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Volume 12
Issue 9
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Atmosphere, Volume 12, Issue 9 (September 2021) – 146 articles

Cover Story (view full-size image): The retrieval of aerosol optical thickness (AOT) from remotely sensed data relies on the adopted aerosol model. However, the method of this technique has been rather limited because of the spatial variability in the aerosol properties over the land surfaces. In this study, we created a custom aerosol model using SKYNET observation data of aerosol volume size distribution and refractive indices, coupled with spectral response functions of satellite visible bands for the visibility-derived AOT estimation from satellite images under clear-sky conditions. View this paper.
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11 pages, 46534 KiB  
Communication
Particle Shape Impact on the Radiative Forcing Efficiency Estimated from Single Levitated (NH4)2SO4 Particles
by Antonio Valenzuela Gutierrez
Atmosphere 2021, 12(9), 1231; https://doi.org/10.3390/atmos12091231 - 21 Sep 2021
Viewed by 2075
Abstract
Levitation of single trapped particles enables the exploration of fundamental physicochemical aerosol properties never previously achieved. Experimental measurements showed that (NH4)2SO4’s particle shape deviated from sphericity during the crystallization process. Despite that, salt aerosols are assumed to [...] Read more.
Levitation of single trapped particles enables the exploration of fundamental physicochemical aerosol properties never previously achieved. Experimental measurements showed that (NH4)2SO4’s particle shape deviated from sphericity during the crystallization process. Despite that, salt aerosols are assumed to be spheres even in low relative humidity (RH) in most climate models. In the analysis performed here, Mie and T-Matrix codes were operated to simulate crucial parameters needed to estimate the radiative forcing efficiency: extinction efficiency, asymmetry parameter and backscattering fraction. The incorporation of non-spherical effects in (NH4)2SO4 particles can cause a difference of up to 46% radiative forcing efficiency compared to the assumption of sphericity in the 0.3–0.6 µm particle radius range. Full article
(This article belongs to the Special Issue Levitating Droplet Clusters in Aerosol Science)
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11 pages, 1668 KiB  
Article
Could Macroscopic Dark Matter (Macros) Give Rise to Mini-Lightning Flashes out of a Blue Sky without Clouds?
by Vernon Cooray, Gerald Cooray, Marcos Rubinstein and Farhad Rachidi
Atmosphere 2021, 12(9), 1230; https://doi.org/10.3390/atmos12091230 - 21 Sep 2021
Cited by 6 | Viewed by 2272
Abstract
A recent study pointed out that macroscopic dark matter (macros) traversing through the Earth’s atmosphere can give rise to hot and ionized channels similar to those associated with lightning leaders. The authors of the study investigated the possibility that when such channels created [...] Read more.
A recent study pointed out that macroscopic dark matter (macros) traversing through the Earth’s atmosphere can give rise to hot and ionized channels similar to those associated with lightning leaders. The authors of the study investigated the possibility that when such channels created by macros pass through a thundercloud, lightning leaders may be locked in by these ionized channels, creating lightning discharges with perfectly straight channels. They suggested the possibility of detecting such channels as a means of detecting the passage of macros through the atmosphere. In this paper, we show that such macros crossing the atmosphere under fair weather conditions could also give rise to mini-lightning flashes with current amplitudes in the order of a few hundred Amperes. These mini-lightning flashes would generate a thunder signature similar to or stronger than those of long laboratory sparks and they could also be detected by optical means. As in the case of thunderstorm-assisted macro lightning, these mini-lightning flashes are also associated with straight channels. Moreover, since the frequency of mini-lightning flashes is about thirty times greater than the macro-generated lightning flashes assisted by thunderstorms, they could be used as a means to look for the paths of macroscopic dark matter crossing the atmosphere. Full article
(This article belongs to the Section Upper Atmosphere)
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16 pages, 1965 KiB  
Article
Characteristics of Potentially Toxic Elements, Risk Assessments, and Isotopic Compositions (Cu-Zn-Pb) in the PM10 Fraction of Road Dust in Busan, South Korea
by Hyeryeong Jeong and Kongtae Ra
Atmosphere 2021, 12(9), 1229; https://doi.org/10.3390/atmos12091229 - 19 Sep 2021
Cited by 22 | Viewed by 3983
Abstract
The pollution status of ten potentially toxic elements (PTEs), isotopic compositions (Cu, Zn, Pb), and the potential ecological risk posed by them were investigated in the PM10 fraction of road dust in Busan Metropolitan city, South Korea. Enrichment factors revealed extremely to [...] Read more.
The pollution status of ten potentially toxic elements (PTEs), isotopic compositions (Cu, Zn, Pb), and the potential ecological risk posed by them were investigated in the PM10 fraction of road dust in Busan Metropolitan city, South Korea. Enrichment factors revealed extremely to strongly polluted levels of Sb, Cd, Zn, Pb, and Cu in the PM10 fraction of road dust, with Sb levels being the highest. Statistical analyses showed that the major cause for contamination with PTEs was non-exhaust traffic emissions such as tire and brake wear. Cu and Zn isotopic compositions of road dust were related to traffic-related emission sources such as brake and tires. Pb isotopic compositions were close to that of road paint, indicating that Pb was a different source from Cu and Zn in this study. No significant health risk was posed by the PTEs. Taking into account the total length of road in Busan, a high quantity of PTEs in road dust (PM10) can have serious deleterious effects on the atmospheric environment and ecosystems. The results of metal concentrations and isotopic compositions in road dust will help identify and manage atmospheric fine particle and coastal metal contamination derived from fine road dust. Full article
(This article belongs to the Special Issue Impacts of Transport Systems on Air Pollution and Human Health)
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20 pages, 4640 KiB  
Article
Chemical Composition and Source Apportionment of Total Suspended Particulate in the Central Himalayan Region
by Rahul Sheoran, Umesh Chandra Dumka, Dimitris G. Kaskaoutis, Georgios Grivas, Kirpa Ram, Jai Prakash, Rakesh K. Hooda, Rakesh K. Tiwari and Nikos Mihalopoulos
Atmosphere 2021, 12(9), 1228; https://doi.org/10.3390/atmos12091228 - 19 Sep 2021
Cited by 14 | Viewed by 4769
Abstract
The present study analyzes data from total suspended particulate (TSP) samples collected during 3 years (2005–2008) at Nainital, central Himalayas, India and analyzed for carbonaceous aerosols (organic carbon (OC) and elemental carbon (EC)) and inorganic species, focusing on the assessment of primary and [...] Read more.
The present study analyzes data from total suspended particulate (TSP) samples collected during 3 years (2005–2008) at Nainital, central Himalayas, India and analyzed for carbonaceous aerosols (organic carbon (OC) and elemental carbon (EC)) and inorganic species, focusing on the assessment of primary and secondary organic carbon contributions (POC, SOC, respectively) and on source apportionment by positive matrix factorization (PMF). An average TSP concentration of 69.6 ± 51.8 µg m−3 was found, exhibiting a pre-monsoon (March–May) maximum (92.9 ± 48.5 µg m−3) due to dust transport and forest fires and a monsoon (June–August) minimum due to atmospheric washout, while carbonaceous aerosols and inorganic species expressed a similar seasonality. The mean OC/EC ratio (8.0 ± 3.3) and the good correlations between OC, EC, and nss-K+ suggested that biomass burning (BB) was one of the major contributing factors to aerosols in Nainital. Using the EC tracer method, along with several approaches for the determination of the (OC/EC)pri ratio, the estimated SOC component accounted for ~25% (19.3–29.7%). Furthermore, TSP source apportionment via PMF allowed for a better understanding of the aerosol sources in the Central Himalayan region. The key aerosol sources over Nainital were BB (27%), secondary sulfate (20%), secondary nitrate (9%), mineral dust (34%), and long-range transported mixed marine aerosol (10%). The potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analyses were also used to identify the probable regional source areas of resolved aerosol sources. The main source regions for aerosols in Nainital were the plains in northwest India and Pakistan, polluted cities like Delhi, the Thar Desert, and the Arabian Sea area. The outcomes of the present study are expected to elucidate the atmospheric chemistry, emission source origins, and transport pathways of aerosols over the central Himalayan region. Full article
(This article belongs to the Special Issue Aerosol Observations at High Altitude Stations)
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11 pages, 4475 KiB  
Article
Impacts of the Wave Train along the Asian Jet on the South China Sea Summer Monsoon Onset
by Li Xu and Zi-Liang Li
Atmosphere 2021, 12(9), 1227; https://doi.org/10.3390/atmos12091227 - 18 Sep 2021
Cited by 4 | Viewed by 2890
Abstract
The South China Sea (SCS) summer monsoon (SCSSM) onset signifies the commencement of large-scale summer monsoon over East Asia and the western North Pacific (WNP). Previous studies on the influencing factors of the SCSSM onset mainly focus on the tropical systems, such as [...] Read more.
The South China Sea (SCS) summer monsoon (SCSSM) onset signifies the commencement of large-scale summer monsoon over East Asia and the western North Pacific (WNP). Previous studies on the influencing factors of the SCSSM onset mainly focus on the tropical systems, such as El Niño-Southern Oscillation (ENSO). This study reveals that the wave train along the Asian jet could act as an extratropical factor to modulate the SCSSM onset, and it is largely independent of ENSO. The SCSSM onset tends to be earlier during the positive phase of the wave train (featured by northerly anomalies over Central Iran plateau and eastern China, southerly anomalies over Arabian Peninsula, eastern Indian subcontinent, and eastern Bonin islands). The wave train affects the SCSSM onset mainly via modulating the WNP subtropical high. The wave train during the positive phase can induce negative geopotential height anomalies in the mid-troposphere and anomalous cyclones in the lower-troposphere over the SCS and the Philippine Sea, leading to the weakening of the WNP subtropical high. Specifically, the anomalous ascending motions associated with the low-level cyclone are favorable for the increased rainfall over the SCS, and the anomalous westerly on the south of the anomalous cyclone is conducive to the transition of the zonal wind (from easterly to westerly). The above circulation anomalies associated with the positive phase of the wave train provide a favorable environment for the advanced SCSSM onset. Full article
(This article belongs to the Special Issue Asian Monsoons: Observation and Prediction)
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14 pages, 3533 KiB  
Article
Analysis of Aerosol Optical Depth from Sun Photometer at Shouxian, China
by Lina Xun, Hui Lu, Congcong Qian, Yong Zhang, Shanshan Lyu and Xin Li
Atmosphere 2021, 12(9), 1226; https://doi.org/10.3390/atmos12091226 - 18 Sep 2021
Cited by 14 | Viewed by 3213
Abstract
We use two cloud screening methods—the clustering method and the multiplet method—to process the measurements of a sun photometer from March 2020 to April 2021 in Shouxian. The aerosol optical depth (AOD) and Angström parameters α and β are retrieved; variation characteristics and [...] Read more.
We use two cloud screening methods—the clustering method and the multiplet method—to process the measurements of a sun photometer from March 2020 to April 2021 in Shouxian. The aerosol optical depth (AOD) and Angström parameters α and β are retrieved; variation characteristics and single scattering albedo are studied. The results show that: (1) The fitting coefficient of AOD retrieved by the two methods is 0.921, and the changing trend is consistent. The clustering method has fewer effective data points and days, reducing the overall average of AOD by 0.0542 (500 nm). (2) Diurnal variation of AOD can be divided into flat type, convex type, and concave type. Concave type and convex type occurred the most frequently, whereas flat type the least. (3) During observation, the overall average of AOD is 0.48, which is relatively high. Among them, AOD had a winter maximum (0.70), autumn and spring next (0.54 and 0.40), and a summer minimum (0.26). The variation trend of AOD and β is highly consistent, and the monthly mean of α is between 0.69 and 1.61, concerning mainly continental and urban aerosols. (4) Compared with others, the single scattering albedo in Shouxian is higher, reflecting strong scattering and weak aerosol absorption. Full article
(This article belongs to the Special Issue Atmospheric Aerosol Optical Properties)
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23 pages, 4282 KiB  
Article
Tropospheric Delay in the Neapolitan and Vesuvius Areas (Italy) by Means of a Dense GPS Array: A Contribution for Weather Forecasting and Climate Monitoring
by Umberto Riccardi, Umberto Tammaro and Paolo Capuano
Atmosphere 2021, 12(9), 1225; https://doi.org/10.3390/atmos12091225 - 18 Sep 2021
Cited by 5 | Viewed by 2883
Abstract
Studying the spatiotemporal distribution and motion of water vapour (WV), the most variable greenhouse gas in the troposphere, is pivotal, not only for meteorology and climatology, but for geodesy, too. In fact, WV variability degrades, in an unpredictable way, almost all geodetic observation [...] Read more.
Studying the spatiotemporal distribution and motion of water vapour (WV), the most variable greenhouse gas in the troposphere, is pivotal, not only for meteorology and climatology, but for geodesy, too. In fact, WV variability degrades, in an unpredictable way, almost all geodetic observation based on the propagation of electromagnetic signal through the atmosphere. We use data collected on a dense GPS network, designed for the purposes of monitoring the active Neapolitan (Italy) volcanoes, to retrieve the tropospheric delay parameters and precipitable water vapour (PWV). This study has two main targets: (a) the analysis of long datasets (11 years) to extract trends of climatological meaning for the region; (b) studying the main features of the time evolution of the PWV during heavy raining events to gain knowledge on the preparatory stages of highly impacting thunderstorms. For the latter target, both differential and precise point positioning (PPP) techniques are used, and the results are compared and critically discussed. An increasing trend, amounting to about 2 mm/decades, has been recognized in the PWV time series, which is in agreement with the results achieved in previous studies for the Mediterranean area. A clear topographic effect is detected for the Vesuvius volcano sector of the network and a linear relationship between PWV and altitude is quantitatively assessed. This signature must be taken into account in any modelling for the atmospheric correction of geodetic and remote-sensing data (e.g., InSAR). Characteristic temporal evolutions were recognized in the PWV in the targeted thunderstorms (which occurred in 2019 and 2020), i.e., a sharp increase a few hours before the main rain event, followed by a rapid decrease when the thunderstorm vanished. Accounting for such a peculiar trend in the PWV could be useful for setting up possible early warning systems for those areas prone to flash flooding, thus potentially providing a tool for disaster risk reduction. Full article
(This article belongs to the Special Issue Modeling Multiscale Dynamics by Statistical Mechanics in Heliophysics and Geophysics)
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19 pages, 3280 KiB  
Article
A Climatological Study of the Mechanisms Controlling the Seasonal Meridional Migration of the Atlantic Warm Pool in an OGCM
by Dahirou Wane, Alban Lazar, Malick Wade and Amadou Thierno Gaye
Atmosphere 2021, 12(9), 1224; https://doi.org/10.3390/atmos12091224 - 18 Sep 2021
Cited by 1 | Viewed by 2119
Abstract
The tropical Atlantic Warm Pool is one of the main drivers of the marine intertropical convergence zone and the associated coastal Northeast Brazilian and West-African monsoons. Its meridional displacement is driven by the solar cycle, modulated by the atmosphere and ocean interactions, whose [...] Read more.
The tropical Atlantic Warm Pool is one of the main drivers of the marine intertropical convergence zone and the associated coastal Northeast Brazilian and West-African monsoons. Its meridional displacement is driven by the solar cycle, modulated by the atmosphere and ocean interactions, whose nature and respective proportions are still poorly understood. This paper presents a climatological study of the upper ocean and lower atmosphere contributions to the warm pool seasonal migration, using an Ocean General Circulation Model (OGCM). First, we provide quantitative, albeit simple, pieces of evidence on how the large amplitude of migration in the west, compared to the east, is mainly due to the strong east–west contrast of the background meridional SST gradient intensities, which is maintained by equatorial and eastern tropical upwellings. Our main results consist first in identifying a diagnostic equation for the migration speed of the two meridional boundary isotherms of the Warm Pool, expressed in terms of the various mixed-layer heat fluxes. We then evidence and quantify how, in general, the migration is forced by air–sea fluxes, and damped by ocean circulation. However, remarkable controls by the ocean are identified in some specific regions. In particular, in the northwestern part of the Warm Pool, characterized by a large temperature inversion area, the boreal spring northward movement speed depends on the restitution of the solar heating by the thermocline. Additionally, over the southern part of the Warm Pool, our study quantifies the key role of the equatorial upwelling, which, depending on the longitude, significantly accelerates or slows down the summer poleward migration. Full article
(This article belongs to the Special Issue Tropical Atlantic Variability)
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10 pages, 1114 KiB  
Article
Potential of Chamomile recutita Plant Material to Inhibit Urease Activity and Reduce NH3 Volatilization in Two Agricultural Soils
by Jie Li, Shuai Wang, Jiafa Luo, Stuart Lindsey, Lingli Wang, Lei Zhang and Yuanliang Shi
Atmosphere 2021, 12(9), 1223; https://doi.org/10.3390/atmos12091223 - 18 Sep 2021
Cited by 4 | Viewed by 2678
Abstract
The large amount of ammonia released during agricultural application of urea fertilizer can result in a partial loss of applied nitrogen, having a detrimental effect on air quality. Although Chamomile recutita has nitrogen transformation inhibitory properties, providing potential agricultural and environmental benefits, the [...] Read more.
The large amount of ammonia released during agricultural application of urea fertilizer can result in a partial loss of applied nitrogen, having a detrimental effect on air quality. Although Chamomile recutita has nitrogen transformation inhibitory properties, providing potential agricultural and environmental benefits, the full extent of the effects of the major constituents of this plant on urease activity and NH3 volatilization in soils is currently unknown. Soil incubation experiments were established using 2-Cyclopenten-1-one and Eugenol, two major constituents of C. recutita, to evaluate their effects on inorganic soil nitrogen pools, urease activity, and NH3 volatilization in grey desert soil and red soil. An application rate of 0.25 g N kg−1 soil fertilizer was applied as urea with and without additives. An unfertilized treatment was also included as a control. In order to compare results, N(butyl) thiophosphoric triamide (NBPT), a common synthetic urease inhibitor, was also used. NBPT, 2-Cyclopenten-1-one and Eugenol were applied at a rate of 0.00125 g kg−1 soil (equivalent to 0.5% N). The results indicated that the rate of urea hydrolysis was higher in grey desert soil compared to red soil. Soil in the urea-only treatments recorded urea hydrolysis to be almost complete within seven days of application. The rate of hydrolysis was inhibited by the two natural compounds, and higher concentrations of urea were maintained for more than two weeks. Soil amended with the two materials exhibited strong soil urease inhibition in both soil treatments (75.1% in the alkaline grey desert soil and 72.8% in the acidic red soil). The strongest inhibitory effect occurred one to three days after incubation in the Eugenol treatment. Moreover, the inhibitory effects of Cyclopenten-1-one and Eugenol were superior to that of NBPT in the two soils. Cyclopenten-1-one and Eugenol also significantly reduced soil NH3 emissions by 14.2 to 45.3%, especially in the acidic red soil. Molecular docking studies confirmed inhibition mechanisms, highlighting that natural compounds interacted with the amino acid residues of the urease active center. This action resulted in the urease active pocket being blocked, thereby inhibiting enzyme activity. Overall, our findings suggest that 2-Cyclopenten-1-one and Eugenol are both capable of hindering urease activity and reducing the risk of N loss in the two tested soils. Results highlight their applicability as urease inhibitors and their effect in delaying the release of ammonia nitrogen, thereby increasing fertilizer N use efficiency. However, in order to fully assess N use efficiency and the N balance due to the presence of Chamomile extract in soil-crop systems, further field scale investigations are required. Full article
(This article belongs to the Special Issue Ammonia Emissions from Agriculture Activities: Sources, Dynamics and Fate)
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10 pages, 1061 KiB  
Article
Effect of Flushing Milk and Acidic Whey on pH and Nitrogen Loss of Cattle Manure Slurry
by Thomas Sepperer, Alexander Petutschnigg and Konrad Steiner
Atmosphere 2021, 12(9), 1222; https://doi.org/10.3390/atmos12091222 - 18 Sep 2021
Cited by 2 | Viewed by 3533
Abstract
With the increasing demand for food worldwide, the use of fertilizers in the agricultural industry has grown. Natural fertilizers derived from the use of animal manure slurry, especially cattle and cow, are responsible for 40% of the agricultural ammonia emission. The EU defined [...] Read more.
With the increasing demand for food worldwide, the use of fertilizers in the agricultural industry has grown. Natural fertilizers derived from the use of animal manure slurry, especially cattle and cow, are responsible for 40% of the agricultural ammonia emission. The EU defined the goal to reduce NH3 emission drastically until 2030, yet until today an overall increase has been observed, making it more difficult to reach the target. In this study, we used two by-products from the dairy industry, namely flushing milk and acidic whey, to lower the pH of cattle manure slurry and therefore mitigate the loss of nitrogen in the form of ammonia into the atmosphere, making it available in the soil. Measurements of pH, ammonium nitrogen, total Kjeldahl nitrogen, and lactic acid bacteria colonies were conducted in a lab-scale experiment to test the hypothesis. Afterwards, pH measurements were conducted on bigger samples. We found that whey effectively reduced the pH of manure below 5, therefore moving the ammonia/ammonium equilibrium strongly towards ammonium. Flushing milk on the other hand lowered the pH to a smaller extent, yet allowed for faster hydrolysis of urea into ammonium. The findings in this study present a suitable and environmentally friendly approach to help reach the climate goals set by the EU by using by-products from the same industry branch, therefore being a suitable example of circular economy. Full article
(This article belongs to the Special Issue Ammonia Emissions from Agriculture Activities: Sources, Dynamics and Fate)
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28 pages, 4777 KiB  
Article
Rapid Evaluation of the Effects of Policies Corresponding to Air Quality, Carbon Emissions and Energy Consumption: An Example from Shenzhen, China
by Shi-Qi Yang, Jia Xing, Wen-Ying Chen, Fen Li and Yun Zhu
Atmosphere 2021, 12(9), 1221; https://doi.org/10.3390/atmos12091221 - 17 Sep 2021
Cited by 7 | Viewed by 3287
Abstract
Efficient environmental policies are necessary in the improvement of air quality and reduction in carbon emissions, and the interactions between policy, activity, emissions, and environment comprise a cycle allowing the evaluation of the effects of implemented policies. Based on the establishment of the [...] Read more.
Efficient environmental policies are necessary in the improvement of air quality and reduction in carbon emissions, and the interactions between policy, activity, emissions, and environment comprise a cycle allowing the evaluation of the effects of implemented policies. Based on the establishment of the connection between environmental parameters and policy context using a quantifiable methodology, in this study, we formulated a rapid and simplified pattern for the evaluation of the effects of policies concerning the atmospheric environment, and applied it to the evaluation and improvement of policies for Carbon dioxide (CO2) reduction and air quality enhancement in the sample city of Shenzhen. The Response Surface Model-Visualization and Analysis Tool (RSM-VAT) in the Air Benefit and Cost and Attainment Assessment System (ABaCAS) was applied as the core tool. The required reductions in Fine particulate matter (PM2.5) and Sulfur dioxide (SO2) emissions for 2014–2019 are expected to be achieved; however, the expected reductions in Nitrogen oxides (NOx) emissions (mainly from road mobile sources) and Volatile organic compounds (VOCs) emissions (mainly from secondary industry and road mobile sources) are less certain. According to the simulated concentration of PM2.5 in 2019, it is necessary to reduce the concentrations of air pollutants, both within and outside Shenzhen. The background weather conditions may be the main reason for the increased concentrations of Ozone (O3) in October compared to those in July. Reductions in NOx and VOCs tend to be the main factors driving changes in O3 concentrations. Policies have been formulated and implemented in a wide array of areas. According to the quantitative comparative analysis of the policies, and the relevant activities, the greatest challenge in reducing NOx and VOCs emissions is presented by the oil-powered vehicles in the road mobile sector and organic solvent production in the secondary industry sector. Therefore, in an effort to achieve better air quality and ensure that CO2 emissions reach a peak in Shenzhen by 2025, we propose key improvements in policies based on interdisciplinary cooperation, involving not only atmospheric and environmental science, but also governance and urban planning. Full article
(This article belongs to the Section Air Quality)
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15 pages, 2501 KiB  
Article
Carbon-Negative Policies by Reusing Waste Wood as Material and Energy Resources for Mitigating Greenhouse Gas Emissions in Taiwan
by Wen-Tien Tsai
Atmosphere 2021, 12(9), 1220; https://doi.org/10.3390/atmos12091220 - 17 Sep 2021
Cited by 7 | Viewed by 3457
Abstract
Carbon-negative policies for mitigating the emissions of greenhouse gas (GHG) from the energy sector are becoming more urgent and important. Therefore, the environmental policies and regulatory promotion for reusing waste wood as a carbon-negative resource in Taiwan were discussed in this work, which [...] Read more.
Carbon-negative policies for mitigating the emissions of greenhouse gas (GHG) from the energy sector are becoming more urgent and important. Therefore, the environmental policies and regulatory promotion for reusing waste wood as a carbon-negative resource in Taiwan were discussed in this work, which focused on mitigating the emissions of GHG from the energy industries and the manufacturing and construction industries. Considering the official GHG inventory report, the trend analysis of GHG emissions from the energy and the manufacturing and construction industries was addressed first. In addition, this study placed emphasis on the environmental policies and regulatory measures for the material and energy resources from waste wood according to the promulgation of the relevant acts. It was found that the total GHG emissions from the energy and the manufacturing and construction industries accounted for over 80% of net GHG emissions in 2018. In review of the resource recycling and circular economy, lignocellulose-based (or bamboo-based) char, ecological building material, and wood-to-biofuel pathways (e.g., solid recovered fuel) were discussed in this work because they have been promoted by the central competent authorities of the Council of Agriculture (COA), the Ministry of Interior (MOI), and the Environmental Protection Administration (EPA), respectively. In order to achieve the sustainable development goals (SDGs) in Taiwan, carbon-negative policies for reusing waste wood as material and energy resources will play an important role in the mitigation of GHG emissions. Full article
(This article belongs to the Special Issue Climate Change and Forest Environment)
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15 pages, 6161 KiB  
Article
Structure of the Pacific Walker Circulation Depicted by the Reanalysis and CMIP6
by Emmanuel Olaoluwa Eresanya and Yuping Guan
Atmosphere 2021, 12(9), 1219; https://doi.org/10.3390/atmos12091219 - 17 Sep 2021
Cited by 5 | Viewed by 4656
Abstract
The Pacific Walker circulation (PWC) is one of the most important components of large-scale tropical atmospheric circulations. The PWC and its influences have been studied extensively by numerical models and reanalysis. The newly released ERA5 and NCEP2 are the most widely used reanalysis [...] Read more.
The Pacific Walker circulation (PWC) is one of the most important components of large-scale tropical atmospheric circulations. The PWC and its influences have been studied extensively by numerical models and reanalysis. The newly released ERA5 and NCEP2 are the most widely used reanalysis datasets and serve as benchmarks for evaluation of model simulations. If the results of these datasets differ significantly, this could lead to a bias in projected long-term climate knowledge. For better understanding of future climate change, it is necessary to evaluate PWC reanalysis productions. As a result, we compared the PWC structures between the ERA5 and NCEP2 datasets from month to seasonal time scales. We used the zonal mass streamfunction (ZMS) over the equatorial Pacific to indicate the strength of the PWC. The PWC’s average monthly or seasonal cycle peaks around July. From February to June, the NCEP2 shows a higher PWC intensity, whereas the ERA5 shows greater intensity from July to December. The circulation center in the NCEP2 is generally stronger and wider than in the ERA5. The ERA5, however, revealed that the PWC’s west edge (zero line of ZMS over the western Pacific) had moved 10 degrees westward in comparison to the NCEP2. In addition, we compared the PWC mean state in the reanalysis and CMIP6 models; the mean state vertical structures of the tropical PWC in the CMIP6 multi-model ensemble (MME) are similar to those of the reanalyses in structure but weaker and wider than in the two reanalysis datasets. The PWC is broader in CMIP6, and the western boundary is 7 and 17 degrees farther west than in the ERA5 and NCEP2, respectively. This study suggests that, when using reanalysis datasets to evaluate PWC structural changes in intensity and western edge, extreme caution should be exercised. Full article
(This article belongs to the Special Issue ENSO: Dynamics, Predictability, Modelling and Teleconnection)
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30 pages, 9500 KiB  
Article
Temporal Variability and Predictability of Intense Cyclones in the Western and Eastern Mediterranean
by Veronika N. Maslova, Elena N. Voskresenskaya, Andrey S. Lubkov and Alexander V. Yurovsky
Atmosphere 2021, 12(9), 1218; https://doi.org/10.3390/atmos12091218 - 17 Sep 2021
Cited by 1 | Viewed by 2328
Abstract
Our understanding of the time variability of intense cyclones in the Mediterranean region is still lacking despite its importance for the long-term forecast of climate anomalies. This study examines the month-to-month variability and predictability of cyclones, the intensity of which exceeded the 75th [...] Read more.
Our understanding of the time variability of intense cyclones in the Mediterranean region is still lacking despite its importance for the long-term forecast of climate anomalies. This study examines the month-to-month variability and predictability of cyclones, the intensity of which exceeded the 75th percentile (intense cyclones) and the 95th percentile (extreme cyclones), over the Western and Eastern Mediterranean. The locations of cyclones were obtained by applying the method of M. Yu. Bardin on the 6-hourly 1000 hPa geopotential height data from the NCEP/NCAR reanalysis for the period 1951–2017 (67 years). It was shown that annual frequencies of cyclones were higher in the Western Mediterranean due to the contribution of spring and autumn; monthly averages were higher in the Eastern Mediterranean in December/January–March for intense/extreme cyclones. In the context of global warming, no linear trends significant at the 90% confidence level were found in the variability of intense and extreme cyclones, except for a positive trend in autumn extreme cyclones over the Eastern Mediterranean. The time series of cyclones in both parts of the Mediterranean were characterized by a pronounced interannual variability with a noticeable decadal modulation. According to spectral analysis, these interannual periods were multiples of 2–3 years corresponding to the main global teleconnection patterns. Seasonally, the most energy was concentrated in winter spectra; spring and autumn spectra had lower comparable magnitudes. The correlation analysis between the frequency of cyclones and the indices of the main atmospheric patterns showed that the main synchronous patterns for intense and extreme Mediterranean cyclones in September–April were the Mediterranean Oscillation (with the opposite signs for the Western and Eastern Mediterranean), Scandinavia pattern (positive correlation), and East Atlantic Oscillation (negative correlation). Additional important synchronous teleconnection patterns for some months were the Arctic Oscillation and East Atlantic/West Russia pattern for the Western Mediterranean, and the Polar/Eurasia pattern and Tropical Northern Hemisphere pattern for the Eastern Mediterranean. The outcome of this paper was the use of an artificial neural network model with inputs of global teleconnection indices both in the atmosphere and ocean to describe the temporal variability of the frequency of intense cyclones in the Western and Eastern Mediterranean. The predictability of intense cyclones was shown with the possibility of forecasts with a lead time of 0, 2, 4, and 6 months for the Western Mediterranean in October, January, February, April, and May, and for the Eastern Mediterranean in January, February, March, April, and May. One of the applications of this model may be in forecasting the evolution of the monthly frequency of cyclones with a lead time of 2 to 6 months. Full article
(This article belongs to the Special Issue Mediterranean Cyclones and Their Impacts in Europe under Current and Future Climate)
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24 pages, 5366 KiB  
Article
Microservice-Based Approach to Simulating Environmentally Friendly Equipment of Infrastructure Objects Taking into Account Meteorological Data
by Roman Kostromin, Olga Basharina, Alexander Feoktistov and Ivan Sidorov
Atmosphere 2021, 12(9), 1217; https://doi.org/10.3390/atmos12091217 - 17 Sep 2021
Cited by 4 | Viewed by 2733
Abstract
Nowadays, simulation modeling is a relevant and practically significant means in the field for research of infrastructure object functioning. It forms the basis for studying the most important components of such objects represented by their digital twins. Applying meteorological data, in this context, [...] Read more.
Nowadays, simulation modeling is a relevant and practically significant means in the field for research of infrastructure object functioning. It forms the basis for studying the most important components of such objects represented by their digital twins. Applying meteorological data, in this context, becomes an important issue. In the paper, we propose a new microservice-based approach for organizing simulation modeling in heterogeneous distributed computing environments. Within the proposed approach, all operations related to data preparing, executing models, and analyzing the obtained results are implemented as microservices. The main advantages of the proposed approach are the parameter sweep computing within simulation modeling and possibility of integrating resources of public access supercomputer centers with cloud and fog platforms. Moreover, we provide automated microservice web forms using special model specifications. We develop and apply the service-oriented tools for studying environmentally friendly equipment of the objects at the Baikal natural territory. Among such objects are recreation tourist centers, children’s camps, museums, exhibition centers, etc. As a result, we have evaluated the costs for the possible use of heat pumps in different operational and meteorological conditions for the typical object. The provided comparative analysis has confirmed the aforementioned advantages of the proposed approach. Full article
(This article belongs to the Special Issue Atmospheric and Ocean Optics: Atmospheric Physics III)
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17 pages, 13555 KiB  
Article
Spatiotemporal Dynamics of Maximum Wind Speed Using the Wind Multiplier Downscaling Method in the Yangtze River Inland Waterway from 1980 to 2017
by Lijun Liu and Fan Zhang
Atmosphere 2021, 12(9), 1216; https://doi.org/10.3390/atmos12091216 - 17 Sep 2021
Cited by 2 | Viewed by 2284
Abstract
Wind speed affects the navigational safety of the Yangtze River, and assessing its spatiotemporal dynamics provides support for navigation management and disaster prevention. We developed a wind multiplier downscaling method integrating the effects of land use and topography, and used meteorological station observations [...] Read more.
Wind speed affects the navigational safety of the Yangtze River, and assessing its spatiotemporal dynamics provides support for navigation management and disaster prevention. We developed a wind multiplier downscaling method integrating the effects of land use and topography, and used meteorological station observations and European Center for Medium-Range Weather Forecasts (ECMWF) Reanalysis Interim (ERA-Interim) reanalysis data for statistical downscaling in the Yangtze River inland waterway region from 1980 to 2017. Compared with reanalysis data, the downscaling products showed improved accuracy (especially at 5–10 m/s), and are consistent with site-based interannual variability observations. Increasing maximum wind speeds in the middle–downstream area was observed from 1980 to 1990, while a decreasing trend was observed from 2010 to 2017; the opposite was observed for the upstream. Land use has significant influence on wind speed, with a decreasing trend observed year by year for wind speed above grade 9. Although the proportion of grade 4–8 wind speed over water is small and the trend is not obvious, grade 9–10 wind speeds displayed an increasing trend from 2010 to 2017, indicating that changes in surface roughness have a significant influence on wind speed in the Yangtze River inland waterway. Full article
(This article belongs to the Special Issue Meteorological Extremes in China)
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24 pages, 4659 KiB  
Article
Improving Ensemble Volcanic Ash Forecasts by Direct Insertion of Satellite Data and Ensemble Filtering
by Meelis J. Zidikheri and Chris Lucas
Atmosphere 2021, 12(9), 1215; https://doi.org/10.3390/atmos12091215 - 17 Sep 2021
Cited by 7 | Viewed by 2052
Abstract
Improved quantitative forecasts of volcanic ash are in great demand by the aviation industry to enable better risk management during disruptive volcanic eruption events. However, poor knowledge of volcanic source parameters and other dispersion and transport modelling uncertainties, such as those due to [...] Read more.
Improved quantitative forecasts of volcanic ash are in great demand by the aviation industry to enable better risk management during disruptive volcanic eruption events. However, poor knowledge of volcanic source parameters and other dispersion and transport modelling uncertainties, such as those due to errors in numerical weather prediction fields, make this problem very challenging. Nonetheless, satellite-based algorithms that retrieve ash properties, such as mass load, effective radius, and cloud top height, combined with inverse modelling techniques, such as ensemble filtering, can significantly ameliorate these problems. The satellite-retrieved data can be used to better constrain the volcanic source parameters, but they can also be used to avoid the description of the volcanic source altogether by direct insertion into the forecasting model. In this study we investigate the utility of the direct insertion approach when employed within an ensemble filtering framework. Ensemble members are formed by initializing dispersion models with data from different timesteps, different values of cloud top height, thickness, and NWP ensemble members. This large ensemble is then filtered with respect to observations to produce a refined forecast. We apply this approach to 14 different eruption case studies in the tropical atmosphere. We demonstrate that the direct insertion of data improves model forecast skill, particularly when it is used in a hybrid ensemble in which some ensemble members are initialized from the volcanic source. Moreover, good forecast skill can be obtained even when detailed satellite retrievals are not available, which is frequently the case for volcanic eruptions in the tropics. Full article
(This article belongs to the Special Issue Data-Driven Methods in Atmospheric Dispersion Modelling)
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9 pages, 1533 KiB  
Article
A Performance Evaluation of Potential Intensity over the Tropical Cyclone Passage to South Korea Simulated by CMIP5 and CMIP6 Models
by Doo-Sun R. Park, Hyeong-Seog Kim, Minho Kwon, Young-Hwa Byun, Maeng-Ki Kim, Il-Ung Chung, Jeong-Soo Park and Seung-Ki Min
Atmosphere 2021, 12(9), 1214; https://doi.org/10.3390/atmos12091214 - 17 Sep 2021
Cited by 6 | Viewed by 3580
Abstract
Potential intensity (PI) is a metric for climate model evaluation of TC-related thermodynamic conditions. However, PI is utilized usually for assessing basin-wide TC-related thermodynamic conditions, and not for evaluating TC passage to a certain region. Here we evaluate model-simulated PI over the passage [...] Read more.
Potential intensity (PI) is a metric for climate model evaluation of TC-related thermodynamic conditions. However, PI is utilized usually for assessing basin-wide TC-related thermodynamic conditions, and not for evaluating TC passage to a certain region. Here we evaluate model-simulated PI over the passage of TCs affecting South Korea (KOR PI) as well as the PI over the entire western North Pacific basin (WNP PI) using 25 CMIP5 and 27 CMIP6 models. In terms of pattern correlations and bias-removed root mean square errors, CMIP6 model performances for KOR PI are found to be noticeably improved over CMIP5 models in contrast to negligible improvement for WNP PI, although it is not in terms of normalized standard deviations. This implies that thermodynamic condition on the route of TCs affecting South Korea is likely better captured by CMIP6 models than CMIP5 models. Full article
(This article belongs to the Section Climatology)
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13 pages, 618 KiB  
Article
Human Health Risk Assessment of Heavy Metals in the Urban Road Dust of Zhengzhou Metropolis, China
by Muhammad Faisal, Zening Wu, Huiliang Wang, Zafar Hussain and Muhammad Imran Azam
Atmosphere 2021, 12(9), 1213; https://doi.org/10.3390/atmos12091213 - 17 Sep 2021
Cited by 32 | Viewed by 5390
Abstract
The goal of this research is to assess hazardous heavy metal levels in PM2.5 fractioned road dust in order to quantify the risk of inhalation and potential health effects. To accomplish this, Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was used to determine [...] Read more.
The goal of this research is to assess hazardous heavy metal levels in PM2.5 fractioned road dust in order to quantify the risk of inhalation and potential health effects. To accomplish this, Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was used to determine concentrations of eight heavy metals (Cr, Cu, Ni, Zn, Cd, As, Pb, and Hg) in the PM2.5 portion of road dust samples from five different land use areas (commercial, residential, industrial, parks, and educational) in Zhengzhou, China. The following were the average heavy metal concentrations in the city: Cr 46.26 mg/kg, Cu 25.13 mg/kg, Ni 12.51 mg/kg, Zn 152.35 mg/kg, Cd 0.56 mg/kg, As 11.53 mg/kg, Pb 52.15 mg/kg, and Hg 0.32 mg/kg. Two pollution indicators, the Pollution Index (PI) and the Geoaccumulation Index (Igeo), were used to determine the degree of contamination. Both PI and Igeo indicated the extreme pollution of Hg and Cd, while PI also ranked Zn in the extreme polluted range. The US Environmental Protection Agency (USEPA) model for adults and children was used to estimate health risks by inhalation. The results identified non-carcinogenic exposure of children to lead (HI > 0.1) in commercial and industrial areas. Both children and adults in Zhengzhou’s commercial, residential, and park areas are exposed to higher levels of copper (Cu), lead (Pb), and zinc (Zn). Full article
(This article belongs to the Special Issue Road Dust in Urban and Industrial Environments: Sources, Pollutants, Impacts, and Management)
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19 pages, 30103 KiB  
Article
Drought Variability and Characteristics in the Muda River Basin of Malaysia from 1985 to 2019
by Zibeon bin Luhaim, Mou Leong Tan, Fredolin Tangang, Zed Zulkafli, Kwok Pan Chun, Zulkifli Yusop and Zaher Mundher Yaseen
Atmosphere 2021, 12(9), 1210; https://doi.org/10.3390/atmos12091210 - 17 Sep 2021
Cited by 16 | Viewed by 5089
Abstract
This study aimed to analyze the spatiotemporal changes of historical droughts over the Muda River basin (MRB), Malaysia, from 1985 to 2019 using the Standardized Precipitation Index (SPI) and the Standardized Streamflow Index (SSI). The Mann–Kendall test and Sens’ slope were used to [...] Read more.
This study aimed to analyze the spatiotemporal changes of historical droughts over the Muda River basin (MRB), Malaysia, from 1985 to 2019 using the Standardized Precipitation Index (SPI) and the Standardized Streamflow Index (SSI). The Mann–Kendall test and Sens’ slope were used to evaluate the trends and magnitude changes in the droughts, respectively, while Spearman’s rho was applied to understand the relationships of the droughts with large-scale atmospheric circulations, such as the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Madden–Julian Oscillation (MJO). The results show that the intense droughts in the MRB mostly occurred in 1991–1992, 1995, 1998, 2002–2003, 2005–2006, 2008, 2012–2013, and 2016. In addition, a declining SPI trend was found from May to December at most of the stations. About 80% of the stations experienced about 10 severely dry droughts, while almost all stations experienced at least 5 extremely dry events. Moreover, a higher response rate of the SSI than the SPI was found during low-rainfall months from January to May. Lastly, ENSO had a larger impact on the drought formations over the MRB compared to the IOD and MJO, especially during the dry period. Full article
(This article belongs to the Special Issue Extreme Hydro-Climate Events: Past, Present, and Future)
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12 pages, 4026 KiB  
Article
Crop Residue Burning in Northeast China and Its Impact on PM2.5 Concentrations in South Korea
by Jin-Ju Lee, Jae-Bum Lee, Okgil Kim, Gookyoung Heo, Hankyung Lee, DaeGyun Lee, Dai-gon Kim and Sang-Deok Lee
Atmosphere 2021, 12(9), 1212; https://doi.org/10.3390/atmos12091212 - 16 Sep 2021
Cited by 6 | Viewed by 2498
Abstract
The impact of crop residue burning in northeastern China on South Korean PM2.5 concentrations was assessed via weather conditions, air quality modeling (AQM), and PM2.5 composition data during two cases exceeding 35 µg·m−3 in November 2015. PM2.5 concentration simulations [...] Read more.
The impact of crop residue burning in northeastern China on South Korean PM2.5 concentrations was assessed via weather conditions, air quality modeling (AQM), and PM2.5 composition data during two cases exceeding 35 µg·m−3 in November 2015. PM2.5 concentration simulations of Case 1 differed from observations by 3.7–17.6 µg·m−3, overestimating the levels by 6–36%; however, Case 2 varied by 20.0–59.8 µg·m−3 from observations, with a 53–91% underestimation. Case 1 was generally well simulated, whereas the Case 2 simulation failed because the emissions of crop residue burning in northeastern China, as confirmed through satellite analysis (MODIS fires and thermal anomalies) and previous research, were not considered. The portion of organic/elemental carbon ratio during Case 2 was 1.6–2.3 times higher than that of Case 1. These results suggest that it is necessary to consider the effects of crop residue burning in northeast China to establish countermeasures to improve air quality and air quality forecasting in South Korea. Full article
(This article belongs to the Section Aerosols)
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17 pages, 3256 KiB  
Article
Prediction of PM2.5 Concentration Based on the LSTM-TSLightGBM Variable Weight Combination Model
by Xuchu Jiang, Yiwen Luo and Biao Zhang
Atmosphere 2021, 12(9), 1211; https://doi.org/10.3390/atmos12091211 - 16 Sep 2021
Cited by 19 | Viewed by 3622
Abstract
PM2.5 is one of the main pollutants that cause air pollution, and high concentrations of PM2.5 seriously threaten human health. Therefore, an accurate prediction of PM2.5 concentration has great practical significance for air quality detection, air pollution restoration, and human [...] Read more.
PM2.5 is one of the main pollutants that cause air pollution, and high concentrations of PM2.5 seriously threaten human health. Therefore, an accurate prediction of PM2.5 concentration has great practical significance for air quality detection, air pollution restoration, and human health. This paper uses the historical air quality concentration data and meteorological data of the Beijing Olympic Sports Center as the research object. This paper establishes a long short-term memory (LSTM) model with a time window size of 12, establishes a T-shape light gradient boosting machine (TSLightGBM) model that uses all information in the time window as the next period of prediction input, and establishes a LSTM-TSLightGBM model pair based on an optimal weighted combination method. PM2.5 hourly concentration is predicted. The prediction results on the test set show that the mean squared error (MAE), root mean squared error (RMSE), and symmetric mean absolute percentage error (SMAPE) of the LSTM-TSLightGBM model are 11.873, 22.516, and 19.540%, respectively. Compared with LSTM, TSLightGBM, the recurrent neural network (RNN), and other models, the LSTM-TSLightGBM model has a lower MAE, RMSE, and SMAPE, and higher prediction accuracy for PM2.5 and better goodness-of-fit. Full article
(This article belongs to the Special Issue Study of Mitigation of PM2.5 and Surface Ozone Pollution)
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56 pages, 11213 KiB  
Article
The Role of Aquatic Refuge Habitats for Fish, and Threats in the Context of Climate Change and Human Impact, during Seasonal Hydrological Drought in the Saxon Villages Area (Transylvania, Romania)
by Doru Bănăduc, Alexandru Sas, Kevin Cianfaglione, Sophia Barinova and Angela Curtean-Bănăduc
Atmosphere 2021, 12(9), 1209; https://doi.org/10.3390/atmos12091209 - 16 Sep 2021
Cited by 27 | Viewed by 4657
Abstract
In spite of the obvious climate changes effects on the Carpathian Basin hydrographic nets fish fauna, studies on their potential refuge habitats in drought periods are scarce. Multiannual (2016–2021) research of fish in some streams located in the Saxon Villages area during hydrological [...] Read more.
In spite of the obvious climate changes effects on the Carpathian Basin hydrographic nets fish fauna, studies on their potential refuge habitats in drought periods are scarce. Multiannual (2016–2021) research of fish in some streams located in the Saxon Villages area during hydrological drought periods identified, mapped, and revealed the refuge aquatic habitats presence, management needs, and importance for fish diversity and abundance for small rivers. The impact of increasing global temperature and other human activities induced hydrologic net and habitats alteration, decreased the refuge habitats needed by freshwater fish, diminished the fish abundance, and influenced the spatial and temporal variation in fish assemblage structure in the studied area. The sites more than one meter in depth in the studied lotic system were inventoried and all 500 m of these lotic systems were also checked to see what species and how many individuals were present, and if there is was difference in their abundance between refuge and non-refuge 500 m sectors. The scarce number of these refuges due to relatively high soil erosion and clogging in those basins and the cumulative effects of other human types of impact induced a high degree of pressure on the fish fauna. Overall, it reduced the role of these lotic systems as a refuge and for reproduction for the fish of downstream Târnava Mare River, into which all of them flow. Management elements were proposed to maintain and improve these refuges’ ecological support capacity. Full article
(This article belongs to the Special Issue Drought Risk Management in Reflect Changing of Meteorological Conditions)
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20 pages, 42708 KiB  
Article
Investigation of Air-Sea Turbulent Momentum Flux over the Aegean Sea with a Wind-Wave Coupling Model
by Panagiotis Portalakis, Maria Tombrou, John Kalogiros, Aggeliki Dandou and Qing Wang
Atmosphere 2021, 12(9), 1208; https://doi.org/10.3390/atmos12091208 - 16 Sep 2021
Viewed by 2431
Abstract
Near surface turbulent momentum flux estimates are performed over the Aegean Sea, using two different approaches regarding the drag coefficient formulation, a wave boundary layer model (referred here as KCM) and the most commonly used Coupled Ocean–Atmosphere Response Experiment (COARE) algorithm. The KCM [...] Read more.
Near surface turbulent momentum flux estimates are performed over the Aegean Sea, using two different approaches regarding the drag coefficient formulation, a wave boundary layer model (referred here as KCM) and the most commonly used Coupled Ocean–Atmosphere Response Experiment (COARE) algorithm. The KCM model incorporates modifications in the energy-containing wave spectrum to account for the wave conditions of the Aegean Sea, and surface similarity to account for the stratification effects. Airborne turbulence data during an Etesian outbreak over Aegean Sea, Greece are processed to evaluate the simulations. KCM estimates found up to 10% higher than COARE ones, indicating that the wave-induced momentum flux may be insufficiently parameterized in COARE. Turbulent fluxes measured at about 150 m, and reduced to their surface values accounting for the vertical flux divergence, are consistently lower than the estimates. Under unstable atmospheric stratification and low to moderate wind conditions, the residuals between estimates and measurements are less than 40%. On the other hand, under stable stratification and strong winds, the majority of the residuals are more than 40%. This discrepancy is associated with the relatively high measurement level, shallow boundary layer, and the presence of a low level jet. Full article
(This article belongs to the Special Issue Atmosphere-Ocean Interactions)
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12 pages, 2253 KiB  
Article
Radiological Risk Assessment for Karstic Springs Used as Drinking Water in Rural Romania
by Alexandra Laura Cucoș, Mircea Claudiu Moldovan, Bety Denissa Burghele, Tiberius Dicu and Oana Teodora Moldovan
Atmosphere 2021, 12(9), 1207; https://doi.org/10.3390/atmos12091207 - 16 Sep 2021
Cited by 9 | Viewed by 2472
Abstract
Seasonal variations of the radon and radium activity concentrations in karstic water sources originating in karstic formations were investigated as part of a premiere systematic survey conducted in Romania. A database including a total of 228 drinking water samples collected from 30 distinct [...] Read more.
Seasonal variations of the radon and radium activity concentrations in karstic water sources originating in karstic formations were investigated as part of a premiere systematic survey conducted in Romania. A database including a total of 228 drinking water samples collected from 30 distinct water sources adjacent to rural communities was compiled. The radon and radium activity concentrations for all seasons, assessed based on solid scintillation, ranged from 2.1 to 19.7 Bq/L and from 0.6 to 3.0 Bq/L, respectively. Overall, the detected radon and radium contents did not exceed the radioprotection standards recommended by national and European legislation. However, in at least one season, the measured values for 31% of the samples exceeded the 11.1 Bq/L maximum contaminant level for radon in drinking water recommended by the Environmental Protection Agency of the United States. The associated radiological risk, reported in terms of annual effective dose, was calculated to be between 9.8 × 10−6 and 6.0 × 10−5 mSv/y for radon and between 5.9 × 10−5 and 2.7 × 10−4 mSv/y for radium, which are considerably below the WHO (World Health Organization) guidelines at a value of 0.1 mSv/y. Full article
(This article belongs to the Special Issue Atmospheric Radon Measurements, Control, Mitigation and Management)
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34 pages, 14302 KiB  
Article
Cluster and Redundancy Analyses of Taiwan Upstream Watersheds Based on Monthly 30 Years AVHRR NDVI3g Data
by Hui Ping Tsai and Wei-Ying Wong
Atmosphere 2021, 12(9), 1206; https://doi.org/10.3390/atmos12091206 - 16 Sep 2021
Cited by 1 | Viewed by 2451
Abstract
The study uses 30 years of the third generation of Advanced Very-High-Resolution Radiometer (AVHRR) NDVI3g monthly data from 1982 to 2012 to identify the natural clusters and important driving factors of the upstream watersheds in Taiwan through hierarchical cluster analysis (HCA) and redundancy [...] Read more.
The study uses 30 years of the third generation of Advanced Very-High-Resolution Radiometer (AVHRR) NDVI3g monthly data from 1982 to 2012 to identify the natural clusters and important driving factors of the upstream watersheds in Taiwan through hierarchical cluster analysis (HCA) and redundancy analysis (RDA), respectively. Subsequently, as a result of HCA, six clusters were identified based on the 30 years of monthly NDVI data, delineating unique NDVI characteristics of the upstream watersheds. Additionally, based on the RDA results, environmental factors, including precipitation, temperature, slope, and aspect, can explain approximately 52% of the NDVI variance over the entire time series. Among environmental factors, nine factors were identified significantly through RDA analysis for explaining NDVI variance: average slope, temperature, flat slope, northeast-facing slope, rainfall, east-facing slope, southeast-facing slope, west-facing slope, and northwest-facing slope, which reflect an intimate connection between climatic and orthographic factors with vegetation. Furthermore, the rainfall and temperature represent different variations in all scenarios and seasons. With consideration of the characteristics of the clusters and significant environmental factors, corresponding climate change adaptation strategies are proposed for each cluster under climate change scenarios. Thus, the results provide insight to assess the natural clustering of the upstream watersheds in Taiwan, benefitting future sustainable watershed management. Full article
(This article belongs to the Special Issue Climate Change and Forest Environment)
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13 pages, 2892 KiB  
Article
Feasibility of Reducing Electricity Consumption of Air Conditioning Equipment by Condenser Direct Evaporative Cooling Technology. Example of Case Study in Dubai
by Anatolijs Borodinecs, Kristina Lebedeva, Aleksejs Prozuments, Arturs Brahmanis, Aldis Grekis, Deniss Zajecs, Artis Zekunde and Nikolai Vatin
Atmosphere 2021, 12(9), 1205; https://doi.org/10.3390/atmos12091205 - 16 Sep 2021
Cited by 12 | Viewed by 3819
Abstract
The use of air conditioning technology is accompanied by an increase in electricity consumption, which is linked to an intensification of fossil fuel extraction. This in turn calls for developing cooling solutions of higher energy efficiency. The aim of this study is to [...] Read more.
The use of air conditioning technology is accompanied by an increase in electricity consumption, which is linked to an intensification of fossil fuel extraction. This in turn calls for developing cooling solutions of higher energy efficiency. The aim of this study is to examine energy consumption reduction of direct evaporative cooling technology for generating cool air in hot-dry climate regions. At the initial stage, already-installed air cooling equipment with a direct evaporative cooling system was studied for the creation of two regression models of electricity consumption representing the “on” and “off” sequences. Water consumption for system operation was taken into consideration. In the following stage, inlet water temperature dependence for pre-cooling purposes for the direct evaporative cooling system was studied. A mathematical model was developed and the subsequent calculations suggested that there is no need to pre-cool water before it enters the system and therefore consume additional energy. Practical application of this study is evaluated based on the case study in Dubai. The results of this study present significant energy saving potential for system operations of the direct evaporative cooling system of approximately 122 MWh per year. The return on investment for the equipment with direct evaporative cooling in case of an office building in Dubai featuring a hot desert climate is around 4.2 years. The purpose of this study is to examine the potential advantage of air cooling equipment with direct evaporative cooling technology compared to cooling equipment without this technology. The results provide the expediency of conducting further research in this area, in particular with regards to analyzing various materials for the adiabatic precooling pads, as well as the possibility of using a newly developed metal precooling pad. Full article
(This article belongs to the Special Issue Efficiency Evaluation in Atmospheric Environment)
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15 pages, 4632 KiB  
Article
Detection of Spatial Rainfall Variation over the Andean Region Demonstrated by Satellite-Based Observations
by Dibas Shrestha, Shankar Sharma, Rocky Talchabhadel, Rashila Deshar, Kalpana Hamal, Nitesh Khadka and Kenji Nakamura
Atmosphere 2021, 12(9), 1204; https://doi.org/10.3390/atmos12091204 - 16 Sep 2021
Cited by 1 | Viewed by 2693
Abstract
Topography has an important role in shaping regional and global climate systems, as it acts as a mechanical barrier to the low-level moisture flow. Thus, a complex spatial pattern of rainfall can exist over the mountainous region. Moreover, it is critical to advance [...] Read more.
Topography has an important role in shaping regional and global climate systems, as it acts as a mechanical barrier to the low-level moisture flow. Thus, a complex spatial pattern of rainfall can exist over the mountainous region. Moreover, it is critical to advance our understanding of the relationship between rainfall and topography in terms of rainfall timing, frequency, and magnitude. In this study, characteristics of austral summer (December–February) precipitation are analyzed using 17-year (1998–2014) high-spatial-resolution (0.05° × 0.05°) data obtained from the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) over the Andean region focusing on topographic impact. We observe an interaction between precipitation patterns and topography, with clear precipitation–elevation relationships in the Andes regions. The rainfall maxima zone was observed over the higher terrain of the central and southern Andes, and the zone is attributed to frequency and intensity of rainfall, respectively. In the foothills of the central Andes, we find there was a persistent rain system when a moist, low-level flow was lifted due to topography. In contrast, steep mountain slopes and a relatively dry atmosphere modulate deep convection in the foothills of southern Andes. Full article
(This article belongs to the Special Issue Satellites Applied in Extreme Weather and Their Atmospheric Mechanisms)
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15 pages, 3908 KiB  
Article
Hygroscopicity of Fresh and Aged Salt Mixtures from Saline Lakes
by Jun Li, Wanyu Liu, Linjie Li, Wenjun Gu, Xiying Zhang, Mattias Hallquist, Mingjin Tang, Sen Wang and Xiangrui Kong
Atmosphere 2021, 12(9), 1203; https://doi.org/10.3390/atmos12091203 - 16 Sep 2021
Viewed by 2280
Abstract
The high hygroscopicity of salt aerosol particles makes the particles active in aerosol and cloud formations. Inland saline lakes are an important and dynamic source of salt aerosol. The salt particles can be mixed with mineral dust and transported over long distances. During [...] Read more.
The high hygroscopicity of salt aerosol particles makes the particles active in aerosol and cloud formations. Inland saline lakes are an important and dynamic source of salt aerosol. The salt particles can be mixed with mineral dust and transported over long distances. During transportation, these particles participate in atmospheric heterogeneous chemistry and further impact the climate and air quality on a global scale. Despite their importance and potential, relatively little research has been done on saline lake salt mixtures from atmospheric perspectives. In this study, we use experimental and model methods to evaluate the hygroscopic properties of saline lake brines, fresh salt aerosol particles, and aged salt aerosol particles. Both original samples and literature data are investigated. The original brine samples are collected from six salt lakes in Shanxi and Qinghai provinces in China. The ionic compositions of the brines are determined and the hygroscopicity measurements are performed on crystallized brines. The experimental results agree well with theoretical deliquescence relative humidity (DRH) values estimated by a thermodynamic model. The correlations between DRHs of different salt components and the correlations between DRHs and ionic concentrations are presented and discussed. Positive matrix factorization (PMF) analysis is performed on the ionic concentrations data and the hygroscopicity results, and the solutions are interpreted and discussed. The fresh and aged salt aerosol particles are analyzed in the same way as the brines, and the comparison shows that the aged salt aerosol particles completely alter their hygroscopic property, i.e., transferring from MgCl2− governed to NH4NO3− governed. Full article
(This article belongs to the Special Issue Physical and Chemical Properties of Aerosols and Their Role in Weather and Climate)
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18 pages, 11469 KiB  
Article
Evaluation of F10.7, Sunspot Number and Photon Flux Data for Ionosphere TEC Modeling and Prediction Using Machine Learning Techniques
by Andres Gilberto Machado da Silva Benoit and Adriano Petry
Atmosphere 2021, 12(9), 1202; https://doi.org/10.3390/atmos12091202 - 16 Sep 2021
Cited by 7 | Viewed by 3259
Abstract
Considering the growing volumes and varieties of ionosphere data, it is expected that automation of analytical model building using modern technologies could lead to more accurate results. In this work, machine learning techniques are applied to ionospheric modeling and prediction using sun activity [...] Read more.
Considering the growing volumes and varieties of ionosphere data, it is expected that automation of analytical model building using modern technologies could lead to more accurate results. In this work, machine learning techniques are applied to ionospheric modeling and prediction using sun activity data. We propose Total Electron Content (TEC) spectral analysis, using discrete cosine transform (DCT) to evaluate the relation to the solar features F10.7, sunspot number and photon flux data. The ionosphere modeling procedure presented is based on the assessment of a six-year period (2014–2019) of data. Different multi-dimension regression models were considered in experiments, where each geographic location was independently evaluated using its DCT frequency components. The features correlation analysis has shown that 5-year data seem more adequate for training, while learning curves revealed overfitting for polynomial regression from the 4th to 7th degrees. A qualitative evaluation using reconstructed TEC maps indicated that the 3rd degree polynomial regression also seems inadequate. For the remaining models, it can be noted that there is seasonal variation in root-mean-square error (RMSE) clearly related to the equinox (lower error) and solstice (higher error) periods, which points to possible seasonal adjustment in modeling. Elastic Net regularization was also used to reduce global RMSE values down to 2.80 TECU for linear regression. Full article
(This article belongs to the Special Issue Ionospheric Monitoring and Modelling for Space Weather)
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