Estimation of Daily Solar Radiation Budget at Kilometer Resolution over the Tibetan Plateau by Integrating MODIS Data Products and a DEM

Climate change impact on photovoltaic power potential in China based on CMIP6 models

China has the largest worldwide cumulative installed photovoltaic (PV) capacity, which is expected to be 1300 GW in 2050. Industrial production, population explosion and fossil fuel combustion would reduce the surface solar radiation that could be received by PV panels. However, it is still a problem to explore the integrated effects of socio-economic and air pollutant emissions on PV power potential in China. In this study, climate change impact on PV power potential in 2023-2100 were assessed using the Coupled Model Intercomparison Project Phase 6 (CMIP6) model, combining Shared Socio-economic Pathway (SSPs) and Representative Concentration Pathways (RCPs). The validation results with ground-based surface solar radiation measurements collected from 17 China Meteorological Administration (CMA) stations showed that the Meteorological Research Institute Earth System Model version 2-0 (MRI-ESM2-0) attained a better performance with mean correlation coefficients (R), Root Mean Square Error (RMSE), and Mean Absolute Error (MAE) of 0.85, 35.80 Wm^-2 and 29.37 Wm^-2, respectively. Then, the MRI-ESM2-0 model was selected to analyze the spatial and temporal variations in PV power potential. PV power potential decreased significantly in SSP585 ranging from 192.71 Wm^-2 to 189.96 Wm^-2 in 2023-2100 corresponding to the growing resource intensity and fossil fuel dependency. In contrast, if China continues on the path of sustainable and low-carbon development and keeps temperature rise to about 1.5 °C by 2100, PV power potential will increase by 1.36-5.90 Wm^-2. Meanwhile, the effects of climatological factors on PV power potential were analyzed by Empirical Orthogonal Function (EOF) method. Results indicated that surface solar radiation had the highest contribution of >50 %, and the contribution of aerosols and cloud cover was about 20 %. This study is conducive to the full utilization of solar resources and has important implications for the future formulation of solar energy policy in China.

Estimation of the Surface Net Radiation Under Clear-Sky Conditions in Areas With Complex Terrain: A Case Study in Haihe River Basin

The surface net radiation as an important component of the surface radiation budget has attracted wide attention; however, it is still an enormous challenge to carry out an accurate estimation of the surface net radiation in areas with complex terrain due to the scarcity of radiation observation sites and high-spatial heterogeneity of the influencing factors of the surface net radiation. Taking the Haihe River Basin as the study area, this study estimated the surface net radiation under clear-sky conditions from 2001∼2019 based on an improved algorithm of the net long-wave radiation, and the solar short-wave radiation in terms of direct radiation, diffuse sky radiation, and reflected radiation from the surrounding terrain. In this study, the regional meteorological factors were inverted based on remote sensing data to make up for the deficiency of meteorological factor interpolation. The solar short-wave radiation was corrected by considering the comprehensive influence of the atmosphere, underlying surface, and terrain, and the net long-wave radiation was optimized by localizing the algorithm coefficients. The results showed the correlation coefficient between the estimated and observed surface net radiation reached approximately 0.9, indicating the accuracy of this improved method is acceptable. Besides, the results suggested the surface net radiation was significantly influenced by the terrain, the highest value of which occurred on the south slope, followed by that on the southwest slope, west or southeast slopes, and the lowest value occurred on the north slope. In addition, there was the highest surface net radiation in summer, and there was the lowest and most frequently negative surface net radiation in winter. This study makes up for the shortcomings of the traditional spatial interpolation of meteorological factors and previous empirical formulas, and can therefore provide an important methodological foundation for the research on the surface radiation, climate, and hydrology in the areas with complex terrain.

Solar Climate Features Taking into Account the Morphometric Conditions of the Area and the Possibility of Using Them in Heliotherapy on the Example of the Cieplice and Kołobrzeg Health Resorts (Poland)

Global solar radiation is an important atmospheric stimulus affecting the human body and has been used in heliotherapy for years. In addition to environmental factors, the effectiveness of global solar radiation is increasingly influenced by human activity. This research was based on the use of heliographic and actinometric data (1996–2015) and the model distribution of global solar radiation to determine the possibility of heliotherapy with the example of two health resorts: Cieplice and Kołobrzeg (Poland). The solar features of health resorts (sunshine duration and global solar radiation) were characterized, and they were correlated with the spatial distribution of global solar radiation data obtained with the use of remote sensing techniques (System for Automated Geoscientific Analyzes-SAGA), including COoRdination and INformation on the Environment (CORINE) land cover (CLC) data. Using the maximum entropy model (MaxEnt), a qualitative and quantitative relationship between morphometric parameters and solar climate features was demonstrated for individual land cover types. Studies have shown that the period of late spring and summer, due to the climate’s solar features, is advisable for the use of heliotherapy. The human activity that determines the land cover is the main element influencing the spatial differentiation of the possibilities of using this form of health treatment. It also affects topographic indicators shown as significant in the MaxEnt predictive model. In general, areas with high openness were shown as predisposed for health treatment using global solar radiation, which is not consistent with areas commonly used for heliotherapy. The conducted research has shown the need for an interdisciplinary approach to the issue of heliotherapy, which will contribute to the optimization of the use of this form of health treatment from the perspective of climate change and human pressure.

Oxidative Stress Responses of Some Endemic Plants to High Altitudes by Intensifying Antioxidants and Secondary Metabolites Content

Most endemic plant species have limited altitudinal ranges. At higher altitudes, they are subjected to various environmental stresses. However, these plants use unique defense mechanisms at high altitudes as a convenient survival strategy. The changes in antioxidant defense system and accumulation of different secondary metabolites (SMs) were investigated as depending on altitude in five endemic endangered species (Nepeta septemcrenata, Origanum syriacum subsp. Sinaicum, Phlomis aurea, Rosa arabica, and Silene schimperiana) naturally growing in Saint Katherine protectorate (SKP). Leaves were collected from different sites between 1600 and 2200 m above sea level to assess the biochemical and physiological variations in response to high altitudes. At higher altitudes, the soil pH and micronutrient soil content decreased, which can be attributed to lower mineralization processes at lower pH. Total phenols, ascorbic acid, proline, flavonoids, and tannins increased in response to different altitudes. SMs progressively increased in the studied species, associated with a significant decrease in the levels of antioxidant enzyme activity. R. arabica, as the most threatened plant, showed the maximum response compared with other species. There was an increase in photosynthetic pigments, which was attained via the increase in chlorophyll a, chlorophyll b, and carotenoid contents. There was a significant increase in total soluble sugars and total soluble protein content in response to different altitudes. SDS-PAGE of leaf proteins showed alteration in the protein profile between different species and the same species grown at a different altitude. These five species can adapt to high-altitude habitats by various physiological mechanisms, which can provide a theoretical basis for the future conservation of these endangered endemic species in SKP.

Improvement in Surface Solar Irradiance Estimation Using HRV/MSG Data

The Advanced Model for the Estimation of Surface Solar Irradiance (AMESIS) was developed at the Institute of Methodologies for Environmental Analysis of the National Research Council of Italy (IMAA-CNR) to derive surface solar irradiance from SEVIRI radiometer on board the MSG geostationary satellite. The operational version of AMESIS has been running continuously at IMAA-CNR over all of Italy since 2017 in support to the monitoring of photovoltaic plants. The AMESIS operative model provides two different estimations of the surface solar irradiance: one is obtained considering only the low-resolution channels (SSI_VIS), while the other also takes into account the high-resolution HRV channel (SSI_HRV). This paper shows the difference between these two products against simultaneous ground-based observations from a network of 63 pyranometers for different sky conditions (clear, overcast and partially cloudy). Comparable statistical scores have been obtained for both AMESIS products in clear and cloud situation. In terms of bias and correlation coefficient over partially cloudy sky, better performances are found for SSI_HRV (0.34 W/m2 and 0.995, respectively) than SSI_VIS (−33.69 W/m2 and 0.862) at the expense of the greater run-time necessary to process HRV data channel.