Atmosphere

19 pages, 6751 KiB

Open AccessArticle

Differences in Air and Sea Surface Temperatures in the Northern and Southern Part of the Adriatic Sea

by Ognjen Bonacci and Adrijana Vrsalović

Atmosphere 2022, 13(7), 1158; https://doi.org/10.3390/atmos13071158 - 21 Jul 2022

Cited by 7 | Viewed by 2021

The paper compares air and sea surface temperatures in recent years on two islands in the Adriatic Sea. The data measured at the climatological station Krk on the island of Krk and the main meteorological station Lastovo on the island of Lastovo are [...] Read more.

The paper compares air and sea surface temperatures in recent years on two islands in the Adriatic Sea. The data measured at the climatological station Krk on the island of Krk and the main meteorological station Lastovo on the island of Lastovo are used. The island of Krk is located in the north of the Adriatic Sea and Lastovo in the south. Since a significant increase in air and sea surface temperatures has been observed over the last thirty years, the goal is to establish how they reflect at these two stations, 313 km apart. The goal of the analysis is to monitor the changes in these two islands to reduce the negative impacts they may cause. The analysis of sea temperatures showed that global warming has a greater impact in the northern Adriatic than in the southern Adriatic. Air and sea surface temperatures have a faster upward trend on Krk than on Lastovo. Similar to the Mediterranean Sea, a positive trend was observed in the Adriatic Sea for both sea surface temperature and air temperature. Full article

(This article belongs to the Special Issue Feature Papers in Atmosphere Science)

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13 pages, 2034 KiB

Open AccessArticle

Predicting Indian Ocean Cyclone Parameters Using an Artificial Intelligence Technique

by C. Purna Chand, M.M. Ali, Borra Himasri, Mark A. Bourassa and Yangxing Zheng

Atmosphere 2022, 13(7), 1157; https://doi.org/10.3390/atmos13071157 - 21 Jul 2022

Cited by 1 | Viewed by 1500

Abstract

Precise prediction of a cyclone track with wind speed, pressure, landfall point, and the time of crossing the land are essential for disaster management and mitigation, including evacuation processes. In this paper, we use an artificial neural network (ANN) approach to estimate the [...] Read more.

Precise prediction of a cyclone track with wind speed, pressure, landfall point, and the time of crossing the land are essential for disaster management and mitigation, including evacuation processes. In this paper, we use an artificial neural network (ANN) approach to estimate the cyclone parameters. For this purpose, these parameters are obtained from the International Best Track Archive for Climate Stewardship (IBTrACS), from the National Oceanic and Atmospheric Administration (NOAA). Since ANN benefits from a large number of data points, each cyclone track is divided into different segments. We use past information to predict the geophysical parameters of a cyclone. The predicted values are compared with the observations. Full article

(This article belongs to the Section Atmospheric Techniques, Instruments, and Modeling)

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20 pages, 5620 KiB

Open AccessArticle

Long-Term COVID-19 Restrictions in Italy to Assess the Role of Seasonal Meteorological Conditions and Pollutant Emissions on Urban Air Quality

by Giovanni Gualtieri, Lorenzo Brilli, Federico Carotenuto, Carolina Vagnoli, Alessandro Zaldei and Beniamino Gioli

Atmosphere 2022, 13(7), 1156; https://doi.org/10.3390/atmos13071156 - 21 Jul 2022

Cited by 2 | Viewed by 1476

Abstract

A year-round air quality analysis was addressed over four Italian cities (Milan, Turin, Bologna, and Florence) following the outbreak of the Coronavirus 2019 (COVID-19) pandemic. NO₂, O₃, PM_2.5, and PM₁₀ daily observations were compared with estimations [...] Read more.

A year-round air quality analysis was addressed over four Italian cities (Milan, Turin, Bologna, and Florence) following the outbreak of the Coronavirus 2019 (COVID-19) pandemic. NO₂, O₃, PM_2.5, and PM₁₀ daily observations were compared with estimations of meteorological variables and observations of anthropogenic emission drivers as road traffic and heating systems. Three periods in 2020 were analysed: (i) the first (winter/spring) lockdown, (ii) the (spring/summer) partial relaxation period, and (iii) the second (autumn/winter) lockdown. During the first lockdown, only NO₂ concentrations decreased systematically (and significantly, between −41.9 and −53.9%), mainly due to the drastic traffic reduction (−70 to −74%); PM_2.5 varied between −21 and +18%, PM₁₀ varied between −23 and +9%, and O₃ increased (up to +17%). During the partly relaxation period, no air quality issues were observed. The second lockdown was particularly critical as, although road traffic significantly reduced (−30 to −44%), PM_2.5 and PM₁₀ concentrations dramatically increased (up to +87 and +123%, respectively), mostly due to remarkably unfavourable weather conditions. The latter was confirmed as the main driver of PM’s most critical concentrations, while strong limitations to anthropogenic activity—including traffic bans—have little effect when taken alone, even when applied for more than two months and involving a whole country. Full article

(This article belongs to the Special Issue Quantifying the Impact of COVID-19 on Air Pollutant Emissions, Air Quality, and Climate Change)

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17 pages, 12906 KiB

Open AccessArticle

Current Conditions and Projected Changes in Crop Water Demand, Irrigation Requirement, and Water Availability over West Africa

by Imoleayo Ezekiel Gbode, Gulilat Tefera Diro, Joseph Daniel Intsiful and Jimy Dudhia

Atmosphere 2022, 13(7), 1155; https://doi.org/10.3390/atmos13071155 - 21 Jul 2022

Cited by 5 | Viewed by 1577

Abstract

Climate variability and change greatly affect agricultural and water resource management over West Africa. This paper presents the current characteristics and projected change in regional crop water demand (CWD), irrigation requirement (IR), and water availability (WA) over West Africa. Observed and simulated daily [...] Read more.

Climate variability and change greatly affect agricultural and water resource management over West Africa. This paper presents the current characteristics and projected change in regional crop water demand (CWD), irrigation requirement (IR), and water availability (WA) over West Africa. Observed and simulated daily rainfall, minimum temperature, maximum temperature, and evapotranspiration are used to derive the above agro-meteorological and hydrological variables. For future periods, high-resolution climate data from three regional climate models under two different scenarios, i.e., representative concentration pathway (RCP) 4.5 and 8.5, are considered. Evaluation of the characteristics of present-day CWD, IR, and WA indicated that the ensemble mean of the model-derived outputs reproduced the prevailing spatial patterns of CWD and IR. Moreover, the wetter part of the domain, especially along the southern coast, was correctly delineated from the drier northern regions, despite having biases. The ensemble model also simulated the annual cycle of water supply and the bimodal pattern of the water demand curves correctly. In terms of future projections, the outcomes from the study suggest an average increase in the CWD by up to 0.808 mm/day and IR by 1.244 mm/day towards the end of the twenty-first century, compared to the baseline period. The hot-spot areas, where there is higher projected increment in CWD and IR, are over Senegal, Southern Mali, and Western Burkina Faso. In most cases, WA is projected to decrease towards the end of the twenty-first century by −0.418 mm/day. The largest decline in WA is found to be over Guinea and most of the eastern parts of West Africa. Despite the current under-utilization of the existing groundwater resources, the threat of global warming in reducing future WA and increasing CWD suggested caution on the scale of irrigation schemes and management strategies. The outcomes from the study could be a crucial input for the agricultural and water managers for introducing effective measures to ensure sustainability of irrigated farm lands. Full article

(This article belongs to the Special Issue State-of-Art in Regional Climate Models)

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11 pages, 6473 KiB

Open AccessArticle

Origin of Moisture for the Precipitation Produced by the Exceptional Winter Storm Formed over the Gulf of Mexico in March 1993

by Patricia Coll-Hidalgo, Albenis Pérez-Alarcón and Luis Gimeno

Atmosphere 2022, 13(7), 1154; https://doi.org/10.3390/atmos13071154 - 21 Jul 2022

Cited by 10 | Viewed by 1560

Abstract

On 12–15 March 1993, a severe winter storm (SC93) formed over the Gulf of Mexico, affecting the Caribbean Islands and the eastern coast of the United States (US) and Canada with a notable amount of precipitation, snow and severe local storms. In this [...] Read more.

On 12–15 March 1993, a severe winter storm (SC93) formed over the Gulf of Mexico, affecting the Caribbean Islands and the eastern coast of the United States (US) and Canada with a notable amount of precipitation, snow and severe local storms. In this study, we investigate the origin of the precipitation generated by SC93 by applying a widely used Lagrangian moisture source diagnostic method. Our findings revealed that most of the moisture came from the western North Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico. Moreover, the eastern US and Mexico acted as notable terrestrial moisture sources. Overall, the moisture contribution from the oceanic origin was higher than the terrestrial counterpart, and the moisture sources progressively shifted northward as the storm moved. In addition, the moisture uptake mainly occurred in the cyclone–anticyclone interaction region. Full article

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16 pages, 2057 KiB

Open AccessArticle

Evaluating Gas Emissions from Different Feed Cropping Systems in the North China Plain: A Two-Year Field Measurement

by Wenhua Liao, Chunjing Liu, Xinxing Zhang, Shanshan Wang, Yujing Fan and Zhiling Gao

Atmosphere 2022, 13(7), 1153; https://doi.org/10.3390/atmos13071153 - 21 Jul 2022

Cited by 5 | Viewed by 1287

Abstract

The cultivation of silage crops is encouraged to enhance the connection between crop and livestock production in the North China Plain (NCP). A field experiment was designed to evaluate the ammonia (NH₃), nitrous oxide (N₂O), and methane (CH₄ [...] Read more.

The cultivation of silage crops is encouraged to enhance the connection between crop and livestock production in the North China Plain (NCP). A field experiment was designed to evaluate the ammonia (NH₃), nitrous oxide (N₂O), and methane (CH₄) emissions of five silage cropping systems, including triticale-summer maize (Tr-SuM), triticale-spring maize (Tr-SpM), triticale-double forage maize (Tr-DFM), double forage maize (DFM), and winter wheat-summer maize (WW-SuM), as well as their biomass- and crude protein-scaled emission intensities, with respect to NH₃ and greenhouse gas (GHG). The annual nitrogen (N) emissions through NH₃, N₂O, and CH₄ emissions of these systems were 13.43–23.77 kg ha⁻¹ (4.2–5.6% of N fertilizer input), 3.43–4.56 kg ha⁻¹ (0.75–1.08% of N fertilizer input) and 2.10–2.85 kg ha⁻¹, respectively. The total GHG emissions of these systems was dominated by the contributions of N₂O. Ranking these systems according to their biomass and crude protein production gave Tr-DFM > DFM > WW-SuM > Tr-SuM and Tr-SpM, their partial factor productivity was in the order of Tr-DFM > WW-SuM > Tr-SuM and Tr-SpM > DFM, and the order of their emission intensity was DFM > Tr-SuM > Tr-DFM > WW-SuM > Tr-SpM. In conclusion, the Tr-DFM needs to be further investigated for its suitability in the NCP, owing to its superior productivity and moderate emission intensities. Full article

(This article belongs to the Section Air Quality)

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18 pages, 6082 KiB

Open AccessArticle

Combining Spatial and Temporal Data to Create a Fine-Resolution Daily Urban Air Temperature Product from Remote Sensing Land Surface Temperature (LST) Data

by David Neil Bird, Ellen Banzhaf, Julius Knopp, Wanben Wu and Laurence Jones

Atmosphere 2022, 13(7), 1152; https://doi.org/10.3390/atmos13071152 - 20 Jul 2022

Cited by 3 | Viewed by 1852

Abstract

Remotely sensed land surface temperature (LST) is often used as a proxy for air temperature in urban heat island studies, particularly to illustrate relative temperature differences between locations. Two sensors are used predominantly in the literature, Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS). [...] Read more.

Remotely sensed land surface temperature (LST) is often used as a proxy for air temperature in urban heat island studies, particularly to illustrate relative temperature differences between locations. Two sensors are used predominantly in the literature, Landsat and Moderate Resolution Imaging Spectroradiometer (MODIS). However, each has shortcomings that currently limit its utility for many urban applications. Landsat has high spatial resolution but low temporal resolution, and may miss hot days, while MODIS has high temporal resolution but low spatial resolution, which is inadequate to represent the fine grain heterogeneity in cities. In this paper, we overcome this inadequacy by combining high spatial frequency Environmental Services (ES), Landsat-driven Normalized Difference Vegetation Index (NDVI), and MODIS low spatial frequency background LST at different spatial frequency bands (spatial spectral composition). The method is able to provide fine scale LST four times daily on any day of the year. Using data from Paris in 2019 we show that (1) daytime cooling by vegetation reaches a maximum of 30 °C, above which there is no further increase in cooling. In addition, (2) the cooling is relatively local and does not extend further than 200 m beyond the boundary of the NBS. This model can be used to quantify the benefits of NBS in providing cooling in cities. Full article

(This article belongs to the Special Issue Cool Cities: Towards Sustainable and Healthy Urban Environments)

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19 pages, 7648 KiB

Open AccessArticle

A Framework on Analyzing Long-Term Drought Changes and Its Influential Factors Based on the PDSI

by Bing Yang, Liang Kong, Chengguang Lai, Dong Huang and Xiangju Cheng

Atmosphere 2022, 13(7), 1151; https://doi.org/10.3390/atmos13071151 - 20 Jul 2022

Cited by 4 | Viewed by 1499

Abstract

Drought is one of the most frequent and most widespread natural disasters worldwide, significantly impacting agricultural production and the ecological environment. An investigation of long-term drought changes and its influencing factors provides not only an understanding of historical droughts but also a scientific [...] Read more.

Drought is one of the most frequent and most widespread natural disasters worldwide, significantly impacting agricultural production and the ecological environment. An investigation of long-term drought changes and its influencing factors provides not only an understanding of historical droughts but also a scientific basis for the protection of future water resources. This study investigated the temporal characteristics of drought in a study site located in the center of Southwest China (SWC) over a 700-year period (AD 1300–2005) using the Palmer Drought Severity Index (PDSI). The linkage between drought and its influencing factors is discussed. An algorithm based on the random forest (RF) method was proposed to analyze the dynamic influence of the factors on drought. We also examined the linkages between the demise of two dynasties and historical drought events. The results showed that the study site was a drought-prone area in the study period and experienced a non-significant drying trend in all centuries, except for the 17th century; a total of 232 droughts were detected in the study site from AD 1300–2005. The wavelet spectrum of the PDSI series showed the existence of 4-, 8-, 16-, 32-, and 128-year-periods. A strong correlation existed between the sunspot numbers and the PDSI. The correlation of the period between the PDSI and El Niño-Southern Oscillation (ENSO) series in the same frequency domain was weak, while the ENSO exhibited a strong interaction with the PDSI in some time periods. The Pacific Decadal Oscillation (PDO) and PDSI had no resonance period in the low-frequency region, but there was a period of 80–130 years in the high-frequency region. The relative rates of influence of the ENSO, sunspot numbers, and PDO during AD 1700–1996 were 38.40%, 31.81%, and 29.8%, respectively. However, the mechanism of the interaction between droughts and the influential factors is complex, and the dominant factor changed over time. The analysis of long-term drought changes based on the PDSI series may provide clues to understand the development of historical events. Full article

(This article belongs to the Special Issue Drought in Arid and Semi-arid Regions)

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17 pages, 4461 KiB

Open AccessArticle

Using 3D Ray Tracing Technology to Study the Disturbance Effect of Rocket Plume on Ionosphere

by Qingfeng Li, Zeyun Li and Hanxian Fang

Atmosphere 2022, 13(7), 1150; https://doi.org/10.3390/atmos13071150 - 20 Jul 2022

Cited by 1 | Viewed by 1461

Abstract

In this paper, the initial neutral atmospheric parameters, background ionospheric parameters and geomagnetic field parameters of the ionosphere are obtained by NRLMSISE-00 model, IRI-2016 model and IGRF-13 model, respectively. Considering the neutral gas diffusion process, ion chemical reaction and plasma diffusion process, a [...] Read more.

In this paper, the initial neutral atmospheric parameters, background ionospheric parameters and geomagnetic field parameters of the ionosphere are obtained by NRLMSISE-00 model, IRI-2016 model and IGRF-13 model, respectively. Considering the neutral gas diffusion process, ion chemical reaction and plasma diffusion process, a three-dimensional dynamic model of chemical substances released by rocket plume disturbing the ionosphere is constructed. The influence of the disturbance on the echo path of high frequency radio waves with different incident frequencies is simulated by using three-dimensional digital ray-tracing technology. Using this model, the process of ionospheric disturbance caused by the main chemical substances H₂ and H₂O in the rocket plume under three different release conditions: fixed-point release at 300 km, vertical path at 250–350 km and parabolic path at 250–350 km, and the influence of the ionospheric cavity on the radio wave propagation of high frequency radio waves at different frequencies are simulated. The main purpose of the article is to focus on the effect of the cavity generated by the rocket exhaust on the propagation of radio waves. It mainly studies the perturbation effect on the ionosphere under different release conditions, considers the neutral gas diffusion process, ion chemical reaction and plasma diffusion process, and establishes the three-dimensional dynamics of the ionospheric electron density and the spatiotemporal distribution of the plume plasma learning model. Finally, the three-dimensional ray-tracing algorithm is used to simulate the propagation path of the radio wave through the disturbance area. We considered three different release conditions, including fixed-point release, vertical path and parabolic path. The ionospheric disturbances produced by these different releases are compared and analyzed, and their effects on the propagation path of radio waves are studied. Full article

(This article belongs to the Section Upper Atmosphere)

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12 pages, 3594 KiB

Open AccessArticle

Source Identification of PM_2.5 during a Smoke Haze Period in Chiang Mai, Thailand, Using Stable Carbon and Nitrogen Isotopes

by Sawaeng Kawichai, Tippawan Prapamontol, Fang Cao, Wenhuai Song and Yanlin Zhang

Atmosphere 2022, 13(7), 1149; https://doi.org/10.3390/atmos13071149 - 20 Jul 2022

Cited by 5 | Viewed by 2011

Abstract

Open biomass burning (BB) has contributed severely to the ambient levels of particulate matter of less than 2.5 μm diameter (PM_2.5) in upper northern Thailand over the last decade. Some methods have been reported to identify the sources of burning using [...] Read more.

Open biomass burning (BB) has contributed severely to the ambient levels of particulate matter of less than 2.5 μm diameter (PM_2.5) in upper northern Thailand over the last decade. Some methods have been reported to identify the sources of burning using chemical compositions, i.e., ions, metals, polycyclic aromatic hydrocarbons, etc. However, recent advances in nuclear techniques have been limited in use due to their specific instrumentation. The aims of this study were to investigate the sources of ambient PM_2.5 in Chiang Mai city using stable carbon (δ¹³C) and nitrogen isotopes (δ¹⁵N). The mean concentrations of total carbon (TC) and total nitrogen (TN) in PM_2.5 were 12.2 ± 5.42 and 1.91 ± 1.07 μg/m³, respectively, whereas δ¹³C and δ¹⁵N PM_2.5 were −26.1 ± 0.77‰ and 10.3 ± 2.86‰, respectively. This isotopic analysis confirmed that biomass burning was the source of PM_2.5 and that C₃ and C₄ plants contributed about 74% and 26%, respectively. These study results confirm that the stable isotope is an important tool in identifying the sources of aerosols. Full article

(This article belongs to the Special Issue Measurement and Application of Isotopes and Organic Tracers in Atmosphere)

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18 pages, 999 KiB

Open AccessReview

Urban Aerobiome and Effects on Human Health: A Systematic Review and Missing Evidence

by Elena Franchitti, Chiara Caredda, Elisa Anedda and Deborah Traversi

Atmosphere 2022, 13(7), 1148; https://doi.org/10.3390/atmos13071148 - 20 Jul 2022

Cited by 3 | Viewed by 2099

Abstract

Urban air pollutants are a major public health concern and include biological matters which composes about 25% of the atmospheric aerosol particles. Airborne microorganisms were traditionally characterized by culture-based methods recognizing just 1.5–15.3% of the total bacterial diversity that was evaluable by genome [...] Read more.

Urban air pollutants are a major public health concern and include biological matters which composes about 25% of the atmospheric aerosol particles. Airborne microorganisms were traditionally characterized by culture-based methods recognizing just 1.5–15.3% of the total bacterial diversity that was evaluable by genome signature in the air environment (aerobiome). Despite the large number of exposed people, urban aerobiomes are still weakly described even if recently advanced literature has been published. This paper aims to systematically review the state of knowledge on the urban aerobiome and human health effects. A total of 24 papers that used next generation sequencing (NGS) techniques for characterization and comprised a seasonal analysis have been included. A core of Proteobacteria, Actinobacteria, Firmicutes, and Bacteroides and various factors that influenced the community structure were detected. Heterogenic methods and results were reported, for both sampling and aerobiome diversity analysis, highlighting the necessity of in-depth and homogenized assessment thus reducing the risk of bias. The aerobiome can include threats for human health, such as pathogens and resistome spreading; however, its diversity seems to be protective for human health and reduced by high levels of air pollution. Evidence of the urban aerobiome effects on human health need to be filled up quickly for urban public health purposes. Full article

(This article belongs to the Special Issue Feature Papers in Air Pollution, Health Effects Indicators, Exposome, and One Health)

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Graphical abstract

5 pages, 224 KiB

Open AccessCommentary

Prevention of Health Risks Related to Occupational Solar Ultraviolet Radiation Exposure in Times of Climate Change and COVID-19 Pandemic

by Alberto Modenese

Atmosphere 2022, 13(7), 1147; https://doi.org/10.3390/atmos13071147 - 20 Jul 2022

Cited by 2 | Viewed by 1544

Abstract

Occupational exposure to solar ultraviolet (UV) radiation is a recognized work-related risk, as is associated with the induction of long-term adverse health effects such as Non-Melanoma Skin Cancers and cataracts. Recent research provided new data suggesting an increased risk of specific forms of [...] Read more.

Occupational exposure to solar ultraviolet (UV) radiation is a recognized work-related risk, as is associated with the induction of long-term adverse health effects such as Non-Melanoma Skin Cancers and cataracts. Recent research provided new data suggesting an increased risk of specific forms of malignant melanoma, i.e., Lentigo Maligna Melanoma, for outdoor workers, while the relation of cumulative exposure to solar radiation with ocular diseases, such as uveal melanoma and macular degeneration, is still debated. Nowadays, one of the main focuses of prevention activities is the organization of multicomponent sun safety initiatives, which are proved to be effective, particularly when including technologies that are able to directly interact with individuals, such as phone apps, such as the recently released SunSmart Global UV App. Nevertheless, we should not forget that we are living in an era of profound changes, and phenomena such as climate change and the COVID-19 pandemic have an impact on all aspects of our lives, including how and when we perform, as well as the perception of, outdoor activities. In the future, this may result in possible changes in the scenario of occupational and leisure-time solar radiation exposure-related health risks. Full article

(This article belongs to the Special Issue Frontiers in Solar UV Radiation Observations, Prediction, and Personal Exposure)

18 pages, 1391 KiB

Open AccessArticle

Modification of

k-ε

Model for Sensible Heat and Momentum Flux Reconstruction from Surface Temperature Data

by Michael Hrebtov and Maxim Bobrov

Atmosphere 2022, 13(7), 1146; https://doi.org/10.3390/atmos13071146 - 20 Jul 2022

Viewed by 1340

Abstract

We present a modified

k-ε

model with a set of wall-functions suitable for reconstruction of sensible heat and momentum fluxes from the observations data (e.g., surface temperature evolution during the diurnal cycle). The modification takes into account stability and buoyancy effects in the [...] Read more.

We present a modified

k-ε

model with a set of wall-functions suitable for reconstruction of sensible heat and momentum fluxes from the observations data (e.g., surface temperature evolution during the diurnal cycle). The modification takes into account stability and buoyancy effects in the Reynolds stress parametrization which affects turbulence production and turbulent heat flux. The single-cell and single-column versions of the model are presented. The model is tested based on CASES-99 observations data for dry ABL. It is shown that the presented modification improves the predictions of sensible heat flux magnitude and leads to a faster onset of a daytime instability, compared to the non-modified

k-ε

model and its scale-limited modification based on Monin-Obukhov similarity theory. Full article

(This article belongs to the Section Biosphere/Hydrosphere/Land–Atmosphere Interactions)

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16 pages, 2520 KiB

Open AccessArticle

Responses of Soil N₂O Emission and CH₄ Uptake to N Input in Chinese Forests across Climatic Zones: A Meta-Study

by Bei Zhang, Yuanyuan Huang, Zhi Qu, Tongbin Zhu and Longfei Yu

Atmosphere 2022, 13(7), 1145; https://doi.org/10.3390/atmos13071145 - 19 Jul 2022

Cited by 2 | Viewed by 1613

Abstract

Enhanced nitrogen (N) deposition has shown significant impacts on forest greenhouse gas emissions. Previous studies have suggested that Chinese forests may exhibit stronger N₂O sources and dampened CH₄ sinks under aggravated N saturation. To gain a common understanding of the [...] Read more.

Enhanced nitrogen (N) deposition has shown significant impacts on forest greenhouse gas emissions. Previous studies have suggested that Chinese forests may exhibit stronger N₂O sources and dampened CH₄ sinks under aggravated N saturation. To gain a common understanding of the N effects on forest N₂O and CH₄ fluxes, many have conducted global-scale meta-analyses. However, such effects have not been quantified particularly for China. Here, we present a meta-study of the N input effects on soil N₂O emission and CH₄ uptake in Chinese forests across climatic zones. The results suggest that enhanced N inputs significantly increase soil N₂O emission (+115.8%) and decrease CH₄ uptake (−13.4%). The mean effects were stronger for N₂O emission and weaker for CH₄ uptake in China compared with other global sites, despite being statistically insignificant. Subtropical forest soils have the highest emission factor (2.5%) and may respond rapidly to N inputs; in relatively N-limited temperate forests, N₂O and CH₄ fluxes are less sensitive to N inputs. Factors including forest type, N form and rate, as well as soil pH, may also govern the responses of N₂O and CH₄ fluxes. Our findings pinpoint the important role of Southern Chinese forests in the regional N₂O and CH₄ budgets. Full article

(This article belongs to the Special Issue Nitrogen in a Changing Atmosphere)

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26 pages, 5470 KiB

Open AccessArticle

An Improved Air Quality Index Machine Learning-Based Forecasting with Multivariate Data Imputation Approach

by Hanin Alkabbani, Ashraf Ramadan, Qinqin Zhu and Ali Elkamel

Atmosphere 2022, 13(7), 1144; https://doi.org/10.3390/atmos13071144 - 18 Jul 2022

Cited by 18 | Viewed by 3793

Abstract

Accurate, timely air quality index (AQI) forecasting helps industries in selecting the most suitable air pollution control measures and the public in reducing harmful exposure to pollution. This article proposes a comprehensive method to forecast AQIs. Initially, the work focused on predicting hourly [...] Read more.

Accurate, timely air quality index (AQI) forecasting helps industries in selecting the most suitable air pollution control measures and the public in reducing harmful exposure to pollution. This article proposes a comprehensive method to forecast AQIs. Initially, the work focused on predicting hourly ambient concentrations of PM_2.5 and PM₁₀ using artificial neural networks. Once the method was developed, the work was extended to the prediction of other criteria pollutants, i.e., O_3, SO₂, NO₂, and CO, which fed into the process of estimating AQI. The prediction of the AQI not only requires the selection of a robust forecasting model, it also heavily relies on a sequence of pre-processing steps to select predictors and handle different issues in data, including gaps. The presented method dealt with this by imputing missing entries using missForest, a machine learning-based imputation technique which employed the random forest (RF) algorithm. Unlike the usual practice of using RF at the final forecasting stage, we utilized RF at the data pre-processing stage, i.e., missing data imputation and feature selection, and we obtained promising results. The effectiveness of this imputation method was examined against a linear imputation method for the six criteria pollutants and the AQI. The proposed approach was validated against ambient air quality observations for Al-Jahra, a major city in Kuwait. Results obtained showed that models trained using missForest-imputed data could generalize AQI forecasting and with a prediction accuracy of 92.41% when tested on new unseen data, which is better than earlier findings. Full article

(This article belongs to the Special Issue Sand and Dust Storms: Impact and Mitigation Methods)

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11 pages, 1123 KiB

Open AccessArticle

Effects of Climate Change on Forest Regeneration in Central Spain

by Álvaro Enríquez-de-Salamanca

Atmosphere 2022, 13(7), 1143; https://doi.org/10.3390/atmos13071143 - 18 Jul 2022

Cited by 4 | Viewed by 2002

Abstract

The Mediterranean climate has dry and hot summers, which is harsh for plants, especially seedlings. During the 1950s and 1960s, most reforestations carried out in Central Spain, a Mediterranean climate area, were successful, but in recent decades an increasing difficulty in forest regeneration [...] Read more.

The Mediterranean climate has dry and hot summers, which is harsh for plants, especially seedlings. During the 1950s and 1960s, most reforestations carried out in Central Spain, a Mediterranean climate area, were successful, but in recent decades an increasing difficulty in forest regeneration has been observed, often attributed to increased summer drought. This study analyses changes in climatic parameters related to forest regeneration through statistical treatment of meteorological data series from the mid-twentieth century to the present. Simple and multiple regressions and ANOVAs were performed for five parameters, considering annual, summer and extended summer values. Rainfall reduction and prolongation of the summer drought period were not statistically significant. The change that better explains regeneration problems is the increase in temperature, especially in July and August, which was mostly significant between 2002 and 2021. Raising temperatures increase the vapor pressure deficit, exacerbating drought effects and plant mortality. Climate change scenarios point to an increase in temperatures until 2100; thus, the tipping point for natural regeneration of some species could be passed. The most affected species are those at their ecological limit. It is necessary to facilitate the adaptation of these forests to climate change, since their future will depend on the actions carried out today. Full article

(This article belongs to the Special Issue Feature Papers in Atmosphere Science)

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14 pages, 3376 KiB

Open AccessArticle

On Applying Large-Scale Correction to Limited-Area Numerical Weather Prediction Models

by Anurag Dipankar, Xiang-Yu Huang and Peter Heng

Atmosphere 2022, 13(7), 1142; https://doi.org/10.3390/atmos13071142 - 18 Jul 2022

Viewed by 1164

Abstract

This paper presents a new blending approach to applying large-scale correction to the initial condition in a limited-area numerical weather prediction (NWP) model. The new approach combines the implementation benefits of the known approaches and shows significant improvement in the forecast quality when [...] Read more.

This paper presents a new blending approach to applying large-scale correction to the initial condition in a limited-area numerical weather prediction (NWP) model. The new approach combines the implementation benefits of the known approaches and shows significant improvement in the forecast quality when implemented in a tropical NWP model. Sensitivity studies indicate that many improvements come from blending the horizontal winds alone. Adding temperature and specific humidity to the horizontal winds result in forecast quality degradation in the early hours of the simulated tropical environment. Full article

(This article belongs to the Section Atmospheric Techniques, Instruments, and Modeling)

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17 pages, 1438 KiB

Open AccessArticle

A Study on the Framework for Estimating Ship Air Pollutant Emissions—Focusing on Ports of South Korea

by Tingting Zhao, Maowei Chen and Hyangsook Lee

Atmosphere 2022, 13(7), 1141; https://doi.org/10.3390/atmos13071141 - 18 Jul 2022

Cited by 5 | Viewed by 1961

Abstract

With the globalization of trade and the rapid development of the world economy, the problem of air pollution emissions produced by shipping is becoming more serious. The exhaust gas emitted by ships has become a significant source of air pollution in ocean and [...] Read more.

With the globalization of trade and the rapid development of the world economy, the problem of air pollution emissions produced by shipping is becoming more serious. The exhaust gas emitted by ships has become a significant source of air pollution in ocean and coastal areas. In recent years, governments have paid more attention to shipping emissions as a major source of environmental problems. Establishing ship emission inventories plays an important role in formulating ship emission control measures and regulations. This study aimed to propose a framework for calculating ship air pollutant emissions by comprehensively considering processes and methods officially used in developed countries such as the US and those in the EU, as well as South Korean circumstances and available data sets. The framework was divided into three sections: defining the inventory, data collection and analysis of the data, and ship air pollutant emission estimation. The results of this study provided a standard for South Korean domestic port emission inventories. A case study focused on the Gwangyang and Yeosu Ports, one of the leading port areas in South Korea, using adaptive data collection and emission-calculation processes. This study can be used as guidelines when the Ministry of Oceans and Fisheries (MOF) or the Ministry of Environment (MOE) adopts a standard process in South Korea in the near future. Subsequently, it is necessary to establish a national port emission management system to respond to world environmental changes. Full article

(This article belongs to the Special Issue Air Quality and Public Health Effects in Korea)

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21 pages, 14974 KiB

Open AccessArticle

Summer Precipitation Extremes over the Yellow River Loop Valley and Its link to European Blocking

by Kan Xu, Yina Diao and Peng Huang

Atmosphere 2022, 13(7), 1140; https://doi.org/10.3390/atmos13071140 - 18 Jul 2022

Cited by 1 | Viewed by 1244

Abstract

Characteristics of extreme precipitation over Yellow River Loop Valley (YRLV) and links to European blocking are investigated in this study. Spatial and temporal analysis of extreme precipitation shows that it contributes more than 30% of the total summer precipitation in the YRLV and [...] Read more.

Characteristics of extreme precipitation over Yellow River Loop Valley (YRLV) and links to European blocking are investigated in this study. Spatial and temporal analysis of extreme precipitation shows that it contributes more than 30% of the total summer precipitation in the YRLV and is characterized by a strong and short period of local rainfall. Most of the extreme rains in the YRLV occur in July and August. Two typical circulation patterns were identified using a k-means clustering method. The extreme precipitation results from the combined actions of intensified high pressure over northeast China (NECH) and the westward extension of the western Pacific subtropical high (WPSH). The intensified southerly flow of the amplified NECH strengthens the water vapor transport induced by the westward extension of the WPSH from the northwest Pacific or Bay of Bengal into the YRLV. The NECH is amplified by the wave energy propagating from European blocking via the Silk Road pattern (SRP). This is the subseasonal cause of extreme precipitation over the YRLV. The composited July and August mean 500 hPa geopotential anomaly pattern for extreme precipitation years shows a high-pressure anomaly over the European continent and a negative phase of the SRP. The former provides a background for the occurrence of European blocking, and the latter explains the preexistence of the NECH and provides a linkage between the activity of European blocking and the subseasonal evolution of the NECH. Thus, the interannual variation in the extreme precipitation over the YRLV is mainly reflected by the phase of the SRP and the stationary waves over Europe. Full article

(This article belongs to the Special Issue Atmospheric Blocking and Weather Extremes)

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13 pages, 2697 KiB

Open AccessArticle

Study on Transpiration Water Consumption and Photosynthetic Characteristics of Landscape Tree Species under Ozone Stress

by Bo Chen, Qingfeng Song and Qinghua Pan

Atmosphere 2022, 13(7), 1139; https://doi.org/10.3390/atmos13071139 - 18 Jul 2022

Cited by 2 | Viewed by 1444

Abstract

Using Pinus bungeana, Platycladus orientalis, Koelreuteria paniculata and Ginkgo biloba as research objects, three open-top chambers with different ozone-concentration gradients were set up (NF, NF40 and NF80) based on trunk sap-flow technology to study the difference in ozone absorption by trees [...] Read more.

Using Pinus bungeana, Platycladus orientalis, Koelreuteria paniculata and Ginkgo biloba as research objects, three open-top chambers with different ozone-concentration gradients were set up (NF, NF40 and NF80) based on trunk sap-flow technology to study the difference in ozone absorption by trees under different ozone concentrations. The results showed that the monthly and diurnal variations of sap-flow density of different tree species decreased with the increase in ozone concentration, and the increase in ozone concentration reduced the water consumption, ozone uptake rate (F_O3), net photosynthetic rate (P_n) and water-use efficiency (WUE) of different tree species. The sap-flow density, water consumption, F_O3 and WUE of Koelreuteria paniculata and Ginkgo biloba were higher than those of Pinus bungeana and Platycladus orientalis under different ozone concentrations. The sap-flow density, water consumption, F_O3 and WUE of Koelreuteria paniculata and Ginkgo biloba decreased significantly at the ozone concentrations of NF40 and NF80; compared with the ozone concentration of NF, the sap flow density of Koelreuteria paniculata and Ginkgo biloba decreased by 1.04 and 1.03 times as much as that of Pinus bungeana and Platycladus orientalis, respectively; the water consumption of Koelreuteria paniculata and Ginkgo biloba decreased by 1.82 and 1.56 times that of Pinus bungeana and Platycladus orientalis, respectively; the decline rate of F_O3 in Koelreuteria paniculata and Ginkgo biloba was 1.30 and 1.04 times that of Pinus bungeana and Platycladus orientalis, respectively; and the decline rate of WUE of Koelreuteria paniculata and Ginkgo biloba was 1.52 and 1.64 times that of Pinus bungeana and Platycladus orientalis, respectively. Pinus bungeana and Platycladus orientalis have stronger tolerance to ozone, while Koelreuteria paniculata and Ginkgo biloba were weak. A variety of conifers can be planted in areas with serious ozone pollution. Full article

(This article belongs to the Special Issue Impact of Land-Use and Climate Change on Vegetation)

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25 pages, 26072 KiB

Open AccessArticle

Spatio-Temporal Analysis of Valley Wind Systems in the Complex Mountain Topography of the Rolwaling Himal, Nepal

by Helge Jentsch and Johannes Weidinger

Atmosphere 2022, 13(7), 1138; https://doi.org/10.3390/atmos13071138 - 18 Jul 2022

Cited by 1 | Viewed by 1982

Abstract

The diurnal, seasonal, and spatio-temporal characteristics of local wind systems in a steep mountain valley in Nepal are analyzed with the identification of valley wind days (VWDs). Distributed across the Rolwaling Himal valley in Nepal between 3700 and 5100 m a.s.l. at eight [...] Read more.

The diurnal, seasonal, and spatio-temporal characteristics of local wind systems in a steep mountain valley in Nepal are analyzed with the identification of valley wind days (VWDs). Distributed across the Rolwaling Himal valley in Nepal between 3700 and 5100 m a.s.l. at eight automated weather stations (AWSs), meteorological data between October 2017 and September 2018 were examined. VWDs were classified by means of ERA5 reanalysis data and in situ observations, employing established thresholds using precipitation, solar radiation, air pressure, and wind speed data at different pressure levels. Thus, overlying synoptic influences are highly reduced and distinctive diurnal patterns emerge. A strong seasonal component in near-surface wind speed and wind direction patterns was detected. Further analyses showed the diurnal characteristics of slow (approximately 0.5–0.9 m s

^{- 1}

), but gradually increasing wind speeds over the night, transitional periods in the morning and evening, and the highest averaged wind speeds of approximately 4.3 m s

^{- 1}

around noon during the VWDs. Wind directions followed a 180

^{\circ}

shift with nocturnal katabatic mountain winds and inflowing anabatic valley winds during the daytime. With AWSs at opposing hillsides, slope winds were clearly identifiable and thermally driven spatio-temporal variations throughout the valley were revealed. Consequently, varying temporal shifts in wind speed and direction along the valley bottom can be extracted. In general, the data follow the well-known schematic of diurnal mountain–valley wind systems, but emphasize the influence of monsoonal seasonality and the surrounding complex mountain topography as decisive factors. Full article

(This article belongs to the Special Issue Climates of the Himalayas: Present, Past and Future)

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17 pages, 1811 KiB

Open AccessArticle

Oscillatory Signatures in the Raindrop Motion Relative to the Air Medium with Terminal Velocity

by Dmitrii N. Gabyshev, Miklós Szakáll, Dmitrii V. Shcherbakov, Alexander A. Fedorets and Sergey M. Dyachkov

Atmosphere 2022, 13(7), 1137; https://doi.org/10.3390/atmos13071137 - 18 Jul 2022

Cited by 3 | Viewed by 1435

Abstract

This paper aims to study the path oscillations of single, spherical water droplets levitated in a wind tunnel to better comprehend the mechanical motion of small raindrops. The observations were carried out in the Mainz vertical wind tunnel. The discrete, fast Fourier transform [...] Read more.

This paper aims to study the path oscillations of single, spherical water droplets levitated in a wind tunnel to better comprehend the mechanical motion of small raindrops. The observations were carried out in the Mainz vertical wind tunnel. The discrete, fast Fourier transform was used to determine the oscillatory frequencies of the droplet paths, and the Hilbert transform was applied to analyze their instantaneous frequency stability. Both transversal and streamwise components of the path oscillations are described with typical frequencies of several tens of Hertz. The studied oscillations elongate the paths, reduce the terminal velocity of the smallest droplets, and make the rain droplet fall in a non-uniform motion even after reaching terminal velocity. The terminal velocity can be considered as physically having been reached if our proposed practical criterion is satisfied. From a fluid mechanics perspective, the paper fills an experimental gap in the studies of the paths oscillations of single, liquid spheres of microscopic sizes at low Bond numbers <1 and relatively low Reynolds numbers ~10². Full article

(This article belongs to the Special Issue Feature Papers in Atmosphere Science)

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20 pages, 19729 KiB

Open AccessArticle

Characteristics and Sources of Volatile Organic Compounds in the Nanjing Industrial Area

by Yuezheng Feng, Junlin An, Guiqian Tang, Yuxin Zhang, Junxiu Wang and Huan Lv

Atmosphere 2022, 13(7), 1136; https://doi.org/10.3390/atmos13071136 - 18 Jul 2022

Cited by 5 | Viewed by 1637

Abstract

In this study, 56 volatile organic compounds species (VOCs) and other pollutants (NO, NO₂, SO₂, O₃, CO and PM_2.5) were measured in the northern suburbs of Nanjing from September 2014 to August 2015. The total [...] Read more.

In this study, 56 volatile organic compounds species (VOCs) and other pollutants (NO, NO₂, SO₂, O₃, CO and PM_2.5) were measured in the northern suburbs of Nanjing from September 2014 to August 2015. The total volatile organic compound (TVOC) concentrations were higher in the autumn (40.6 ± 23.8 ppbv) and winter (41.1 ± 21.7 ppbv) and alkanes were the most abundant species among the VOCs (18.4 ± 10.0 ppbv). According to the positive matrix factorization (PMF) model, the VOCs were found to be from seven sources in the northern suburbs of Nanjing, including liquefied petroleum gas (LPG) sources, gasoline vehicle emissions, iron and steel industry sources, industrial refining coke sources, solvent sources and petrochemical industry sources. One of the sources was influenced by seasonal variations: it was a diesel vehicle emission source in the spring, while it was a coal combustion source in the winter. According to the conditional probability function (CPF) method, it was found that the main contribution areas of each source were located in the easterly direction (mainly residential areas, industrial areas, major traffic routes, etc.). There were also seasonal differences in concentration, ozone formation potential (OFP), OH radical loss rate (L^OH) and secondary organic aerosols potential (SOAP) for each source due to the high volatility of the summer and autumn temperatures, while combustion increases in the winter. Finally, the time series of O₃ and OFP was compared to that PM_2.5 and SOAP and then they were combined with the wind rose figure. It was found that O₃ corresponded poorly to the OFP, while PM_2.5 corresponded well to the SOAP. The reason for this was that the O₃ generation was influenced by several factors (NO_x concentration, solar radiation and non-local transport), among which the influence of non-local transport could not be ignored. Full article

(This article belongs to the Special Issue Tropospheric Ozone in China: Current Situation, Formation Mechanism and Control Measures)

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11 pages, 2220 KiB

Open AccessArticle

Impact of AIS Data Thinning on Ship Air Pollutant Emissions Inventories

by Yujun Tian, Lili Ren, Hongyan Wang, Tao Li, Yupeng Yuan and Yan Zhang

Atmosphere 2022, 13(7), 1135; https://doi.org/10.3390/atmos13071135 - 18 Jul 2022

Cited by 5 | Viewed by 2035

Abstract

This article examines the impact of automatic identification system (AIS) data thinning on ship emissions inventory results. AIS data thinning is theoretically proven to lead to a smaller result for a ship’s air pollutant emissions inventory. The AIS dynamic data of six sampled [...] Read more.

This article examines the impact of automatic identification system (AIS) data thinning on ship emissions inventory results. AIS data thinning is theoretically proven to lead to a smaller result for a ship’s air pollutant emissions inventory. The AIS dynamic data of six sampled ships for 1 day and for 1 year were thinned at 1 min, 3 min, 10 min, 30 min, and 1 h time intervals, and then CO₂, NO_X, CH, PM, SO₂, and other air pollutant emissions were estimated both with and without AIS data thinning in the different time intervals. The results show that AIS data thinning affects the air pollutant emissions inventory results of the ships, and the impact is greater as the thinning interval increases. When the thinning interval is less than 10 min, the impact is less than 10%, but the impact increases to about 10–15% at a 30 min interval and about 15–20% at a 60 min interval. The impacts of thinning on the emissions of ships with acutely fluctuating speeds are more significant because the constantly changing speed is the main reason why data thinning affects the ship emissions inventory. Therefore, these data suggest that the AIS data can be thinned at intervals of 5 or 10 min when establishing a coastal or national ship air pollutant emissions inventory, the AIS data should be thinned at intervals of less than 3 min when establishing the air pollutant emissions inventory of inland river ships, and data thinning is not recommended when establishing a port or smaller-scale ship air pollutant emissions inventory. Full article

(This article belongs to the Special Issue Atmospheric Shipping Emissions and Their Environmental Impacts)

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9 pages, 3745 KiB

Open AccessArticle

Urban Particulate Matter Hazard Mapping and Monitoring Site Selection in Nablus, Palestine

by Tawfiq Saleh and Abdelhaleem Khader

Atmosphere 2022, 13(7), 1134; https://doi.org/10.3390/atmos13071134 - 18 Jul 2022

Viewed by 1901

Abstract

Few air pollution studies have been applied in the State of Palestine and all showed an increase in particulate matter concentrations above WHO guidelines. However, there is no clear methodology for selecting monitoring locations. In this study, a methodology based on GIS and [...] Read more.

Few air pollution studies have been applied in the State of Palestine and all showed an increase in particulate matter concentrations above WHO guidelines. However, there is no clear methodology for selecting monitoring locations. In this study, a methodology based on GIS and locally calibrated low-cost sensors was tested. A GIS-based weighted overlay summation process for the potential sources of air pollution (factories, quarries, and traffic), taking into account the influence of altitude and climate, was used to obtain an air pollution hazard map for Nablus, Palestine. To test the methodology, eight locally calibrated PM sensors (AirUs) were deployed to measure PM_2.5 concentrations for 55 days from 7 January to 2 March 2022. The results of the hazard map showed that 82% of Nablus is exposed to a high and medium risk of PM pollution. Sensors’ readings showed a good match between the hazard intensity and PM concentrations. It also shows an elevated PM_2.5 concentrations above WHO guidelines in all areas. In summary, the overall average for PM_2.5 in the Nablus was 48 µg/m³. This may indicate the effectiveness of mapping methodology and the use of low-cost, locally calibrated sensors in characterizing air quality status to identify the potential remediation options. Full article

(This article belongs to the Special Issue Physical, Chemical and Optical Properties of Aerosols)

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21 pages, 5140 KiB

Open AccessArticle

Impacts of Transition Approach of Water Vapor-Related Microphysical Processes on Quantitative Precipitation Forecasting

by Zhanshan Ma, Qijun Liu, Chuanfeng Zhao, Zhe Li, Xiaolin Wu, Jiong Chen, Fei Yu, Jian Sun and Xueshun Shen

Atmosphere 2022, 13(7), 1133; https://doi.org/10.3390/atmos13071133 - 18 Jul 2022

Cited by 5 | Viewed by 1362

Abstract

The water vapor-related microphysical processes (WVRMPs) in cloud microphysics schemes are crucial to the formation and dissipation of clouds, which have a significant impact on the quantitative precipitation forecasting of numerical weather prediction models. In this study, a well physics-based parallel-split transition approach [...] Read more.

The water vapor-related microphysical processes (WVRMPs) in cloud microphysics schemes are crucial to the formation and dissipation of clouds, which have a significant impact on the quantitative precipitation forecasting of numerical weather prediction models. In this study, a well physics-based parallel-split transition approach (PSTA) to compute the WVRMPs from the same temperature and humidity state is developed and compared with the original sequential-update transition approach (SUTA) in a double-moment cloud microphysics scheme. Case study and batch experiments were carried out to investigate their different impacts on the clouds and precipitation simulated by the Global/Regional Assimilation and Prediction System (GRAPES) regional 3 km high-resolution model of the China Meteorological Administration (CMA), named CMA-MESO. The results show that the PSTA experiment tends to simulate a narrower and more concentrated precipitation area with a higher-intensity center compared to those of the SUTA experiment, which is more consistent with the observations. In the cold region, the net transition rates of WVRMPs from the PSTA experiment with more ice-phase hydrometeors are higher than those from the SUTA experiment. While in the warm region, the condensation and evaporation rates with violent fluctuation simulated by the SUTA are significantly larger than those from the PSTA experiment, resulting in less precipitation. The batch experiments indicate that the equitable threat scores (ETSs) of 24-h precipitation simulated by the PSTA are just slightly better than those of the SUTA, yet its ETSs of 48-h precipitation have been systematically improved for all magnitude levels against the SUTA. It is demonstrated that more attention should be paid to the reasonable treatments of the WVRMPs in developing cloud microphysics schemes. Full article

(This article belongs to the Section Meteorology)

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24 pages, 11000 KiB

Open AccessReview

Stratospheric Polar Vortex as an Important Link between the Lower Atmosphere Circulation and Solar Activity

by Svetlana Veretenenko

Atmosphere 2022, 13(7), 1132; https://doi.org/10.3390/atmos13071132 - 18 Jul 2022

Cited by 7 | Viewed by 4174

Abstract

The stratospheric polar vortex is a large-scale cyclonic circulation that forms in a cold air mass in the polar region and extends from the middle troposphere to the stratosphere. The polar vortex is implicated in a variety of atmospheric processes, such as the [...] Read more.

The stratospheric polar vortex is a large-scale cyclonic circulation that forms in a cold air mass in the polar region and extends from the middle troposphere to the stratosphere. The polar vortex is implicated in a variety of atmospheric processes, such as the formation of ozone holes, the North Atlantic and the Arctic Oscillations, variations in extratropical cyclone tracks, etc. The results presented in this work show that the vortex plays an important part in the mechanism of solar activity influence on lower atmosphere circulation, with variations in the vortex intensity being responsible for temporal variability in the correlation links observed between atmospheric characteristics and solar activity phenomena. In turn, the location of the vortex is favorable for the influence of ionization changes associated with charged particle fluxes (cosmic rays, auroral and radiation belt electrons) that affect the chemical composition and temperature regime of the polar atmosphere as well as its electric properties and cloudiness state. In this work, recent results concerning solar activity effects on the state of the stratospheric polar vortex as well as its role in solar–atmospheric links are discussed. Full article

(This article belongs to the Special Issue Solar Activity Influence on Atmospheric Dynamics)

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13 pages, 5269 KiB

Open AccessArticle

Is the Apparent Correlation between Solar-Geomagnetic Activity and Occurrence of Powerful Earthquakes a Casual Artifact?

by Mehdi Akhoondzadeh and Angelo De Santis

Atmosphere 2022, 13(7), 1131; https://doi.org/10.3390/atmos13071131 - 18 Jul 2022

Cited by 8 | Viewed by 2640

Abstract

So far, many efforts have been made to provide a reliable and robust mechanism for the occurrence of large earthquakes. In recent years, different studies have been conducted on the possible correlation between solar-terrestrial interactions and the occurrence of earthquakes. In this paper, [...] Read more.

So far, many efforts have been made to provide a reliable and robust mechanism for the occurrence of large earthquakes. In recent years, different studies have been conducted on the possible correlation between solar-terrestrial interactions and the occurrence of earthquakes. In this paper, the hypothesis that there is a correlation between solar-geomagnetic activities and powerful earthquakes first is investigated in three case studies, and then it is discussed by studying the variations of indices, including F10.7, K_p, a_p, and D_st, before 333 large earthquakes (M_w ≥ 7.0) that occurred between 1 January 2000 and 28 April 2022. As the time series of the solar index follows special cycles, in another scenario, after removing the non-linear variations with fitting a polynomial, the anomalous F10.7 variations above and below the median ± 1.25 × interquartile ranges were considered. Although anomalies in solar and magnetic indices are observed in 33% of earthquakes one day before the occurrence, by analyzing 100 simulated data sets, we find that analogous anomalies can be found. Therefore, it can be concluded that there is no significant correlation between solar and geomagnetic indices and the occurrence of strong earthquakes. These findings could be effective in better defining alternative robust mechanisms for the occurrence of earthquakes that are more of internal origin than external to the Earth system. Full article

(This article belongs to the Special Issue Lithosphere-Atmosphere Coupling during Natural Hazard )

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17 pages, 6367 KiB

Open AccessArticle

Theoretical Perspectives on the Gas-Phase Oxidation Mechanism and Kinetics of Carbazole Initiated by OH Radical in the Atmosphere

by Zhuochao Teng, Xiaotong Wang, Mohammad Hassan Hadizadeh, Yanan Han, Xianwei Zhao, Qi Zhang, Hetong Wang, Ying Li, Fei Xu and Yanhui Sun

Atmosphere 2022, 13(7), 1129; https://doi.org/10.3390/atmos13071129 - 18 Jul 2022

Cited by 3 | Viewed by 1643

Abstract

Carbazole is one of the typical heterocyclic aromatic compounds (NSO-HETs) observed in polluted urban atmosphere, which has become a serious environmental concern. The most important atmospheric loss process of carbazole is the reaction with OH radical. The present work investigated the mechanism of [...] Read more.

Carbazole is one of the typical heterocyclic aromatic compounds (NSO-HETs) observed in polluted urban atmosphere, which has become a serious environmental concern. The most important atmospheric loss process of carbazole is the reaction with OH radical. The present work investigated the mechanism of OH-initiated atmospheric oxidation degradation of carbazole by using density functional theory (DFT) calculations at the M06-2X/6-311++G(3df,2p)//M06-2X/6-311+G(d,p) level. The rate constants were determined by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory. The lifetime of carbazole determined by OH was compared with other typical NSO-HETs. The theoretical results show that the degradation of carbazole initiated by OH radical includes four types of reactions: OH additions to “bend” C atoms, OH additions to “benzene ring” C atoms, H abstractions from C-H bonds and the H abstraction from N-H bond. The OH addition to C1 atom and the H abstraction from N-H bond are energetically favorable. The main oxidation products are hydroxycarbazole, dialdehyde, carbazolequinone, carbazole-ol, hydroxy-carbazole-one and hydroperoxyl-carbazole-one. The calculated overall rate constant of carbazole oxidation by OH radical is 6.52 × 10⁻¹² cm³ molecule⁻¹ s⁻¹ and the atmospheric lifetime is 37.70 h under the condition of 298 K and 1 atm. The rate constant of carbazole determined by OH radical is similar with that of dibenzothiophene oxidation but lower than those of pyrrole, indole, dibenzofuran and fluorene. This work provides a theoretical investigation of the oxygenated mechanism of NSO-HETs in the atmosphere and should help to clarify their potential health risk for determining the reaction pathways and environmental influence of carbazole. Full article

(This article belongs to the Special Issue New Insights into Secondary Organic Aerosol Formation)

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15 pages, 4347 KiB

Open AccessArticle

Prediction Model of Carbon Dioxide Concentration in Pig House Based on Deep Learning

by Jianjun Zang, Shuqin Ye, Zeying Xu, Junjun Wang, Wenchao Liu, Yungang Bai, Cheng Yong, Xiuguo Zou and Wentian Zhang

Atmosphere 2022, 13(7), 1130; https://doi.org/10.3390/atmos13071130 - 17 Jul 2022

Viewed by 1392

Abstract

The air environment (e.g., high concentration of carbon dioxide) in a pig house will affect the health conditions and growth performance of the pigs, and the quality of pork as well. In order to reduce the cumulative concentration of carbon dioxide in the [...] Read more.

The air environment (e.g., high concentration of carbon dioxide) in a pig house will affect the health conditions and growth performance of the pigs, and the quality of pork as well. In order to reduce the cumulative concentration of carbon dioxide in the pig house, the prediction model was established by the deep learning method to predict the changes of the carbon dioxide cumulative concentration in a pig house. This model will also be used for the real-time monitoring and adjustment of the concentration of carbon dioxide of the pig house. The experiment was designed to collect environmental parameters (e.g., temperature, humidity, wind speed, and carbon dioxide concentration) data in the pig house for several months. The ensemble empirical mode decomposition–gated recurrent unit (EEMD–GRU) prediction model was established in the prediction of carbon dioxide concentration in the pig house. The results show that compared with the other models, the prediction accuracy of the EEMD–GRU model is the highest, and the root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE), and r-squared (R²) of carbon dioxide concentration in autumn and winter are 123.2 ppm, 88.3 ppm, 3.2%, and 0.99, respectively. The RMSE, MAE, MAPE, and R² for carbon dioxide concentration are 129.1 ppm, 93.2 ppm, 5.9%, and 0.76 in spring and summer. The prediction model proposed in this paper can effectively predict the concentration of carbon dioxide in the pig house and provide effective help for the precise control of the pig house environment. Full article

(This article belongs to the Section Biosphere/Hydrosphere/Land–Atmosphere Interactions)

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