Rising soil salinity poses significant challenges to Mediterranean viticulture. While some rootstocks effectively reduce salt accumulation in grafted scions, the mechanisms and performance of novel rootstocks remain largely unexplored. This study compared two novel M-series rootstocks (M2, M4) with established commercial rootstocks (1103 Paulsen, R110) to evaluate their physiological responses and salt tolerance under irrigation with varying salinity levels (0, 25, 50, and 75 mM NaCl) over 5 months. Growth parameters, photosynthetic efficiency, chlorophyll content (SPAD), ion homeostasis, and visual symptoms were monitored. Results revealed genotype-specific strategies: 1103 Paulsen exhibited robust photosynthetic efficiency and ion exclusion, maintaining growth and chlorophyll stability; M2 demonstrated superior biomass retention and moderate ion compartmentalization but showed reduced photosynthetic performance at higher salinity levels; R110 displayed effective ion management at moderate salinity but experienced significant growth reduction under severe stress; and M4 was the most sensitive, with severe reductions in growth and ion homeostasis. Organ-specific responses highlighted roots acting as primary ion reservoirs, particularly for sodium and calcium; leaves exhibited high potassium and chloride concentrations, critical for photosynthesis but prone to ionic imbalance under stress; and stems and wood played a buffering role, compartmentalizing excess sodium and minimizing damage to photosynthetic tissues. The reported findings provide valuable insights for rootstock selection and breeding programs, particularly for regions facing increasing soil and water salinization challenges.

The negative effects of PM2.5 concentration in urban development are becoming more and more prominent. Bernaola-Galvan Segmentation Algorithm (BGSA) and wavelet analysis are powerful tools for processing non-linear and non-stationary signals. First, we use BGSA that reveals there are 41 mutation points in the PM2.5 concentration in Guiyang. Then, we reveal the multi-scale evolution of PM2.5 concentration in Guiyang by wavelet analysis. In the first part, we performed one-dimensional continuous wavelet transform (CWT) on the eight monitoring points in the study area, and the results showed that they have obviously similar multi-scale evolution characteristics, with a high-energy and significant oscillation period of 190-512 days. Next, the wavelet transform coherence (WTC) reveals the mutual relationship between the PM2.5 concentration and the atmospheric pollutants and meteorological factors. PM2.5 concentration variation is closely linked to that of PM10 concentration. But, it is not to be ignored that the increase in the SO2 and NO2 concentrations will cause the PM2.5 concentration to rise on different scales. Lastly, the variation of the PM2.5 concentration can be better explained by the combination of multiple factors (2-4) using the multiple-wavelet coherence (MWC). Under the combination of the two factors, the average temperature (Avgtem) and relative humidity (ReH) have the highest AWC and PASC. In the case of the combination of four factors, CO-Avgtem-Wind-ReH plays the largest role in determining PM2.5 concentration.

Brown carbon (BrC) has been recognized as an important light-absorbing carbonaceous aerosol, yet understanding of its influence on regional climate and air quality has been lacking, mainly due to the ignorance of regional coupled meteorology-chemistry models. Besides, assumptions about its emissions in previous explorations might cause large uncertainties in estimates. Here, we implemented a BrC module into the WRF-Chem model that considers source-dependent absorption and avoids uncertainties caused by assumptions about emission intensities. To our best knowledge, we made the first effort to consider BrC in a regional coupled model. We then applied the developed model to explore the impacts of BrC absorption on radiative forcing, regional climate, and air quality in East Asia. We found notable increases in aerosol absorption optical depth (AAOD) in areas with high OC concentrations. The most intense forcing of BrC absorption occurs in autumn over Southeast Asia, and values could reach around 4 W m(-2). The intensified atmospheric absorption modified surface energy balance, resulting in subsequent declines in surface temperature, heat flux, boundary layer height, and turbulence exchanging rates. These changes in meteorological variables additionally modified near-surface dispersion and photochemical conditions, leading to changes of PM2.5 and O-3 concentrations. These findings indicate that BrC could exert important influence in specific regions and time periods. A more in-depth understanding could be achieved later with the developed model.

China experiences severe particulate matter (PM) pollution. Although a monitoring network for PM2.5 (diameter < 2.5 mu m) has been set up in more than 100 major Chinese cities, insufficient spatial coverage of observations limits the study of the temporal and spatial characteristics, influencing factors, and component of PM2.5. In this study, we conducted a one year air quality simulation using a regional climate-chemistry model and evaluated the simulation's performance based on in situ observations concerning meteorological elements and PM2.5 concentrations. The simulated results showed that, higher PM2.5 concentrations appeared in northern China and the Sichuan Basin, and the maximal value occurred in winter. Furthermore, Vertical PM2.5 concentrations presented a gradual decreasing trend from the surface, whereas in southern coastal cities the profiles were unsteady with a secondary peak in the lower layer. Meteorological conditions were conducive to both pollutant diffusion and removal in summer, whereas stagnant conditions appeared in winter, characterized by high sea level pressure (SLP), the lowest planetary boundary layer height (PBLH), and 2-m temperature (T2). In provincial capital cities, PM2.5 was positively correlated with residential emissions but negatively correlated with precipitation, 10-m wind speed, T2, PBLH, and industrial emissions. Finally, we utilized the simulation results to investigate the component variations of PM2.5. Results indicated that primary PM2.5 components had significantly higher concentrations in northern China where residential heating is the major source of PM2.5 emissions, whereas they had lower concentrations in southern China. Secondary components played a crucial role in PM2.5 mass in eastern China. This study provided a clear perspective of seasonal variations, horizontal and vertical distributions of PM2.5 and its components and influence factors, which could be used in subsequent studies to investigate the formation mechanism and emission sources of PM2.5.

Soil erosion caused by rain and runoff is a global issue that keeps getting worse over time. Damage caused by this phenomenon includes accelerated silting of dams. Considering that the storage capacity of major hydraulic structures gradually degrades owing to cumulative sedimentation, Tunisia faces severe environmental threats due to the annual decrease in reservoir capacity. Plant cover and land use are the most significant factors influencing the severity of soil erosion. In this vein, this study investigated the effect of soil cover on erosion at two agricultural sites in the El Kbir watershed, north Tunisia, using the cesium-137 (Cs-137) radioisotope tracer method. This radioactive element has been successfully used for investigating rates and patterns of soil erosion. The cesium-137 inventory obtained for the reference site is about 1341 Bq m-2. For study plots cultivated with olive trees and cereal crops, Cs-137 inventories are about 1036.37 Bq m-2 and 426.82 Bq m-2, respectively. The results show that the net erosion rate estimated by the mass balance model 2 (MBM2) was significantly higher in the cereal cultivated plot with 28.95 t ha-1 year-1 than in the olive cultivated plot with 7.16 t ha-1 year-1. The difference in net erosion rates between the two fields reveals the crucial role of the soil cover, as olive trees showed better resistance to erosive effects because of their system of roots. In contrast, culture of cereal crops, which occupy around 50% of the total area in the region, does not effectively protect and maintain the soil against erosion, which in turn induces intensive erosion of soil, resulting in sedimentation in dams. Soil erosion can therefore be reduced by adapting land use and increasing adequate vegetation cover.

PM2.5 impacts the atmospheric temperature structure through scattering or absorbing solar radiation, whose concentration and composition can affect the impact. This study calculated the effect of PM2.5 on the temperature structures in the urban centre and the suburbs of Nanjing, as well as their differences. The results show that the optical parameters, atmospheric heating rate, radiative forcing, and temperature are all impacted by the concentration and composition of PM2.5. The uneven distribution of PM2.5 influences the differences in those factors between the urban centre and suburbs. In spring, summer, autumn, and winter, surface temperatures in the urban centre were approximately 283 K, 285 K, 305 K, and 277 K, while those in the suburbs were approximately 282 K, 283 K, 304 K, and 274 K. The urban heat island intensity has been reduced by 0.1-0.4 K due to the presence of PM2.5 in Nanjing. Due to the black carbon component's warming effect on the top of the boundary layer, the impact of PM2.5 on the urban heat island intensity profile drops quickly at the 0.75-1.25 km. PM2.5 may mask the warm city problem and have a more complex impact on the urban climate.

Air pollutants can be transported to the pristine regions such as the Tibetan Plateau, by monsoon and stratospheric intrusion. The Tibetan Plateau region has limited local anthropogenic emissions, while this region is influenced strongly by transport of heavy emissions mainly from South Asia. We conducted a comprehensive study on various air pollutants (PM2.5, total gaseous mercury, and surface ozone) at Nam Co Station in the inland Tibetan Plateau. Monthly mean PM2.5 concentration at Nam Co peaked in April before monsoon season, and decreased during the whole monsoon season (June-September). Monthly mean total gaseous mercury concentrations at Nam Co peaked in July and were in high levels during monsoon season. The Indian summer monsoon acted as a facilitator for transporting gaseous pollutants (total gaseous mercury) but a suppressor for particulate pollutants (PM2.5) during the monsoon season. Different from both PM2.5 and total gaseous mercury variabilities, surface ozone concentrations at Nam Co are primarily attributed to stratospheric intrusion of ozone and peaked in May. The effects of the Indian summer monsoon and stratospheric intrusion on air pollutants in the inland Tibetan Plateau are complex and require further studies. (C) 2021 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V.

To understand the characteristics of particulate matter (PM) and other air pollutants in Xinjiang, a region with one of the largest sand-shifting deserts in the world and significant natural dust emissions, the concentrations of six air pollutants monitored in 16 cities were analyzed for the period January 2013-June 2019. The annual mean PM2.5, PM10, SO2, NO2, CO, and O-3 concentrations ranged from 51.44 to 59.54 mu g m(-3), 128.43-155.28 mu g m(-3), 10.99-17.99 mu g m(-3), 26.27-31.71 mu g m(-3), 1.04-1.32 mg m(-3), and 55.27-65.26 mu g m(-3), respectively. The highest PM concentrations were recorded in cities surrounding the Taklimakan Desert during the spring season and caused by higher amounts of wind-blown dust from the desert. Coarse PM (PM10-2.5) was predominant, particularly during the spring and summer seasons. The highest PM2.5/PM10 ratio was recorded in most cities during the winter months, indicating the influence of anthropogenic emissions in winters. The annual mean PM2.5 (PM10) concentrations in the study area exceeded the annual mean guidelines recommended by the World Health Organization (WHO) by a factor of ca. similar to 5-6 (similar to 7-8). Very high ambient PM concentrations were recorded during March 19-22, 2019, that gradually influenced the air quality across four different cities, with daily mean PM2.5 (PM10) concentrations similar to 8-54 (similar to 26-115) times higher than the WHO guidelines for daily mean concentrations, and the daily mean coarse PM concentration reaching 4.4 mg m(-3). Such high PM2.5 and concentrations pose a significant risk to public health. These findings call for the formulation of various policies and action plans, including controlling the land degradation and desertification and reducing the concentrations of PM and other air pollutants in the region. (C) 2020 Elsevier Ltd. All rights reserved.

Fine particles (PM2.5) scatter and absorb solar radiation affecting the atmospheric temperature structure, and the effects vary with different concentrations and compositions. This study investigated the effect of PM2.5 on the urban temperature structure of Nanjing through concen- tration-and species-sensitive experiments using a box model. The results show that the optical parameters, atmospheric heating rate, radiative forcing, and temperature are affected by the PM2.5 concentration, PM2.5 composition, and relative humidity. Under 80% relative humidity, the asymmetry and single scattering albedo (SSA) were 0.7 and 0.88, while under 20% relative hu-midity, they were 0.6 and 0.77, respectively. PM2.5 increased the atmospheric heating rate by 1-18 K/day; while the surface temperature decreased with the presence of PM2.5. Furthermore, the heterogeneous concentration and composition distributions of PM2.5 led to changes in urban heat island (UHI) intensity. The UHI intensity could be reduced by 1-3 K by PM2.5, and the reduction increased with the increase in PM2.5 concentration and absorbing compositions. The existence of absorbing compositions and high concentrations of PM2.5 may work together to mask the UHI effect and other problems of urban development from 2000s till the present.

Ambient fine particulate matter (PM2.5) concentrations in India frequently exceed 100 mu g/m(3) during fall and winter pollution episodes. We use the GEOS-Chem chemical transport model with the TwO-Moment Aerosol Sectional microphysics scheme with 15 size bins (TOMAS15) to assess PM2.5 composition and impacts on radiation and cloud condensation nuclei (CCN) during pollution episodes as compared to the seasonal (October-December) average. We conduct high resolution (0.25 degrees x 0.3125 degrees) nested-domain simulations over India for short-duration, high-PM2.5 episodes in the fall of 2015 and 2017. The simulations capture the magnitude and spatial patterns of pollution episodes measured by surface monitors (r(PM2.5)(2) = 0.69) although aerosol optical depth is underestimated. During the episodes, near-surface organic matter (OM), black carbon (BC), and secondary inorganic aerosol concentrations increase from seasonal averages by up to 36, 7, and 7 mu g/m(3), respectively. Episodic aerosol increases enhance cooling by lowering the top-of-atmosphere clear-sky direct radiative effect (DRETOA) during the 2015 episode (-6 W/m(2)), with a smaller impact during the 2017 episode (-1 W/m(2)). Differences in DRETOA reflect larger increases in scattering aerosols in the column during the 2015 episode (+17 mg/m(2)) than in 2017 (+13 mg/m(2)), while absorbing aerosol column enhancements are smaller (+3 mg/m(2)) in both years. Changes in shortwave radiation at the surface (SWsfc) are spatially similar to DRETOA and mostly negative during both episodes. CCN enhancements (0.2% supersaturation) during these episodes occur across the western Indo-Gangetic Plain, coincident with higher PM2.5 concentrations. Changes in DRETOA, SWsfc, and CCN during high-PM2.5 episodes may have implications for crops, the hydrologic cycle, and surface temperature.