On the multi-scale analysis of land-surface mass and energy exchanges for the tropical Andean páramo of Southern Ecuador

Studies on the atmosphere-surface exchange processes over montane regions represent a growing field. This is particular on the scope of ecohydrological investigations, which assess the estimation and prediction of water, carbon and energy fluxes, among other functional key-indicators of the biomes. Therefore, the understanding of the complexity of energy-driven processes such as actual evapotranspiration (ETa) and carbon dioxide (CO2) exchange is fundamental, particularly for the biodiverse tropical highlands, which are exposed to human-induced treats (e.g., global warming and land cover change). Herein, the Andean páramo region of Ecuador (3200-5000 m a.s.l.) supports vital ecosystem services, such as water supply, carbon storage and biodiversity. This biome is crucially important for the sustainability of the inter-Andean valleys’ inhabitants, mainly due to its role as a massive water reservoir. Atmosphere-surface exchange processes in the páramo are largely unknown. The aim of this thesis is to analyze the water, energy and carbon flux transfer mechanisms in páramo catchments of Southern Ecuador, by a multi-scale approach, which considers point-scale (ecosystem) and spatial-scale (catchment), through ground-level (instrumental-based) and remote sensing level (model-based). This methodology allows to quantify the accuracy of each technique, and to identify the most appropriate method according to site characteristics. This work has contemplated: (i) The analysis of the spatial dynamics of ETa derived from satellite products (Landsat and MODIS) with a calibrated energy balance-based model (METRIC), and the evaluation with a global ETa product (MOD16) and with ETa obtained as water balance residual (WB); (ii) the detection and analysis of ground-level and ecosystem-scale ETa, energy and CO2 fluxes (through eddy covariance (EC) and micrometeorological methods), their interaction with environmental controls, and the comparison of EC ETa with widely applied reference ET models (ETr); and finally, (iii) the evaluation of simulated ETa and energy fluxes obtained from a state-of-art land-surface model (CLM) parameterized to the biophysical and climate conditions of two páramo catchments. The CLM outcomes evaluation was performed with METRIC ETa, energy fluxes observations (EC) and with WB-derived ETa. The findings of the first analysis reveal that spatial ETa can be successfully estimated when a proper calibration of the model parameters and a high resolution satellite product is used simultaneously. The ETa temporal dynamics from this approach showed consistent results with WB ETa. The results of the second part, demonstrate the plausibility of EC for gas and energy flux detection on this mountain ecosystem. The CO2 budget (at different time scales) reveals the ‒carbon source‒ behavior of the páramo, which constitutes an outstanding discovery in the knowledge about this region. Mathematical functions between carbon fluxes and biophysical controls (available light and soil temperature) are also reported. The quantification of water loss in the form of ETa, and its comparison with modeled ETr, allowed for the first time, to report truthful crop coefficients for the páramo grasslands. Finally, the third analysis revealed the plausibility of CLM for ETa prediction, in spite of a poor performance of the model for the simulation of specific energy fluxes (net radiation, sensible and soil heat). The evaluation between methods, also demonstrated that METRIC ETa values are closer to the EC ETa observations, and revealed that WB ETa rendered poorly. These analyses provide insights on the methods’ selection for future studies in similar locations. The current investigation provides solid answers to unsolved questions about the dynamics of the ETa, CO2 and energy fluxes of the páramo, and the multiscale approach adopted enhance our understanding of the ecohydrological processes of this unique Andean ecosystem

Actual Evapotranspiration in the High Andean Grasslands: A Comparison of Measurement and Estimation Methods

Actual evapotranspiration (ETa) explains the exchange of water and energy between soil, land surface, and atmosphere. Despite its importance, it remains difficult to measure directly. Grasslands represent a widespread ecosystem for which further assessment of the measurement and estimation of ETa is needed. Thus, the objective of this study was to compare measurements and estimations of ETa in a mountain grassland ecosystem made using different approaches. The study was conducted in the Zhurucay Ecohydrological Observatory, located in the high Andes of Ecuador between 3,500 and 3,900 m a.s.l. The study area is a representative site of the páramo ecosystem, in which the vegetation mainly consists of tussock grasslands. ETa was measured or estimated using the following methods: eddy-covariance (EC), volumetric lysimeters (Lys), water balance (WB), energy balance (EB), the calibrated Penman-Monteith equation (PMCal), and two hydrological models [the Probability Distribution Model (PDM) and the Hydrologiska Byråns Vattenbalansavdelning model (HBV-light)]. During 1 year, precipitation (P) accumulated to 1,094 mm while ETa (measured with EC) accumulated to 622 mm (with ETa/P = 0.57). On a daily basis, the EC method measured average ETa rates of 1.7 mm/day. The best daily estimates according to percentage bias (pbias), normalized root mean square error (nRMSE), Pearson's correlation coefficient (r) and the volumetric coefficient (ve) came from the HBV-light model, followed by the PMCal and the PDM (pbias: −2 to −20%, nRMSE: 12–15%, r: 0.7–0.9, and ve: 0.7–0.8). On the other hand, the WB, EB, and Lys estimates showed a poor performance (pbias: −10 to −19%, nRMSE: 25–93%, r: −0.4 to 0.5, and ve: −0.5 to 0.7). As the methods used in this study are of different types (hydrological, micrometeorological, and analytical), their suitability and applications are discussed in terms of their costs, temporal resolution, and accuracy. This study identifies low-cost and easy-to-implement alternatives to EC measurements, such as hydrological models and the calibrated Penman-Monteith equation. This study also allows us to provide an increment of progress on the accurate closure of the water balance in grasslands

INTERACCIONES ENTRE ÍNDICE DE ÁREA FOLIAR, DENSIDAD DEL DOSEL Y PRECIPITACIÓN EFECTIVA DE UN BOSQUE DE POLYLEPIS RETICULATA UBICADO EN UN ECOSISTEMA DE PÁRAMO

La medición de la cobertura vegetal es fundamental para conocer qué porcentaje de la precipitación queda interceptada sobre la misma. Las técnicas más utilizadas para medir la cobertura in situ son el índice de área foliar (IAF) y la densidad del dosel (DD). Sin embargo, no se ha puesto atención en las diferencias registradas en el uso de las dos técnicas ni cómo estas variables influyen sobre el balance hidrológico particularmente sobre la precipitación efectiva (PE). Por tal motivo, el objetivo del estudio es evaluar la relación entre las mediciones de la cobertura vegetal realizadas por los métodos de IAF y DD e identificar cómo se relacionan con la PE, importante para aplicaciones hidrológicas. El estudio se desarrolló en un bosque de Polylepis reticulata de 15633 m2, ubicado en el Observatorio Ecohidrológico Zhurucay, sur de Ecuador, en un rango altitudinal de 3765 a 3809 m s.n.m. El IAF se midió con el equipo CI-110 Plant Canopy Imager y la DD con un densiómetro esférico, cubriendo un amplio rango de valores de cobertura de dosel. Para medir la PE se instrumentó el sitio de estudio con 9 pluviógrafos. Los resultados indican que el IAF y DD son en promedio 2,43 m2 m2 y 88%, respectivamente; cuya relación resulta ser significativa (R2 = 0,913; p< 0,05). La PE media anual es de 773,2 mm, que tiende a disminuir con el incremento del IAF y DD; aunque su relación resulta estadísticamente no significativa (valores p> 0,05). Este estudio muestra la importancia de caracterizar la cobertura vegetal para entender la interacción con la PE.//The measurement of vegetation cover is fundamental to quantify the precipitation percentage intercepted by it. The most widely techniques used to measure the cover in situ are the leaf area index (LAI) and the canopy density (CD). However, no attention has been paid to the differences recorded in the use of the two techniques or how these variables influence the hydrological balance on the throughfall (TF). For this reason, the objective of the study is to evaluate the relationship between vegetation cover measurements conducted by the LAI and CD methods and to identify how they relate with the TF, important for hydrological applications. The study was developed in a Polylepis reticulata forest of 15633 m2, located at the Zhurucay Ecohydrological Observatory, south of Ecuador, in an altitudinal range of 3765 to 3809 m.a.s.l. The LAI was measured with the CI-110 Plant Canopy Imager equipment and CD with a spherical densiometer, covering a wide range of canopy cover values. The study site was instrumented with 9 tipping-bucket rain gauges to measure TF. The results indicate that LAI and CD averages are 2.43 m2 m2 y 88% respectively; whose relationship is significant (R2 = 0.913; p< 0.05). Mean annual TF is 773.2 mm, which tends to decrease with the increase of the LAI and CD; although, their relationship is not statistically significant (p-value> 0.05). This study shows the importance of characterizing the vegetation cover to understand the interaction with TF

Dynamic Mapping of Evapotranspiration Using an Energy Balance-Based Model over an Andean Páramo Catchment of Southern Ecuador

Understanding of evapotranspiration (ET) processes over Andean mountain environments is crucial, particularly due to the importance of these regions to deliver water-related ecosystem services. In this context, the detection of spatio-temporal changes in ET remains poorly investigated for specific Andean ecosystems, like the páramo. To overcome this lack of knowledge, we implemented the energy-balance model METRIC with Landsat 7 ETM+ and MODIS-Terra imagery for a páramo catchment. The implementation contemplated adjustments for complex terrain in order to obtain daily, monthly and annual ET maps (between 2013 and 2014). In addition, we compared our results to the global ET product MOD16. Finally, a rigorous validation of the outputs was conducted with residual ET from the water balance. ET retrievals from METRIC (Landsat-based) showed good agreement with the validation-related ET at monthly and annual steps (mean bias error &lt;8 mm·month−1 and annual deviation &lt;17%). However, METRIC (MODIS-based) outputs and the MOD16 product were revealed to be unsuitable for our study due to the low spatial resolution. At last, the plausibility of METRIC to obtain spatial ET retrievals using higher resolution satellite data is demonstrated, which constitutes the first contribution to the understanding of spatially-explicit ET over an alpine catchment in the neo-tropical Andes

Programa de eficiencia energética térmica y eléctrica en una fábrica panificadora, estudio de caso: fábrica Panesa

El estudio de tesis de la empresa PANESA S.A. de Cuenca, se realizó entre abril 2007 febrero 2008. Abarca el panorama energético de consumo térmico y eléctrico de la empresa, así como los niveles de material particulado e iluminación. El análisis energético térmico demuestra que la fábrica posee un potencial de ahorro de combustible del 20por cambio de tecnología de quemadores de los hornos y que puede ser mejorado con la corrección de pérdidas de calor por los aislamientos de las paredes de los hornos. En el análisis energético eléctrico se ha encontrado algunas fallas en la forma de consumo, por la presencia de picos significativos que afectan el factor de potencia, se recomiendan mejoras y cambios del sistema de iluminación para obtener ahorros de energía eléctrica. Se ha analizado también la incidencia de contaminación por material particulado (hollín de combustión de los hornos) en las áreas de trabajo, encontrándose algunas áreas de la planta que sobrepasan los valores limites normativos, se hacen las respectivas recomendaciones. Se ha analizado también el aspecto de niveles de iluminación en la planta y el aprovechamiento de la luz natural para generar ahorros de energía eléctrica y mejora en las condiciones laboralesMagister en Gestión AmbientalCuenc

Eficiencia energética eléctrica para la industria de alimentos: guía práctica

La energía, al igual que los materiales usados en los procesos de transformación, es un recurso controlable, por lo tanto, al usarse de manera eficiente contribuye a mejorar la rentabilidad de las actividades al reducir sus costos. Usar la energía eficientemente significa consumir menos energía para los mismos beneficios en términos de cantidad y calidad. En el ámbito industrial significará mantener los niveles de producción y calidad del producto con una menor facturación energética. La Eficiencia Energética, EE, ha mostrado ser a lo largo de los años, una de las mejores alternativas con las que puede contar los administradores y técnicos en su afán de reducir los costos de producción, incrementar la competitividad de los productos o servicios y reducir el impacto ambiental: reducción de emisiones y del daño ambiental; es decir, reducir el vínculo entre crecimiento económico y consumo de energía con la consecuente degradación ambiental. Por otro lado, la EE está al alcance de todas las organizaciones sin importar su tamaño u orientación.Cuenc

Estudio reológico, microbiológico y cinético en la elaboración de cremogenado de tomate de árbol

El estudio de las pulpas y cremogenados de frutas en la actualidad requiere la investigación de sus características en base a las nuevas técnicas de análisis que sugieren las ciencias de reología de alimentos, microbiología y cenética química. Este trabajo ha encontrado en los métodos analíticos aplicados, las respuestas a las inquietudes en las ciencias de reología que difieren la consistencia del producto y caracterización organoléptica, así como la estabilidad del cremogenado en conservación variada y los modelos cinéticos en su deterioro, para conocer si este cremogenado de tomate de árbol es una opción de producción industrialIngeniero QuímicoCuenc

DYNA

El estudio exploratorio muestra los resultados de aplicación de programas de eficiencia energética eléctrica en 7 empresas alimentarias en Cuenca, Ecuador. La investigación contempló fases de diagnóstico, intervención y evaluación. Se condujo un análisis comparativo entre las empresas: consumo de energía versus producción, análisis de calidad de energía, relación cumplimiento/consumo específico de energía, e impacto sobre emisiones CO2. Los resultados revelaron que la aceptación hacia las recomendaciones de ahorro, se basa en el nivel de inversión y la voluntad/disponibilidad administrativa. El estudio mostró que las intervenciones tuvieron un efecto parcial sobre la reducción del consumo específico de energía en 4 empresas. Adicionalmente se obtuvo un efecto positivo en la corrección de factor de potencia en una empresa y en la mejora del balance de corriente en 5. La investigación mostró la existencia de una reducción significativa de emisiones post-intervención, resaltando la efectividad de los programas.This exploratory study illustrates the effects of the application of electrical energy efficiency programs in 7 food processing companies in Cuenca, Ecuador. The research encompassed phases of diagnosis, intervention and evaluation. A comparative analysis between the companies was conducted: energy consumption versus product volume, energy-quality analysis, relation between compliance/specific energy consumption, and the impact on CO2 emissions. Results revealed that the acceptance to the recommendations of savings is biased by the level of investments and the willing/proneness of the administration. The study showed that interventions had a partial effect on the reduction of the specific energy consumption in 4 companies. In addition, it has obtained a positive effect on the power factor correction in one company and an improvement on the load balance in 5. The research showed the existence of a significant reduction of emissions post-intervention, highlighting the effectiveness of the programs.volumen 81; número 18

Interações entre índice de área foliar, densidade do dossel e precipitação efetiva de uma floresta de Polylepis reticulata localizada em um ecossistema de páramo

La medición de la cobertura vegetal es fundamental para conocer qué porcentaje de la precipitación queda interceptada sobre la misma. Las técnicas más utilizadas para medir la cobertura in situ son el índice de área foliar (IAF) y la densidad del dosel (DD). Sin embargo, no se ha puesto atención en las diferencias registradas en el uso de las dos técnicas ni cómo estas variables influyen sobre el balance hidrológico particularmente sobre la precipitación efectiva (PE). Por tal motivo, el objetivo del estudio es evaluar la relación entre las mediciones de la cobertura vegetal realizadas por los métodos de IAF y DD e identificar cómo se relacionan con la PE, importante para aplicaciones hidrológicas. El estudio se desarrolló en un bosque de Polylepis reticulata de 15633 m2, ubicado en el Observatorio Ecohidrológico Zhurucay, sur de Ecuador, en un rango altitudinal de 3765 a 3809 m s.n.m. El IAF se midió con el equipo CI-110 Plant Canopy Imager y la DD con un densiómetro esférico, cubriendo un amplio rango de valores de cobertura de dosel. Para medir la PE se instrumentó el sitio de estudio con 9 pluviógrafos. Los resultados indican que el IAF y DD son en promedio 2,43 m2 m-2 y 88%, respectivamente; cuya relación resulta ser significativa (R2= 0,913; p&lt;0,05). La PE media anual es de 773,2 mm, que tiende a disminuir con el incremento del IAF y DD; aunque su relación resulta estadísticamente no significativa (valores p&gt;0,05). Este estudio muestra la importancia de caracterizar la cobertura vegetal para entender la interacción con la PE.The measurement of vegetation cover is fundamental to quantify the precipitation percentage intercepted by it. The most widely techniques used to measure the cover in situ are the leaf area index (LAI) and the canopy density (CD). However, no attention has been paid to the differences recorded in the use of the two techniques or how these variables influence the hydrological balance on the throughfall (TF). For this reason, the objective of the study is to evaluate the relationship between vegetation cover measurements conducted by the LAI and CD methods and to identify how they relate with the TF, important for hydrological applications. The study was developed in a Polylepis reticulata forest of 15633 m2, located at the Zhurucay Ecohydrological Observatory, south of Ecuador, in an altitudinal range of 3765 to 3809 m.a.s.l. The LAI was measured with the CI-110 Plant Canopy Imager equipment and CD with a spherical densiometer, covering a wide range of canopy cover values. The study site was instrumented with 9 tipping-bucket rain gauges to measure TF. The results indicate that LAI and CD averages are 2.43 m2 m-2 y 88% respectively; whose relationship is significant (R2= 0.913; p&lt;0.05). Mean annual TF is 773.2 mm, which tends to decrease with the increase of the LAI and CD; although, their relationship is not statistically significant (p-value&gt;0.05). This study shows the importance of characterizing the vegetation cover to understand the interaction with TF.A medição da cobertura vegetal é fundamental para saber qual a porcentagem da precipitação é interceptada sobre a mesma. As técnicas mais utilizadas para medir a cobertura in situ são o índice de área foliar (IAF) e a densidade do dossel (DD). No entanto, nenhuma atenção tem sido dada às diferenças registradas no uso das duas técnicas ou como essas variáveis ??influenciam o balanço hidrológico, particularmente a precipitação efetiva (EP). Por esse motivo, o objetivo do estudo é avaliar a relação entre as medições da cobertura vegetal feitas pelos métodos IAF e DD e identificar como elas se relacionam com a PE, importante para aplicações hidrológicas. O estudo foi realizado em uma floresta de Polylepis reticulata de 15.633 m2, localizada no Observatório Ecohidrológico Zhurucay, sul do Equador, na faixa altitudinal de 3765 a 3809 m. a.s.l. O IAF foi medido com o equipamento CI-110 Plant Canopy Imager e o DD com densiômetro esférico, cobrindo uma ampla gama de valores de cobertura de dossel. Para medir o PE, o local do estudo foi equipado com 9 pluviômetros. Os resultados indicam que o IAF e o DD são em média 2,43 m2 m-2 e 88%, respectivamente, cuja relação acaba sendo significativa (R2 = 0,913; p &lt;0,05). O PE médio anual é de 773,2 mm, que tende a diminuir com o aumento do IAF e DD; embora sua relação não seja estatisticamente significativa (valores de p&gt; 0,05). Este estudo mostra a importância da caracterização da cobertura vegetal para o entendimento da interação com o PE

Estimating turbulent fluxes in the tropical andes

The correct estimation of Sensible Heat Flux (H) and Latent Heat Flux (LE) (i.e., turbulent fluxes) is vital in the understanding of exchange of energy and mass among hydrosphere, atmosphere, and biosphere in an ecosystem. One of the most popular methods to measure these fluxes is the Eddy Covariance (EC) technique; however, there are a number of setbacks to its application, especially in remote and topographically complex terrain such as the higher altitudes of the Andes. Efforts have been made by the scientific community to parameterise these fluxes based on other more commonly measured variables. One of the most widespread methods is the so-called bulk method, which relates average temperature, humidity, and wind vertical profiles to the turbulent fluxes. Another approach to estimate LE is the Penman-Monteith (PM) equation which uses meteorological measurements at a single level. The objective of this study was to validate these methods for the first time in the Tropical Andes in Southern Ecuador (in the paramo ecosystem at 3780 m a.s.l.) using EC and meteorological measurements. It was determined that the bulk method was the best to estimate H, although some adjustments had to be made to the typical assumptions used to estimate surface meteorological values. On the other hand, the PM equation yielded the best LE estimations. For both fluxes, the error in the estimations was within the uncertainty range of the EC measurements. It can be concluded that it is possible to accurately estimate H and LE using the methods described in this paper in this ecosystem when no direct measurements are available.</p