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Rangelands face threats from climate and land-use change, including inappropriate climate change mitigation initiatives such as tree planting in grassy ecosystems. The marginalization and impoverishment of rangeland communities and their indigenous knowledge systems, and the loss of biodiversity and ecosystem services, are additional major challenges. To address these issues, we propose the wilder rangelands integrated framework, co-developed by South African and European scientists from diverse disciplines, as an opportunity to address the climate, livelihood, and biodiversity challenges in the world’s rangelands. More specifically, we present a Theory of Change to guide the design, monitoring, and evaluation of wilder rangelands. Through this, we aim to promote rangeland restoration, where local communities collaborate with regional and international actors to co-create new rangeland use models that simultaneously mitigate the impacts of climate change, restore biodiversity, and improve both ecosystem functioning and livelihoods.

The world's forests store large amounts of carbon (C), and growing forests can reduce atmospheric CO2 by storing C in their biomass. This has provided the impetus for world-wide tree planting initiatives to offset fossil-fuel emissions. However, forests interact with their environment in complex and multifaceted ways that must be considered for a balanced assessment of the value of planting trees. First, one needs to consider the potential reversibility of C sequestration in trees through either harvesting or tree death from natural factors. If carbon storage is only temporary, future temperatures will actually be higher than without tree plantings, but cumulative warming will be reduced, contributing both positively and negatively to future climate-change impacts. Alternatively, forests could be used for bioenergy or wood products to replace fossil-fuel use which would obviate the need to consider the possible reversibility of any benefits. Forests also affect the Earth's energy balance through either absorbing or reflecting incoming solar radiation. As forests generally absorb more incoming radiation than bare ground or grasslands, this constitutes an important warming effect that substantially reduces the benefit of C storage, especially in snow-covered regions. Forests also affect other local ecosystem services, such as conserving biodiversity, modifying water and nutrient cycles, and preventing erosion that could be either beneficial or harmful depending on specific circumstances. Considering all these factors, tree plantings may be beneficial or detrimental for mitigating climate-change impacts, but the range of possibilities makes generalisations difficult. Their net benefit depends on many factors that differ between specific circumstances. One can, therefore, neither uncritically endorse tree planting everywhere, nor condemn it as counter-productive. Our aim is to provide key information to enable appropriate assessments to be made under specific circumstan, QC 20231204

Agrivoltaic system combines solar energy and agriculture which is an effective way to utilize the lands full potential. Crops can be grown between vertical panels or under tilted panels among other designs. Combining solar panels and agriculture leads to optimization of space. This degree project evaluates a comparison of several parameters measured both in a vertical agrivoltaic system and a reference control plot located in Kärrbo Prästgård, Västerås, Sweden. Specifically, the correlation between the ground albedo and normalized difference vegetation index (NDVI) under the two treatments are investigated. Correlations between the albedo and the NDVI against different weather parameters are also explored. Linear regression models are developed separately for the albedo and NDVI with the most correlated parameters. In addition, because the albedo in the reference is not the same as the albedo in the agrivoltaic system, a linear regression model linking the albedo of the agrivoltaic system, and the albedo of the reference system is further developed. With this latter model, power production from the vertical agrivoltaic system is simulated under different albedo considerations: using measured albedo from the agrivoltaic system, using predicted albedo from the linear regression model, and using measured albedo from the reference system. These power estimations are then compared to the real power production from the agrivoltaic system. The study employs MATLAB for data analysis, models development and power production simulations. The study compared the correlation between ground albedo and NDVI in an agrivoltaic system and a control plot. The albedo model revealed that the reference system could explain 87% of the albedo variance in the agrivoltaic system, but the NDVI model showed that the reference system could only account for 39.6% of the variation in the agrivoltaic system. Furthermore, for the power production comparison, using the actual measured albedo in th

Agrivoltaics, also referred as agrivoltaic systems, present an appealing solution, owing to its dual land use and integrated food-energy system, for the shift to renewable energy. However, it raises concerns about the complex synergies and trade-offs between crop growth and solar photovoltaic panels. Crops grown under open-field traditional agriculture receive uniformly distributed Sun irradiance, whereas agrivoltaics introduces variable shadowing, which interferes with the homogeneity of light collected by crops. Agrivoltaics emphasises the significance of the diffuse irradiance component during shading conditions when direct irradiance is blocked by solar panels. Decomposition models are essential for estimating the diffuse light component from the global one. This thesis conducts a benchmarking investigation of state-of-the-art solar irradiance decomposition models to identify the most suitable ones for decomposing photosynthetically active radiation in specific Swedish sites. The results lead to a novel separation model that outperforms the top models revealed in the benchmarking analysis. Various scenarios common in agrivoltaic sites are used to test the applicability of the model and guide model selection based on available data. In agrivoltaic systems, where solar panels disrupt incoming sunlight to crops, the crop reflectivity or albedo influences solar panels, particularly those with bifacial solar cells. This thesis further investigates how ground-reflected irradiance components affect the front and rear sides of bifacial system designs under varied ground albedo circumstances. Using Agri-OptiCE®, this research examines how albedo data quality affects bifacial systems. The findings contribute to improve the precision of plane-of-array irradiance and power output estimations, hence aiding the practical implementation of agrivoltaic systems across the globe.

Earth's Northern and Southern Hemispheres (NH and SH, respectively) have significantly different properties: the NH has a higher concentration of bright land surface area and aerosol emissions than the SH, making the Earth's clear-sky albedo hemispherically asymmetric. However, satellite observations have shown that higher cloud amount and reflectivity in the SH exactly compensate for this, making Earth's planetary albedo hemispherically symmetric. A physical explanation for this symmetry has not yet been found, but because it would give constraints for global cloud cover and its features, discovery of one may be a powerful tool in predicting the behavior of clouds in a changing climate. The first chapter of this thesis investigates the hemispheric albedo symmetry in observations, and finds that its variability primarily stems from the tropics. General circulation models (GCMs) exhibit a large spread in albedo asymmetry biases; comparing these with observations reveals that the extratropics control mean-state modeled albedo asymmetry. The second chapter compares the evolution of albedo asymmetries in GCMs when forced with increased CO2 concentrations. Models agree on an initial asymmetry response due to Arctic warming and albedo reductions, but diverge thereafter, with some models recovering their pre-industrial asymmetry. Those that recover their asymmetry do so via SH extratropical cloud loss and thus have stronger positive cloud feedbacks, illustrating that an albedo symmetry-maintaining mechanism could have implications for climate sensitivity. Sources of modeled albedo asymmetry biases are investigated in a single atmospheric GCM using a perturbed parameter ensemble in the third chapter. The most significant parameters to simulated albedo asymmetry are those controlling warm rain formation, turbulent dissipation, and sea salt aerosol emissions. Parameters controlling warm rain formation and turbulent dissipation primarily affect extratropical low cloud cover, a

The aim of this work is to provide a full description of how air temperature and solar radiation induce changes in the land cover over an Antarctic site. We use shortwave broadband albedo (albedo integrated in the range 300–3000 nm) from a spaceborne sensor and from field surveys to calculate the monthly relative abundance of landscape units. Field albedo data were collected in January 2019 using a portable albedometer over seven landscape units: clean fresh snow; clean old snow; rugged landscape composed of dirty snow with disperse pyroclasts and rocky outcrops; dirty snow; stripes of bare soil and snow; shallow snow with small bare soil patches; and bare soil. The MODIS MCD43A3 daily albedo products were downloaded using the Google Earth Engine API from the 2000–2001 season to the 2020–2021 season. Each landscape unit was characterized by an albedo normal distribution. The monthly relative abundances of the landscape units were calculated by fitting a linear combination of the normal distributions to a histogram of the MODIS monthly mean albedo. The monthly relative abundance of the landscape unit consisting of rugged landscape composed of dirty snow with dispersed clasts and small rocky outcrops exhibits a high positive linear correlation with the monthly mean albedo (R2 = 0.87) and a high negative linear correlation with the monthly mean air temperature (R2 = 0.69). The increase in the solar radiation energy flux from September to December coincides with the decrease in the relative abundance of the landscape unit composed of dirty snow with dispersed clasts and small rocky outcrops. We propose a mechanism to describe the evolution of the landscape: uncovered pyroclasts act as melting centers favoring the melting of surrounding snow. Ash does not play a decisive role in the melting of the snow. The results also explain the observed decrease in the thaw depth of the permafrost on the island in the period 2006–2014, resulting from an incre

La tesis doctoral presenta un avance innovador en el análisis de entornos urbanos, profundizando en elementos fundamentales que regulan sus cambios y procesos. Se centra en los desafíos del análisis urbano de zonas extensas y complejas y del estudio a medida en escalas locales, con la implementación de conjuntos de datos de múltiples fuentes (datos abiertos y teledetección) para identificar áreas de interés para su intervención de forma remota. Este enfoque integra características biofísicas existentes del entorno construido, la vegetación (prestando atención a la escala espacio-temporal y su impacto en servicios ecosistémicos), el albedo de banda ancha, y la temperatura superficial del suelo (LST). El desarrollo de la tesis se estructura en cuatro secciones, que comienzan con una revisión exhaustiva de los métodos de evaluación urbana en remoto, seguida por la caracterización detallada de la vegetación. Posteriormente, se propone un marco de clasificación de las características biofísicas, se diagnostica el entorno urbano según el comportamiento de las características existentes y, finalmente, se definen patrones morfológicos. Las secciones concluyen con el diseño de un método para caracterizar áreas de interés y su aplicación en los procesos de toma de decisiones. El diseño del método se fundamenta en la extracción de características y cálculo de variables biofísicas a distancia, fusionando datos del Catastro (una base de datos de edificaciones en España), imágenes satelitales de alta y muy alta resolución, y datos infrarrojos térmicos (TIR). Para validar el método, se lleva a cabo en un caso de estudio que cumple con criterios establecidos previamente en la metodología, ubicado en el barrio de Canillas, Madrid, España. Los desarrollados en la tesis priorizan la integración de componentes biofísicos urbanos en su estado actual, con detalles intrincados y escalas espacio-temporales esenciales para la planificación urbana. Los resultados abordan los desafíos en los, The PhD thesis represents an innovative advance in the analysis of urban environments, delving into fundamental elements that drive their changes and processes. It focuses on the challenges of urban analysis of extensive and complex areas and tailored studies at local scales, using multisouce datasets (open data and remote sensing) to remotly identify areas of interest for intervention. This approach integrates existing biophysical characteristics of the built environment, vegetation (with attention to the spatio-temporal scale and its impact on ecosystem services), broadband albedo, and land surface temperature (LST). The thesis is structured in four sections, starting with an exhaustive review of remote urban assessment methods, followed by a detailed characterisation of vegetation. Subsequently, a classifi cation framework for biophysical features is proposed, the urban context in diagnosed according to the behaviour of the existing features and, fi nally, morphological patterns are defi ned. The sections conclude with the design of a method to characterise areas of interest to be applied in decision-making processes. The design of the method relies on the retrieval of the characteristics and calculation of biophysical variables by fusing data from the Cadastre (a database of buildings in Spain), high and very-high-resolution satellite images, and thermal infrared (TIR) data. To validate the method, it is conducted in a case study that meets the criteria previously established in the methodology, located in the neighbourhood of Canillas, Madrid, Spain. The processes carried out in the thesis prioritise the integration of urban biophysical components in their current state, with intricate details and spatiotemporal scales essential for urban planning. The results address challenges in current urban analyses and have been disseminated through papers published in scientifi c journals, books, congresses and international conferences proceedings, recognised for their

Uppsalas miljö innefattar stora områden med asfalterade ytor som parkeringar, bilvägar, cykelvägar och gångvägar. Asfalt innehar ett lågt albedo och absorberar en stor mängd av den inkommande kortvågiga strålningen. Den absorberade strålningen lagras som värmeenergi och alstras sedan till kringliggande miljö vilket ökar temperaturen. Albedo blir således viktigt i planering av mikroklimat i relation till de stigande temperaturerna orsakade av klimatförändringar och hur det kan komma att påverka lokala områden. Syftet med studien var undersöka vilken effekt en vitfärgad asfaltsyta hade på albedo och den mängden solenergi som ytan absorberade.Resultatet av studien visade att medelvärdet för albedo ökade när ytan vitbehandlades, från 0,13 till 0,22. Studien utfördes i södra Fyrislund i Uppsala vilket är ett område med stor mängd asfalterade ytor. Den totala arealen för studiens kartlagda asfalterade ytor uppgick till 490 000 kvadratmeter. Skulle samtliga större asfalterade ytor i södra Fyrislund ytbehandlas på samma sätt som studieområdet hade det inneburit en reducering av absorberande solenergi på 11,5% för hela området. Således indikerar resultatet på att den reducerade absorptionsmängd solenergi skulle kunna påverka asfaltens yttemperatur. Albedomodifiering kan därför ses som ett bra komplement till andra klimatlösningar då det har en positiv inverkan på lokalsamhället och folkhälsan.

We propose a simple method for the determination of the mass absorption coefficient (MAC) of light-absorbing impurities in snow. It is based on the spectral albedo/reflectance measurements in combination with standard gravimetry techniques for the measurements of the impurity mass concentration in snow. The technique has been applied for the estimation of the dust MAC in snow close to the mining facilities in Kiruna (Sweden).

Terrestrial ecosystems affect climate by reflecting solar irradiation, evaporative cooling, and carbon sequestration. Yet very little is known about how plant traits affect climate regulation processes (CRPs) in different habitat types. Here, we used linear and random forest models to relate the community-weighted mean and variance values of 19 plant traits (summarized into eight trait axes) to the climate-adjusted proportion of reflected solar irradiation, evapotranspiration, and net primary productivity across 36,630 grid cells at the European extent, classified into 10 types of forest, shrubland, and grassland habitats. We found that these trait axes were more tightly linked to log evapotranspiration (with an average of 6.2% explained variation) and the proportion of reflected solar irradiation (6.1%) than to net primary productivity (4.9%). The highest variation in CRPs was explained in forest and temperate shrubland habitats. Yet, the strength and direction of these relationships were strongly habitat-dependent. We conclude that any spatial upscaling of the effects of plant communities on CRPs must consider the relative contribution of different habitat types.

Differences between seven authentic samples of Citrus sinensis var. Valencia peel (albedo and flavedo) and juices from Spain and Uruguay, in addition to a concentrate obtained from Brazil, were investigated by untargeted metabolic profiling. Sixty-six metabolites were detected by nano-liquid chromatography coupled to a high-resolution electrospray-ionization quadrupole time-of-flight mass spectrometer (nLC-ESI-qTOF-MS) belonging to phenolic acids, coumarins, flavonoid glycosides, limonoids, terpenes, and fatty acids. Eleven metabolites were detected for the first time in Citrus sinensis and identified as citroside A, sinapic acid pentoside, apigenin-C-hexosyl-O-pentoside, chrysoeriol-C-hexoside, di-hexosyl-diosmetin, perilloside A, gingerol, ionone epoxide hydroxy-sphingenine, xanthomicrol, and coumaryl alcohol-O-hexoside. Some flavonoids were completely absent from the juice, while present most prominently in the Citrus peel, conveying more industrial and economic prospects to the latter. Multivariate data analyses clarified that the differences among orange parts overweighed the geographical source. PCA analysis of ESI-(−)-mode data revealed for hydroxylinoleic acid abundance in flavedo peel from Uruguay the most distant cluster from all others. The PCA analysis of ESI-(+)-mode data provided a clear segregation of the different Citrus sinensis parts primarily due to the large diversity of flavonoids and coumarins among the studied samples.

Markmonterade solcellsanläggningar i norra Sverige behöver ta hänsyn till förekomsten av snö och risken för markinterferens, vilket innebär att snömängden i framkant av panelerna gör att den snö som ackumuleras ovanpå inte kan glida av. Följden blir skuggning av panelerna som därmed får nedsatt eller helt utebliven elproduktion. Syftet med arbetet var att besvara frågeställningar kring vilken montagehöjd som krävs för att undvika problemet samt om den ökade engångskostnaden kompenseras av potentialen till ökad produktion under vintermånaderna. Metoden bestod främst av att jämföra produktionsdata från en solpark i Östersund med värden för solinstrålning och snödjup från SMHI för att avgöra vilken effekt snöskuggning haft på produktionen och hur utfallet skulle ha sett ut vid olika monteringshöjder av anläggningen. Resultaten visar att det finns stor potential till goda produktionsvärden under vårvintern, förutsatt att markinterferens inte finns närvarande. Anledningen beror troligtvis på högt albedo från snötäckt mark och lägre lufttemperaturer vilket har en positiv inverkan på modulernas verkningsgrad. En beräkningsmodell utvecklades för att uppskatta en lämplig monteringshöjd för en solpark utifrån dess tänkta utformning och det förväntade snödjupet på platsen. Förhoppningen är att modellen kan bidra till ökad kunskap för att främja utbyggnad av markmonterade solcellsanläggningar även på nordliga breddgrader. Lönsamheten för ett högre montage undersöktes genom en jämförelse mellan ett prisexempel från en uppförd solpark och ett uppskattat produktionsbortfall från solparken i Östersund vid en teoretiskt lägre monteringshöjd. Det visade att en höjning av Östersundsparken från 50 till 90 centimeter skulle betala av sig enbart genom tillskottet i produktion under perioden februari till april de tre första vintrarna., Ground-mounted PV installations in northern Sweden need to consider the presence of snow and the risk of ground interference, meaning that the buildup of snow in front of the panels prevents the snow accumulated on top from sliding off. The result is shading of the panels, which in turn reduces or eliminates the electricity production. The purpose of this work was to answer questions regarding the mounting height required to avoid this problem and whether the increased one-time cost for higher mounting is compensated for by the enhanced production during winter months. The method consisted mainly of comparing production data from a solar park in Östersund to solar radiation values and snow depth from SMHI to determine the effect of snow shading on production and the outcome at different installation heights of the plant. The results showed that there is great potential for valuable energy production during the late winter season, provided that ground interference is not present. This is probably due to high albedo from snow-covered ground and lower air temperatures resulting in a positive impact on the efficiency of the modules. A computational model was developed to estimate a suitable mounting height for a solar park based on the intended design and expected snow depth at the site. The intention is that the model can contribute to increased knowledge to promote the deployment of ground-mounted PV systems in northern latitudes. The profitability of higher mounting was investigated by comparing a price example from an existing solar facility and an estimated production loss from the solar park in Östersund at a theoretical lower mounting height. It showed that increasing the height of the Östersund site from 50 to 90 centimeters in front would pay off solely on the enhanced production during the period February to April of the first three winters.

The Northern and Southern Hemispheres reflect on average almost equal amounts of sunlight due to compensating hemispheric asymmetries in clear-sky and cloud albedo. Recent work indicates that the cloud albedo asymmetry is largely due to clouds in extratropical oceanic regions. Here, we investigate the proximate causes of this extratropical cloud albedo asymmetry using a cloud-controlling factor (CCF) approach. We develop a simple index that measures the skill of CCFs, either individually or in combination, in predicting the asymmetry. The index captures the contribution to the asymmetry due to interhemispheric differences in the probability distribution function of daily CCF values. Cloud albedo is quantified using daily MODIS satellite retrievals, and is related to range of CCFs derived from the ERA5 product. We find that sea surface temperature is the CCF that individually explains the largest fraction of the asymmetry, followed by surface wind. The asymmetry is predominantly due to low clouds, and our results are consistent with prior local-scale modeling work showing that marine boundary layer clouds become thicker and more extensive as surface wind increases and surface temperature cools. The asymmetry is consistent with large-scale control of storm-track intensity and surface winds by meridional temperature gradients: persistently cold and windy conditions in the Southern Hemisphere keep cloud albedo high year-round. Our results have important implications for global-scale cloud feedbacks and contribute to efforts to develop a theory for planetary albedo and its symmetry.

Introduction: Citrus fruits are one of the most frequently counterfeited processed products in the world. In the juice production alone, the peels, divided into flavedo and albedo, are the main waste product. The extracts of this by-product are enriched with many bioactive substances. Newer extraction techniques generally have milder extraction conditions with simultaneous improvement of the extraction process. Methods: This study presents a combinatorial approach utilizing data-independent acquisition-based ion mobility spectrometry coupled to tandem mass spectrometry. Integrating orthogonal collision cross section (CCS) data matching simultaneously improves the confidence in metabolite identification in flavedo and albedo tissues from Citrus sinensis. Furthermore, four different extraction approaches [conventional, ultrasonic, High Hydrostatic Pressure (HHP) and Pulsed Electric Field (PEF)] with various optimized processing conditions were compared in terms of antioxidant effects and flavonoid profile particularly polymethoxy flavones (PMFs). Results: A total number of 57 metabolites were identified, 15 of which were present in both flavedo and albedo, forming a good qualitative overlapping of distributed flavonoids. For flavedo samples, the antioxidant activity was higher for PEF and HHP treated samples compared to other extraction methods. However, ethyl acetate extract exhibited the highest antioxidant effects in albedo samples attributed to different qualitative composition content rather than various quantities of same metabolites. The optimum processing conditions for albedo extraction using HHP and PEF were 200 MPa and 15 kJ/kg at 10 kV, respectively. While, HHP at medium pressure (400 MPa) and PEF at 15 kJ/kg/3 kV were the optimum conditions for flavedo extraction. Conclusion: Chemometric analysis of the dataset indicated that orange flavedo can be a valid source of soluble phenolic compounds especially PMFs. In order to achieve cross-application of produc

In the context of urban microclimates, thermal comfort serves as the key indicator to describe people's subjective impression of temperature in open spaces. It gives a general review of how the sun, wind, air temperature, and humidity affect the ability to perceive heat. But nowadays human thermal comfort is being compromised due to the urban heat island effect. The phenomenon known as the urban heat island (UHI) occurs when the temperature in metropolitan regions is higher than in the nearby rural areas. Urban heat islands are a source of growing concern since they can have an impact on communities by worsening air pollution and greenhouse gas emissions (due to increased air conditioner use), increasing the likelihood of heat-related disease, and possibly even raising mortality rates. For this purpose, evaluating the human thermal comfort level would be a significant step in adapting feasible solutions to reduce the adverse effect of the urban heat island. The goal of this study is to simulate the microclimate using the ENVImet (V4) computer and the RayMan model to increase albedo, or the ratio of reflected incoming radiation, for the human thermal comfort index. The ENVImet (V4) software is validated using air temperature and solar radiation data gathered in several USA locations. The microclimate simulator ENVImet can be used to determine the high-resolution geographical and temporal distribution of microclimate variables within an urban region .The RayMan model was created for the physiological equivalent temperature measurement and the estimation of the mean radiation temperature along with thermal indices in simple and complex situations . Historical information about places with changeable seasonal circumstances was used for simulation and analysis after the necessary inputs and limits for the models are determined. The results of the simulation was used to assess the level of thermal comfort for both adults and children and recommendations would be provided

The urban heat island effect poses a growing threat to human society, especially in densely populated and developed megacities. With the introduction of the Local Climate Zones (LCZ) framework, new perspectives and findings have been brought to urban heat island studies. This study investigated the cooling effect of vegetation and albedo on the surface urban heat island (SUHI) in the classification system of LCZ during different seasons, using three Chinese megacities as case study areas. Single-factor linear regression and Pearson’s correlation coefficient were applied to analyze the seasonal cooling effect of both albedo and the NDVI on the SUHI within different LCZs. The results show that (1) the variability of the SUHI is reflected in its dominance and intensity within certain LCZs in different cities and in the efficiency of cooling factors; (2) the cooling effect of vegetation is dominant in each season, and the cooling effect produced by albedo within specific seasons can be differentiated by LCZs. This study provides valuable information for the mitigation of the SUHI magnitude in specific regions and at specific times of the year., Optical and Laser Remote Sensing

Rising temperatures, heat wave frequency, and anthropogenic pollution pose significant challenges to urban dwellers’ health. This study aimed to assess the effects of urban conditions on health in three sites in Barcelona, namely the La Pau neighbourhood, a portion of La Dreta de l’Eixample, and El Barri Gotic. The study focused on morphology, use, Sky View Factor, solar reflection, and trees. The objective was to quantify the impacts of Years of life loss and mortality rate and with the endeavour to improve public health. The study found that land use and tree coverage had varying influences on public health outcomes. The abundance of public spaces in La Pau, with its narrower streets and lower traffic intensity, emerged as a significant contributing factor to better air quality. Tree coverage, estimated at 37.6% of La Pau, showed modest preventable mortality from air quality improvements of harmful pollutants - PM2.5, PM10, and NO2. Trees performed better for heat prevention, with 0.69 C° reduction compared to Barcelona’s average tree cover and 0.5 C° less than La Dreta de l’Eixample as calculated through the mean UHI max of the Summer 2015 and compared with the scientific literature. However, the tree coverage estimated at 14.8% for La Dreta and 4.3% for Gotic had a lower impact on heat and their higher emissions levels. Nevertheless, white roofs were found to reduce heat by up to 2.5 C° in the first site and 1.2 degrees in the second. The study provides valuable insights into the effects of urban conditions on health and the potential for health to be used as a trojan horse for environmental and sustainable urban interventions.

The climate impact of food production plays a big part in the anthropogenic climate impact. Mitigation strategies from this sector are hence of great importance. One area which mainly has been used to calculate climate impact is albedo, the overall reflectance of incoming radiation in all directions. Albedo has been measured for a long time and is vital when calculating the energy balance of an area or biome. It is mainly measured and calculated with the MODIS satellites with a 500 m resolution. This study aims to use the Sentinel-2 spectral instrument with a 10 m resolution to measure the albedo of individual crops effectively. The result shows that the method used to calculate albedo from the Sentinel-2 instrument effectively follows changes in albedo equal to MODIS, for example, changes in seasons over a year. Which means that Sentinel-2 has great potential in being used to give more detailed data with less disturbing factors such as built-up areas, water or other crops within the same pixel. This study also shows differences in albedo between crops, crops and bare soil, and between normal years and years with droughts., The climate change induced by human sources is vast, and when implementing mitigation strategies, it is important to do this where it has the greatest impact. One of the biggest climate impacts from human sources is from agricultural land. As much as 26% of the greenhouse gas (GHG) emissions from humans originate from agriculture at present time. One way in which the impact from different land covers, including agricultural land, is evaluated is through the use of satellite remote sensing data. When analysing climate impact through remote sensing one important variable is albedo, which is the ratio of reflected long- and short-wave radiation at the earth's surface. Albedo is at the present time most commonly derived from the MODIS-satellite instrument, which has a resolution down to 500m. This project investigated the use of a Sentinel-2 satellite instrument which has a resolution down to 10m. This would mean that land areas could be analysed with more details, for example analysing different crops climate impact. The method used a narrow-to-broadband calculation of the different wavelengths to calculate the surface albedo from the Sentinel-2 data and compare the results with the MODIS data. Followed by testing the albedo calculations from the Sentinel-2 data on six different crops and bare soil in an area in southwestern Skåne in Sweden. The results show that it would be viable to use Sentinel-2 data to analyse surface albedo. It proved to be much easier to exclude land cover which is not needed, for example in this study built-up areas, water, and crops on nearby fields were excluded. All of which would be an issue to exclude in a coarser dataset, e.g., the MODIS data. The data also show significant differences between the crops analysed and between crops and bare soil. Future research should focus on further evaluating the albedo calculations based on the Sentinel-2 instrument.

Surface albedo estimations from remote sensing are invaluable for energy balance descrip- tions in climate research. The aim of this work is to evaluate the possibility of using Sentinel-2 satellite data to get the total albedo of a small, vegetated area. In this thesis, a simple machine learning model is created to convert simulated Sentinel-2 reflectance measurements to surface albedo. The Forest Reflectance and Transmission model is used to simulate the reflectance behaviour of a pine forest and a field vegetation stand. The angular behaviour was analysed, and it was found that the directional reflectances at near-nadir view angles are typically lower than the hemispherical reflectance, though this effect also depends on the solar angle. As a result, it is important to include angular modelling in the albedo estimations. Next, a direct- estimation and narrow-to-broadband linear regression model were trained with FRT simulated reflectance data. The ability to predict albedo from the FRT data was high, with r2 > 0.94 for the direct estimation and r2 > 0.999 for the narrow-to-broadband model. Finally, the models for the pine forest and field were compared and found to be distinctly different. In conclusion, it is important to include angular modelling in albedo estimations. The regression models presented in this thesis perform well for the simulated vegetation stands. Moreover, it is valuable to train separate models for different land use classes. With some further improvements, the regression models for Sentinel-2 data have potential for accurate evaluation of surface albedo at a fine spatial resolution., The past years, climate change has been one of the biggest concerns for most of the world. We are all aware that the average temperature on Earth is increasing, and many initiatives are set up to work against further temperature increase. To battle climate change, it is important to study the energy balance of the Earth as a system. The sun brings energy into the system in the form of electromagnetic radiation. Part of this energy is scattered and absorbed in the atmosphere. The rest of the radiation reaches the surface, and there it is either reflected or absorbed. The part of the incoming solar power that is reflected by either the atmosphere or the surface simply leaves the system again, but the absorbed radiation contributes to the global warming. The term surface albedo describes the reflectivity of the surface. This reflectivity depends on the land cover. A higher albedo means that more light is reflected by the Earth's surface. In the interest of decreasing the accelerated global warming, a high albedo is desired. Changing the land usage is a way to influence the albedo. But before taking this step, it is critical to know the effects on the surface albedo of changing the vegetation. Remote sensing and satellite data have been invaluable for monitoring the Earth in recent years. The Sentinel-2 satellite constellation from the European Space Agency is a system that provides reflectance data. The satellite measures the reflectance in thirteen separate wavelength ranges and does so at a very fine spatial resolution. The reflectance is measured by the satellite at one specific angle, but not all incoming sunlight is reflected at this exact angle. Similarly, the satellite measures the reflectance for a selection of wavelength ranges, and not for the complete solar wavelength spectrum. To get the total reflectance for the hemisphere and the solar wavelength spectrum, a conversion must be applied to the satellite data. The aim of this work is to evaluate the possibil

Glacier surfaces are highly heterogeneous mixtures of ice, snow, light-absorbing impurities and debris material. The spatial and temporal variability of these components affects ice surface characteristics and strongly influences glacier energy and mass balance. Remote sensing offers a unique opportunity to characterize glacier optical and thermal properties, enabling a better understanding of different processes occurring at the glacial surface. In this study, we evaluate the potential of optical and thermal data collected from field and drone platforms to map the abundances of predominant glacier surfaces (i.e., snow, clean ice, melting ice, dark ice, cryoconite, dusty snow and debris cover) on the Zebrù glacier in the Italian Alps. The drone surveys were conducted on the ablation zone of the glacier on 29 and 30 July 2020, corresponding to the middle of the ablation season. We identified very high heterogeneity of surface types dominated by melting ice (30% of the investigated area), dark ice (24%), clean ice (19%) and debris cover (17%). The surface temperature of debris cover was inversely related to debris-cover thickness. This relation is influenced by the petrology of debris cover, suggesting the importance of lithology when considering the role of debris over glaciers. Multispectral and thermal drone surveys can thus provide accurate high-resolution maps of different snow and ice types and their temperature, which are critical elements to better understand the glacier’s energy budget and melt rates.

This work focuses on proposing prediction models associated with incident solar radiation on the earth's surface of the Tumbabiro parish in Urcuquí - Imbabura. The methodology is based on obtaining an optimal model where prediction models that respond to different statistical methods are used. The data of the fundamental parameters that arise from solar radiation are obtained from the database provided by the NREL. AR, ARMA, ARMAX and Recurrent Neural Networks-RNN models are used, where a comparison of statistically significant predictive models is carried out, allowing us to observe that, of the former, an ARMAX(1,1) is significant, with an error of 9.87. % ; but, the best forecasts were acquired from the LSTM model with an error of 0.18%., Este trabajo se enfoca en plantear modelos de predicción asociados a la radiación solar incidente sobre la superficie terrestre de la parroquia de Tumbabiro en Urcuquí – Imbabura. La metodología está basada en obtener un modelo óptimo donde se utiliza modelos de predicción que responden a distintos métodos estadísticos. Los datos de los parámetros fundamentales que afectan a la radiación solar se obtienen de la base de datos que proporciona el NREL. Se utiliza modelos AR, ARMA, ARMAX y de Redes Neuronales Recurrentes-RNN, donde se realiza una contrastación modelos predictivos estadísticamente significativos, permitiendo observar que, de los primeros, es significativo un ARMAX(1,1), con un error de 9.87%; pero, los mejores pronósticos se obtuvieron del modelo LSTM con error del 0.18%.

In agrivoltaic systems combining solar photovoltaic and agricultural activities, ground albedo is mainly characterized by the crop and its seasonal variations. This study examines the effects of using fixed, satellite-derived, and hourly measured albedo on the performance of a vertical bifacial system and a 1-axis tracking system using a bifacial photovoltaic model (AgriOptiCE®). The model is developed with Matlab® and partially based on the open-source package pvlib. AgriOptiCE® is firstly validated by comparing estimated front and rear irradiances with on-site measurements for specific periods from a 1-axis tracker site in Golden, USA and a vertical agrivoltaic system in Västerås, Sweden. Furthermore, photovoltaic system power output estimations using AgriOptiCE® are also validated for the vertical agrivoltaic system and the conventional ground-mounted fixed-tilt system at the same location. The validations demonstrate the high accuracy of the proposed model in estimating front and rear irradiances and power output, obtaining R2 > 0.85 for all the studied cases. The study results indicate that measured albedo provides the highest accuracy, while satellite- derived albedo has poorer results due to the broader spatial, temporal, and spectral resolution. Fixed albedo is not recommended for yearly assessment of bifacial PV systems because it cannot account for snow events and daily variations, resulting in lower overall accuracy., Accepted manuscript

Surface mass loss from the Greenland ice sheet (GrIS) has accelerated over the past decades, mainly due to enhanced surface melting and liquid water runoff in response to atmospheric warming. A large portion of runoff from the GrIS originates from exposure of the darker bare ice in the ablation zone when the overlying snow melts, where surface albedo plays a critical role in modulating the energy available for melting. In this regard, it is imperative to understand the processes governing albedo variability to accurately project future mass loss from the GrIS. Bare-ice albedo is spatially and temporally variable and contingent on non-linear feedbacks and the presence of light-absorbing constituents. An assessment of models aiming at simulating albedo variability and associated impacts on meltwater production is crucial for improving our understanding of the processes governing these feedbacks and, in turn, surface mass loss from Greenland. Here, we report the results of a comparison of the bare-ice extent and albedo simulated by the regional climate model Modèle Atmosphérique Régional (MAR) with satellite imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) for the GrIS below 70∘ N. Our findings suggest that MAR overestimates bare-ice albedo by 22.8 % on average in this area during the 2000–2021 period with respect to the estimates obtained from MODIS. Using an energy balance model to parameterize meltwater production, we find this bare-ice albedo bias can lead to an underestimation of total meltwater production from the bare-ice zone below 70∘ N of 42.8 % during the summers of 2000–2021.

In this paper, the effect of dynamic albedo on modelling energy generation of a floating offshore photovoltaic system is quantified, for a system assumed to be installed at the North Sea. The dynamic albedo is modeled as a function of solar irradiation, wind speed and solar zenith angle at an hourly time resolution. The energy output of a floating offshore PV system is compared considering two scenarios (i) implementing constant albedo and (ii) implementing a modeled dynamically varying albedo. The quantified results show that the system performance in case of a varying albedo is larger by about 1.03% compared to using a constant albedo.

La producción de energía eléctrica mediante radiación solar, o más conocida como fotovoltaica, está incrementándose exponencialmente. A menudo, nuevas tecnologías y materiales van surgiendo con el propósito de mejorar la calidad de esta energía, y aumentar el rendimiento de sus instalaciones. Hasta ahora, la mayoría de la producción solar se debía a los módulos monofaciales, introduciéndose paulatinamente los paneles bifaciales. Aunque es cierto que su funcionamiento es muy similar al de los primeros, es necesario el estudio de los factores que afectan a su cara trasera tales como el tipo de suelo y su reflexión además de vigilar también los ángulos de inclinación. En el siguiente trabajo de fin de carrera se va a hacer hincapié en el estudio de los módulos bifaciales; especialmente en las diferentes inclinaciones posibles para un panel, y se determinará el ángulo óptimo de producción mediante la comparación entre dos módulos bifaciales monitorizados., The production of electrical energy through solar radiation, or better known as photovoltaics, is increasing exponentially. Often, new technologies and materials are emerging with the purpose of improving the quality of this energy and increasing the performance of your installations. Until now, most of the solar production is due to monofacial modules, gradually introducing bifacial panels. Although it is true that its operation is very similar to that of the former, it is necessary to study the factors that worsen its rear face, such as the type of soil and its reflection, and also studying the angles of inclination. In the following Final Degree Project, the study of bifacial modules will be made to reflect; especially the different possible inclinations for a panel, and the optimal production angle will be determined by comparing two monitored bifacial modules., Departamento de Física de la Materia Condensada, Cristalografía y Mineralogía, Grado en Ingeniería Eléctrica

Despite the unequal partitioning of land and aerosol sources between the hemispheres, Earth’s albedo is observed to be persistently symmetric about the equator. This symmetry is determined by the compensation of clouds to the clear-sky albedo. Here, the variability of this interhemispheric albedo symmetry is explored by decomposing observed radiative fluxes in the CERES EBAF satellite data record into components reflected by the atmosphere, clouds, and the surface. We find that the degree of interhemispheric albedo symmetry has not changed significantly throughout the observational record. The variability of the interhemispheric difference in reflected solar radiation (asymmetry) is strongly determined by tropical and subtropical cloud cover, particularly those related to nonneutral phases of El Niño–Southern Oscillation (ENSO). As ENSO is the most significant source of interannual variability in reflected radiation on a global scale, this underscores the interhemispheric albedo symmetry as a robust feature of Earth’s current annual mean climate. Comparing this feature in observations with simulations from coupled models reveals that the degree of modeled albedo symmetry is mostly dependent on biases in reflected radiation in the midlatitudes, and that models that overestimate its variability the most have larger biases in reflected radiation in the tropics. The degree of model albedo symmetry is improved when driven with historical sea surface temperatures, indicating that the degree of symmetry in Earth’s albedo is dependent on the representation of cloud responses to coupled ocean–atmosphere processes., For erratum, see (DOI):https://doi.org/10.1175/JCLI-D-22-0128.1

Biochar is a carbon-based substance made by the pyrolysis of organic waste. The amount of biochar produced is determined by the type of feedstock and pyrolysis conditions. Biochar is frequently added to the soil for various reasons, including carbon sequestration, greenhouse gas mitigation, improved crop production by boosting soil fertility, removing harmful contaminants, and drought mitigation. Biochar may also be used for waste management and wastewater treatment. Biochar’s various advantages make it a potentially appealing instrument material for current science and technology. Although biochar’s impacts on soil chemical qualities and fertility have been extensively researched, little is known about its impact on enhancing soil physical qualities. This review is intended to describe biochar’s influence on some crucial soil physical and hydrological properties, including bulk density of soil, water holding capacity, soil porosity, soil hydraulic conductivity, soil water retention, water repellence–available plant water, water infiltration, soil temperature, soil color, and surface albedo. Therefore, we propose that the application of biochar in soils has considerable advantages, and this is especially true for arable soils with low fertility., Validerad;2022;Nivå 2;2022-09-06 (johcin)

1. It is of prime importance to understand feedbacks due to the release of carbon (C) stored in permafrost soils (permafrost-climate feedback) and direct impacts of climatic variations on permafrost dynamics therefore received considerable attention. However, indirect effects of global change, such as the variation in soil nutrient availability and grazing pressure, can alter soil and surface properties of the Arctic tundra, with the potential to modify soil heat transfers toward the permafrost and impact resilience of Arctic ecosystems. 2. We determined the potential of nutrients availability and grazing to alter soil energy balance using a 16-year split-plot experiment crossing fertilization at different doses of nitrogen (N) and phosphorus (P) with protection from goose grazing. Moss biomass and some determinants of the surface energy budget (leaf area index (LAI), dead vascular plant biomass and albedo) were quantified and active layer thaw depth repeatedly measured during three growing seasons. We measured soil physical properties and thermal conductivity and used a physical model to link topsoil organic accumulation processes to heat transfer. Fertilization increased LAI and albedo, whereas grazing decreased dead vascular plant biomass and albedo. 3. Fertilization increased organic accumulation at the top of the soil leading to drier and more porous topsoil, whereas grazing increased water content of topsoil. As a result, topsoil thermal conductivity was higher in grazed plots than in ungrazed ones. Including these properties into a simulation model, we showed that, after 16 years, nutrient addition tended to shallow the active layer whereas grazing deepened mean July active layer by 3.3 cm relative to ungrazed subplots. As a result of OM accumulation at the surface, fertilization increased permafrost vertical aggradation rate by almost an order of magnitude (up to 5 mm‧year-1 instead of 0.7 mm‧year-1), whereas grazing slowed down permafrost aggradati

Diverse microbes have been revealed to live in glaciers worldwide, but only a few biological studies were dedicated to glaciers in tropical Africa. These glaciers are shrinking rapidly and are expected to disappear shortly. In this study, we carried out biological and glaciological field observations on Stanley Glacier, the largest remaining glacier in the Rwenzori Mountains, Uganda, Africa. Microbial aggregates ranging from micrometer to centimeter in size were found on the glacier surface and contained moss and various types of Chlorophyta, among which a new endemic species of green alga. Concentrations of total impurities on the glacier surface, including microbial aggregates, varied spatially and decreased as altitude increased. The large microbial aggregates (larger than 4 cm in diameter) were found only at the glacier surface near the terminus and side margins, where the surface was less frequently covered with snow. It is also shown that the total organic matter on the glacier surface is determined by the timing of snow cover, which affects the quantity of solar radiation reaching the glacier ice surface. Furthermore, the total impurity content was negatively correlated with surface reflectivity, revealing their potential role in albedo reduction at the glacier surface through positive feedback between enhanced meltwater and increased biological growth.

The Urban Heat Island (UHI) effect is a phenomenon that threatens life in cities nowadays. Among other strategies to adapt cities to this phenomenon is the use of the tempering potential of courtyards and changes in the albedo of the surfaces. However, there is little literature about the influence of the albedo on the thermal performance of the courtyard. This research aims to analyze the effect of albedo alteration of the surfaces of a courtyard located in Seville on its tempering potential and the comfort of the users. Besides, it evaluates the accuracy and suitability of the simulation tool ENVI-met, widely used for the simulation of outdoor spaces, by contrasting monitoring and simulation results. It is concluded that high reflectance surfaces reduce the surface temperature by reflecting solar radiation, so they accumulate less heat during daylight hours and release less heat at night, however, the high reflection compromises user comfort.

Land surface temperature (LST) and land surface albedo (LSA) are the two key regional and global climate-controlling parameters; assessing their behavior would likely result in a better understanding of the appropriate adaptation strategies to mitigate the consequences of climate change. This study was conducted to explore the spatiotemporal variability in LST and LSA across different land use/cover (LULC) classes in northwest Iran. To do so, we first applied an object-oriented algorithm to the 10 m resolution Sentinel-2 images of summer 2019 to generate a LULC map of a 3284 km2 region in northwest Iran. Then, we computed the LST and LSA of each LULC class using the SEBAL algorithm, which was applied to the Landsat-8 images from the summer of 2019 and winter of 2020. The results showed that during the summer season, the maximum and minimum LSA values were associated with barren land (0.33) and water bodies (0.11), respectively; during the winter season, the maximum LSA value was observed for farmland and snow cover, and the minimum value was observed in forest areas (0.21). The maximum and minimum LST values in summer were acquired from rangeland (37 °C) and water bodies (24 °C), respectively; the maximum and minimum values of winter values were detected in forests (4.14 °C) and snow cover (−21.36 °C), respectively. Our results revealed that barren land and residential areas, having the maximum LSA in summer, were able to reduce the heating effects to some extent. Forest areas, due to their low LSA and high LST, particularly in winter, had a greater effect on regional warming compared with other LULC classes. Our study suggests that forests might not always mitigate the effects of global warming as much as we expect., Validerad;2023;Nivå 2;2023-01-01 (joosat);Licens full text: CC BY license

Diverse microbes have been revealed to live in glaciers worldwide, but only a few biological studies were dedicated to glaciers in tropical Africa. These glaciers are shrinking rapidly and are expected to disappear shortly. In this study, we carried out biological and glaciological field observations on Stanley Glacier, the largest remaining glacier in the Rwenzori Mountains, Uganda, Africa. Microbial aggregates ranging from micrometer to centimeter in size were found on the glacier surface and contained moss and various types of Chlorophyta, among which a new endemic species of green alga. Concentrations of total impurities on the glacier surface, including microbial aggregates, varied spatially and decreased as altitude increased. The large microbial aggregates (larger than 4 cm in diameter) were found only at the glacier surface near the terminus and side margins, where the surface was less frequently covered with snow. It is also shown that the total organic matter on the glacier surface is determined by the timing of snow cover, which affects the quantity of solar radiation reaching the glacier ice surface. Furthermore, the total impurity content was negatively correlated with surface reflectivity, revealing their potential role in albedo reduction at the glacier surface through positive feedback between enhanced meltwater and increased biological growth.

El fenómeno denominado Isla Térmica (IT) se reconoce cuando la temperatura, bien sea por frio o por calor, de un segmento de ciudad es mayor que el de la periferia inmediata o el de su contexto rural cercano. Este evento ocurre por factores ya reconocidos como por ejemplo el hecho de impermeabilizar el suelo urbano con materiales como la piedra, el asfalto y hormigón o utilizar en las edificaciones materiales de fachada y cubierta con colores oscuros que absorben y retienen el calor; adicionalmente, a nivel de proyectos urbanos las intervenciones no planificadas que eliminan las zonas verdes y los árboles, ayudan en gran medida a la configuración de las islas térmicas. El retiro de estos elementos naturales ha comprometido a gran escala el confort climático de las ciudades debido a que, dependiendo de la especie, la temperatura bajo sus copas puede ser menor entre 2º y 6 ºC. En el presente trabajo, se explica y define el significado de isla Térmica, se abordarán ejemplos de dos ciudades que están afectadas por este fenómeno, se expondrán alternativas que ayuden a mitigar y/o prevenir los efectos y ocurrencia de este para finalmente dejar claro que las estrategias para la lucha contra las IT y sus efectos debe ser un esfuerzo aunado entre el sector público y privado, que requiere ser estructurado por una normativa urbana de carácter obligatoria. Con las propuestas recogidas en el presente trabajo, combinadas entre sí, se puede lograr mantener una temperatura urbana entre 12º y 30ºC durante todo el año. Estas propuestas y/o ejemplos ya materializados se tomarán con fundamento en los resultados de su aplicación que se han obtenido en algunos países., The phenomenon known as Thermal Island (TI) is recognized when the temperature, either due to cold or heat, of a segment of a city is higher than that of the immediate periphery or its nearby rural context. This event occurs due to already recognized factors such as the fact of waterproofing the urban soil with materials such as stone, asphalt and concrete or using in building’s facade and roof materials with dark colors that absorb and retain heat; additionally, at the level of urban projects, unplanned interventions that eliminate green areas and trees, help greatly to the configuration of thermal islands. The removal of these natural elements has compromised the climatic comfort of cities on a large scale because, depending on the species, the temperature under their canopies can be lower by 2 to 6 degrees10. Additionally, there are factors that are inherent to the current rhythm of human life and contribute positively to the consolidation of thermal islands, these are associated to the daily routines of people and in general to the dynamics of modern society, which demands large displacements to comply with issues associated with work, education, commerce and housing. These activities can be affected by tools such as urban planning, which is why, in this document, the importance of involving in urban regulations elements or criteria that regulate human interventions on the land will be made explicit. In this paper, the meaning of thermal island is explained and defined, examples of two cities that are affected by this phenomenon will be discussed, alternatives that help to mitigate and/or prevent the effects and occurrence of this phenomenon will be presented, and finally it will be made clear that the strategies for the fight against TI and its effects must be a joint effort between the public and private sectors, which needs to be structured by mandatory urban regulations

Ice surface albedo is a primary modulator of melt and runoff, yet our understanding of how reflectance varies over time across the Greenland Ice Sheet remains poor. This is due to a disconnect between point or transect scale albedo sampling and the coarser spatial, spectral and/or temporal resolutions of available satellite products. Here, we present time-series of bare-ice surface reflectance data that span a range of length scales, from the 500 m for Moderate Resolution Imaging Spectrometer’s MOD10A1 product, to 10 m for Sentinel-2 imagery, 0.1 m spot measurements from ground-based field spectrometry, and 2.5 cm from uncrewed aerial drone imagery. Our results reveal broad similarities in seasonal patterns in bare-ice reflectance, but further analysis identifies short-term dynamics in reflectance distribution that are unique to each dataset. Using these distributions, we demonstrate that areal mean reflectance is the primary control on local ablation rates, and that the spatial distribution of specific ice types and impurities is secondary. Given the rapid changes in mean reflectance observed in the datasets presented, we propose that albedo parameterizations can be improved by (i) quantitative assessment of the representativeness of time-averaged reflectance data products, and, (ii) using temporally-resolved functions to describe the variability in impurity distribution at daily time-scales. We conclude that the regional melt model performance may not be optimally improved by increased spatial resolution and the incorporation of sub-pixel heterogeneity, but instead, should focus on the temporal dynamics of bare-ice albedo.

In this paper, we made use of PRISMA imaging spectroscopy data for retrieving surface snow properties in the Nansen Ice Shelf (East Antarctica). PRISMA satellite mission has been launched in 2019 and it features 239 spectral bands covering the 400-2500 nm interval. These data are promising for cryospheric applications, since several snow and ice parameters can be derived from reflectance in the Visible Near InfraRed - Short Wave InfraRed (VNIR-SWIR) wavelength interval. Here we analyze, for the first time, PRISMA data collected in Antarctica. Our scene was acquired on December 2020 over the Nansen Ice Shelf (NIS). Using PRISMA data we estimated various snow parameters (effective grain diameter, snow specific surface area, snow spectral and broadband albedo, bottom of atmosphere snow reflectance, type of impurities in snow and their concentration), and we compared them with data presented in the scientific literature.

Land surface albedo plays an extremely important role in the surface energy budget, by determining the proportion of incoming solar radiation, which is available to drive photosynthesis and surface heating, and that which is reflected directly back to space. In northern high latitude regions, the albedo of snow-covered vegetation and open, leafless forest canopies in winter, is quite high, while the albedo of boreal evergreen conifers can either be quite low (even with extensive snow lying under the canopy) or rather bright depending on the structure and density of the canopy. Here, we present the further development and evaluation of a 30 m Landsat albedo product, including an operational blue-sky albedo product, for application in the circumpolar domain. The surface reflectances from the Landsat satellite constellation are coupled with surface anisotropy information (Bidirectional Reflectance Distribution Function, BRDF) from the MODerate-resolution Imaging Spectroradiometer (MODIS). The product is extensively validated across diverse land cover and conditions and performs well with root mean squared error of 0.0395 and negligible bias when compared to coincident tower-based albedo measurements. The development of this Landsat albedo products allows for better capture of ephemeral, heterogeneous and dynamic surface conditions at the landscape scale across the circumpolar domain.

[ES] Este vídeo tiene como objetivo explicar los cambios que se están produciendo en el océano Ártico y el impacto que tienen en nuestras vidas. Y es que, las temperaturas en el Ártico están aumentando mucho más rápidamente que en el resto del planeta y esto está acelerando el deshielo. Esto implica, entre otros, que haya más agua dulce en el océano Ártico, lo que puede producir cambios en la circulación oceánica global, que regula el clima de la Tierra…El video acaba haciendo énfasis en que lo que ocurre en el Ártico no se queda en el Ártico, sino que tiene consecuencias globales., [CA] Aquest vídeo té com a objectiu explicar els canvis que s'estan produint a l'oceà Àrtic i l'impacte que tenen a les nostres vides. I és que, les temperatures a l'Àrtic estan augmentant molt més ràpidament que a la resta del planeta i això està accelerant el desglaç. Això implica, entre altres, que hi hagi més aigua dolça a l'oceà Àrtic, cosa que pot produir canvis en la circulació oceànica global, que regula el clima de la Terra. El video acaba fent èmfasis en que el que passa a l'Àrtic no es queda a l'Àrtic, sino que te conseqüències globals.

In this chapter, we introduce the physic principle and applications of bifacial PV technology. We present different bifacial PV cell and module technologies as well as investigate the advantages of using bifacial PV technology in the field. We describe the measurement and modeling of Albedo, which is one of the important factors for the energy yield of bifacial PV technology. For an accurate assessment of the performance ratio of bifacial PV strings, it is necessary to measure the albedo irradiance using an albedometer or the front- and rear-side plane of array (POA) irradiance. We also discuss the advanced techniques for the characterization of bifacial PV modules. By means of simulation, we give insight into what boundary conditions result in new bifacial technology gains and the influence of the mounting position of irradiance sensors. We executed several simulations by varying the sensor positions on the rear side of the PV modules, different places, different albedo numbers, mounting heights, different geographical locations with various tilts, seasons, and weather types. To validate the simulation results, we performed various experiments in the field under different conditions. The results prove that the bifacial gain is highly dependent on the mounting heights of PV modules, tilt angles, weather conditions, latitude, and location., Photovoltaic Materials and Devices

Meteorological variables (e.g., air temperature (T2), radiation flux, and precipitation) determine the evolution of glacier mass and characteristics. Observations of these variables are not available with adequate spatial coverage and spatiotemporal resolution over the Tibetan Plateau. Albedo is the key factor of net radiation and is determined by the land cover and snow-related variables. This study focuses on evaluating the performance of the albedo parameterization scheme in WRF coupled with Noah-MP in terms of glacio-meteorological variables, by conducting experiments applying the standard surface albedo scheme with the default vegetation and corrected to ice cover and the modified glacial albedo scheme to the Parlung No. 4 Glacier in the 2016 ablation season. In situ glacio-meteorological element observations and MODIS-retrieved albedo are selected to assess the performance of the model. The key results are as follows. First, compared to the air temperature bias of 1.56 °C in WRF applying the standard surface albedo scheme and the default vegetation cover, realistic land-use categories considerably reduce the model warm bias on the glacier. The model using realistic land-use categories yields similar T2 diurnal patterns to the observations, with a mean bias of only −0.5 °C, no matter which glacial albedo scheme is implemented. Second, the default glacial albedo scheme gives a rather high albedo value of 0.68, causing an apparent underestimation of the net shortwave radiation and net radiation; the modified glacial albedo scheme gives a mean albedo value of 0.35, close to the in situ observations, helping to relieve underestimations of net shortwave radiation and net radiation. Compared with the MODIS albedo of the glacier, WRF applying the default glacial albedo scheme apparently overestimates the albedo with a mean error of 0.18, while WRF applying the modified glacial albedo scheme slightly underestimates the albedo with a mean error of only −0.08. Third, the, Optical and Laser Remote Sensing

Surface melt is an important process for the stability of ice shelves, and therewith the Antarctic ice sheet. In Antarctica, absorption of solar radiation is mostly the largest energy source for surface melt, which is further enhanced by the snowmelt-albedo feedback (SMAF): Refrozen snow has a lower albedo than new snow, which causes it to absorb more solar radiation, further increasing the energy available for surface melt. This feedback has previously been shown to increase surface melt by approximately a factor of 2.5 at Neumayer Station in East Antarctica. In this study, we use a regional climate model to quantify SMAF for the entire Antarctic ice sheet. We find that it is most effective on ice shelves in East Antarctica, and is less important in the Antarctic Peninsula and on the Ross and Filchner-Ronne ice shelves. We identify a relationship between SMAF and average summer 2 m air temperatures, and find that SMAF is most important around 265 ± 2 K. On a subseasonal scale, we identify several parameters that contribute to SMAF: the length of dry periods, the time between significant snowfall events and snowmelt events, and prevailing temperatures. We then apply the same temperature dependency of SMAF to the Greenland ice sheet and find that it is potentially active in a narrow band around the ice sheet, and finally discuss how the importance of SMAF could change in a warming climate.

Along three-quarters of its edge, the Antarctic ice sheet is fringed by ice shelves. These floating extensions of the ice sheet buttress the grounded ice sheet, slowing down the rate at which it is flowing into the ocean. In the recent past, ice shelves have been subject to significant change: in 1995 and 2002, two ice shelves in the Antarctic Peninsula completely disintegrated. As ice shelves float on the ocean, their disappearance does not directly contribute to sea-level rise. However, when ice shelves disappear, so does their buttressing effect on the grounded ice sheet, which causes the ice sheet to flow into the ocean at a faster rate, raising global mean sea level. An ice shelf is susceptible to a process called 'hydrofracturing'. This occurs when snow melts at the ice-shelf surface, forming melt ponds. The meltwater can fill and deepen pre-existing crevasses and eventually, the crevasse can reach the bottom of the ice shelf. If snowmelt is widespread on the ice-shelf surface, this can potentially destabilise the ice shelf, causing it to disintegrate. Whether snowmelt occurs is determined by the surface energy balance: the sum of all energy fluxes towards and away from the surface. An important energy source is the absorption of solar radiation. The amount of sunlight that is absorbed by the surface is determined by its reflectivity: the surface albedo. Fresh snow has a high albedo (85 %), but when snow melts it becomes darker, reflecting perhaps 70 %, and thus absorbs two times more solar radiation. If the surface absorbs more energy, more snow can melt, darkening the surface even further. This process is known as the snowmelt-albedo feedback. In this thesis, we explicitly model this process and quantify how strongly it influences snowmelt events on the vast Antarctic ice sheet. In Chapter 3, this is first done for a single location, using meteorological observations from a German research station situated on an ice shelf in coastal Dronning Maud Land, East

An important part of the climate system of Earth are the ice sheets of Greenland and Antarctica. Crucial for the development of an ice sheet is the reflectivity of sunlight, or albedo, at the surface. To better understand a process like albedo and the climate system of the past, present and future, we use climate models. More specifically, we use a regional climate model to study the climate of ice sheets. There is still room for improvements in such models, however, as the description of some processes like snow albedo is rather limited. The goal of this research is therefore to implement a new snow albedo scheme in the regional climate model RACMO2, and analyze its impact on the development of the major ice sheets. In this thesis, we present the steps taken, discuss the implemented new physical processes and evaluate the results. To improve the representation of snow albedo in RACMO2, we implement the two-stream radiative transfer in snow model TARTES. TARTES will allow for more physical processes to be included in RACMO2, introducing an explicit wavelength-dependent albedo and subsurface energy absorption. As TARTES is a spectral model, it performs radiation calculations for sets of single wavelengths. RACMO2, in contrast, uses fourteen wavelength bands, the so-called narrowbands, for its atmospheric radiation calculations. Therefore, we developed the spectral-to-narrowband albedo coupling module SNOWBAL. With SNOWBAL, TARTES has been successfully implemented into RACMO2. The modeled albedo of this new RACMO2 version matches well with in situ and remote sensing observations of the Greenland ice sheet, with a negligible domain-averaged bias for the interior. Some discrepancies in the albedo are, however, observed around the ice sheet margins. The surface mass balance and energy budget are in good agreement with observations. An important improvement is that absorption of sunlight beneath the surface leads to higher snow temperatures, which is also in agreement wit

Cool paints on exterior walls will save energy in air-conditioned buildings at hot-climate universities, such as the University of California, Davis (UC Davis). Cool paints are more reflective, typically lighter-colored versions of conventional paints. They can reduce air-conditioning demand by reducing the wall's solar heat gain and decreasing heat flow into the occupied space. We calculated potential energy savings from cool paint modifications for 49 UC Davis main campus buildings. We analyzed the baseline building stock, directly measured wall albedos (solar reflectances), and created a model that estimates albedo from wall color. We also developed a method to identify those buildings that could benefit most from cool paint. About 35% of UC Davis campus buildings could be modified with cool paint, which could save annually up to $45,000 of energy costs, 3.1 TJ of source energy, and 86 t of CO2 equivalent emissions. Since light-colored paints cost no more than dark paints, payback time would be zero if cool paints are chosen when buildings are routinely repainted.

Antropogen inverkan på växthuseffekten är en bidragande faktor i den globala uppvärmningen, som i sin tur kommer att förstärka värmeböljor och den urbana värmeöeffekten. Kombinationen av dessa fenomen kan ha förödande konsekvenser. Höga temperaturer medför en minskad komfort för städers invånare och risken för värmerelaterad sjukdom och dödlighet ökar. Geoengineering som höjer det urbana albedot är en möjlig metod för att motverka allt mer intensiva värmeböljor, vilket i denna studie appliceras på Uppsala stad i form av vita tak. Den totala arean av mörka tak i Uppsala uppgår till 2,8 · 106 m2, vilket utgör mer än en tredjedel av Uppsalas totala takyta. Denna studie visar att implementeringen av vit plåt på mörka tak kan öka takets albedo med 0,42 vilket innebär att det finns en stor potential att öka det urbana albedot i Uppsala. Tidigare forskning tyder på ett samband mellan en ökning av det urbana albedot och en minskad medeltemperatur i städer. Det är därför rimligt att anta att en storskalig implementering av denna typ av geoengineering i Uppsala skulle kunna lindra effekterna av framtida värmeböljor.