Atmosphere

21 pages, 15981 KiB

Open AccessArticle

A Systematic Study of 7 MHz Greyline Propagation Using Amateur Radio Beacon Signals

by Sam Lo, Nikola Rankov, Cathryn Mitchell, Benjamin Axel Witvliet, Talini Pinto Jayawardena, Gary Bust, William Liles and Gwyn Griffiths

Atmosphere 2022, 13(8), 1340; https://doi.org/10.3390/atmos13081340 - 22 Aug 2022

Cited by 3 | Viewed by 2300

Abstract

This paper investigates 7 MHz ionospheric radio wave propagation between pairs of distant countries that simultaneously lie on the terminator. This is known as greyline propagation. Observations of amateur radio beacon transmitters recorded in the Weak Signal Propagation Reporter (WSPR) database are used [...] Read more.

This paper investigates 7 MHz ionospheric radio wave propagation between pairs of distant countries that simultaneously lie on the terminator. This is known as greyline propagation. Observations of amateur radio beacon transmitters recorded in the Weak Signal Propagation Reporter (WSPR) database are used to investigate the times of day that beacon signals were observed during the year 2017. The WSPR beacon network consists of thousands of automated beacon transmitters and observers distributed over the globe. The WSPR database is a very useful resource for radio science as it offers the date and time at which a propagation path was available between two radio stations, as well as their precise locations. This paper provides the first systematic study of grey-line propagation between New Zealand/Eastern Australia and UK/Europe. The study shows that communications were predominantly made from the United Kingdom (UK) to New Zealand at around both sunset and sunrise times, whereas from New Zealand to the UK, communication links occurred mainly during UK sunrise hours. The lack of observations at the UK sunset time was particularly evident during the UK summer. The same pattern was found in the observations of propagation from Eastern Australia to UK, and from New Zealand and Eastern Australia to Italy and the surrounding regions in Europe. The observed asymmetry in reception pattern could possibly be due to the increase in electromagnetic noise across Europe in the summer afternoon/evening from thunderstorms. Full article

(This article belongs to the Special Issue Recent Advances in Ionosphere Observation and Investigation)

► Show Figures

Figure 1

15 pages, 1771 KiB

Open AccessArticle

The Physical Experimental Modelling of the Formation Processes of Upward Discharges from Grounded Objects in the Artificial Thunderstorm Cell’s Electric Field

by Nikolay Lysov, Alexander Temnikov, Leonid Chernensky, Alexander Orlov, Olga Belova, Tatiana Kivshar, Dmitry Kovalev, Garry Mirzabekyan, Natalia Lebedeva and Vadim Voevodin

Atmosphere 2022, 13(8), 1339; https://doi.org/10.3390/atmos13081339 - 22 Aug 2022

Cited by 3 | Viewed by 1243

Abstract

The results of the physical modelling of the formation processes of upward discharges from grounded objects in the artificial thunderstorm cell’s electric field are presented. We established the considerable influence of the electrode tip’s radius on the pulse streamer corona stem’s parameters and, [...] Read more.

The results of the physical modelling of the formation processes of upward discharges from grounded objects in the artificial thunderstorm cell’s electric field are presented. We established the considerable influence of the electrode tip’s radius on the pulse streamer corona stem’s parameters and, subsequently, on the probability of the transformation of the impulse streamer corona first flash’s stem into a first stage of upward leader. We determined the diapason of the optimal tip radii for a lightning rod or lightning conductor, which allows for the most probable formation of the first impulse streamer corona, with the parameters providing the best conditions for the upward leader’s start, the purpose of which is the lowering of the probability of lightning striking the object under protection. A considerable difference between the electrical characteristics of the first impulse corona flash with and without the streamer–leader transition was established. It was shown that the amplitude of the streamer corona flash current impulse is considerable, but not the main defining factor of the streamer–leader transition. It is established that the charge value of the streamer corona first flash is not a threshold requirement for the formation of the upward leader from a ground object, but only defines the probability of the successful upward leader formation. Based on the analysis of the experimental data received, we suggest that there is a dependency between the probability of upward positive leader formation from the grounded objects and the charge value of the first pulse streamer corona flash for the rod (centered) and rope (elongated) lightning conductors and objects in the electric field of the thundercloud and downward lightning leader. The obtained results can be used for mathematical modelling of the formation processes of upward discharges from grounded objects in the artificial thunderstorm’s electric field, as in a natural thunderstorm situation. Full article

(This article belongs to the Special Issue Lightning Physics)

► Show Figures

Figure 1

18 pages, 9484 KiB

Open AccessArticle

Temperature and Precipitation Bias Patterns in a Dynamical Downscaling Procedure over Europe during the Period 1951–2010

by Ioannis Stergiou, Efthimios Tagaris and Rafaella-Eleni P. Sotiropoulou

Atmosphere 2022, 13(8), 1338; https://doi.org/10.3390/atmos13081338 - 22 Aug 2022

Viewed by 1333

Abstract

The Weather Research and Forecasting (WRF) mesoscale meteorological model is used to dynamically downscale data from the Goddard Institute for Space Studies (GISS) atmospheric general circulation model (GCM) CMIP5 version (Model E2-R) over Europe at a 0.25° grid size resolution, for the period [...] Read more.

The Weather Research and Forecasting (WRF) mesoscale meteorological model is used to dynamically downscale data from the Goddard Institute for Space Studies (GISS) atmospheric general circulation model (GCM) CMIP5 version (Model E2-R) over Europe at a 0.25° grid size resolution, for the period of 1951 to 2010. The model configuration is single nested with grid resolutions of 0.75° to 0.25°. Two 30-year datasets are produced for the periods of 1951–1980 and 1981–2010, representing the historic and current periods, respectively. Simulated changes in climate normals are estimated and compared against the change derived from the E-OBS gridded dataset at 0.25° spatial analysis. Results indicate that the model consistently underpredicts the temperature fluctuations observed across all subregions, indicative of a colder model climatology. Winter has the strongest bias of all seasons, with the northeastern part of the domain having the highest. This is largely due to the land–atmosphere interactions. Conversely, spring and summer have the lowest regional biases, owing to a combination of low snow cover (relative to winter) and milder radiation effects (as opposed to summer). Precipitation has a negative bias in most cases, regardless of the subregion analyzed, due to the physical mechanism employed and the topographic features of each region. Both the change in the number of days when the temperature exceeds 25 °C and the change in the number of days when precipitation exceeds 5 mm/day are captured by the model reasonably well, exhibiting similar characteristics with their counterpart means. Full article

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

► Show Figures

Figure 1

32 pages, 11435 KiB

Open AccessArticle

Enhancing Capacity for Short-Term Climate Change Adaptations in Agriculture in Serbia: Development of Integrated Agrometeorological Prediction System

by Ana Vuković Vimić, Vladimir Djurdjević, Zorica Ranković-Vasić, Dragan Nikolić, Marija Ćosić, Aleksa Lipovac, Bojan Cvetković, Dunja Sotonica, Dijana Vojvodić and Mirjam Vujadinović Mandić

Atmosphere 2022, 13(8), 1337; https://doi.org/10.3390/atmos13081337 - 22 Aug 2022

Cited by 2 | Viewed by 1896

Abstract

The Integrated Agrometeorological Prediction System (IAPS) was a two-year project for the development of the long term forecast (LRF) for agricultural producers. Using LRF in decision-making, to reduce the risks and seize the opportunities, represents short-term adaptation to climate change. High-resolution ensemble forecasts [...] Read more.

The Integrated Agrometeorological Prediction System (IAPS) was a two-year project for the development of the long term forecast (LRF) for agricultural producers. Using LRF in decision-making, to reduce the risks and seize the opportunities, represents short-term adaptation to climate change. High-resolution ensemble forecasts (51 forecasts) were made for a period of 7 months and were initiated on the first day of each month. For the initial testing of the capacity of LRF to provide useful information for producers, 2017 was chosen as the test year as it had a very hot summer and severe drought, which caused significant impacts on agricultural production. LRF was very useful in predicting the variables which bear the memory of the longer period, such are growing degree days for the prediction of dates of the phenophases’ occurrences and the soil moisture of deeper soil layers as an indicator for the drought. Other project activities included field observations, communication with producers, web portal development, etc. Our results showed that the selected priority forecasting products were also identified by the producers as being the highest weather-related risks, the operational forecast implementation with the products designed for the use in agricultural production is proven to be urgent and necessary for decision-making, and required investments are affordable. The total cost of the full upgrade of agrometeorological climate services to meet current needs (including monitoring, seamless forecasting system development and the development of tools for information dissemination) was found to be about three orders of magnitude lower than the assessed losses in agricultural production in the two extreme years over the past decade. Full article

(This article belongs to the Special Issue Adaptation for Crop Production and Sustainable Agriculture in a Changing Climate (2nd Edition))

► Show Figures

Figure 1

14 pages, 1813 KiB

Open AccessArticle

Potential Yield of World Rice under Global Warming Based on the ARIMA-TR Model

by Chengzhi Cai, Hongyan Yang, Lin Zhang and Wenfang Cao

Atmosphere 2022, 13(8), 1336; https://doi.org/10.3390/atmos13081336 - 22 Aug 2022

Cited by 4 | Viewed by 1394

Abstract

As one of two most important cereals in the world, and with the continuous increase in population and demand for food consumption worldwide, rice has been attracting researchers’ attention for improving its potential yield in the future, particularly as it relates to climate [...] Read more.

As one of two most important cereals in the world, and with the continuous increase in population and demand for food consumption worldwide, rice has been attracting researchers’ attention for improving its potential yield in the future, particularly as it relates to climate change. However, what will be the potential limit of world rice yield in the future, and how does global warming affect the yield of world rice? Therefore, analyzing the potential yield of world rice affected by global warming is of great significance to direct crop production worldwide in the future. However, by far, most modeled estimations of rice yield are based on the principle of production function from static biological dimension and at local or regional levels, whereas few are based on a time series model from a dynamic evolutionary angle and on global scale. Thus, in this paper, both average and top (national) yields of world rice by 2030 are projected creatively using the Auto-regressive Integrated Moving Average and Trend Regression (ARIMA-TR) model and based on historic yields since 1961; in addition, the impact of global warming on the yields of world rice is analyzed using a binary regression model in which global mean temperature is treated as the independent variable whereas the yield is expressed as the dependent variable. Our study concludes that between 2021 and 2030, the average yield of world rice is projected to be from 4835 kg/ha to 5195 kg/ha, the top yield from 10,127 kg/ha to 10,269 kg/ha, or the average yield ranging from 47.74% to 50.59% of the top yield. From 1961 to 2020, through to2030, global warming will exert a negative impact on the average yield of world rice less than that of the top yield, which partly drives the gap between these two yields and gradually narrowed; for world rice by 2030, the opportunities for improving global production should be dependent on both high and low yield countries as the average yield is approaching the turning point of an S-shaped curve in the long-term trend. These insights provide the academic circle with innovative comprehension of world rice yield and its biological evolution for global food security relating to global warming in the future. Full article

(This article belongs to the Section Biometeorology)

► Show Figures

Figure 1

21 pages, 8461 KiB

Open AccessArticle

A Success Story in Controlling Sand and Dust Storms Hotspots in the Middle East

by Ali Al-Dousari, Ali Omar, Ali Al-Hemoud, Abdulaziz Aba, Majid Alrashedi, Mohamad Alrawi, Alireza Rashki, Peter Petrov, Modi Ahmed, Noor Al-Dousari, Omar Baloshi, Meshael Jarba, Ala Esmail, Abeer Alsaleh and Teena William

Atmosphere 2022, 13(8), 1335; https://doi.org/10.3390/atmos13081335 - 22 Aug 2022

Cited by 8 | Viewed by 2377

Abstract

Using 30 years of satellite observations, two sand and dust storms (SDS) source locations (hotspots) were detected on the southern side of the Mesopotamian Flood Plain. Around 40 million people in the region are affected by the two hotspots, including populations in Iraq, [...] Read more.

Using 30 years of satellite observations, two sand and dust storms (SDS) source locations (hotspots) were detected on the southern side of the Mesopotamian Flood Plain. Around 40 million people in the region are affected by the two hotspots, including populations in Iraq, Iran, Kuwait, Saudi Arabia, Qatar, Bahrain, and Emirates. Both hotspots encompass roughly 8212 km² and contribute 11% to 85% in 2005 and 2021, respectively, of the total SDS in the region. Dust physical (particle surface area and size percentages) and chemical (mineralogy, major and trace elements, and radionuclides) properties show close similarities between source and downwind samples during SDS originated solely from the two hotspots. Deposited dust size particles show a finning trend towards the north in the Middle East compared to the south. A comprehensive assessment of the chemical and physical properties of soil and dust samples was conducted as an essential step in developing and implementing a mitigation plan in order to establish a success story in reducing SDS, improving air quality, and benefiting the gulf countries and neighboring regions. Full article

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

► Show Figures

Figure 1

13 pages, 5930 KiB

Open AccessArticle

Modeling PM2.5 and PM10 Using a Robust Simplified Linear Regression Machine Learning Algorithm

by João Gregório, Carla Gouveia-Caridade and Pedro J. S. B. Caridade

Atmosphere 2022, 13(8), 1334; https://doi.org/10.3390/atmos13081334 - 22 Aug 2022

Cited by 11 | Viewed by 2372

Abstract

The machine learning algorithm based on multiple-input multiple-output linear regression models has been developed to describe PM2.5 and PM10 concentrations over time. The algorithm is fact-acting and allows for speedy forecasts without requiring demanding computational power. It is also simple enough that it [...] Read more.

The machine learning algorithm based on multiple-input multiple-output linear regression models has been developed to describe PM2.5 and PM10 concentrations over time. The algorithm is fact-acting and allows for speedy forecasts without requiring demanding computational power. It is also simple enough that it can self-update by introducing a recursive step that utilizes newly measured values and forecasts to continue to improve itself. Starting from raw data, pre-processing methods have been used to verify the stationary data by employing the Dickey–Fuller test. For comparison, weekly and monthly decompositions have been achieved by using Savitzky–Golay polynomial filters. The presented algorithm is shown to have accuracies of

30 %

for PM2.5 and

26 %

for PM10 for a forecasting horizon of 24 h with a quarter-hourly data acquisition resolution, matching other results obtained using more computationally demanding approaches, such as neural networks. We show the feasibility of using multivariate linear regression (together with the small real-time computational costs for the training and testing procedures) to forecast particulate matter air pollutants and avoid environmental threats in real conditions. Full article

(This article belongs to the Special Issue Air Quality Prediction and Modeling)

► Show Figures

Figure 1

9 pages, 1631 KiB

Open AccessCommunication

Network Theory to Reveal Ionospheric Anomalies over North America and Australia

by Ilya V. Zhivetiev and Yury V. Yasyukevich

Atmosphere 2022, 13(8), 1333; https://doi.org/10.3390/atmos13081333 - 22 Aug 2022

Cited by 1 | Viewed by 1814

Abstract

There are significant challenges to model the ionosphere due to different anomalies, especially under the increasing requirements for precision level. We used network theory to construct an ionospheric network analysis based on the data of global ionospheric maps for the period from 1998 [...] Read more.

There are significant challenges to model the ionosphere due to different anomalies, especially under the increasing requirements for precision level. We used network theory to construct an ionospheric network analysis based on the data of global ionospheric maps for the period from 1998 to 2015. The network approach revealed different domains in the ionosphere. Besides the well-known equatorial anomaly, we revealed two more essential areas with “anomalous” behavior in the total electron content (TEC). Both anomalies are located at mid-latitudes: the first over most of North America, and the second one over the southeast part of Australia and the adjacent part of the Indian Ocean. The revealed areas partly coincide with the winter anomaly regions. Our results demonstrate that complex ionosphere/magnetic field/neutral atmosphere interaction can result in atypical ionosphere dynamics in huge areas. Full article

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

► Show Figures

Figure 1

13 pages, 1583 KiB

Open AccessArticle

Early Night Fog Prediction Using Liquid Water Content Measurement in the Monterey Bay Area

by Steven Kim, Conor Rickard, Julio Hernandez-Vazquez and Daniel Fernandez

Atmosphere 2022, 13(8), 1332; https://doi.org/10.3390/atmos13081332 - 22 Aug 2022

Cited by 2 | Viewed by 1482

Abstract

Fog is challenging to predict, and the accuracy of fog prediction may depend on location and time of day. Furthermore, accurate detection of fog is difficult, since, historically, it is often carried out based on visual observations which can be biased and are [...] Read more.

Fog is challenging to predict, and the accuracy of fog prediction may depend on location and time of day. Furthermore, accurate detection of fog is difficult, since, historically, it is often carried out based on visual observations which can be biased and are often not very frequent. Furthermore, visual observations are more challenging to make during the night. To overcome these limitations, we detected fog using FM-120 instruments, which continuously measured liquid water content in the air in the Monterey, California (USA), area. We used and compared the prediction performance of logistic regression (LR) and random forest (RF) models each evening between 5 pm and 9 pm, which is often the time when advection fog is generated in this coastal region. The relative performances of the models depended on the hours between 5 pm and 9 pm, and the two models often generated different predictions. In such cases, a consensus approach was considered by revisiting the past performance of each model and weighting more heavily the more trustworthy model for a given hour. The LR resulted in a higher sensitivity (hit rate) than the RF model early in the evening, but the overall performance of the RF was usually better than that of the LR. The consensus approach provided more robust prediction performance (closer to a better accuracy level between the two methods). It was difficult to conclude which of the LR and RF models was superior consistently, and the consensus approach provided robustness in 3 and 2 h forecasts. Full article

(This article belongs to the Special Issue Decision Support System for Fog)

► Show Figures

Figure 1

9 pages, 2175 KiB

Open AccessArticle

Electric Field Variations Caused by Low, Middle and High-Altitude Clouds over the Negev Desert, Israel

by Roy Yaniv and Yoav Yair

Atmosphere 2022, 13(8), 1331; https://doi.org/10.3390/atmos13081331 - 21 Aug 2022

Cited by 3 | Viewed by 1401

Abstract

Ground-based measurements of the electric field from a station located in the arid Negev region of southern Israel have been conducted continuously since 2013. We present here results of observations of the electric field (Potential Gradient, PG) variability during 22 cloudy days, with [...] Read more.

Ground-based measurements of the electric field from a station located in the arid Negev region of southern Israel have been conducted continuously since 2013. We present here results of observations of the electric field (Potential Gradient, PG) variability during 22 cloudy days, with varying cloud types and cloud base heights, and compare the measured values with the mean fair-weather PG. The results show an increase of PG (~+10 to +70 V m⁻¹) from mean fair weather values during times of low clouds. During times of mid-altitude (alto) clouds or during a superposition of low and high clouds, there were small departures in the PG values (~0 to −30 V m⁻¹) compared to mean fair weather PG values. During times of high-altitude cirrus clouds there is a clear decrease of the PG (~−40 to −90 V m⁻¹). The data was compared with the Israeli meteorological service cloud data and with MODIS 7 satellite cloud top height maps. In addition, AERONET aerosol optical depth values and wind speed magnitude from a local meteorological station were analyzed. Full article

(This article belongs to the Special Issue Atmospheric Electricity)

► Show Figures

Figure 1

12 pages, 642 KiB

Open AccessArticle

Statistical Associations between Geomagnetic Activity, Solar Wind, Cosmic Ray Intensity, and Heart Rate Variability in Patients after Open-Heart Surgery

by Jone Vencloviene, Margarita Beresnevaite, Sonata Cerkauskaite, Nijole Ragaisyte, Rugile Pilviniene and Rimantas Benetis

Atmosphere 2022, 13(8), 1330; https://doi.org/10.3390/atmos13081330 - 21 Aug 2022

Viewed by 2315

Abstract

The aim of this study was to identify associations of the parameters of heart rate variability (HRV) with the variations in geomagnetic activity (GMA), solar wind, and cosmic ray intensity (CRI) in patients after coronary artery bypass grafting or valve surgery in Kaunas, [...] Read more.

The aim of this study was to identify associations of the parameters of heart rate variability (HRV) with the variations in geomagnetic activity (GMA), solar wind, and cosmic ray intensity (CRI) in patients after coronary artery bypass grafting or valve surgery in Kaunas, Lithuania, during 2008–2012. The data from 5-minute electrocardiograms (ECGs) in 220 patients were used. ECGs were carried out at 1.5 months, 1 year, and 2 years after the surgery (N = 495). A lower (higher) very-low-frequency-band (VLF) and a higher (lower) high-frequency band (HF) in normalised units (n.u.) were associated with a low maximal daily 3-hourly ap (the DST index > 1). A lower mean standard deviation of beat-to-beat intervals (SDNN) and VLF, LF, and HF powers were lower in patients when Ap < 8 occurred two days after the surgery, and a low solar wind speed (SWS) occurred two days before the ECG. The effect of CRI was non-significant if the linear trend was included in the model. Low GMA and a low SWS may effect some HRV variables in patients after open-heart surgery. The GMA during the surgery may affect the SDNN in short-term ECG during the longer period. Full article

(This article belongs to the Section Biometeorology)

► Show Figures

Figure 1

18 pages, 7249 KiB

Open AccessArticle

Microphysical and Kinematic Characteristics of Anomalous Charge Structure Thunderstorms in Cordoba, Argentina

by Bruno Medina, Lawrence Carey, Wiebke Deierling and Timothy Lang

Atmosphere 2022, 13(8), 1329; https://doi.org/10.3390/atmos13081329 - 21 Aug 2022

Cited by 1 | Viewed by 1624

Abstract

Some thunderstorms in Cordoba, Argentina, present a charge structure with an enhanced low-level positive charge layer, and practically nonexistent upper-level positive charge. Storms with these characteristics are uncommon in the United States, even when considering regions with a high frequency of anomalous charge [...] Read more.

Some thunderstorms in Cordoba, Argentina, present a charge structure with an enhanced low-level positive charge layer, and practically nonexistent upper-level positive charge. Storms with these characteristics are uncommon in the United States, even when considering regions with a high frequency of anomalous charge structure storms such as Colorado. In this study, we explored the microphysical and kinematic conditions inferred by radar that led to storms with this unique low-level anomalous charge structure in Argentina, and compared them to conditions conducive for anomalous and normal charge structures. As high liquid water contents in the mixed-phase layer lead to positive charging of graupel and anomalous storms through the non-inductive charging mechanism, we explored radar parameters hypothesized to be associated with large cloud supercooled liquid water contents in the mixed-phase layer and anomalous storms, such as mass and volume of hail and high-density graupel, large reflectivity associated with the growth of rimed precipitation to hail size, and parameters that are proxies for strong updrafts such as echo-top and Z_dr column heights. We found that anomalous storms had higher values of mass and volume of hail in multiple sub-layers of the mixed-phase zone and higher frequency of high reflectivity values. Low-level anomalous events had higher hail mass in the lower portion of the mixed-phase zone when compared to normal events. Weaker updraft proxies were found for low-level anomalous events due to the shallow nature of these events while there was no distinction between the updraft proxies of normal and anomalous storms. Full article

(This article belongs to the Special Issue Advances in Atmospheric Electricity)

► Show Figures

Figure 1

17 pages, 4361 KiB

Open AccessArticle

Relationship between Land Use and Spatial Variability of Atmospheric Brown Carbon and Black Carbon Aerosols in Amazonia

by Fernando G. Morais, Marco A. Franco, Rafael Palácios, Luiz A. T. Machado, Luciana V. Rizzo, Henrique M. J. Barbosa, Fabio Jorge, Joel S. Schafer, Brent N. Holben, Eduardo Landulfo and Paulo Artaxo

Atmosphere 2022, 13(8), 1328; https://doi.org/10.3390/atmos13081328 - 21 Aug 2022

Cited by 9 | Viewed by 2652

Abstract

The aerosol radiative effect is an important source of uncertainty in estimating the anthropogenic impact of global climate change. One of the main open questions is the role of radiation absorption by aerosols and its relation to land use worldwide, particularly in the [...] Read more.

The aerosol radiative effect is an important source of uncertainty in estimating the anthropogenic impact of global climate change. One of the main open questions is the role of radiation absorption by aerosols and its relation to land use worldwide, particularly in the Amazon Rainforest. Using AERONET (Aerosol Robotic Network) long-term measurements of aerosol optical depth (AOD) at a wavelength of 500 nm and absorption AOD (AAOD) at wavelengths of 440, 675, and 870 nm, we estimated the fraction and seasonality of the black carbon (BC) and brown carbon (BrC) contributions to absorption at 440 nm. This was conducted at six Amazonian sites, from central Amazon (Manaus and the Amazon Tall Tower Observatory—ATTO) to the deforestation arc (Rio Branco, Cuiabá, Ji-Paraná, and Alta Floresta). In addition, land use and cover data from the MapBiomas collection 6.0 was used to access the land transformation from forest to agricultural areas on each site. The results showed, for the first time, important geographical and seasonal variability in the aerosol optical properties, particularly the BC and BrC contributions. We observed a clear separation between dry and wet seasons, with BrC consistently accounting for an average of approximately 12% of the aerosol AAOD at 440 nm in the deforestation arc. In central Amazon, the contribution of BrC was approximately 25%. A direct relationship between the reduction in forests and the increase in the area dedicated to agriculture was detected. Moreover, places with lower fractions of forest had a smaller fraction of BrC, and regions with higher fractions of agricultural areas presented higher fractions of BC. Therefore, significant changes in AOD and AAOD are likely related to land-use transformations and biomass burning emissions, mainly during the dry season. The effects of land use change could introduce differences in the radiative balance in the different Amazonian regions. The analyses presented in this study allow a better understanding of the role of aerosol emissions from the Amazon Rainforest that could have global impacts. Full article

(This article belongs to the Special Issue Aerosols and Particulate Matters in the Southern Hemisphere)

► Show Figures

Figure 1

13 pages, 3813 KiB

Open AccessArticle

Moisture Sources for the Precipitation of Tropical-like Cyclones in the Mediterranean Sea: A Case of Study

by Patricia Coll-Hidalgo, Albenis Pérez-Alarcón and Raquel Nieto

Atmosphere 2022, 13(8), 1327; https://doi.org/10.3390/atmos13081327 - 20 Aug 2022

Cited by 5 | Viewed by 1910

Abstract

Tropical-like cyclones (TLCs) are hybrid low-pressure systems formed over the Mediterranean Sea, showing the characteristics of tropical and extratropical cyclones. The literature review revealed that several studies have focused on determining the physical mechanisms that favour their formation; however, their rainfall has received [...] Read more.

Tropical-like cyclones (TLCs) are hybrid low-pressure systems formed over the Mediterranean Sea, showing the characteristics of tropical and extratropical cyclones. The literature review revealed that several studies have focused on determining the physical mechanisms that favour their formation; however, their rainfall has received little attention. In this study, we attempted to identify the origin of the precipitation produced by TLCs through a Lagrangian approach based on the analysis of moisture sources for the TLC Qendresa from 6 to 9 November 2014. For the Lagrangian analysis, we used the trajectories of air parcels from the global outputs of the FLEXPART model fed by the ERA-5 reanalysis provided by the European Centre for Medium-Range Weather Forecast and backtracked those parcels that precipitated within the outer radius of the storm up to 10 days. Our results showed that the moisture mainly came from the western Mediterranean Sea, Northern Africa, the central Mediterranean Sea, Western Europe, the eastern North Atlantic, and the eastern Mediterranean Sea with contributions of 35.09%, 27.6%, 18.62%, 10.40%, 6.79%, and 1.5%, respectively. The overall large-scale conditions for the genesis of Qendresa agreed with previous climatological studies. Therefore, our findings contribute to the understanding of precipitation associated with TLCs. Future studies will focus on a climatological analysis of the origin of rainfall produced by these hybrid cyclones. Full article

(This article belongs to the Section Meteorology)

► Show Figures

Figure 1

18 pages, 4728 KiB

Open AccessArticle

Climate and the Radial Growth of Conifers in Borderland Natural Areas of Texas and Northern Mexico

by José Villanueva-Díaz, David W. Stahle, Helen Mills Poulos, Matthew D. Therrell, Ian Howard, Aldo Rafael Martínez-Sifuentes, David Hermosillo-Rojas, Julián Cerano-Paredes and Juan Estrada-Ávalos

Atmosphere 2022, 13(8), 1326; https://doi.org/10.3390/atmos13081326 - 19 Aug 2022

Viewed by 1649

Abstract

The forests of northern Mexico and the southwestern United States have been subjected to warmer temperatures, persistent drought, and more intense and widespread wildfire. Tree-ring data from four conifer species native to these borderlands forests are compared with regional and large-scale precipitation and [...] Read more.

The forests of northern Mexico and the southwestern United States have been subjected to warmer temperatures, persistent drought, and more intense and widespread wildfire. Tree-ring data from four conifer species native to these borderlands forests are compared with regional and large-scale precipitation and temperature data. These species include Abies durangensis, Pinus arizonica, Pinus cembroides, and Pseudotsuga menziesii. Twelve detrended and standardized ring-width chronologies are derived for these four species, all are cross-correlated during their common interval of 1903–2000 (r = 0.567 to 0.738, p < 0.01), and all load positively on the first principal component of radial growth, which alone represents 56% of the variance in the correlation matrix. Correlation with monthly precipitation and temperature data for the study area indicates that all four species respond primarily to precipitation during the cool season of autumn and winter, October–May (r = 0.71, p < 0.01, 1931–2000), and to temperature primarily during the late spring and early summer, January–July (r 0 −0.67, p < 0.01, 1931–2000), in spite of differences in phylogeny and microsite conditions. The instrumental climate data for the region indicate that warmer conditions during the January–July season most relevant to radial growth are beginning to exceed the warmest episode of the 20th century in both intensity and duration. The strong negative correlation between temperature and tree growth indicates that these four conifer species may be challenged by the warmer temperatures forecast in the coming decades for the borderlands region due to anthropogenic forcing. This information could constitute a baseline to analyze the impact of climate change in other regions of Mexico and the USA, where conifer species are of great ecological and socioeconomical importance. Full article

(This article belongs to the Special Issue Development and Application of Indices for Assessing the Potential Impacts of Climate Change)

► Show Figures

Figure 1

10 pages, 2053 KiB

Open AccessArticle

Sensitivity of the 4–10-Day Planetary Wave Structures in the Middle Atmosphere to the Solar Activity Effects in the Thermosphere

by Andrey V. Koval, Nikolai M. Gavrilov, Ksenia A. Didenko, Tatiana S. Ermakova and Elena N. Savenkova

Atmosphere 2022, 13(8), 1325; https://doi.org/10.3390/atmos13081325 - 19 Aug 2022

Cited by 3 | Viewed by 1626

Abstract

Numerical simulation of the general atmospheric circulation was performed to estimate changes in amplitudes of the westward-travelling planetary waves (PWs) at altitudes from the Earth’s surface up to 300 km under different solar activity (SA) levels. The three-dimensional nonlinear mechanistic model of circulation [...] Read more.

Numerical simulation of the general atmospheric circulation was performed to estimate changes in amplitudes of the westward-travelling planetary waves (PWs) at altitudes from the Earth’s surface up to 300 km under different solar activity (SA) levels. The three-dimensional nonlinear mechanistic model of circulation of the middle and upper atmosphere “MUAM” was used. The atmospheric general circulation and PW amplitudes were calculated based on ensembles containing 16 model runs for conditions corresponding to low and high SA. PWs having periods of 4–10 days were considered. Comparison with the data of digital ionosondes showed that the MUAM model is capable of reproducing the considered PW modes at thermospheric heights. It is shown that under high SA conditions, PW amplitudes are significantly larger in the thermosphere and smaller in the middle atmosphere. The observed PW structures are influenced not only by changes in atmospheric refractive index and Eliassen–Palm flux but also by varying PW reflection in the lower thermosphere, which can change proportions of the wave energy transferred from the lower atmosphere to the upper layers and reflected downwards. Full article

(This article belongs to the Special Issue Links between Solar Activity and Atmospheric Circulation (2nd Volume))

► Show Figures

Figure 1

20 pages, 5086 KiB

Open AccessArticle

Offline Diagnostics of Skin Sea Surface Temperature from a Prognostic Scheme and Its Application in Typhoon Forecasting Using the CMA-TRAMS Model over South China

by Yanxia Zhang, Daosheng Xu, Zitong Chen and Weiguang Meng

Atmosphere 2022, 13(8), 1324; https://doi.org/10.3390/atmos13081324 - 19 Aug 2022

Cited by 5 | Viewed by 1647

Abstract

In the Tropical Regional Atmospherical Model System of South China of the China Meteorological Administration (CMA-TRAMS), the skin sea surface temperature (

T_{s}

) remains fixed during the forecast time. This limits the model’s performance in describing interactions between air and sea. [...] Read more.

In the Tropical Regional Atmospherical Model System of South China of the China Meteorological Administration (CMA-TRAMS), the skin sea surface temperature (

T_{s}

) remains fixed during the forecast time. This limits the model’s performance in describing interactions between air and sea. The offline diagnostics and online analysis coupled with the CMA-TRAMS of

T_{s}

prognostic scheme were discussed. The results of the offline diagnostics showed that the profile shape parameter, ν, and initial temperature,

T_{b}

, were sensitive to the forecasted

T_{s}

. Based on our observations, when ν was set to 0.2 and

T_{b}

was the averaged

T_{s}

without obvious diurnal variation, the forecasted

T_{s}

was relatively reasonable. The forecasted

T_{s}

of CMA-TRAMS after coupling with the

T_{s}

scheme had diurnal variations during the overall forecast time, which was different from the fixed

T_{s}

from the uncoupled model. There existed a certain difference of forecasted

T_{s}

between uncoupled and coupled models in those days influenced by typhoons. The biases and Root Mean Square Errors (RMSEs) for the temperature and moisture in the lower layer and those for the wind speed in most layers were reduced and, therefore, the accuracy of environmental field forecasting was improved from the coupled model. The typhoon track errors after 36-h decreased due to the improvement of steering flow on the west side of subtropical high from the coupled model. However, the difference of typhoon intensity errors was insignificant, which might mean that the differences of forecasted

T_{s}

and heat flux between uncoupled and coupled model are small. The reasons for the small difference need to be further investigated. Full article

(This article belongs to the Special Issue Advances in Mesoscale Numerical Weather Prediction and Its Applications (2nd Volume))

► Show Figures

Figure 1

23 pages, 6707 KiB

Open AccessArticle

Spatio-Temporal Variation of Precipitation and Evaporation on the Tibetan Plateau and Their Influence on Regional Drought

by Yuanzhi Tang, Junjun Huo, Dejun Zhu, Tailai Gao and Xiaoxuan Jiang

Atmosphere 2022, 13(8), 1323; https://doi.org/10.3390/atmos13081323 - 19 Aug 2022

Viewed by 1816

Abstract

The Tibetan Plateau (TP) is an important water source in Asia, and precipitation and evaporation patterns at different geographical and temporal scales play a significant role in managing water resource distribution. Based on quality control data from 87 meteorological stations, this study analyzed [...] Read more.

The Tibetan Plateau (TP) is an important water source in Asia, and precipitation and evaporation patterns at different geographical and temporal scales play a significant role in managing water resource distribution. Based on quality control data from 87 meteorological stations, this study analyzed the spatial and temporal evolution patterns of precipitation and pan evaporation (Epan) on the TP in 1966–2016 using the Mann–Kendall test, the moving t-test, wavelet analysis, Sen’s slope method, and correlation analysis. The results revealed that the average mean temperature in the TP area increased by about 2.1 °C during the study period, and precipitation steadily increased at an average rate of 8.2 mm/10a, with summer and autumn precipitation making up about 80% of the year. In contrast, Epan showed an overall decreasing trend at a decline rate of 20.8 mm/10a, with spring and summer Epan values making up about 67% of the year. The time series of the precipitation and Epan within the TP region clearly exhibit nonstationary features. Precipitation is more concentrated in the southeast than in the northwest, while Epan is mostly concentrated in the southwest and northeast of the plateau around the Qaidam Basin. The “evaporation paradox” phenomenon was common in the TP region for about 40 years (1960s–1990s) and gradually faded in the 21st century. In addition, we introduced a standardized precipitation evaporation index (SPEI) to investigate the differences and relationships between precipitation and Epan time series over the past 50 years. The findings indicate that the southern Qinghai was dominated by an arid trend, while the central and southeast TP remained wet. Droughts and floods coexist in the eastern Qinghai and southern Tibet areas with high population concentrations, and the risk of both is rising as the inhomogeneity of precipitation distribution in the TP region will increase in the future. This study can be used as a reference for managing water resources and predicting regional drought and flood risk. Full article

(This article belongs to the Special Issue Hydrological Responses under Climate Changes)

► Show Figures

Figure 1

21 pages, 7752 KiB

Open AccessArticle

Conversion Coefficient Analysis and Evaporation Dataset Reconstruction for Two Typical Evaporation Pan Types—A Study in the Yangtze River Basin, China

by Ziheng Li, Xuefeng Sang, Siqi Zhang, Yang Zheng and Qiming Lei

Atmosphere 2022, 13(8), 1322; https://doi.org/10.3390/atmos13081322 - 19 Aug 2022

Cited by 4 | Viewed by 1332

Abstract

For the day-by-day evaporation observation data in the Yangtze River Basin from 1951 to 2019, the effects of the gradual shift of observation instruments from 20 cm diameter evaporation pan (D20) to E601 evaporation pan after 1980 are discussed, including inconsistent data series, [...] Read more.

For the day-by-day evaporation observation data in the Yangtze River Basin from 1951 to 2019, the effects of the gradual shift of observation instruments from 20 cm diameter evaporation pan (D20) to E601 evaporation pan after 1980 are discussed, including inconsistent data series, and missing and anomalous data. This study proposes a governance and improvement method for dual-source evaporation data (GIME). The method can accomplish the homogenization of data from different observation series and solve the problem of inconsistent and missing data, and we applied it in practice on data of the Yangtze River Basin. Firstly, the primary and secondary periods of the data were obtained by wavelet periodicity analysis; secondly, we considered the first cycle of observations to be representative of the sample and calculated the conversion relationship between the primary and secondary periods; thirdly, the conversion coefficient between the dual-source observations was calculated, and the results were corrected for stations outside the main cycle; finally, the daily evaporation dataset of E601 pan was established through data fusion and interpolation technology. The study found that the annual average conversion coefficients of the D20 and E601 pans in the Yangtze River Basin are basically between 0.55 and 0.80, and there are obvious differences in different regions. The conversion coefficient is positively correlated with relative humidity, wind speed, minimum temperature and altitude; and negatively correlated with sunshine duration, average temperature and maximum temperature. Evaporation is high in the upper reaches of the basin and low in the middle and lower reaches; in particular, evaporation is highest in the southwest, which is associated with the drought hazards. In addition, the article presents the spatial distribution of the conversion coefficients of D20 and E601 pans in the Yangtze River Basin. The results can realize the rapid correction of the evaporation data of the local meteorological department, and can be extended to the processing of other types of data in similar areas. Full article

(This article belongs to the Special Issue Data Assimilation Development: Theory, Algorithm, and Applications in Meteorology)

► Show Figures

Figure 1

16 pages, 1676 KiB

Open AccessArticle

A Coverage Sampling Path Planning Method Suitable for UAV 3D Space Atmospheric Environment Detection

by Lunke Yang, Shurui Fan, Binggang Yu and Yingmiao Jia

Atmosphere 2022, 13(8), 1321; https://doi.org/10.3390/atmos13081321 - 19 Aug 2022

Cited by 3 | Viewed by 1520

Abstract

Air pollution affects people’s life and health, and controlling air pollution requires the collection of polluting gas information. Unmanned aerial vehicles (UAVs) have been used for environmental detection due to their characteristics. However, the limitation of onboard energy sources of UAVs will limit [...] Read more.

Air pollution affects people’s life and health, and controlling air pollution requires the collection of polluting gas information. Unmanned aerial vehicles (UAVs) have been used for environmental detection due to their characteristics. However, the limitation of onboard energy sources of UAVs will limit the coverage of the detection area and the number of gas samples collected, which will affect the assessment of pollution levels. In addition, to truly and completely reflect the distribution of atmospheric pollutants, it is necessary to sample the entire three-dimensional space. This paper proposes a three-dimensional space path planning method suitable for UAV atmospheric environment detection, which can generate a full-coverage path with optimal coverage density under energy constraints. Simulation results show that the proposed method can effectively improve the coverage density compared with other path generation methods. Field experiments show that the proposed method is reliable and accurate in the application of UAV atmospheric environment space detection. Full article

(This article belongs to the Special Issue Air Pollution Modelling)

► Show Figures

Figure 1

16 pages, 3183 KiB

Open AccessArticle

Assessment and Characterization of Alkylated PAHs in Selected Sites across Canada

by Andrzej Wnorowski, David Harnish, Ying Jiang, Valbona Celo, Ewa Dabek-Zlotorzynska and Jean-Pierre Charland

Atmosphere 2022, 13(8), 1320; https://doi.org/10.3390/atmos13081320 - 19 Aug 2022

Cited by 7 | Viewed by 1609

Abstract

Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs), dibenzothiophenes (DBTs), and unsubstituted polycyclic aromatic hydrocarbons (PAHs) are naturally present in fossil fuels. Thus, they can be considered as candidates for markers of pollution from petrogenic emissions such as those from traffic. Consequently, ambient air concentrations of [...] Read more.

Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs), dibenzothiophenes (DBTs), and unsubstituted polycyclic aromatic hydrocarbons (PAHs) are naturally present in fossil fuels. Thus, they can be considered as candidates for markers of pollution from petrogenic emissions such as those from traffic. Consequently, ambient air concentrations of alkyl-PAHs, DBTs, and PAHs at selected ambient air monitoring sites of various types (residential, near-road, urban-industrial, agricultural) in Montréal, Toronto, Hamilton, Edmonton, and Simcoe, were evaluated from 2015 to 2016 to study their profiles, trends, and assess potential primary emission source types. Alkyl-PAHs were the prevailing species at all sites and were most elevated at the high-traffic impacted near-road site in Toronto which was also accompanied by the highest unsubstituted PAH concentrations. Comparison of relative abundance ratios of alkyl-PAH and PAH groupings suggests that the profile differences amongst sites were small. Source attribution with cluster grouping suggested similar emission sources of alkyl-PAH and PAH at all sites, with the exception of Hamilton which was particularly impacted by additional emission sources of PAHs. The Principal Component Analysis further indicated distinct PAC profiles at HWY401 and HMT that have the same variability of “heavy PACs” but differ in “medium mass PAHs” sources. Seasonality affected the bulk species trends (alkylated naphthalenes, fluorenes, and phenanthrenes/anthracenes), especially at sites with lower concentrations of these species. This study findings confirm a notable contribution of traffic emissions to alkyl-PAH levels in urban ambient air at the studied Canadian sites, and show that enhanced speciation of alkyl-PAHs provides more data on ambient air quality and additional health risks, and can also help distinguish petrogenic-influenced sources from other sources. Full article

(This article belongs to the Special Issue Monitoring and Modelling Air Pollution and Thermal Environment through Applications in Urban Areas)

► Show Figures

Figure 1

14 pages, 3017 KiB

Open AccessArticle

A 3D Monte Carlo Simulation of Convective Diffusional Deposition of Ultrafine Particles on Fiber Surfaces

by Shixian Wu, Yongping Chen, Can Qi, Chunyu Liu, Gang Li and Hui Zhu

Atmosphere 2022, 13(8), 1319; https://doi.org/10.3390/atmos13081319 - 18 Aug 2022

Cited by 1 | Viewed by 1455

Abstract

The microscale simulation of ultrafine particle transport and deposition in fibrous filtration media was achieved with a novel particle tracking model using a 3D Monte Carlo model. The particle deposition process is governed by the convection–diffusion field. Simulations were performed by considering the [...] Read more.

The microscale simulation of ultrafine particle transport and deposition in fibrous filtration media was achieved with a novel particle tracking model using a 3D Monte Carlo model. The particle deposition process is governed by the convection–diffusion field. Simulations were performed by considering the fibrous filtration media as an array of identical parallel fibers, in which the flow field was accurately described by an analytical solution. The model of particle movement was described by the random probability distribution characterized by a dimensionless factor, the Peclet number (Pe), based on a convection–diffusive equation of particle transport in fluid. The influence of the particle Peclet number (Pe) on the particle deposition process and the resulting deposition morphology was investigated. The results were analyzed in terms of dust layer growth, particles’ trajectories and dust layer porosity for a vast range of Peclet numbers. The development of distinct deposition morphologies was found by varying the Peclet number (Pe). With a small Peclet number, diffusion dominated deposition and led to the formation of a more open and looser dust layer structure, while with larger Peclet numbers, convection dominated deposition and was found to form compact deposits. According to the change in the location of the packing densities along the dust layer height direction, the dust layer structure could be divided into three typical parts: the substructure, main profile and surface layer. In addition, the deposit morphologies observed for a high Pe were in good agreement with the experimental results found in the literature. Full article

(This article belongs to the Special Issue Developments and Applications of Scrubbers and Auxiliary Facilities for Air Pollution Control)

► Show Figures

Figure 1

12 pages, 3356 KiB

Open AccessArticle

Effects of Horizontal Transport and Vertical Mixing on Nocturnal Ozone Pollution in the Pearl River Delta

by Honglong Yang, Chao Lu, Yuanyuan Hu, Pak-Wai Chan, Lei Li and Li Zhang

Atmosphere 2022, 13(8), 1318; https://doi.org/10.3390/atmos13081318 - 18 Aug 2022

Cited by 8 | Viewed by 1835

Abstract

Based on the meteorological, ozone (O₃), and vertical observation data of 2020, this study sought to evaluate the daily variation in O₃, particularly the characteristics of nocturnal ozone pollution. We also discuss the effect of local and mesoscale horizontal [...] Read more.

Based on the meteorological, ozone (O₃), and vertical observation data of 2020, this study sought to evaluate the daily variation in O₃, particularly the characteristics of nocturnal ozone pollution. We also discuss the effect of local and mesoscale horizontal transport and vertical mixing on the formation of nocturnal O₃ pollution. Distinct seasonal characteristics of the daily O₃ variation in Shenzhen were identified. In particular, significant nocturnal peaks were found to regularly occur in the winter and spring (November–December and January–April). The monthly average of daily variation had a clear bimodal distribution. During the period, O₃ pollution frequently occurred at night, with the maximum hourly O₃ concentration reaching 203.5 μg/m³. Nocturnal O₃ pollution was closely associated with horizontal transport and vertical mixing. During the study period, the O₃ maximum values were recorded on 68 nights, primarily between 23:00 and 03:00, with occasional observation of two peaks. The impact of horizontal transport and vertical mixing on the nocturnal secondary O₃ maximum values was elaborated in two case studies, where vertical mixing was mainly associated with low-level jets, with strong wind shear enhancing turbulent mixing and transporting O₃ from the upper layers to the surface. Full article

(This article belongs to the Special Issue Monitoring and Modelling Air Pollution and Thermal Environment through Applications in Urban Areas)

► Show Figures

Figure 1

20 pages, 1062 KiB

Open AccessArticle

Life Cycle Assessment of a Prospective Technology for Building-Integrated Production of Broccoli Microgreens

by Michael G. Parkes, Julieth P. Cubillos Tovar, Filipe Dourado, Tiago Domingos and Ricardo F. M. Teixeira

Atmosphere 2022, 13(8), 1317; https://doi.org/10.3390/atmos13081317 - 18 Aug 2022

Cited by 8 | Viewed by 2792

Abstract

Indoor Vertical Farms (IVF) can contribute to urban circular food systems by reducing food waste and increasing resource use efficiency. They are also known for high energy consumption but could potentially be improved by integration with buildings. Here, we aim to quantify the [...] Read more.

Indoor Vertical Farms (IVF) can contribute to urban circular food systems by reducing food waste and increasing resource use efficiency. They are also known for high energy consumption but could potentially be improved by integration with buildings. Here, we aim to quantify the environmental performance of a prospective building-integrated urban farm. We performed a Life Cycle Assessment for a unit installed in a university campus in Portugal, producing broccoli microgreens for salads. This technology integrates IVF, product processing and Internet of Things with unused space. Its environmental performance was analyzed using two supply scenarios and a renewable energy variation was applied to each scenario. Results show that the IVF system produces 7.5 kg of microgreens daily with a global warming potential of 18.6 kg CO₂e/kg in the case of supply direct on campus, or 22.2 kg CO₂e/kg in the case of supply off campus to retailers within a 10-km radius. Consistently in both scenarios, electricity contributed the highest emission, with 10.03 kg CO₂e/kg, followed by seeds, with 4.04 kg CO₂e/kg. The additional use of photovoltaic electricity yields a reduction of emissions by 32%; an improvement of approximately 16% was found for most environmental categories. A shortened supply chain, coupled with renewable electricity production, can contribute significantly to the environmental performance of building-integrated IVF. Full article

(This article belongs to the Special Issue Urban Design, Microclimate and Environment)

► Show Figures

Figure 1

18 pages, 4856 KiB

Open AccessArticle

Analysis of Spatial and Temporal Variations of the Near-Surface Wind Regime and Their Influencing Factors in the Badain Jaran Desert, China

by Ziying Hu, Guangpeng Wang, Yong Liu, Peijun Shi, Guoming Zhang, Jifu Liu, Yu Gu, Xichen Huang, Qingyan Zhang, Xu Han, Xueling Wang, Jiewen Du, Ruoxin Li and Lianyou Liu

Atmosphere 2022, 13(8), 1316; https://doi.org/10.3390/atmos13081316 - 18 Aug 2022

Cited by 1 | Viewed by 1573

Abstract

Wind regime is one of the main natural factors controlling the evolution and distribution of aeolian sand landforms, and sand drift potential (DP) is usually used to study the capacity of aeolian sand transport. The Badain Jaran Desert (BJD) is located where polar [...] Read more.

Wind regime is one of the main natural factors controlling the evolution and distribution of aeolian sand landforms, and sand drift potential (DP) is usually used to study the capacity of aeolian sand transport. The Badain Jaran Desert (BJD) is located where polar cold air frequently enters China. Based on wind data of eight nearby meteorological stations, this research is intended to explore the temporal variation and spatial distribution features of wind speed and DP using linear regression and cumulative anomaly method, and reveal the relationship between atmospheric circulation and wind speed with correlation analysis. We found that the wind speed and frequency of sand-blowing wind in the BJD decreased significantly during 1971–2016, and the wind speed obviously mutated in 1987. The regional wind speed change was affected by the Asian polar vortex, the northern hemisphere polar vortex and the Tibet Plateau circulation. The wind rose of the annual sand-blowing wind in this region was the “acute bimodal” type. Most of the annual wind directions clustered into the W-NW, and the prevailing wind direction was WNW. During 1971–2016, the annual DP, the resultant drift potential (RDP) and the directional variability (PDP/DP) in the desert showed an obvious downtrend, with a “cliff-like” decline in the 1980s and relative stable fluctuation thereafter. The BJD was under a low-energy wind environment with the acute bimodal wind regime. Wind speed, sand-blowing wind frequency and DP were high in the northeast and low in the southwest. Full article

(This article belongs to the Topic Wind, Wave and Tidal Energy Technologies in China)

► Show Figures

Figure 1

16 pages, 2799 KiB

Open AccessArticle

Study of Absorbing CO₂ from Emissions Using a Spray Tower

by Zhongcheng Wang, Xiaoyu Liu and Ke Li

Atmosphere 2022, 13(8), 1315; https://doi.org/10.3390/atmos13081315 - 18 Aug 2022

Cited by 2 | Viewed by 1744

Abstract

In order to reduce the environmental impact caused by CO₂ emissions from ships and achieve the goal of green shipping, a spray tower using NaOH solution for the absorption of CO₂ has been established in this paper. Using the characteristics of [...] Read more.

In order to reduce the environmental impact caused by CO₂ emissions from ships and achieve the goal of green shipping, a spray tower using NaOH solution for the absorption of CO₂ has been established in this paper. Using the characteristics of a 6135G128ZCa marine diesel engine, the CO₂ absorption system was designed and mathematical models of CO₂ absorption efficiency were developed. The effects of the variation in engine exhaust gas temperature, the concentration of NaOH solution, the exhaust gas velocity, different load conditions, and different nozzle types on the absorption efficiency of CO₂ were thoroughly investigated experimentally. Moreover, the mechanism of CO₂ absorption was analyzed. The developed model was verified by comparing the test results with the simulation results. The results of the study proved that using NaOH solution to absorb CO₂ from ship exhausts could reduce the level of CO₂ emissions from ships by more than 20%, which indicates that this technology could be used in the future to reduce the level of CO₂ emissions from ships. Full article

(This article belongs to the Special Issue Advances of Materials and Processes in CO₂ Capture and Utilization)

► Show Figures

Figure 1

15 pages, 4346 KiB

Open AccessArticle

Revealing the Effects of Water Imbibition on Gas Production in a Coalbed Matrix Using Affected Pore Pressure and Permeability

by Yi Lou, Yuliang Su, Ke Wang, Peng Xia, Wendong Wang, Wei Xiong, Linjie Shao and Fuqin Yang

Atmosphere 2022, 13(8), 1314; https://doi.org/10.3390/atmos13081314 - 18 Aug 2022

Cited by 2 | Viewed by 1288

Abstract

The effect of water imbibition on characteristics of coalbed methane reservoirs, such as permeability, gas occurrence state, and gas production, is controversial. According to the mechanism of imbibition, gas and water distribution in blind pores is reconfigured during the fracturing process. Therefore, a [...] Read more.

The effect of water imbibition on characteristics of coalbed methane reservoirs, such as permeability, gas occurrence state, and gas production, is controversial. According to the mechanism of imbibition, gas and water distribution in blind pores is reconfigured during the fracturing process. Therefore, a new comprehensive model of pore pressure and permeability, based on the perfect gas equation and the weighted superposition of viscous flow and Knudsen diffusion, was established for micro- and nanoscale blind pores during water drainage. Using the numerical simulation module in the Harmony software, the effects of imbibition on coal pore pressure, permeability, and gas production were analyzed. The results showed that (1) water imbibition can increase pore pressure and reduce permeability, and (2) water imbibition is not always deleterious to gas production and estimated ultimate reserve (EUR), when the imbibition is constant, the thicker water film is deleterious to coalbed methane wells; when the thickness of water film is constant, more imbibition is beneficial to gas production and EUR. This research is beneficial to optimize the operation of well shut-ins after fracturing and provides methods for optimizing key parameters of gas reservoirs and insights into understanding the production mechanism of coalbed methane wells. Full article

(This article belongs to the Special Issue CO2 Sequestration, Capture and Utilization)

► Show Figures

Figure 1

9 pages, 826 KiB

Open AccessArticle

Evaluating the Atmospheric Loss of H₂ by NO₃ Radicals: A Theoretical Study

by Manolis N. Romanias and Thanh Lam Nguyen

Atmosphere 2022, 13(8), 1313; https://doi.org/10.3390/atmos13081313 - 18 Aug 2022

Viewed by 1258

Abstract

Molecular hydrogen (H₂) is now considered among the most prominent substitute for fossil fuels. The environmental impacts of a hydrogen economy have received more attention in the last years, but still, the knowledge is relatively poor. In this work, the reaction [...] Read more.

Molecular hydrogen (H₂) is now considered among the most prominent substitute for fossil fuels. The environmental impacts of a hydrogen economy have received more attention in the last years, but still, the knowledge is relatively poor. In this work, the reaction of H₂ with NO₃ radical (the dominant night-time detergent of the atmosphere) is studied for the first time using high-level composite G3B3 and modification of high accuracy extrapolated ab initio thermochemistry (mHEAT) methods in combination with statistical kinetics analysis using non-separable semi-classical transition state theory (SCTST). The reaction mechanism is characterized, and it is found to proceed as a direct H-abstraction process to yield HNO₃ plus H atom. The reaction enthalpy is calculated to be 12.8 kJ mol⁻¹, in excellent agreement with a benchmark active thermochemical tables (ATcT) value of 12.2 ± 0.3 kJ mol⁻¹. The energy barrier of the title reaction was calculated to be 74.6 and 76.7 kJ mol⁻¹ with G3B3 and mHEAT methods, respectively. The kinetics calculations with the non-separable SCTST theory give a modified-Arrhenius expression of k(T) = 10⁻¹⁵ × T^0.7 × exp(−6120/T) (cm³ s⁻¹) for T = 200–400 K and provide an upper limit value of 10⁻²² cm³ s⁻¹ at 298 K for the reaction rate coefficient. Therefore, as compared to the main consumption pathway of H₂ by OH radicals, the title reaction plays an unimportant role in H₂ loss in the Earth’s atmosphere and is a negligible source of HNO₃. Full article

(This article belongs to the Special Issue Atmospheric Pollution Caused by Solid Fuels Combustion)

► Show Figures

Figure 1

13 pages, 3889 KiB

Open AccessArticle

Research on the Influence of Weather Patterns on Ozone Concentration: A Case Study in Tianjin

by Yuan Li, Jiguang Wang, Liwei Li, Yu Bai, Jingyun Gao, Lei He, Miao Tang and Ning Yang

Atmosphere 2022, 13(8), 1312; https://doi.org/10.3390/atmos13081312 - 18 Aug 2022

Cited by 2 | Viewed by 1459

Abstract

Ozone (O₃) is an important secondary substance that plays a significant role in atmospheric chemistry and climate change. Although O₃ is essential in the stratosphere, it is harmful to human health in the troposphere, where this study was conducted. In [...] Read more.

Ozone (O₃) is an important secondary substance that plays a significant role in atmospheric chemistry and climate change. Although O₃ is essential in the stratosphere, it is harmful to human health in the troposphere, where this study was conducted. In recent years, O₃ pollution in the Beijing-Tianjin-Hebei (BTH), Yangtze River Delta (YRD), and Pearl River Delta (PRD) regions has deteriorated, which has become an important environmental problem. The generation of O₃ is closely related to meteorological factors. In this study, the weather classification method was adopted to study the effect of meteorological conditions on O₃ concentration. In the BTH region, Tianjin was selected as the representative city for the research. The real-time pollutants data, meteorological re-analysis data, and meteorological data in 2019 were combined for the analysis. The subjective weather classification method was adopted to investigate the effects of different weather types on O₃ concentration. The backward trajectory tracking model was used to explore the characteristics and changes of O₃ pollution under two extreme weather types. The results indicate there is a good correlation between O₃ concentration and ambient temperature. Under the control of low pressure on the ground and the influence of southwest airflow in the upper air for Tianjin, heavy O₃ pollution occurred frequently. The addition of external transport and local generation will cause high O₃ values when the weather system is weak. The O₃ concentration is closely related to ambient temperature. Continuous high-temperature weather is conducive to the photochemical reaction. The multi-day O₃ pollution process would occur when the weather system is robust. The first and second types of extreme weather are more likely to cause persistent O₃ pollution processes. Under the premise of stable emission sources, the change in weather patterns was the main reason affecting the O₃ concentration. This study aims to improve O₃ pollution control and air quality prediction in the BTH region and large cities in China. Full article

(This article belongs to the Special Issue Advances in Understanding Ozone Pollution)

► Show Figures

Figure 1

14 pages, 37873 KiB

Open AccessArticle

Numerical Simulation of a Typical Convective Precipitation and Its Cloud Microphysical Process in the Yushu Area, Based on the WRF Model

by Minghao He, Shaobo Zhang, Xianyu Yang and Shucheng Yin

Atmosphere 2022, 13(8), 1311; https://doi.org/10.3390/atmos13081311 - 17 Aug 2022

Cited by 1 | Viewed by 1382

Abstract

Cloud microphysical processes significantly impact the time variation and intensity of precipitation. However, due to the high altitude of the Tibetan Plateau (TP) and the lack of observational data, the understanding of cloud microphysical processes on the TP is relatively insufficient, affecting the [...] Read more.

Cloud microphysical processes significantly impact the time variation and intensity of precipitation. However, due to the high altitude of the Tibetan Plateau (TP) and the lack of observational data, the understanding of cloud microphysical processes on the TP is relatively insufficient, affecting the accuracy of precipitation simulations around the TP. To further reveal the characteristics of convective precipitation and cloud microphysical structure over the TP, the mesoscale numerical model, WRF, and various observational data were used to simulate and evaluate typical convective precipitation in the Yushu area, which was recorded from 11 to 12 August 2020. The results showed that the combination of the Lin scheme in the WRF model could effectively reproduce this case’s characteristics and evolution process. In the simulation process, the particles of each phase were distributed at different altitudes, and their mass and density over time reflected the characteristics of surface precipitation changes. Among the particles mentioned above, rainwater contributed the most to the initiation and growth of graupel particles. Further research established that the initiation of graupel was mainly affected by the freezing effect of rainwater and cloud ice, while the growth of graupel was influenced primarily by the collision of graupel particles and rainwater. On the whole, from the evolution characteristics of microphysical processes over time, it was found that the ice phase process plays an essential role in this typical convective precipitation. Full article

(This article belongs to the Special Issue Land-Atmosphere Interaction on the Tibetan Plateau)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Atmosphere, Volume 13, Issue 8 (August 2022) – 182 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI