Stable Climate Research Articles

Patterns and Drivers of Pollen Temperature Tolerance.

Pollen, a pivotal stage in the plant reproductive cycle, is highly sensitive to temperature fluctuations, impacting seed quality and quantity. While the importance of understanding pollen temperature limits (Tmin, Topt, Tmax - collectively PTLs) is recognized, a comprehensive synthesis of underlying drivers is lacking. Here, we examined PTLs, correlating them with vegetative tissue thermotolerance and assessing variability at the intra- and interspecific levels across 191 species with contrasting phylogeny, cultivation history, growth form and ecology. At the species level, the PTLs range from 9.0 to 42.4°C, with considerable differences among individual species. Vegetative tissue showed greater tolerance to both low and high temperatures than pollen. A significant, though weak, correlation was observed between PTLs and leaf temperature tolerance. Pollen heat tolerance was independent of that in leaves and stems. The greatest intraspecific variability was observed in pollen cold tolerance (Tmin), followed by Topt and Tmax. Phylogenetic analysis revealed family-level conservation in all three pollen temperature tolerance measures. Climate emerged as a significant PTL driver of pollen cold tolerance, with species from colder and stable climates exhibiting enhanced cold tolerance. Cultivated and wild species did not differ in their pollen temperature tolerances. Herbaceous plants showed higher tolerance to high temperatures compared to shrubs and trees, potentially reflecting divergent thermal conditions during anthesis. This study provides the first formal analysis of complex relationships between pollen temperature limits, plant characteristics and environmental factors, providing crucial insights into climate change impacts on plant reproduction.

Incorporation of Phase Change Materials in Buildings

This review paper explores the integration of phase change materials (PCMs) in building insulation systems to enhance energy efficiency and thermal comfort. Through an extensive analysis of existing literature, the thermal performance of PCM-enhanced building envelopes is evaluated under diverse environmental conditions. This review highlights that PCMs effectively moderate indoor temperatures by absorbing and releasing heat during phase transitions, maintaining a stable indoor climate. This paper also delves into the detailed concepts of PCMs, including their classification and various applications within building insulation. It is noted that different types of PCMs have unique thermal properties and potential uses, which can be tailored to specific building requirements and climatic conditions. Furthermore, cost–benefit and environmental assessments presented in the reviewed studies suggest that incorporating PCMs into building materials offers significant potential for reducing energy consumption and mitigating environmental impacts. These assessments indicate that PCMs can lead to substantial energy savings by decreasing the reliance on heating and cooling systems, thereby lowering overall energy costs and carbon emissions. However, despite the promising outlook, this review identifies a need for further research to optimize PCM formulations and integration methods. This optimization is essential for overcoming current challenges and facilitating the widespread adoption of PCMs in the construction industry. Addressing issues such as long-term durability, compatibility with existing building materials, and cost-effectiveness will be crucial for maximizing the benefits of PCMs in enhancing energy efficiency and sustainability in buildings. Overall, this review underscores the transformative potential of PCMs in building insulation practices. By providing a comprehensive overview of PCM classifications, applications, and their impacts on energy efficiency and environmental sustainability, this paper lays the groundwork for future advancements and research directions in the field of PCM-enhanced building technologies.

FDI, defense spending, and economic prosperity

AbstractThe relationship between foreign direct investment (FDI) and military spending in the Middle East and North Africa (MENA) region is complex and multifaceted. High levels of military spending can deter foreign investors, as it creates an uncertain and potentially volatile investment climate. However, countries that invest in their military infrastructure and capabilities may be seen as more stable and secure, which can attract foreign investors. Taking into account several factors that can influence this relationship, including political stability, security concerns, and economic factors, this work analyzes whether military spending attracts foreign capital into the region. Using a dynamic panel data methodology along with other relevant macroeconomic variables, results show that the military expenditure has a positive and significant impact on FDI inflows into the MENA region. The paper highlights the fact that policymakers in the region must carefully balance military spending with investments in other areas of the economy in order to create a stable and favorable investment climate that attracts foreign investors and contributes to long‐term economic growth and development achieving both security and welfare.

Canadian Association of Radiologists Statement on Planetary Health Education in Radiology.

The health of Canadians is already impacted by climate change due to wildfire smoke, heat domes, floods, droughts, and the changing distribution of vector borne disease. The healthcare sector contributes to climate change, accounting for approximately 4.6% of annual greenhouse gas emissions in Canada. Healthcare teams have a responsibility and opportunity to reduce harm by limiting emissions and waste, and engaging the public in understanding the planetary health links between clean air and water, a stable climate, a healthy planet and human health. Transformation of Canadian healthcare to a low carbon, climate resilient system will be enhanced by physician engagement and leadership. Cornerstones to physician participation include knowledge of the anthropogenic etiology of the climate crisis, the human health impacts, and the contribution providing healthcare makes to the climate crisis. Integration of climate change knowledge into the Canadian Radiology educational curricula is essential to position radiologists to lead transformative change in mitigation and adaptation of the healthcare system to the climate crisis. This statement is intended to provide guidelines to optimize education and research for current and future Canadian radiologists, and builds on existing planetary healthcare education publications and the Canadian Association of Radiologists Statement on Environmental Sustainability in Medical Imaging.

Human Rights at the Climate Crossroads: Analysis of the Interconnection between Human Rights, Right to Climate, and Intensification of Extreme Climate Events

This paper analyzes the theoretical foundation and practical implications of recognizing the right to a stable climate as a fundamental human right. Further, it examines the intersection of human rights, right to climate, and the intensification of extreme climate events. Through a bibliometric analysis, the study highlights the increase in scholarly attention paid to this nexus. The intensification of extreme climate events, such as the Cumbre Vieja volcano in Spain, is also analyzed as a catalyst for recognizing the right to climate as a human right, as a fundamental requirement for its enactment. Indeed, it is argued that this recognition is necessary to achieve climate justice. These thoughts about the necessity of recognizing the right to climate as a human right are also based on a similar case, the enactment of the rights to water and sanitation, which is presented as a case study, demonstrating how specific environmental rights can be integrated into human rights discourse. The results and discussion section synthesizes these findings, highlighting the imperative of recognizing climate rights to ensure justice and sustainability amidst escalating climate challenges.

Climate resilience in aquaculture: A cluster analysis of Chinese coastal regional production and farming practices in the face of climatic shifts 2017–2021

This study conducts a comprehensive analysis of the aquaculture industry across 11 coastal regions in eastern China from 2017 to 2021 to assess their adaptability and resilience in the face of climate change. Cluster analysis was employed to examine regional variations in aquaculture adaptation by analyzing data on annual average temperatures, annual extreme high/low temperatures, annual average relative humidity, annual sunshine duration, and total yearly precipitation alongside various aquaculture practices. The findings reveal that southern regions, such as Fujian and Guangdong, demonstrate higher adaptability and resilience due to their stable subtropical climates and advanced aquaculture technologies. In contrast, northern regions like Liaoning and Shandong, characterized by more significant climatic fluctuations, exhibit varying degrees of cluster changes, indicating a continuous need to adjust aquaculture strategies to cope with climatic challenges. Additionally, the study explores the specific impacts of climate change on species selection, disease management, and water resource utilization in aquaculture, emphasizing the importance of developing region-specific strategies. Based on these insights, several strategic recommendations are proposed, including promoting species diversification, enhancing disease monitoring and control, improving water quality management techniques, and urging governmental support for policies and technical guidance to enhance the climate resilience and sustainability of the aquaculture sector. These strategies and recommendations aim to assist the aquaculture industry in addressing future climate challenges and fostering long-term sustainable development.

Bronze Age to Roman period salt production in the coastal areas of peninsular Italy: Palaeoenvironments, production methods and archaeological evidence

The landscape characteristics and salt production methods along the coasts of peninsular Italy from the Bronze Age to the Roman period are examined, with a focus on the significance of marine salt for Italy's ancient food economy, given the limited availability of rock salt. Two main methods of marine salt production are highlighted. Briquetage involves using clay or pottery containers to evaporate seawater, which requires specific environmental conditions such as clay availability and significant human labour and technological skill. Conversely, salterns consist of creating shallow ponds or pools for seawater evaporation, demanding flat coastal areas, a stable climate, and controlled seawater flow. While this method is less labour-intensive, it requires substantial initial infrastructure.The potential for salt production in Italy's coastal palaeoenvironments using either method has been evaluated. Key factors include coastal geomorphology, climate stability, and access to raw materials. This environmental data supports an analysis of archaeological remains from salt production sites active from the Bronze Age to the Roman period. The assessment focuses on the material evidence such as clay containers from briquetage and structural remains of salterns, aiming to understand the spatial and temporal distribution of these sites.The discussion also explores the geopolitical implications of salt production, examining how the distribution and development of these sites were affected by broader geopolitical shifts in Italy, including the impact of (proto)urbanization on the expansion and adaptation of salt production practices.

Q-triplet characterization of atmospheric time series at Antofagasta: A missing values problem

Abstract Located in northern Chile (23.7°S, 70.4°W), Antofagasta has an exceptionally arid and stable climate characterized by minimal precipitation and consistent weather patterns. Nevertheless, despite these climate conditions being meaningful for several research and practical applications, our understanding of weather dynamics remains limited. The available meteorological data from 1969 to 2016 is analogical, which presents a significant challenge to analyze because these records are riddled with missing values, some measurements were taken at irregular measuring intervals, making it an interesting puzzle to grasp the Antofagasta’s climate scenario. To overcome this issue, we present a comprehensive statistical analysis of atmospheric temperature, pressure, and humidity time series. Our analytical approach involves the q-triplet calculation method, serving as a powerful tool to identify distinctive behavior within systems under non-equilibrium states. Our results suggest that, in general, the q-triplet values satisfy the condition q sens < 1 < q stat < q rel, a pattern that has been observed in previous studies.

Bridging climate refuges for climate change adaptation: A spatio-temporal connectivity network approach

Enhancing the spatio-temporal connectivity of dynamic landscapes is crucial for species to adapt to climate change. However, a spatio-temporal connectivity network approach considering climate change and species movement is often overlooked. Taking Tibetan wild ass on the Qinghai-Xizang Plateau as an example, we simulated species distribution under current (2019) and future scenarios (2100), constructed spatio-temporal connectivity networks, and assessed the spatio-temporal connectivity. The results show that under the current, SSP2-4.5 and SSP3-7.0 scenarios, the suitable habitats for Tibetan wild ass account for 21.11%, 21.34%, and 20.95% of the total area, respectively, which show more fragmentation in 2100. 78.35% of habitats which are predicted to be suitable under current conditions will remain suitable in the future, which can be regarded as stable climate refuges. With the increase in future emission intensity, the number percentage of auxiliary connectivity corridors increases from 27.65% to 33.57%. This indicates that more patches will function as temporary refuges and the auxiliary connectivity corridors will gradually weaken the dominance of direct connectivity corridors. Under different SSP-RCP scenarios, the internal spatio-temporal connectivity is the highest, accounting for 42%–43%. Compared with the spatio-temporal perspective, the purely spatial perspective overestimates network connectivity by about 28% considering all current and future patches, and underestimates network connectivity by 16%–21% when only considering all current or future patches. In this study, a new approach of spatio-temporal connectivity network is proposed to bridge climate refuges, which contributes to the long-term effectiveness of conservation networks for species’ adaptation to climate change.

Patterns of Species Richness and Its Endemism of Beetles in the Beijing–Tianjin–Hebei Region of China

The Beijing–Tianjin–Hebei region lies between the Mongolia-Xinjiang Zoogeographic Region and the Central China Zoogeographic Region in China, harboring relatively rich biodiversity. This study specifically examined the species diversity, richness and endemic areas of beetles in this area. By analyzing 5965 detailed distribution records of 2047 beetle species in the Beijing–Tianjin–Hebei region, the species richness maps were created with a grid size of 0.5°. Additionally, two methods, parsimony analysis of endemism (PAE) and endemicity analysis (EA) were applied to detect areas of endemism (AOEs) with different grid sizes (0.1°, 0.25° and 0.5°), resulting in the identification of three AOEs in the southern mountainous areas of the Taihang Mountains, Yanshan Mountains, and Xiaowutai Mountains. It also verified that AOEs are consistent with the hypothesis that endemic areas are predominantly located in mountain ranges, as proposed by previous related studies. These findings highlight the importance of complex topography and stable climate in shaping AOEs and conserving biodiversity.

Flexible oviposition behavior enabled the evolution of terrestrial reproduction

Among vertebrates, nearly all oviparous animals are considered to have either obligate aquatic or terrestrial oviposition, with eggs that are specialized for developing in those environments. The terrestrial environment has considerably more oxygen but is dry and thus presents both opportunities and challenges for developing embryos, particularly those adapted for aquatic development. Here, we present evidence from field experiments examining egg-laying behavior, egg size, and egg jelly function of 13 species of Central and South American treefrogs in the genus Dendropsophus, which demonstrates that flexible oviposition (individuals laying eggs both in and out of water) and eggs capable of both aquatic and terrestrial development are the likely factors which enable the transition from aquatic to terrestrial reproduction. Nearly half of the species we studied had previously undescribed degrees of flexible oviposition. Species with obligate terrestrial reproduction have larger eggs than species with aquatic reproduction, and species with flexible reproduction have eggs of intermediate sizes. Obligate terrestrial breeding frogs also have egg masses that absorb water more quickly than those with flexible oviposition. We also examined eight populations of a single species, Dendropsophus ebraccatus, and document substantial intraspecific variation in terrestrial oviposition; populations in rainy, stable climates lay fewer eggs in water than those in drier areas. However, no differences in egg size were found, supporting the idea that the behavioral component of oviposition evolves before other adaptations associated with obligate terrestrial reproduction. Collectively, these data demonstrate the key role that behavior can have in facilitating major evolutionary transitions.

Fungal Biodeterioration Risk in Monastic Libraries without Climate Control.

Fungi have always posed an unquestionable threat to heritage collections worldwide. Now, in a future of climate change, biological risk factors may have to be considered even more than before. Models and simulations to assess possible impacts a changing outdoor climate will have on indoor environments and, in turn, on biodeterioration are still underdeveloped and require a more substantial data basis. This study aimed at filling some of these knowledge gaps through a broad-based approach combining microclimatic and microbiological monitoring in four historic libraries in Austria with an uncontrolled indoor climate: Altenburg Abbey, Melk Abbey, Klosterneuburg Monastery and the Capuchin Monastery in Vienna. Data were generated from thermohygrometric sensors, cultivation-dependent air- and surface sampling and further surface dust sampling for cultivation-independent analyses. Results gave insights on the status quo of microbiological loads in the libraries and outdoor-indoor relationships. Influences of the geographic location and room-use on corresponding indoor fungal profiles were identified. Lower fungal diversities were found at the most rural site with the strongest climatic fluctuations and extreme values than in the most urban, sheltered library with a very stable climate. Further, the humidity-stabilizing potential of large collections of hygroscopic materials, such as books, was also examined. Implications for a sustainable approach to prevent future biodeterioration are discussed, supporting the long-term preservation of these valuable historic collections.

Remote Mountainous Area Inevitably Becomes Temporal Sink for Microplastics Driven by Atmospheric Transport.

Atmospheric transport drives the widespread distribution of microplastic (MP) in various ecosystems, posing a growing potential threat to environmental safety and human health. Understanding the source and fate of atmospheric MPs is thus crucial to constrain MP's widespread exposure. However, the source-sink dynamics of atmospheric MPs, especially in remote areas, are uncertain, and their transport routes have yet to be identified. Here, we conducted a 13-month monitoring of the atmospheric MPs in the uninhabited area of Mount Taibai, estimated the potential risk of MP exposure to the environment, and modeled the MP trajectory to analyze their transportation. We first found that as many as 15 polymer types of MPs, whose shapes mainly include fiber, fragments, films, and granules, maintained abundance (0.7 and 0.3 particle/m3 for PM10 and PM2.5, respectively) in the mountain atmosphere at respirable sizes. It is worth noting that the risk assessment results that comprehensively consider the influences of abundance and morphological characteristics suggest that the exposure level of MPs exhibits a risk even in this remote mountainous area that is not disturbed by frequent human activities. Backward trajectories revealed the likely source of MPs in the sparsely populated Liupan Mountains and Qinling Mountains of short-range transport. Further, polymer characteristics of MPs and airflow-based source analysis indicated the emission source of MPs in southern Xianyang in a longer-range transport. MPs were directionally transported to Mount Taibai through atmospheric transport under the premise of stable climate and geographical conditions. These suggest that MPs inevitably occur in remote mountainous areas driven by atmospheric transport, and the mountainous areas are persistently bearing the environmental impact of MP exposure. This study reveals the risk impacts of MP exposure and the transport dynamics of atmospheric MPs in a mountain ecosystem.

Late Triassic (Norian) strontium and oxygen isotopes from the Baoshan block, southwestern China: Possible causes and implications for climate change

The Norian Stage (Late Triassic) has long been regarded as an interval of stable climates, but, in fact, there are only sparse studies of the paleoclimate variations during this longest (>20 Myr) stage of the Phanerozoic. Here, oxygen and strontium isotopes have been measured on conodont apatite from the open-marine shelf succession at the Xiquelin section (Baoshan block, Yunnan Province, China). Magnetostratigraphy linked to conodont biostratigraphy indicates that the succession was deposited during the Sevatian substage, upper Norian. The δ18Oapatite values from conodonts indicate that low-latitude average sea-surface temperatures in eastern Tethys were ∼32 °C during the earliest Sevatian, cooled to ∼25 °C through the middle Sevatian, and then increased again to ∼29 °C by the late Sevatian. The seawater 87Sr/86Sr values maintained a high plateau through the entire Sevatian, with very little variation between inferred warm and cool episodes. The possible explanation for the observed trends in sea-surface temperature and 87Sr/86Sr during Sevatian is an enhanced weathering of silicates exposed during the closure of the Paleo-Tethys Ocean at the zenith of Pangea supercontinent assembly.

Understanding Key Stressors for Marine and Coastal Biodiversity Loss: An Overview

Biodiversity hotspots are the regions with high levels of endemic species and significant habitat loss. Coastal areas can exhibit distinct biodiversity hotspots due to their diverse habitats, such as coral reefs, mangrove forests, and intertidal zones. These hotspots often support unique assemblages of species adapted to specific coastal conditions. Ecosystem services provided by marine biodiversity include provisioning services (seafood, resources for medicine); regulating services (stable climate and clean water); cultural services (recreational and mental benefits: sea bathing); and supporting services (nutrient circulation and photosynthesis). Despite some successful conservation efforts, biodiversity continues to decline. Marine ecosystems are vulnerable to rapid changes in diversity and function. Major pressures and threats causing increasing pressure on coastal and marine biodiversity include climate change, ocean acidification, habitat destruction and changes in sea use, invasive species, overexploitation, and pollution. Preservation of coastal biodiversity is of prime importance for human wellbeing. The coastal ecosystems sustain diverse life forms and also safeguard essential ecological services. Therefore conservation and restoration of coastal biodiversity is a timeless responsibility for sustainable development. In light of these observations, this review aims to update recent information from the available literature on the key stressors of marine and coastal biodiversity loss. This study also suggests the strategies to be implemented for successful conservation and restoration of coastal and marine biodiversity.

Investigating the complex landscape of climate finance in least developed countries (LDCs)

This study aimed to investigate the complex landscape of climate finance, assessing the adequacy, predictability, and implications for sustainable development in least developed countries (LDCs). This study is motivated by the pressing need to assess the adequacy, predictability, and implications of climate finance for sustainable development in least developed countries (LDCs). Employing an econometric framework, this study utilizes ARIMA models to analyze time series data (from 2000 to 2021) on climate finance. The analysis revealed a notable gap between the needed and actual climate funding received by LDCs. Despite an annual requirement of $93.7 billion according to the UK-based International Institute for Environment and Development (IIED), LDCs have only received an average of $14.8 billion annually since 2015. The study suggests that climate funding for LDCs lacks predictability and falls short in meeting their needs, potentially facing an 80% decrease by 2030 under certain scenarios. It advocates for a strategic revamp in climate finance mechanisms to ensure adequacy and predictability, urging policymakers and international funding bodies to adopt more robust, fair, and needs-based approaches to climate financing. This research emphasizes the responsibility of developed nations and global agencies in bridging the considerable funding gap faced by LDCs. By integrating advanced forecasting techniques with a comprehensive analysis of global economic and political factors, this study sheds light on the challenges LDCs encounter in securing stable and sufficient climate finance, stressing the urgency for systemic reforms in global climate finance policies.

Influence of Political Stability on Foreign Direct Investment (FDI) Inflows in Nigeria

Purpose: The aim of the study was to assess the influence of political stability on foreign direct investment (FDI) inflows in Nigeria. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: The study indicated that political stability significantly influences foreign direct investment (FDI) inflows, as investors seek environments where their investments are secure and can yield predictable returns. Stable political conditions reduce risks related to government policy changes, expropriation, and civil unrest, thereby attracting more FDI. Conversely, political instability, marked by frequent government changes, corruption, and social unrest, deters investors due to increased uncertainty and risk. Studies have shown that countries with stable political climates tend to receive higher FDI inflows as they offer a safer, more predictable investment environment. Additionally, strong institutions and good governance practices further enhance investor confidence, leading to sustained economic growth through increased foreign investment. Implications to Theory, Practice and Policy: Institutional theory, risk theory and eclectic paradigm may be used to anchor future studies on assessing the influence of political stability on foreign direct investment (FDI) inflows in Nigeria. In practical terms, businesses and investors should focus on strengthening political institutions to create a stable and predictable environment. Policymakers play a crucial role in creating an environment conducive to FDI by prioritizing the implementation of political reforms that enhance stability. Ensuring free and fair elections, protecting civil liberties, and promoting effective governance structures are vital steps in this direction.

Coordination dynamics between fuel cell and battery technologies in the transition to clean cars

Significant progress reconciling economic activities with a stable climate requires radical and rapid technological change in multiple sectors. Here, we study the case of the automotive industry's transition to electric vehicles, which involved choosing between two different technologies: fuel cell electric vehicles (FCEVs) or battery electric vehicles (BEVs). We know very little about the role that such technological uncertainty plays in shaping the strategies of firms, the efficacy of technological and climate policies, and the speed of technological transitions. Here, we explain that the choice between these two technologies posed a global and multisectoral coordination game, due to technological complementarities and the global organization of the industry's markets and supply chains. We use data on patents, supply-chain relationships, and national policies to document historical trends and industry dynamics for these two technologies. While the industry initially focused on FCEVs, around 2008, the technological paradigm shifted to BEVs. National-level policies had a limited ability to coordinate global players around a type of clean car technology. Instead, exogenous innovation spillovers from outside the automotive sector played a critical role in solving this coordination game in favor of BEVs. Our results suggest that global and cross-sectoral technology policies may be needed to accelerate low-carbon technological change in other sectors, such as shipping or aviation. This enriches the existing theoretical paradigm, which ignores the scale of interdependencies between technologies and firms.

Stable isotope revealed hydroclimate transition and topography growth in the Northern Tibetan Plateau at ∼ 10 Ma

The Middle to Late Miocene uplift of the northern Tibetan Plateau had been revealed in a large amount of studies, however, its effects on hydrological and climatic evolution in Asia remains unclear due to the lack of well dated direct hydrological records in this region. Here, we report a carbonate oxygen isotope record (δ18Oc) from the western Qaidam Basin, and compare it with the δ18Oc records of five different basins in the Northern Tibetan Plateau. These data reconstruct the hydroclimatic evolution in this region and show a divergence of δ18Oc variation pattern in different basins at ∼11.5–8.5 Ma, which is different with a consistent evolution pattern of them before and after this time interval. This divergence is characterized by a significant decrease of δ18Oc in the windward locations while an increase in the leeward locations. This δ18Oc divergence was decoupling with the concurrent stable global climate, but consistent with the contemporaneous uplift of the northern Tibetan plateau. This suggests a possible link between δ18Oc divergence and topographic growth, which is further supported by a ∼ 1000 m paleoelevation increase revealed by our δ18Oc paleoelevation reconstruction. We suggest that the topography growth of the northern Tibetan Plateau especially the surrounding mountains would have facilitated water vapor transport to the windward regions, resulting in isotopic depletion in the water vapor masses. Whilst, a blocking of water vapor masses would induce aridity and increased evaporation in the leeward slopes, thus enriching heavy isotopes in precipitation there. This study corroborates the extensive uplift of the Northern Tibetan Plateau during ∼11.5–8.5 Ma from an isotopic perspective. A comparison of the obtained δ18Oc records with modern ones further suggests an establishment of modern hydroclimatic patterns in northern Tibetan Plateau at ∼8.5 Ma.

A universal tool for estimating monthly solar radiation on tilted surfaces from horizontal measurements: A machine learning approach

In this study, a universal method for estimating monthly solar radiation on tilted surfaces from horizontal measurements was developed and validated, targeting the optimal design and performance of solar energy systems. Using data from the Photovoltaic Geographical Information System (PVGIS) across 740 global locations, three machine learning models—linear regression, random forest, and k-nearest neighbors (KNN)—along with a multilayer perceptron deep learning model, were evaluated. The dataset spanned tilt angles from 0° to 90° at 1° increments and 11,511,773 rows with six input features for predicting irradiance on any tilt angle. The KNN model was selected for further testing analysis due to its superior accuracy, achieving the lowest root mean square error (RMSE) of 1.42 kWh/m2 and mean absolute error (MAE) of 0.7 kWh/m2 on the validation dataset. Testing was conducted with 16 years of data from five locations not included in the training dataset, obtained from PVGIS and Solcast. Results show that the KNN model consistently outperformed the traditional isotropic model in four out of five cities using PVGIS data and in two using Solcast data, especially excelling in regions with stable climates and consistent irradiance profiles. Moreover, better prediction performance was observed with PVGIS data compared to Solcast data across all five cities, with PVGIS data yielding an RMSE of 3.03 kWh/m2 and an MAE of 2.41 kWh/m2, while Solcast data exhibited a higher RMSE of 5.22 kWh/m2 and MAE of 4.14 kWh/m2. Finally, these results advocate for a shift towards data-driven methodologies highlighting their enhanced reliability.