fundamentar las investigaciones en geografía y humanidades.

A. B. Harper, A. B. Harper, K. E. Williams et al.

<p>Drought is predicted to increase in the future due to climate change, bringing with it myriad impacts on ecosystems. Plants respond to drier soils by reducing stomatal conductance in order to conserve water and avoid hydraulic damage. Despite the importance of plant drought responses for the global carbon cycle and local and regional climate feedbacks, land surface models are unable to capture observed plant responses to soil moisture stress. We assessed the impact of soil moisture stress on simulated gross primary productivity (GPP) and latent energy flux (LE) in the Joint UK Land Environment Simulator (JULES) vn4.9 on seasonal and annual timescales and evaluated 10 different representations of soil moisture stress in the model. For the default configuration, GPP was more realistic in temperate biome sites than in the tropics or high-latitude (cold-region) sites, while LE was best simulated in temperate and high-latitude (cold) sites. Errors that were not due to soil moisture stress, possibly linked to phenology, contributed to model biases for GPP in tropical savanna and deciduous forest sites. We found that three alternative approaches to calculating soil moisture stress produced more realistic results than the default parameterization for most biomes and climates. All of these involved increasing the number of soil layers from 4 to 14 and the soil depth from 3.0 to 10.8 m. In addition, we found improvements when soil matric potential replaced volumetric water content in the stress equation (the “soil14_psi” experiments), when the critical threshold value for inducing soil moisture stress was reduced (“soil14_p0”), and when plants were able to access soil moisture in deeper soil layers (“soil14_dr*2”). For LE, the biases were highest in the default configuration in temperate mixed forests, with overestimation occurring during most of the year. At these sites, reducing soil moisture stress (with the new parameterizations mentioned above) increased LE and increased model biases but improved the simulated seasonal cycle and brought the monthly variance closer to the measured variance of LE. Further evaluation of the reason for the high bias in LE at many of the sites would enable improvements in both carbon and energy fluxes with new parameterizations for soil moisture stress. Increasing the soil depth and plant access to deep soil moisture improved many aspects of the simulations, and we recommend these settings in future work using JULES or as a general way to improve land surface carbon and water fluxes in other models. In addition, using soil matric potential presents the opportunity to include plant functional type-specific parameters to further improve modeled fluxes.</p>

Julio C. Navas, T. Imielinski

S. Gangestad, D. Buss

Frederic S. Castruccio, Alicia R. Karspeck, Gokhan Danabasoglu et al.

Abstract An ensemble optimal interpolation (EnOI) data assimilation system for a high‐resolution (0.1° horizontal) version of the Community Earth System Model Version 2 (CESM2) ocean component is presented. For this purpose, a new version of the Data Assimilation Research Testbed (DART Manhattan) that enables large‐state data assimilation by distributing state vector information across multiple processors at high resolution is used. The EnOI scheme uses a static (but seasonally varying) 84‐member ensemble of precomputed perturbations to approximate samples from the forecast error covariance and utilizes a single model integration to estimate the forecast mean. Satellite altimetry and sea surface temperature observations along with in situ temperature and salinity observations are assimilated. This new data assimilation framework is then used to produce a global high‐resolution retrospective analysis for the 2005–2016 period. Not surprisingly, the assimilation is shown to generally improve the time‐mean ocean state estimate relative to an identically forced ocean model simulation where no observations are ingested. However, diminished improvements are found in undersampled regions. Lack of adequate salinity observations in the upper ocean actually results in deterioration of salinity there. The EnOI scheme is found to provide a practical and cost‐effective alternative to the use of an ensemble of forecasts.

O. Gureje, G. Simon, T. Ustun et al.

Yuying Zhang, Shaocheng Xie, Wuyin Lin et al.

Abstract This study systematically evaluates clouds simulated by the Energy Exascale Earth System Model Atmosphere Model version 1 (EAMv1) against satellite cloud observations. Both low‐ (1°) and high‐ (0.25°) resolution EAMv1 configurations generally underestimate clouds in low latitudes and midlatitudes and overestimate clouds in the Arctic, although the error is smaller in the high‐resolution model. The underestimate of clouds is due to the underestimate of optically thin to intermediate clouds, as EAMv1 generally overestimates optically intermediate to thick clouds. Other model errors include the largely underpredicted marine stratocumulus along the coasts and high clouds over the tropical deep convection regions. The underestimate of thin clouds results in too much longwave radiation being emitted to space and too little shortwave radiation being reflected back to space, while the overestimate of optically intermediate and thick clouds leads to too little longwave radiation being emitted to space and too much shortwave radiation being reflected back to space. EAMv1 shows better skill in reproducing the observed distribution of clouds and their properties and has smaller radiatively relevant errors in the distribution of clouds than most of the CFMIP1 and CFMIP2 models. It produces more supercooled liquid cloud fraction than CAM5 and most CMIP5 models primarily due to a new ice nucleation scheme and secondarily due to a reduction of the ice deposition growth rate.

Alice Bonou Fandohan, Belarmain Fandohan, Anselme Adegbidi et al.

Este trabalho examina o valor econômico dos produtos florestais não madeireiros e sua contribuição para a renda da população que reside na Reserva Transnacional W da Biosfera em Benim. No estudo, 148 pessoas de dois grupos étnicos foram entrevistadas. Os dados foram analisados com base no método de estimativa indireta de custo de oportunidade e margem bruta. Os resultados mostram que a população local colhe cinco tipos de produtos: lenha (não comercializado) e quatro produtos comercializados (Vitellaria paradoxa, C.F.Gaertn, sementes e polpa de Parkia biglobosa (Jacq.) R. Br. ex G. Don e folhas de Adansonia digitata L.). A média da contribuição dos produtos comercializados dentre os entrevistados foi estimada em XOF 255,484 ($US 510.968) (desvio padrão: XOF 37,109), representando cerca de 11,46% da renda anual dos domicílios. Grupos de idade e aspectos sociolinguísticos foram os maiores determinantes da exploração de produtos florestais não madeireiros. Tendo em vista o valor desses produtos para as comunidades, deve-se priorizar a domesticação e conservação as plantas identificadas neste estudo.

R. Fitjar, A. Rodríguez‐Pose

George E Clark, S. Moser, S. Ratick et al.

R. Singh

L. Thornton, J. Pearce, A. Kavanagh

Features of the built environment are increasingly being recognised as potentially important determinants of obesity. This has come about, in part, because of advances in methodological tools such as Geographic Information Systems (GIS). GIS has made the procurement of data related to the built environment easier and given researchers the flexibility to create a new generation of environmental exposure measures such as the travel time to the nearest supermarket or calculations of the amount of neighbourhood greenspace. Given the rapid advances in the availability of GIS data and the relative ease of use of GIS software, a glossary on the use of GIS to assess the built environment is timely. As a case study, we draw on aspects the food and physical activity environments as they might apply to obesity, to define key GIS terms related to data collection, concepts, and the measurement of environmental features.

Juliana Porto Machado, Ronaldo Bernardino Colvero

A guasqueria, é um ofício artesanal que trabalha com couro cru, possui técnica de transmissão de um saber fazer, em um processo de criar objetos que segue uma estrutura dorsal, sendo ela: I) Carnear, II) Estaquear, III) Secar; IV) Lonquear; V) Sovar; VI) Tirar tentos e VII) Trançar. Esse ofício está fortemente relacionado com o trabalho do campeiro/peão, figura que está sempre realizando tarefas de campo nas estâncias, principalmente com auxílio do cavalo. Todavia, em vista dessa estruturação que se mantém o objetivo deste artigo é discutir acerca da tradição como uma ferramenta cultural que está em um processo contínuo de transformação e que influência na identidade dos sujeitos que praticam um ofício secular como a guasqueria.  Uma vez que, a produção e reprodução do artesanato em couro cru, guasqueria, ocorre pela transmissão da técnica de um sujeito para o outro, principalmente quando estes exercem a profissão de peão, ocorrendo um compartilhamento de saberes. Fazendo com que esses sujeitos praticantes se identifiquem como guasqueiros.