Fechamento do Balanço de Energia em Torres de Fluxos através do Método dos Mínimos Quadrados

O balanço de energia à superfície pode ter suas variáveis determinadas através medidas realizadas em torres de fluxos e, em tese, elas devem obedecer um fechamento. No entanto, como todo sistema de observação, os sensores envolvidos apresentam incertezas associadas aos materiais e a metodologia utilizada nas medições. Tais incertezas colaboram para o não fechamento do balanço, o que na prática é muito frequente. Utilizando a informação de que o fechamento do balanço de energia deve ser garantido, nesse trabalho é apresentado uma metodologia baseada no método dos mínimos quadrados para ajustar as observações através de uma solução que minimiza o quadrado dos resíduos

Patterns and controls of the latent and sensible heat fluxes in the brazilian Pampa biome

Energy and water exchange between the surface and the atmosphere are important drivers to Earth’s climate fromlocal to global scale. In thisstudy, the energy dynamic and the biophysical mechanisms thatcontrol the energy partitioning overa natural grassland pasture overthe Brazilian Pampa biome are investigated using two micrometeorological sites located 300 km apart, in Southern Brazil. The latent heatflux, LE, was the maincomponent of the energy balance in bothautumn-winter (AW)and spring-summer (SS)periods. Annually, approximately 60% of the available energy is usedfor evapotranspiration (ET). However, the Bowen ratio presents seasonal variability greater in AW than SS. Global radiation, Rg, is the atmospheric variable controlling LE and sensible heatflux, H. Hysteresis curves in the daily cycle wereobserved for ET and surface conductance, Cs, regarding the environmental variables, net radiation, vapor pressure deficit, and air temperature. Among the variables analyzed in the Pampa biome, surface conductance and evapotranspiration respond more strongly to the vapor pressure deficit. The hysteresis cycles formed by ET and conductance show a substantial biophysical control in the ET process. The results obtained here allowed a comprehension of the biophysical mechanisms involved in the energy partition process in natural grassland. Therefore, thisstudy can be usedas abasefor research on land-use changes in this unique ecosystem of the Pampa biome

Precipitation comparison for the CFSR, MERRA, TRMM3B42 and Combined Scheme datasets in Bolivia

AbstractAn overwhelming number of applications depend on reliable precipitation estimations. However, over complex terrain in regions such as the Andes or the southwestern Amazon, the spatial coverage of rain gauges is scarce. Two reanalysis datasets, a satellite algorithm and a scheme that combines surface observations with satellite estimations were selected for studying rainfall in the following areas of Bolivia: the central Andes, Altiplano, southwestern Amazonia, and Chaco. These Bolivian regions can be divided into three main basins: the Altiplano, La Plata, and Amazon. The selected reanalyses were the Modern-Era Retrospective Analysis for Research and Applications, which has a horizontal resolution (~50km) conducive for studying rainfall in relatively small precipitation systems, and the Climate Forecast System Reanalysis and Reforecast, which features an improved horizontal resolution (~38km). The third dataset was the seventh version of the Tropical Rainfall Measurement Mission 3B42 algorithm, which is conducive for studying rainfall at an ~25km horizontal resolution. The fourth dataset utilizes a new technique known as the Combined Scheme, which successfully removes satellite bias. All four of these datasets were aggregated to a coarser resolution. Additionally, the daily totals were calculated to match the cumulative daily values of the ground observations. This research aimed to describe and compare precipitations in the two reanalysis datasets, the satellite-algorithm dataset, and the Combined Scheme with ground observations. Two seasons were selected for studying the precipitation estimates: the rainy season (December–February) and the dry season (June–August). The average, bias, standard deviation, correlation coefficient, and root mean square error were calculated. Moreover, a contingency table was generated to calculate the accuracy, bias frequency, probability of detection, false alarm ratio, and equitable threat score.All four datasets correctly depicted the spatial rainfall pattern. However, CFSR and MERRA overestimated precipitation along the Andes' eastern-facing slopes and exhibited a dry bias over the eastern Amazon; TRMM3B42 and the Combined Scheme depicted a more realistic rainfall distribution over both the Amazon and the Andes. When separating the precipitation into classes, MERRA and CFSR overestimated light to moderate precipitation (1–20mm/day) and underestimated very heavy precipitation (>50mm/day). TRMM3B42 and CoSch depicted behaviors similar to the surface observations; however, CoSch underestimated the precipitation in very intense systems (>50mm/day).The statistical variables indicated that CoSch's correlation coefficient was highest for every season and basin. Additionally, the bias and RMSE values suggested that CoSch closely represented the surface observations

Climatological analysis of the precipitation and umidity transport on the SACZ region using the new generation of reanalysis

O conhecimento do desempenho das reanálises e dos erros associados a elas apresenta um papel fundamental na compreensão dos processos físicos que ocorrem na atmosfera. Este trabalho tem por objetivo documentar as principais características da precipitação associada à Zona de Convergência do Atlântico Sul (ZCAS), baseado em seis conjuntos de reanálises atmosféricas (MERRA, ERA-Interim, ERA-40, NCEP 1, NCEP 2 e NCEP CFSR) e cinco conjuntos de produtos observados de precipitação (SALDAS, CPC, CMAP, GPCP e GLDAS). Através destes dados também foi analisado o transporte de umidade sobre a região da ZCAS, para os anos de 1979 a 2007. Em resumo, este trabalho evidencia o avanço das novas reanálises na tentativa de representar de forma mais adequada a variável precipitação acumulada. Os diagramas de Taylor mostram que os produtos de precipitação estão bem correlacionados com o ponto de referência (CPC), com coeficientes entre 0,6 e 0,9. Somente a reanálise do NCEP CFSR possui correlações próximas as dos produtos de precipitação. Os conjuntos mais antigos de reanálises apresentam correlações menores, abaixo de 0,6. O Oceano Atlântico é a fonte principal do fluxo de umidade para a direção da ZCAS, que diminui na direção do continente. Na Região SE do Brasil, a topografia tem um papel importante para a convergência de umidade. Já na parte noroeste da ZCAS, este fator deve estar associado a processos termodinâmicos

Estimativa da Evapotranspiração sobre a Bacia do Prata Utilizando Climatologia do IAF

Este trabalho teve por objetivo gerar uma mapa daevapotranspiração anual na área delimitada pela Bacia do Prata através dométodo de Penman-Monteith, escrito de forma que a vegetação seja representadapelo índice de área foliar (IAF). Este índice foi obtido atravésde dados de sensoriamento remoto, utilizando uma climatologiacorrespondente ao período de 1987 a 2007, estimada pelo sensor AVHRR.Os forçantes atmosféricos são obtidos do South American Land DataAssimilation System (SALDAS), e referem-se ao ano de 2000. Os resultadosdemonstram que o método aqui utilizado tem superestimado aevapotranspiração média anual sobre a Bacia do Prata, enquanto sua representaçãoespacial está de acordo com demais estimativas

Evaluation of MOD16 algorithm over irrigated rice paddy using flux tower measurements in Southern Brazil

Evapotranspiration (ET) is an important component of the hydrological cycle. Understanding the ET process has become of fundamental importance given the scenario of global change and increasing water use, especially in the agricultural sector. Determining ET over large agricultural areas is a limiting factor due to observational data availability. In this regard, remote sensing data has been used to estimate ET. In this study, we evaluated the Moderate-Resolution Imaging Spectroradiometer (MODIS) land surface ET product estimates (hereafter MOD16 ET - MODIS Global Terrestrial Evapotranspiration Product) over two rice paddy areas in Southern Brazil, through the ET measured using the eddy covariance technique (hereafter EC). The energy balance components were evaluated during fallow and flooded seasons showing latent heat flux dominates in both seasons. The results showed that MOD16 ET underestimated EC measurements. Overall, the RMSE (root mean square error) ranged between 13.40 and 16.35 mm 8-day-1 and percent bias (PBIAS) ranged between -33.7% and -38.7%. We also assessed the ET (measured and estimated) main drivers, with EC yielding higher correlation against observed net radiation (Rn) and global radiation (Rg), followed by air temperature (Temp) and vapor pressure deficit (VPD), whilst MOD16 ET estimates yielded higher correlation against leaf area index (LAI) and fraction of photosynthetically active radiation (fPAR). The MOD16 algorithm was forced with meteorological measurements but the results did not improve as expected, suggesting a low sensitivity to meteorological inputs. Our results indicated when a water layer was present over the soil surface without vegetation (LAI around zero), the largest differences between EC measurements and MOD16 ET were found. In this period, the expected domain of soil evaporation was not observed in MOD16 ET physical processes partition, indicating the algorithm was not able to detect areas with high soil moisture. In general, the MOD16 ET product presented low accuracy when compared against experimental measurements over flooded rice paddy, suggesting more studies are necessary, in order to reduce uncertainties associated to the land cover conditions

Isometry of Potential Attachment Sites for the Iliotrochanteric Suture in Dogs: an ex vivo Study

Background: Coxofemoral luxation is the most common traumatic luxation in dogs and the iliotrochanteric suture is one of the surgical treatment options. The orthopedic suture aimed at surgically restoring joint movement should be employed in an isometric manner in order to maintain adequate tension throughout the arc of motion. This study aimed to determine the isometric points for the iliotrochanteric suture in dogs during the joint extension and flexion movements. This evaluation was performed both in the intact hip joint and in the luxation model, establishing the best combination, among the determined points, for the reestablishment of normal joint movement.Materials, Methods & Results: Radiographic analyses of 12 canine cadaveric hips, both intact and in craniodorsal luxation model, were performed in a neutral position, flexion at 50°, and extension at 150°. In the trochanteric segment, two parallel lines were drawn, creating the central vertical axis and the secondary vertical axis. Three points were then determined on each axis, from proximal to distal, corresponding to 25, 50, and 75% of the height of the axis, and were labelled as T1, T2, and T3 and T4, T5, and T6, respectively. In the iliac segment, a line perpendicular to the longitudinal axis of the ilium was drawn, and 25, 50, and 75% of this height corresponded to points I1, I2, and I3, respectively. The lengths between the points were measured, with the objective of evaluating which combination of points presented less variation in the joint positions. The central location of the iliac and trochanteric segments, determined respectively by I2 and T2, provided smaller variations during the maximal movements of hip flexion and extension.Discussion: The surgical techniques of iliotrochanteric suture target to maintain the internal rotation of the femoral head inside the acetabulum and abduction of the femur until the soft tissues have healed. The described techniques for the iliotrochanteric suture present a great anatomical variety in the arrangement of the anchor points of the suture. It is known that if during motion, the attachment sites move closer to one another, the suture will become lax and, if the attachment sites move away from one another, the suture will tighten. Therefore, the implantation in isometric sites assists in reducing the variation of the distance between the points of origin and insertion of the suture during joint movement, keeping the suture tension constant and allowing the functional recovery of the joint. This study demonstrates that there are some locations for the origin and insertion of an iliotrochanteric suture that are associated with less length change than others. I2-T2 combination is the point closest to isometry for the iliotrochanteric suture during hip extension and flexion, so that, T2 is the most central point of the greater trochanter, corresponding to 50% of the height of its central vertical axis, as well as I2, which corresponds to the most central point of the ilium, representing 50% of the height of the most caudal portion of its body. The isometric point found by us details the exact location of perforation in all aspects (height and length), both in the ilium and the trochanter. In addition, it is a personalized point created for each patient from its radiographic examination and taking into consideration its anatomical variations, so that there is no damage to the suture during hip extension and flexion movements

Amostragem rápida da fauna de vespas sociais (Hymenoptera, Vespidae) em ecótono de Mata Atlântica e Cerrado, associado a área de mineração

There are few studies on the richness of social wasps in ecotones, particularly in mining regions. These transitional environments exhibit specific geophysical conditions, host species from both biomes, and can act as barriers to evolutionary processes and gene flow. In view of this, this study aimed to document the occurrence of social wasps by a rapid sampling method in a transition region between the Atlantic Forest and Cerrado in the vicinity of a mining area in Itatiaiuçu, Minas Gerais, Brazil. The sampling effort was 24 h, distributed over three field days in December 2022. A total of 18 species were sampled. One noteworthy record is that of Parachartergus smithii (de Saussure, 1854), a rare species in the state, previously documented in an ecotone region between the Caatinga and Cerrado. These findings demonstrate the importance of ecotone systems in supporting the diversity of social wasps.Existem poucos estudos sobre a riqueza de vespas sociais em ecótonos, principalmente em regiões associadas à mineração. Estes ambientes de transição possuem condições geofísicas específicas, compartilham espécies de ambos os biomas e podem atuar como barreiras em processos evolucionários e fluxos genéticos. Neste sentido, o objetivo deste estudo é registrar a ocorrência de vespas sociais, por amostragem rápida, em uma região de transição entre Floresta Estacional de Mata Atlântica e Cerrado, no entorno de uma área de mineração, no município de Itatiaiuçu, Minas Gerais. O esforço amostral foi de 24 horas, distribuídas em três dias de campo, no mês de dezembro de 2022. Foram amostradas 18 espécies com destaque para Parachartergus smithii (de Saussure, 1854), considerada rara no estado, e também registrada em região de ecótono (Caatinga e Cerrado), demonstrando a importância destes ecossistemas para a diversidade de vespas sociais