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Volume 11
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Atmosphere, Volume 11, Issue 9 (September 2020) – 137 articles

Cover Story (view full-size image): In the Gobi Desert, which is known as the source of Asian dust, surface-distributed viable bacteria are associated with topographical features and ecosystems. The existence of various strains in the Gobi region suggests that the ecosystem and atmospheric environment are closely related. These findings have taught us that environmental monitoring based on the One Health concept is important for global health. View this paper
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14 pages, 259 KiB  
Article
The CO2 Emissions Drivers of Post-Communist Economies in Eastern Europe and Central Asia
by Rui Li, Hong Jiang, Iryna Sotnyk, Oleksandr Kubatko and Ismail Almashaqbeh Y. A.
Atmosphere 2020, 11(9), 1019; https://doi.org/10.3390/atmos11091019 - 22 Sep 2020
Cited by 36 | Viewed by 4316
Abstract
CO2 emissions have become a key environmental contaminant that is responsible for climate change in general and global warming in particular. Two geographical groups of countries that previously belonged to the former bloc of socialist countries are used for the estimations of [...] Read more.
CO2 emissions have become a key environmental contaminant that is responsible for climate change in general and global warming in particular. Two geographical groups of countries that previously belonged to the former bloc of socialist countries are used for the estimations of CO2 emissions drivers. The research covers such Eastern European countries as Bulgaria, Czech Republic, Hungary, Russian Federation, Poland, Romania, Slovak Republic, and Ukraine and such Central Asian states as Kazakhstan and Uzbekistan during the period 1996–2018. The main goal of the research is to identify common drivers that determine carbon dioxide emissions in selected states. To control for the time fixed effects (like EU membership), random effect model was used for the analysis of the panel data set. Results: It is found that energy efficiency progress reduces per capita CO2 emissions. Thus, an increase in GDP by 100 USD per one ton of oil equivalent decreases per capita CO2 emissions by 17–64 kg. That is, the more energy-efficient the economy becomes, the less CO2 emissions per capita it produces in a group of selected post-communist economies. Unlike energy efficiency, an increase in GDP per capita by 1000 USD raises CO2 emissions by 260 kg per capita, and the richer the economy becomes, the more CO2 emissions per capita it generates. The increase in life expectancy by one year leads to an increase in CO2 emissions per capita by 200−370 kg, with average values of 260 kg per capita. It was found that an increase in agriculture, forestry, and fishing sector share (as a % of GDP) by one percentage point leads to the decrease in CO2 emissions by 67–200 kg per capita, while an increase in industrial sector share by one percentage point leads to the increase in CO2 per capita emissions by 37–110 kg. Oil prices and foreign direct investment appeared to be statistically insignificant factors in a group of selected post-communist economies. Conclusions: The main policy recommendation is the promotion of energy efficiency policy and the development of green economy sectors. The other measures are the promotion of a less energy-intensive service sector and the modernization of the industrial sector, which is still characterized by high energy and carbon intensity. Full article
(This article belongs to the Special Issue Air Pollution Estimation)
11 pages, 2332 KiB  
Article
Assessment of the Impact of PM2.5 Exposure on the Daily Mortality of Circulatory System in Shijiazhuang, China
by Fu Guiqin, An Xingqin, Liu Huayue, Tian Yaqin and Wang Pengpeng
Atmosphere 2020, 11(9), 1018; https://doi.org/10.3390/atmos11091018 - 22 Sep 2020
Cited by 7 | Viewed by 2955
Abstract
Air pollution can increase the morbidity and mortality of cardiovascular and cerebrovascular diseases, but there are few related studies in counties and cities with serious pollution in China. China is at a critical stage of environmental pollution control. Assessing the health impact of [...] Read more.
Air pollution can increase the morbidity and mortality of cardiovascular and cerebrovascular diseases, but there are few related studies in counties and cities with serious pollution in China. China is at a critical stage of environmental pollution control. Assessing the health impact of PM2.5 (particulate matter with a diameter equal or lower than 2.5 micrometers) on the death toll from cardiovascular and cerebrovascular diseases in heavily polluted counties and cities is of great importance to the formulation of air defense policies related to PM 2.5. Generalized additive models (GAMs) were used to analyze the effects of PM2.5 exposure on the death toll of circulatory system diseases in 16 districts, counties and cities in Shijiazhuang from 2014 to 2016 after controlling the long-term trend of the time series, seasonal effects, holiday effects, air temperature, relative humidity and other factors. The average PM2.5 concentration was 121.2 ± 96.6 μg/m3; during the corresponding period, the daily mean mortality of circulatory system diseases in Shijiazhuang was 4.6 ± 4.7. With the increase of PM2.5 by 10 μg/m3, the risk of total death from circulatory system diseases with a lag of two days (lag02) increased by 3.3‰ (95% confidence interval (CI): 1.0025, 1.0041). The relative risk (RR) of the effect of PM2.5 exposure on the death toll of the circulatory system in Shijiazhuang is consistent with the spatial distribution of the PM2.5 concentration and the mortality of circulatory system diseases: the RR of the eastern plain with heavy pollution and a relatively dense population is high, while the RR of the western mountainous area with relatively light pollution and a relatively sparse population is low. For every 10-μg/m3 increase of PM2.5, the risk of the increasing death toll from circulatory system diseases in Luancheng of the eastern plain is the highest at 11.9‰ (95% CI: 1.0071, 1.0168), while the RR of Pingshan of the western mountainous area is the lowest at 2.1‰ (95% CI: 0.9981, 1.0062). Conclusions: Based on the epidemiological analysis and GAMs model, after controlling for other confounding factors, PM2.5 exposure increased the death risk of the circulatory system in Shijiazhuang, and the risk is higher in heavily polluted plain areas. It provides a scientific basis for formulating scientific air pollution prevention and control policies and provides a reference for improving the prevention awareness of sensitive groups. Full article
(This article belongs to the Special Issue Contributions of Aerosol Sources to Health Impacts)
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14 pages, 4207 KiB  
Article
Meteorological Storm Influence on the Ionosphere Parameters
by Olga Borchevkina, Ivan Karpov and Mikhail Karpov
Atmosphere 2020, 11(9), 1017; https://doi.org/10.3390/atmos11091017 - 22 Sep 2020
Cited by 16 | Viewed by 2822
Abstract
This paper presents the observations of ionospheric parameters in Kaliningrad (54° N, 20° E) during a meteorological storm in the Baltic Sea during October 2017 and 2018. Analysis of the total electronic content (TEC) during the storm showed that perturbations of the TEC [...] Read more.
This paper presents the observations of ionospheric parameters in Kaliningrad (54° N, 20° E) during a meteorological storm in the Baltic Sea during October 2017 and 2018. Analysis of the total electronic content (TEC) during the storm showed that perturbations of the TEC values from the median can reach two standard deviations of the value. For the critical frequency of the F2 layer, it was 1.5–1.6 times the standard deviations. On days of a meteorological storm, significant changes were noted in the dynamics of the E-layer’s critical frequency. The reasons for the occurrence of the observed phenomena were due to the propagation of acoustic-gravity waves generated by convective processes in the lower atmosphere during periods of a meteorological storm. Spectral analysis of TEC variations revealed an increase in the amplitudes of ionospheric variations 10–16 min over the area of a meteorological storm. The analysis allowed us to conclude that ionospheric perturbations during the meteorological perturbation were caused by increased acoustic-gravity wave (AGW) generation processes in the lower atmosphere. The most likely cause of negative ionospheric disturbances were processes associated with the dissipation of AGW propagating from the area of a meteorological storm and increased turbulence in the lower thermosphere. Full article
(This article belongs to the Special Issue Mesosphere and Lower Thermosphere: New Diagnostic Methods and Recent Observations)
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15 pages, 4521 KiB  
Article
The Response of Parameterized Orographic Gravity Waves to Rapid Warming over the Tibetan Plateau
by Runqiu Li, Xin Xu, Yuan Wang, Miguel A. C. Teixeira, Jianping Tang and Yixiong Lu
Atmosphere 2020, 11(9), 1016; https://doi.org/10.3390/atmos11091016 - 22 Sep 2020
Cited by 4 | Viewed by 3744
Abstract
Using the ERA-Interim reanalysis during 1979–2017, this work for the first time investigates the climatology and long-term trend of orographic gravity waves (OGWs) in the Tibetan Plateau (TP). The linkage between the trends of OGWs and the rapid warming over the TP is [...] Read more.
Using the ERA-Interim reanalysis during 1979–2017, this work for the first time investigates the climatology and long-term trend of orographic gravity waves (OGWs) in the Tibetan Plateau (TP). The linkage between the trends of OGWs and the rapid warming over the TP is also studied. Climatologically, the most prominent surface wave momentum flux (SWMF) of OGWs occurs in the western and southeastern TP, while it is weak in the central TP. The SWMF is stronger in winter and spring than in autumn and summer. Overall, the mean SWMF over the TP experienced a weak decreasing trend. The decrease of SWMF mainly took place in the western and southeastern TP in spring. However, increasing trends were found in the central TP in winter. Changes of SWMF are mainly caused by the changes of horizontal wind near the surface, while buoyancy frequency and air density play a minor role. In response to the inhomogeneous warming over the TP, the surface winds were adjusted through thermal wind balance. In spring (winter), the most remarkable warming occurred in the northern (southern) TP, which reduced (enhanced) the meridional temperature gradient across the plateau, and thus led to a deceleration (acceleration) of the horizontal wind. Full article
(This article belongs to the Special Issue Gravity Waves in the Atmosphere)
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17 pages, 2373 KiB  
Article
Traffic-Related Airborne VOC Profiles Variation on Road Sites and Residential Area within a Microscale in Urban Area in Southern Taiwan
by Jiun-Horng Tsai, Yen-Ting Lu, I-I Chung and Hung-Lung Chiang
Atmosphere 2020, 11(9), 1015; https://doi.org/10.3390/atmos11091015 - 22 Sep 2020
Cited by 16 | Viewed by 3684
Abstract
The sampling sites, including roadsides and residential areas, were set up to collect ambient air and determine the volatile organic species it contained. For the roadside air, the average VOCs (volatile organic compounds) abundant at rush hour periods was two times that at [...] Read more.
The sampling sites, including roadsides and residential areas, were set up to collect ambient air and determine the volatile organic species it contained. For the roadside air, the average VOCs (volatile organic compounds) abundant at rush hour periods was two times that at non-rush hour periods. In the residential area, the VOC concentrationswere106 and 129 ppb during rush hour periods. The VOC concentration ratios of roadside and residential areas were in the range of 1.08–1.75 and the traffic emissions were related to the VOCs abundant in air. The highest VOC concentration was 168 ppb at midnight at residential sites and the VOC abundance could be two times that of roadside sites. This level of concentration could be attributed to the application of solvents and to human activity in a nearby motorcycle/vehicle maintenance plant, laundry rooms, etc. High abundant species were similar in both the roadside and residential air samples. These highly abundant species included toluene, acetone, acetonitrile, m,p-xylene and n-pentane, all of which can be emitted from traffic exhaust. Benzene, acrolein, formaldehyde, vinyl chloride and 1,3-butadiene were the main species with health impacts collected at both sites. In the micro-scale environment, the residential ambient air was affected by traffic flow from morning to night. In the midnight period, some local activities (a motorcycle/vehicle maintenance shop and laundry shops) affected the concentrations of certain VOCs (acetonitrile, toluene, hexane, 2-methylpentane, methyl cyclopentane and 3-methylpentane). The traffic and motor vehicles’ effects were determined, which could be useful for air quality management and strategy development in an urban area. Full article
(This article belongs to the Special Issue Traffic-Related Air Pollution and Its Impacts on Human Health)
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16 pages, 815 KiB  
Article
Urban-Scale NO2 Prediction with Sensors Aboard Bicycles: A Comparison of Statistical Methods Using Synthetic Observations
by Christophe Bertero, Jean-François Léon, Gilles Trédan, Mathieu Roy and Alexandre Armengaud
Atmosphere 2020, 11(9), 1014; https://doi.org/10.3390/atmos11091014 - 22 Sep 2020
Cited by 6 | Viewed by 2720
Abstract
Mobile devices for city-scale air quality monitoring is receiving increasing attention due to the advent of low-cost and miniaturized sensors. Mobility and crowdsensing have emerged as a new means to investigate the ambient air quality in urban areas. However, the design of the [...] Read more.
Mobile devices for city-scale air quality monitoring is receiving increasing attention due to the advent of low-cost and miniaturized sensors. Mobility and crowdsensing have emerged as a new means to investigate the ambient air quality in urban areas. However, the design of the network (e.g., number of sensors per unit area) and the scientific interpretation of collected data with an ad hoc method are still challenging. In this paper, we focus on the use of a fleet of private bicycles to monitor NO2 concentrations in the city of Marseille, France. The study is based on synthetic observations generated by means of a regional air quality simulation system at a spatial resolution of 25 m × 25 m and simulated bike trips that are randomly generated in the city. The bike trips correspond to a maximum of 4500 bike commuters and are generated using a web-based navigation service. Simulated bike tracks are validated using available statistics on bike counts. Each bike track is associated with the along-track corresponding NO2 concentrations collected from the air quality simulations and physical features on the ground collected from Open Street Map. Spatialization of the information collected aboard the bikes is tested by using three different algorithms: kriging, land-use regression (LUR) and neural network (NN). LUR and NN show that the fleet can be limited to below 100 bikes while the performance of kriging is steadily increasing with the number of bikes. Increasing the sample distance above 200 m also impairs the citywide prediction of simulated NO2 concentrations. Full article
(This article belongs to the Special Issue Air Pollution and Environment in France)
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18 pages, 5845 KiB  
Article
Sea Breeze Front and Outdoor Thermal Comfort during Summer in Northeastern Brazil
by Max Anjos, António Lopes, Andrews José de Lucena and Francisco Mendonça
Atmosphere 2020, 11(9), 1013; https://doi.org/10.3390/atmos11091013 - 22 Sep 2020
Cited by 11 | Viewed by 4099
Abstract
Characterizing the behaviour of the sea breeze phenomenon is the foremost factor in the reduction in the heat stress and the achievement of the pleasant environment in coastal cities globally. However, this seminal study shows that the Sea Breeze Front (SBF) development can [...] Read more.
Characterizing the behaviour of the sea breeze phenomenon is the foremost factor in the reduction in the heat stress and the achievement of the pleasant environment in coastal cities globally. However, this seminal study shows that the Sea Breeze Front (SBF) development can be related to an increase in outdoor thermal discomfort in a northeastern Brazilian city during summer. We explored the relationship between SBF and thermal comfort conditions using in situ meteorological observations, the SBF identification method, local climate zones (LCZs) classification, and the Physiological Equivalent Temperature (PET) thermal comfort index. SBF days and Non-SBF days were characterized in terms of weather conditions, combining meteorological data and technical bulletins. SBF days included hot and sunny days associated with the centre of the Upper Tropospheric Cyclonic Vortices (UTCV). In contrast, Non-SBF days were observed in UTCV’s periphery because of cloudy sky and rainfall. The results showed that the mean temperature and PET in the SBF days were 2.0 °C and 3.8 °C higher, respectively, compared to Non-SBF days in all LCZ sites. The highest PET, of 40.0 °C, was found on SBF days. Our findings suggest that SBF development could be an aggravating factor for increasing heat stress of the people living in the northeastern coast of the Brazilian city, after SBF passage. Full article
(This article belongs to the Special Issue Challenges in Applied Human Biometeorology)
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21 pages, 3272 KiB  
Article
Variability and Trend in Integrated Water Vapour from ERA-Interim and IGRA2 Observations over Peninsular Malaysia
by Ezekiel Kaura Makama and Hwee San Lim
Atmosphere 2020, 11(9), 1012; https://doi.org/10.3390/atmos11091012 - 22 Sep 2020
Cited by 11 | Viewed by 3622
Abstract
Integrated water vapour (IWV) is the total amount of precipitable water in an atmospheric column between the Earth’s surface and space. The implication of its variability and trend on the Earth’s radiation budget and precipitation makes its monitoring on a regular basis important. [...] Read more.
Integrated water vapour (IWV) is the total amount of precipitable water in an atmospheric column between the Earth’s surface and space. The implication of its variability and trend on the Earth’s radiation budget and precipitation makes its monitoring on a regular basis important. ERA-Interim reanalysis (ERA) and radiosonde (RS) data from 1988 to 2018 were used to investigate variability and trend in IWV over Peninsular Malaysia. ERA performed excellently when gauged with RS. Trend analysis was performed using the non-parametric Mann–Kendall and Theil–Sen slope estimator tests. ERA and RS IWV revealed double fluctuations at the seasonal time scale, with maxima in May and November, which are the respective beginnings of the southwest monsoon (SWM) and northeast monsoon (NEM) seasons, as well as coincidental peaks of precipitation in the region. IWV decreased in a southeast–northwest orientation, with regional maximum domiciled over the southeastern tip of the region. Steep orography tended to shape intense horizontal gradients along the edges of the peninsular, with richer gradients manifesting along the western boundary during SWM, which harbours more water vapour in the peninsular. IWV trends, both at the annual and seasonal time series, were positive and statistically significant at the 95% level across the stations, except at Kota Bharu, where a nonsignificant downward trend manifested. Trends were mostly higher in the NEM, with the greatest rate being 0.20 ± 0.42 kgm−2 found at Penang. Overall, the IWV trend in Peninsular Malaysia was positive and consistent with the upward global changes in IWV reported elsewhere. Full article
(This article belongs to the Section Meteorology)
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20 pages, 6484 KiB  
Article
Evaluation of High-Resolution Crop Model Meteorological Forcing Datasets at Regional Scale: Air Temperature and Precipitation over Major Land Areas of China
by Qiuling Wang, Wei Li, Chan Xiao and Wanxiu Ai
Atmosphere 2020, 11(9), 1011; https://doi.org/10.3390/atmos11091011 - 21 Sep 2020
Cited by 13 | Viewed by 3067
Abstract
Air temperature and precipitation are two important meteorological factors affecting the earth’s energy exchange and hydrological process. High quality temperature and precipitation forcing datasets are of great significance to agro-meteorology and disaster monitoring. In this study, the accuracy of air temperature and precipitation [...] Read more.
Air temperature and precipitation are two important meteorological factors affecting the earth’s energy exchange and hydrological process. High quality temperature and precipitation forcing datasets are of great significance to agro-meteorology and disaster monitoring. In this study, the accuracy of air temperature and precipitation of the fifth generation of atmospheric reanalysis produced by the European Centre for Medium-Range Weather Forecasts (ERA5) and High-Resolution China Meteorological Administration Land Data Assimilation System (HRCLDAS) datasets are compared and evaluated from multiple spatial–temporal perspectives based on the ground meteorological station observations over major land areas of China in 2018. Concurrently, the applicability to the monitoring of high temperatures and rainstorms is also distinguished. The results show that (1) although both forcing datasets can capture the broad features of spatial distribution and seasonal variation in air temperature and precipitation, HRCLDAS shows more detailed features, especially in areas with complex underlying surfaces; (2) compared with the ground observations, it can be found that the air temperature and precipitation of HRCLDAS perform better than ERA5. The root-mean-square error (RMSE) of mean air temperature are 1.3 °C for HRCLDAS and 2.3 °C for ERA5, and the RMSE of precipitation are 2.4 mm for HRCLDAS and 5.4 mm for ERA5; (3) in the monitoring of important weather processes, the two forcing datasets can well reproduce the high temperature, rainstorm and heavy rainstorm events from June to August in 2018. HRCLDAS is more accurate in the area and magnitude of high temperature and rainstorm due to its high spatial and temporal resolution. The evaluation results can help researchers to understand the superiority and drawbacks of these two forcing datasets and select datasets reasonably in the study of climate change, agro-meteorological modeling, extreme weather research, hydrological processes and sustainable development. Full article
(This article belongs to the Special Issue Climate Change and Agrometeorological Time Series)
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14 pages, 4195 KiB  
Article
The GPM Validation Network and Evaluation of Satellite-Based Retrievals of the Rain Drop Size Distribution
by Patrick N. Gatlin, Walter A. Petersen, Jason L. Pippitt, Todd A. Berendes, David B. Wolff and Ali Tokay
Atmosphere 2020, 11(9), 1010; https://doi.org/10.3390/atmos11091010 - 21 Sep 2020
Cited by 29 | Viewed by 4579
Abstract
A unique capability of the Global Precipitation Measurement (GPM) mission is its ability to better estimate the raindrop size distribution (DSD) on a global scale. To validate the GPM DSD retrievals, a network of more than 100 ground-based polarimetric radars from across the [...] Read more.
A unique capability of the Global Precipitation Measurement (GPM) mission is its ability to better estimate the raindrop size distribution (DSD) on a global scale. To validate the GPM DSD retrievals, a network of more than 100 ground-based polarimetric radars from across the globe are utilized within the broader context of the GPM Validation Network (VN) processing architecture. The GPM VN ensures quality controlled dual-polarimetric radar moments for use in providing reference estimates of the DSD. The VN DSD estimates are carefully geometrically matched with the GPM core satellite measurements for evaluation of the GPM algorithms. We use the GPM VN to compare the DSD retrievals from the GPM’s Dual-frequency Precipitation Radar (DPR) and combined DPR–GPM Microwave Imager (GMI) Level-2 algorithms. Results suggested that the Version 06A GPM core satellite algorithms provide estimates of the mass-weighted mean diameter (Dm) that are biased 0.2 mm too large when considered across all precipitation types. In convective precipitation, the algorithms tend to overestimate Dm by 0.5–0.6 mm, leading the DPR algorithm to underestimate the normalized DSD intercept parameter (Nw) by a factor of two, and introduce a significant bias to the DPR retrievals of rainfall rate for DSDs with large Dm. The GPM Combined algorithm performs better than the DPR algorithm in convection but provides a severely limited range of Nw estimates, highlighting the need to broaden its a priori database in convective precipitation. Full article
(This article belongs to the Special Issue Measurement and Modeling of the Precipitation Particle Size Distribution)
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20 pages, 3727 KiB  
Article
Hydroclimatic Information Needs of Smallholder Farmers in the Lower Bengal Delta, Bangladesh
by Uthpal Kumar, Saskia Werners, Spyridon Paparrizos, Dilip Kumar Datta and Fulco Ludwig
Atmosphere 2020, 11(9), 1009; https://doi.org/10.3390/atmos11091009 - 21 Sep 2020
Cited by 11 | Viewed by 3918
Abstract
Hydroclimatic information services are vital for sustainable agricultural practices in deltas. They advance adaptation practices of farmers that lead to better economic benefit through increased yields, reduced production costs, and minimized crop damage. This research explores the hydroclimatic information needs of farmers by [...] Read more.
Hydroclimatic information services are vital for sustainable agricultural practices in deltas. They advance adaptation practices of farmers that lead to better economic benefit through increased yields, reduced production costs, and minimized crop damage. This research explores the hydroclimatic information needs of farmers by addressing (1) what kind of information is needed by the periurban delta farmers, and (2) whether information needs have any temporal dimension that changes with time following capacity building during coproduction of information services. Results reveal that the attributes of weather and water-related forecasts most affecting the farmers are rainfall, temperature, water, and soil salinity, along with extreme events such as cyclone and storm surges. The majority of the male farmers prefer one- to two-week lead-time forecasts for strategic and tactical decision-making; while female farmers prefer short-time forecasts with one-day to a week lead time that suggests the difference of purpose of the forecasts between male and female farmers. Contrarily, there is little preference for monthly, seasonal, and real-time forecasts. Information communication through a smartphone app is preferred mostly because of its easy accessibility and visualization. Farmers foresee that capacity building on acquiring hydroclimatic information is vital for agricultural decision-making. We conclude that a demand-driven coproduction of a hydroclimatic information service created through iterative interaction with and for farmers will enable the farmers to understand their information needs more explicitly. Full article
(This article belongs to the Special Issue Agricultural Production in Relation to Local and Regional Climate Change)
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17 pages, 1175 KiB  
Article
Observational Practices for Urban Microclimates Using Meteorologically Instrumented Unmanned Aircraft Systems
by Kevin Adkins, Peter Wambolt, Adrian Sescu, Christopher Swinford and Nickolas D. Macchiarella
Atmosphere 2020, 11(9), 1008; https://doi.org/10.3390/atmos11091008 - 21 Sep 2020
Cited by 8 | Viewed by 3442
Abstract
The urban boundary layer (UBL) is one of the most important and least understood atmospheric domains and, consequently, warrants deep understanding and rigorous analysis via sophisticated experimental and numerical tools. When field experiments have been undertaken, they have primarily been accomplished with either [...] Read more.
The urban boundary layer (UBL) is one of the most important and least understood atmospheric domains and, consequently, warrants deep understanding and rigorous analysis via sophisticated experimental and numerical tools. When field experiments have been undertaken, they have primarily been accomplished with either a coarse network of in-situ sensors or slow response sensors based on timing or Doppler shifts, resulting in low resolution and decreasing performance with height. Small unmanned aircraft systems (UASs) offer an opportunity to improve on traditional UBL observational strategies that may require substantive infrastructure or prove impractical in a vibrant city, prohibitively expensive, or coarse in resolution. Multirotor UASs are compact, have the ability to take-off and land vertically, hover for long periods of time, and maneuver easily in all three spatial dimensions, making them advantageous for probing an obstacle-laden environment. Fixed-wing UASs offer an opportunity to cover vast horizontal and vertical distances, at low altitudes, in a continuous manner with high spatial resolution. Hence, fixed-wing UASs are advantageous for observing the roughness sublayer above the highest building height where traditional manned aircraft cannot safely fly. This work presents a methodology for UBL investigations using meteorologically instrumented UASs and discusses lessons learned and best practices garnered from a proof of concept field campaign that focused on the urban canopy layer and roughness sublayer of a large modern city with a high-rise urban canopy. Full article
(This article belongs to the Special Issue Interaction between Urban Microclimates and the Buildings)
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20 pages, 4562 KiB  
Article
Evaluation of the Four-Dimensional Ensemble-Variational Hybrid Data Assimilation with Self-Consistent Regional Background Error Covariance for Improved Hurricane Intensity Forecasts
by Shixuan Zhang and Zhaoxia Pu
Atmosphere 2020, 11(9), 1007; https://doi.org/10.3390/atmos11091007 - 21 Sep 2020
Cited by 2 | Viewed by 2810
Abstract
The feasibility of a hurricane initialization framework based on the Gridpoint Statistical Interpolation (GSI)-based four-dimensional ensemble-variational (GSI-4DEnVar) hybrid data assimilation system for the Hurricane Weather Research and Forecasting model (HWRF) model is evaluated in this study. The system considers the temporal evolution of [...] Read more.
The feasibility of a hurricane initialization framework based on the Gridpoint Statistical Interpolation (GSI)-based four-dimensional ensemble-variational (GSI-4DEnVar) hybrid data assimilation system for the Hurricane Weather Research and Forecasting model (HWRF) model is evaluated in this study. The system considers the temporal evolution of error covariances via the use of four-dimensional ensemble perturbations that are provided by high-resolution, self-consistent HWRF ensemble forecasts. It is different from the configuration of the GSI-based three-dimensional ensemble-variational (GSI-3DEnVar) hybrid data assimilation system, similar to that used in the operational HWRF, which employs background error covariances provided by coarser-resolution global ensembles from the National Centers for Environmental Prediction (NCEP) Global Forecast System (GFS) ensemble Kalman filtering data assimilation system. In addition, our proposed initialization framework discards the empirical intensity correction in the vortex initialization package that is employed by the GSI-3DEnVar initialization framework in operational HWRF. Data assimilation and numerical simulation experiments for Hurricanes Joaquin (2015), Patricia (2015), and Matthew (2016) are conducted during their intensity changes. The impacts of two initialization frameworks on the HWRF analyses and forecasts are compared. It is found that GSI-4DEnVar leads to a reduction in track, minimum sea level pressure (MSLP), and maximum surface wind (MSW) forecast errors in all of the HWRF simulations, compared with the GSI-3DEnVar initialization framework. With assimilating high-resolution observations within the hurricane inner-core region, GSI-4DEnVar can produce the initial hurricane intensity reasonably well without the empirical vortex intensity correction. Further diagnoses with Hurricane Joaquin indicate that GSI-4DEnVar can significantly alleviate the imbalances in the initial conditions and enhance the performance of the data assimilation and subsequent hurricane intensity and precipitation forecasts. Full article
(This article belongs to the Special Issue Modeling and Data Assimilation for Tropical Cyclone Forecasts)
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24 pages, 2266 KiB  
Article
CO2 and Air Pollutants Emissions under Different Scenarios Predicted by a Regional Energy Consumption Modeling System for Shanghai, China
by Jing Wang, Yan Zhang, Libo Wu, Weichun Ma and Limin Chen
Atmosphere 2020, 11(9), 1006; https://doi.org/10.3390/atmos11091006 - 21 Sep 2020
Cited by 7 | Viewed by 2743
Abstract
About 75% energy demand and emissions all concentrate in urban areas, especially in the metropolises, placing a heavy burden on both the energy supply system and the environment system. To explore low emission pathways and provide policy recommendations for the Shanghai energy system [...] Read more.
About 75% energy demand and emissions all concentrate in urban areas, especially in the metropolises, placing a heavy burden on both the energy supply system and the environment system. To explore low emission pathways and provide policy recommendations for the Shanghai energy system and the environmental system to reach the carbon dioxide (CO2) peak by 2030 and attain emission reduction targets for local air pollutants (LAPs), a regional energy–environment optimization model was developed in this study, considering system costs, socio-economic development and technology. To verify the reliability of the model simulation and evaluate the model risk, a historical scenario was defined to calculate the emissions for 2004–2014, and the data were compared with the bottom-up emission inventory results. By considering four scenarios, we simulated the energy consumption and emissions in the period of 2020–2030 from the perspective of energy policies, economic measures and technology updates. We found that CO2 emissions might exceed the amount of 250 million tons by the end of 2020 under the current policy, and carbon tax with a price of 40 CNY per ton of carbon dioxide is an imperative measure to lower carbon emissions. Under the constraints, the emissions amount of SO2, NOx, PM10, and PM2.5 will be reduced by 95.3–180.8, 207.8–357.1, 149.4–274.5, and 59.5–119.8 Kt in 2030, respectively. Full article
(This article belongs to the Section Air Quality)
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29 pages, 10290 KiB  
Article
Evaluation of Historical CMIP6 Model Simulations of Seasonal Mean Temperature over Pakistan during 1970–2014
by Rizwan Karim, Guirong Tan, Brian Ayugi, Hassen Babaousmail and Fei Liu
Atmosphere 2020, 11(9), 1005; https://doi.org/10.3390/atmos11091005 - 20 Sep 2020
Cited by 30 | Viewed by 5453
Abstract
This work employed recent model outputs from coupled model intercomparison project phase six to simulate surface mean temperature during the June–July–August (JJA) and December–January–February (DJF) seasons for 1970–2014 over Pakistan. The climatic research unit (CRU TS4.03) dataset was utilized as benchmark data to [...] Read more.
This work employed recent model outputs from coupled model intercomparison project phase six to simulate surface mean temperature during the June–July–August (JJA) and December–January–February (DJF) seasons for 1970–2014 over Pakistan. The climatic research unit (CRU TS4.03) dataset was utilized as benchmark data to analyze models’ performance. The JJA season exhibited the highest mean temperature, whilst DJF displayed the lowest mean temperature in the whole study period. The JJA monthly empirical cumulative distribution frequency (ECDF) range (26 to 28 °C) was less than that of DJF (7 to 10 °C) since JJA matched closely to CRU. The JJA and DJF seasons are warming, with higher warming trends in winters than in summers. On temporal scale, models performed better in JJA with overall low bias, low RMSE (root mean square error), and higher positive CC (correlation coefficient) values. DJF performance was undermined with higher bias and RMSE with weak positive correlation estimates. Overall, CanESM5, CESM2, CESM2-WACCM, GFDL-CM4, HadGEM-GC31-LL, MPI-ESM1-2-LR, MPI-ESM1-2-HR, and MRI-ESM-0 performed better for JJA and DJF. Full article
(This article belongs to the Special Issue Climate Events and Extreme Weather)
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28 pages, 10863 KiB  
Article
Sensitivity of Simulated PM2.5 Concentrations over Northeast Asia to Different Secondary Organic Aerosol Modules during the KORUS-AQ Campaign
by Hyo-Jung Lee, Hyun-Young Jo, Chang-Keun Song, Yu-Jin Jo, Shin-Young Park and Cheol-Hee Kim
Atmosphere 2020, 11(9), 1004; https://doi.org/10.3390/atmos11091004 - 20 Sep 2020
Cited by 19 | Viewed by 3676
Abstract
A numerical sensitivity study on secondary organic aerosol formation has been carried out by employing the WRF-Chem (Weather Research and Forecasting model coupled with Chemistry). Two secondary organic aerosol formation modules, the Modal Aerosol Dynamics model for Europe/Volatility Basis Set (MADE/VBS) and the [...] Read more.
A numerical sensitivity study on secondary organic aerosol formation has been carried out by employing the WRF-Chem (Weather Research and Forecasting model coupled with Chemistry). Two secondary organic aerosol formation modules, the Modal Aerosol Dynamics model for Europe/Volatility Basis Set (MADE/VBS) and the Modal Aerosol Dynamics model for Europe/Secondary Organic Aerosol Model (MADE/SORGAM) were employed in the WRF-Chem model, and surface PM2.5 (particulate matter less than 2.5 μm in size) mass concentration and the composition of its relevant chemical sources, i.e., SO42−, NO3−, NH4+, and organic carbon (OC) were simulated during the Korea-United States Air Quality (KORUS-AQ) campaign period (1 May to 12 June 2016). We classified the KORUS-AQ period into two cases, the stagnant period (16–21 May) which was dominated by local emission and the long-range transport period (25–31 May) which was affected by transport from the leeward direction, and focused on the differences in OC secondary aerosol formation between two modules over Northeast Asia. The simulated surface PM2.5 chemical components via the two modules showed the largest systematic biases in surface OC, with a mean bias of 4.5 μg m−3, and the second largest in SO42− abundance of 2.2 μg m−3 over Seoul. Compared with surface observations at two ground sites located near the western coastal Korean Peninsula, MADE/VBS exhibited the overpredictions in OC by 170–180%, whereas MADE/SORGAM showed underpredictions by 49–65%. OC and sulfate via MADE/VBS were simulated to be much higher than that simulated by MADE/SORGAM by a factor of 2.8–3.5 and 1.5–1.9, respectively. Model verification against KORUS-AQ aircraft measurements also showed large discrepancies in simulated non-surface OC between the two modules by a factor of five, with higher OC by MADE/VBS and lower IC by MADE/SORGAM, whereas much closer MADE/VBS simulations to the KORUS-AQ aircraft measurements were found. On the basis of the aircraft measurements, the aggregated bias (sum of four components) for PM2.5 mass concentrations from the MADE/VBS module indicated that the simulation was much closer to the measurements, nevertheless more elaborate analysis on the surface OC simulation performance would be needed to improve the ground results. Our findings show that significant inconsistencies are present in the secondary organic aerosol formation simulations, suggesting that PM2.5 forecasts should be considered with great caution, as well as in the context of policymaking in the Northeast Asia region. Full article
(This article belongs to the Special Issue Regional Air Quality Modeling)
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31 pages, 4002 KiB  
Article
Generalized Description of Intermittency in Turbulence via Stochastic Methods
by Jan Friedrich and Rainer Grauer
Atmosphere 2020, 11(9), 1003; https://doi.org/10.3390/atmos11091003 - 19 Sep 2020
Cited by 8 | Viewed by 2799
Abstract
We present a generalized picture of intermittency in turbulence that is based on the theory of stochastic processes. To this end, we rely on the experimentally and numerically verified finding by R. Friedrich and J. Peinke [Phys. Rev. Lett. 78, 863 (1997)] that [...] Read more.
We present a generalized picture of intermittency in turbulence that is based on the theory of stochastic processes. To this end, we rely on the experimentally and numerically verified finding by R. Friedrich and J. Peinke [Phys. Rev. Lett. 78, 863 (1997)] that allows for an interpretation of the turbulent energy cascade as a Markov process of velocity increments in scale. It is explicitly shown that phenomenological models of turbulence, which are characterized by scaling exponents ζn of velocity increment structure functions, can be reproduced by the Kramers–Moyal expansion of the velocity increment probability density function that is associated with a Markov process. We compare the different sets of Kramers–Moyal coefficients of each phenomenology and deduce that an accurate description of intermittency should take into account an infinite number of coefficients. This is demonstrated in more detail for the case of Burgers turbulence that exhibits pronounced intermittency effects. Moreover, the influence of nonlocality on Kramers–Moyal coefficients is investigated by direct numerical simulations of a generalized Burgers equation. Depending on the balance between nonlinearity and nonlocality, we encounter different intermittency behavior that ranges from self-similarity (purely nonlocal case) to intermittent behavior (intermediate case that agrees with Yakhot’s mean field theory [Phys. Rev. E 63 026307 (2001)]) to shock-like behavior (purely nonlinear Burgers case). Full article
(This article belongs to the Special Issue Turbulence, Waves and Transport in Stratified, Rotating Fluid and Plasma Flows)
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23 pages, 6247 KiB  
Article
Spatial Variation and Trend of Extreme Precipitation in West Africa and Teleconnections with Remote Indices
by Samo Diatta, Cheikh Waly Diedhiou, Didier Maria Dione and Soussou Sambou
Atmosphere 2020, 11(9), 999; https://doi.org/10.3390/atmos11090999 - 18 Sep 2020
Cited by 26 | Viewed by 4163
Abstract
Extreme precipitation is a great concern for West Africa country, as it has serious consequence on key socio-economic activities. We use high resolution data from the Climate Hazards Group InfraRed Precipitation Stations (CHIRPS) to determine the spatial variability, trend of 8 extreme precipitation [...] Read more.
Extreme precipitation is a great concern for West Africa country, as it has serious consequence on key socio-economic activities. We use high resolution data from the Climate Hazards Group InfraRed Precipitation Stations (CHIRPS) to determine the spatial variability, trend of 8 extreme precipitation indices in West Africa and their relationship to remote indices. Spatial variability of extreme is characterized by maximum precipitation over the orographic regions, and in southern Sahel. The trend analysis shows a decrease of dry condition in Sahel and Sahara, and an increase tendency of wet indices over western Sahel and southern Sahel. The correlation analysis reveals that extreme precipitation in Sahel is strongly teleconnected to the Eastern Mediterranean Sea (EMS), whereas western and western-north Sahel is associated with both Atlantic Meridional Mode (AMM), Maiden Julian Oscillation phase 8 (MJO8), El Niño 3.4 index (NINO.3.4), and Trans-Atlantic-Pacific Ocean Dipole Index (TAPODI) but with different characteristics or directions. Guinean coast extreme precipitation is highly associated with Atlantic zone 3 SST anomaly (ATL3), Northern Cold Tongue Index (NCTI), TAPODI but also with an opposite sign with NINO.3.4 and in somewhat with the MJO8. Full article
(This article belongs to the Special Issue Trends in Hydrological and Climate Extremes in Africa)
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21 pages, 5333 KiB  
Article
Insights for Air Quality Management from Modeling and Record Studies in Cuenca, Ecuador
by René Parra and Claudia Espinoza
Atmosphere 2020, 11(9), 998; https://doi.org/10.3390/atmos11090998 - 18 Sep 2020
Cited by 15 | Viewed by 3889
Abstract
On-road traffic is the primary source of air pollutants in Cuenca (2500 m. a.s.l.), an Andean city in Ecuador. Most of the buses in the country run on diesel, emitting high amounts of NOx (NO + NO2) and PM2.5 [...] Read more.
On-road traffic is the primary source of air pollutants in Cuenca (2500 m. a.s.l.), an Andean city in Ecuador. Most of the buses in the country run on diesel, emitting high amounts of NOx (NO + NO2) and PM2.5, among other air pollutants. Currently, an electric tram system is beginning to operate in this city, accompanied by new routes for urban buses, changing the spatial distribution of the city’s emissions, and alleviating the impact in the historic center. The Ecuadorian energy efficiency law requires that all vehicles incorporated into the public transportation system must be electric by 2025. As an early and preliminary assessment of the impact of this shift, we simulated the air quality during two scenarios: (1) A reference scenario corresponding to buses running on diesel (DB) and (2) the future scenario with electric buses (EB). We used the Eulerian Weather Research and Forecasting with Chemistry (WRF-Chem) model for simulating the air quality during September, based on the last available emission inventory (year 2014). The difference in the results of the two scenarios (DB-EB) showed decreases in the daily maximum hourly NO2 (between 0.8 to 16.4 µg m−3, median 7.1 µg m−3), and in the 24-h mean PM2.5 (0.2 to 1.8 µg m−3, median 0.9 µg m−3) concentrations. However, the daily maximum 8-h mean ozone (O3) increased (1.1 to 8.0 µg m−3, median 3.5 µg m−3). Apart from the primary air quality benefits acquired due to decreases in NO2 and PM2.5 levels, and owing to the volatile organic compounds (VOC)-limited regime for O3 production in this city, modeling suggests that VOC controls should accompany future NOx reduction for avoiding increases in O3. Modeled tendencies of these pollutants when moving from the DB to EB scenario were consistent with the tendencies observed during the COVID-19 lockdown in this city, which is a unique reference for appreciating the potentiality and identifying insights for air quality improvements. This consistency supports the approach and results of this contribution, which provides early insights into the effects on air quality due to the recent operability of the electric tram and the future shift from diesel to electric buses in Cuenca. Full article
(This article belongs to the Special Issue Coronavirus Pandemic Shutdown Effects on Urban Air Quality)
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42 pages, 13209 KiB  
Article
Advanced Global Model Ensemble Forecasts of Tropical Cyclone Formation, and Intensity Predictions along Medium-Range Tracks
by Russell L. Elsberry, Hsiao-Chung Tsai, Wei-Chia Chin and Timothy P. Marchok
Atmosphere 2020, 11(9), 1002; https://doi.org/10.3390/atmos11091002 - 18 Sep 2020
Cited by 7 | Viewed by 3130
Abstract
Marchok vortex tracker outputs from the European Centre for Medium-Range Weather Forecasts ensemble (ECEPS) and National Centers for Environmental Prediction ensemble (GEFS) are utilized to provide the Time-to-Formation (T2F of 25 kt or 35 kt) timing and positions along the weighted-mean vector motion [...] Read more.
Marchok vortex tracker outputs from the European Centre for Medium-Range Weather Forecasts ensemble (ECEPS) and National Centers for Environmental Prediction ensemble (GEFS) are utilized to provide the Time-to-Formation (T2F of 25 kt or 35 kt) timing and positions along the weighted-mean vector motion (WMVM) track forecasts, and our weighted analog intensity Pacific (WAIP) technique provides 7-day intensity forecasts after the T2F. Example T2F(35) forecasts up to 5 days in advance of two typhoons and one non-developer in the western North Pacific are described in detail. An example T2F forecast of pre-Hurricane Kiko in the eastern North Pacific indicated that Hawaii would be under threat by the end of the 15-day ECEPS WMVM track forecast. An example T2F forecast of pre-Hurricane Lorenzo in the eastern Atlantic demonstrates that both the ECEPS and GEFS predict up to 5 days in advance that the precursor African wave will become a Tropical Storm off the west coast and will likely become a hurricane. Validations of the T2F(25) and T2F(35) timing and position errors are provided for all ECEPS and GEFS forecasts of the two typhoons and Hurricanes Kiko and Lorenzo. If the T2F timing errors are small (<1 day), the T2F position errors along the WMVM track forecasts will be small (<300 km). Although the primary focus is on the western North Pacific, the examples from the Atlantic and eastern/central North Pacific indicate the potential for future application in other basins. Full article
(This article belongs to the Special Issue Modeling and Data Assimilation for Tropical Cyclone Forecasts)
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40 pages, 65362 KiB  
Article
Future Projections for Wind, Wind Shear and Helicity in the Iberian Peninsula
by Joana Martins, Alfredo Rocha, Carolina Viceto, Susana Cardoso Pereira and João A. Santos
Atmosphere 2020, 11(9), 1001; https://doi.org/10.3390/atmos11091001 - 18 Sep 2020
Cited by 8 | Viewed by 3983
Abstract
Wind is among the most important climatic elements. Its characteristics are determinant for a wide range of natural processes and human activities. However, ongoing climate change is modifying these characteristics, which may have important implications. Climatic changes on wind speed and direction, wind [...] Read more.
Wind is among the most important climatic elements. Its characteristics are determinant for a wide range of natural processes and human activities. However, ongoing climate change is modifying these characteristics, which may have important implications. Climatic changes on wind speed and direction, wind shear intensity, and helicity, over the 21st century and for 26 cities in the Iberian Peninsula, under the Representative Concentration Pathway (RCP) 8.5 anthropogenic forcing scenario, are assessed. For this purpose, the Weather Research and Forecasting (WRF) model was used, with initial and boundary conditions being obtained from simulations with the Max Planck Institute for Meteorology Earth System Model (MPI-ESM-LR) climate model and ERA-Interim reanalysis. Quantile-quantile bias correction was applied to the simulated data prior to subsequent analysis. Overall, the results hint at a reduction in the intensity of both near-surface and 850 hPa (approx. 5%) wind in the future. Nevertheless, for the 300 hPa level, a decrease in summertime wind speed is accompanied by a slight increase in the remaining months. Furthermore, significant increases in the number of occurrences of extreme wind events were also identified, mainly in northwestern Iberia. For wind shear, an intensity increase is projected throughout most of the year (approx. 5% in the upper quantiles), mainly in southwestern Iberia. Helicity is also projected to undergo a strengthening, mostly in summer months and over southwestern Iberia, with greater emphasis on events of longer duration and intensity. This study highlights some important projected changes in the wind structure and profile under future anthropogenic forcing. This knowledge may support decisions on climate change adaptation options and risk reduction of several major sectors, such as energy and aviation, thus deserving further research. Full article
(This article belongs to the Special Issue Climate Events and Extreme Weather)
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15 pages, 4073 KiB  
Article
Application of the Hidden Markov Bayesian Classifier and Propagation Concept for Probabilistic Assessment of Meteorological and Hydrological Droughts in South Korea
by Muhammad Nouman Sattar, Muhammad Jehanzaib, Ji Eun Kim, Hyun-Han Kwon and Tae-Woong Kim
Atmosphere 2020, 11(9), 1000; https://doi.org/10.3390/atmos11091000 - 18 Sep 2020
Cited by 18 | Viewed by 3027
Abstract
Drought is one of the most destructive natural hazards and results in negative effects on the environment, agriculture, economics, and society. A meteorological drought originates from atmospheric components, while a hydrological drought is influenced by properties of the hydrological cycle and generally induced [...] Read more.
Drought is one of the most destructive natural hazards and results in negative effects on the environment, agriculture, economics, and society. A meteorological drought originates from atmospheric components, while a hydrological drought is influenced by properties of the hydrological cycle and generally induced by a continuous meteorological drought. Several studies have attempted to explain the cross dependencies between meteorological and hydrological droughts. However, these previous studies did not consider the propagation of drought classes. Therefore, in this study, to consider the drought propagation concept and to probabilistically assess the meteorological and hydrological drought classes, characterized by the Standardized Precipitation Index (SPI) and Standardized Runoff Index (SRI), respectively, we employed the Markov Bayesian Classifier (MBC) model that combines the procedure of iteration of feature extraction, classification, and application for assessment of drought classes for both SPI and SRI. The classification results were compared using the observed SPI and SRI, as well as with previous findings, which demonstrated that the MBC was able to reasonably determine drought classes. The accuracy of the MBC model in predicting all the classes of meteorological drought varies from 36 to 76% and in predicting all the classes of hydrological drought varies from 33 to 70%. The advantage of the MBC-based classification is that it considers drought propagation, which is very useful for planning, monitoring, and mitigation of hydrological drought in areas having problems related to hydrological data availability. Full article
(This article belongs to the Special Issue Meteorological Extremes in Korea: Prediction, Assessment, and Impact)
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18 pages, 2859 KiB  
Article
Changes in Methane Emission and Community Composition of Methane-Cycling Microorganisms Along an Elevation Gradient in the Dongting Lake Floodplain, China
by Yijie Ren, Lianlian Zhu, Zhengmiao Deng, Yonghong Xie, Chengyi Zhang, Fengjin Xiao, Xinsheng Chen, Feng Li, Yeai Zou, Rong Sheng, Xiaoyan Zhang and Xian Chen
Atmosphere 2020, 11(9), 997; https://doi.org/10.3390/atmos11090997 - 17 Sep 2020
Cited by 4 | Viewed by 3442
Abstract
Methane (CH4) emission and environmental controls of CH4-cycling microorganisms are unclear in inland floodplains. Here, we examined soil CH4 emissions and the community composition of CH4-cycling microorganisms under three vegetation types—mudflat (MF, no vegetation cover), Carex [...] Read more.
Methane (CH4) emission and environmental controls of CH4-cycling microorganisms are unclear in inland floodplains. Here, we examined soil CH4 emissions and the community composition of CH4-cycling microorganisms under three vegetation types—mudflat (MF, no vegetation cover), Carex meadow (CM, mainly Carex brevicuspis), and reed land (RL, mainly Miscanthus sacchariflorus)—from water-adjacent areas to higher-elevation land in the Dongting Lake floodplain, China. The results showed that CH4 emission is the highest in CM, while significant absorption was observed in the RL site. The abundance ratio of methanogen/methanotroph was the highest in CM, intermediate in MF, and lowest in RL. The Methanosarcinaceae family represented the dominant methanogens in the three sampling sites (41.32–75.25%). The genus Methylocystis (60.85%, type II methanotrophs) was dominant in CM, while Methylobacter and Methylosarcina (type I methanotrophs) were the dominant genera in MF (51.00%) and RL (50.24%), respectively. Structural equation model analysis showed that methanogen and methanotroph abundance were affected by water table depth, soil water content, and pH indirectly through soil organic content, total nitrogen, microbial biomass carbon, and microbial biomass nitrogen. These results indicated that the Dongting Lake floodplain may change from a CH4 source to a CH4 sink with vegetation succession with an increase in elevation, and the methanogen/methanotroph ratio can be used as a proxy for CH4 emission in wetland soils. The continuous increase in reed area combined with the decrease in Carex meadow may mitigate CH4 emission and enhance the CH4 sink function during the non-flood season in the Dongting Lake floodplain. Full article
(This article belongs to the Special Issue Climate-Ecosystem Interaction in Northern Wetlands)
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19 pages, 8343 KiB  
Article
Did ERA5 Improve Temperature and Precipitation Reanalysis over East Africa?
by Stephanie Gleixner, Teferi Demissie and Gulilat Tefera Diro
Atmosphere 2020, 11(9), 996; https://doi.org/10.3390/atmos11090996 - 17 Sep 2020
Cited by 172 | Viewed by 10263
Abstract
Reanalysis products are often taken as an alternative solution to observational weather and climate data due to availability and accessibility problems, particularly in data-sparse regions such as Africa. Proper evaluation of their strengths and weaknesses, however, should not be overlooked. The aim of [...] Read more.
Reanalysis products are often taken as an alternative solution to observational weather and climate data due to availability and accessibility problems, particularly in data-sparse regions such as Africa. Proper evaluation of their strengths and weaknesses, however, should not be overlooked. The aim of this study was to evaluate the performance of ERA5 reanalysis and to document the progress made compared to ERA-interim for the fields of near-surface temperature and precipitation over Africa. Results show that in ERA5 the climatological biases in temperature and precipitation are clearly reduced and the representation of inter-annual variability is improved over most of Africa. However, both reanalysis products performed less well in terms of capturing the observed long-term trends, despite a slightly better performance of ERA5 over ERA-interim. Further regional analysis over East Africa shows that the representation of the annual cycle of precipitation is substantially improved in ERA5 by reducing the wet bias during the rainy season. The spatial distribution of precipitation during extreme years is also better represented in ERA5. While ERA5 has improved much in comparison to its predecessor, there is still demand for improved products with even higher resolution and accuracy to satisfy impact-based studies, such as in agriculture and water resources. Full article
(This article belongs to the Section Meteorology)
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10 pages, 230 KiB  
Editorial
May SARS-CoV-2 Diffusion Be Favored by Alkaline Aerosols and Ammonia Emissions?
by Maurizio Manigrasso, Carmela Protano, Ettore Guerriero, Matteo Vitali and Pasquale Avino
Atmosphere 2020, 11(9), 995; https://doi.org/10.3390/atmos11090995 - 17 Sep 2020
Cited by 5 | Viewed by 7056
Abstract
Ammonia is a common factor linking air in bat caves and air pollution in the proximity of agricultural fields treated with livestock farming sewage and slaughterhouses, where important clusters of COVID-19 have recently been reported all over the world. Such a commonality has [...] Read more.
Ammonia is a common factor linking air in bat caves and air pollution in the proximity of agricultural fields treated with livestock farming sewage and slaughterhouses, where important clusters of COVID-19 have recently been reported all over the world. Such a commonality has a further connection with the known behavior of some viruses of the coronavirus family, such as the murine hepatitis virus, whose spike glycoprotein (S) can be triggered to a membrane-binding conformation at pH 8.0. Within the airborne route of virus transmission, with particular relevance for crowded and enclosed environments, these observations have prompted a hypothesis that may represent a contributing cause to interpret the geographical variability of the virus diffusion and the surging rise of COVID-19 cases in slaughterhouses all over the world. The hypothesis is that, in these environments, the SARS-CoV-2 S protein may find on a fraction of the airborne particles an alkaline pH, favorable to trigger the conformational changes, needed to induce the fusion of the viral envelope with the plasma membrane of the target cells. Full article
7 pages, 521 KiB  
Article
Helicopter Pilots Encountering Fog: An Analysis of 109 Accidents from 1992 to 2016
by Alex de Voogt, Hilary Kalagher and Andrew Diamond
Atmosphere 2020, 11(9), 994; https://doi.org/10.3390/atmos11090994 - 17 Sep 2020
Cited by 1 | Viewed by 3079
Abstract
Helicopters have the ability to make maneuvers or precautionary off-airport landings to avoid flights into instrument meteorological conditions (IMC) such as fog. Flight accidents in which fog was encountered as well as inadvertent and intentional flights into fog were examined to understand their [...] Read more.
Helicopters have the ability to make maneuvers or precautionary off-airport landings to avoid flights into instrument meteorological conditions (IMC) such as fog. Flight accidents in which fog was encountered as well as inadvertent and intentional flights into fog were examined to understand their occurrence. A 25-year period in the United States using the National Transportation Safety Board online database was used to collect 109 accident reports of which 73 (67%) were fatal. Pilots flying intentionally into IMC were more likely to be a part of a fatal accident than those who did so inadvertently. Those pilots who were reported as being under pressure when encountering fog conditions were also more likely to be in an accident. The findings confirm a high prevalence and an added danger to intentional flights into IMC. In addition, decision-making under pressure when encountering IMC conditions is now linked to a higher proportion of fatalities, emphasizing that helicopter pilots should be made aware of these specific decision-making circumstances in their operations. Full article
(This article belongs to the Special Issue Weather and Aviation Safety)
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16 pages, 1058 KiB  
Article
Assessment of Children’s Potential Exposure to Bioburden in Indoor Environments
by Carla Viegas, Beatriz Almeida, Marta Dias, Liliana Aranha Caetano, Elisabete Carolino, Anita Quintal Gomes, Tiago Faria, Vânia Martins and Susana Marta Almeida
Atmosphere 2020, 11(9), 993; https://doi.org/10.3390/atmos11090993 - 17 Sep 2020
Cited by 14 | Viewed by 3496
Abstract
The exposure to particles and bioaerosols has been associated with the increase in health effects in children. The objective of this study was to assess the indoor exposure to bioburden in the indoor microenvironments more frequented by children. Air particulate matter (PM) and [...] Read more.
The exposure to particles and bioaerosols has been associated with the increase in health effects in children. The objective of this study was to assess the indoor exposure to bioburden in the indoor microenvironments more frequented by children. Air particulate matter (PM) and settled dust were sampled in 33 dwellings and four schools with a medium volume sampler and with a passive method using electrostatic dust collectors (EDC), respectively. Settled dust collected by EDC was analyzed by culture-based methods (including azole resistance profile) and using qPCR. Results showed that the PM2.5 and PM10 concentrations in classrooms (31.15 μg/m3 and 57.83 μg/m3, respectively) were higher than in homes (15.26 μg/m3 and 18.95 μg/m3, respectively) and highly exceeded the limit values established by the Portuguese legislation for indoor air quality. The fungal species most commonly found in bedrooms was Penicillium sp. (91.79%), whereas, in living rooms, it was Rhizopus sp. (37.95%). Aspergillus sections with toxigenic potential were found in bedrooms and living rooms and were able to grow on VOR. Although not correlated with PM, EDC provided information regarding the bioburden. Future studies, applying EDC coupled with PM assessment, should be implemented to allow for a long-term integrated sample of organic dust. Full article
(This article belongs to the Special Issue Indoor Air Quality—What Is Known and What Needs to Be Done)
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20 pages, 7830 KiB  
Article
Modeling Ozone Source Apportionment and Performing Sensitivity Analysis in Summer on the North China Plain
by Yujing Zhang, Yuncheng Zhao, Jie Li, Qizhong Wu, Hui Wang, Huiyun Du, Wenyi Yang, Zifa Wang and Lili Zhu
Atmosphere 2020, 11(9), 992; https://doi.org/10.3390/atmos11090992 - 17 Sep 2020
Cited by 14 | Viewed by 3538
Abstract
In recent years, air quality issues due to fine particulate matter have been sufficiently treated. However, ozone (O3) has now become the primary pollutant in summer on the North China Plain (NCP). In this study, a three-dimensional chemical transport model (the [...] Read more.
In recent years, air quality issues due to fine particulate matter have been sufficiently treated. However, ozone (O3) has now become the primary pollutant in summer on the North China Plain (NCP). In this study, a three-dimensional chemical transport model (the Nested Air Quality Prediction Model System, NAQPMS) coupled with an online source apportionment module was applied to investigate the sources of O3 pollution over the NCP. Generally, the NAQPMS adequately captured the observed spatiotemporal features of O3 during the period of July 1st to August 31st in 2017 on the NCP. The results of the source apportionment indicated that the contributions of local emissions and transport from the NCP accounted for the largest proportion of O3, with magnitudes of 25% and 39%, respectively. Compared with those in the average monthly results, the local contribution and regional transport during O3 episodes on the NCP increased by 7% and 10%, respectively. Based on sensitivity tests, two thresholds of the sensitivity indicator P(H2O2)/P(HNO3) were detected, at 0.08 and 0.2. Ozone formation in the urban sites of Beijing, Tianjin, and the southern part of Hebei Province was controlled by VOCs, while the other sites were mainly controlled by NOX. Biogenic emissions contributed approximately 18% to O3 formation in July in the southwestern part of Hebei Province. Full article
(This article belongs to the Section Air Quality)
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18 pages, 6366 KiB  
Article
Temporal Variation and Source Analysis of Carbonaceous Aerosol in Industrial Cities of Northeast China during the Spring Festival: The Case of Changchun
by Mengduo Zhang, Shichun Zhang, Qiuyang Bao, Chengjiang Yang, Yang Qin, Jing Fu and Weiwei Chen
Atmosphere 2020, 11(9), 991; https://doi.org/10.3390/atmos11090991 - 16 Sep 2020
Cited by 18 | Viewed by 2836
Abstract
Carbonaceous aerosol, one of the major components of atmospheric aerosols, significantly affects haze episodes, climate change, and human health. Northeastern China suffers severe air pollution, especially in some periods (e.g., the Spring Festival). However, studies on carbonaceous aerosols in typical northeast industrial cities [...] Read more.
Carbonaceous aerosol, one of the major components of atmospheric aerosols, significantly affects haze episodes, climate change, and human health. Northeastern China suffers severe air pollution, especially in some periods (e.g., the Spring Festival). However, studies on carbonaceous aerosols in typical northeast industrial cities (i.e., Changchun) are rare, limiting further comprehension of the atmospheric haze formation. In this study, we monitored the concentrations of carbonaceous aerosols (i.e., OC and EC) in Changchun during the Lunar New Year of 2018 (i.e., from Lunar 20 December to Lunar 20 January), and analyzed the temporal variation and source contributions via the HYbrid-Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model with the potential source contribution factor weights (PSCF) method. The daily concentrations of OC and EC were 9.00 ± 2.81 and 1.57 ± 0.46 µg m−3, respectively, and were significantly lower at nighttime than at the day during the Spring Festival. The concentrations during the major period (i.e., OC: 8.13 ± 2.93 µg m−3; EC: 1.47 ± 0.47 µg m−3 in festival days), including the Lunar Little New Year; the Lunar New Year’s Eve; New Year’s Day; Lunar 5 January, and the Spring Lantern Festival, were mainly from the northwestward with the wind speed of 4–6 m/s being lower than that of normal period (OC: 9.87 ± 2.46 µg m−3; EC: 1.67 ± 0.44 µg m−3) from the southeastward with a wind speed of 6–7 m/s. The direction of the airflow trajectory was mainly in local, northwestward, and northward, carrying particulate matter and gaseous pollutants. In major period, the daily concentration of atmospheric pollutants presented a bimodal trend, with peaks appearing regularly from 11:00 a.m. to 12:00 p.m. and 5:00 p.m. 10:00 p.m., which might be related to traffic, cooking, and firecrackers. The OC/EC was greater than 2 during the whole period, indicating the generation of secondary organic aerosols (i.e., SOC). This study was essential to understand the formation mechanisms of severe pollution episodes and develop control measures for the industrial cities of Northeast China during the Spring Festival. Full article
(This article belongs to the Special Issue Secondary Organic Aerosol Formation and Composition)
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22 pages, 4867 KiB  
Article
Temporal Variability of Drought in Nine Agricultural Regions of China and the Influence of Atmospheric Circulation
by Haowei Sun, Haiying Hu, Zhaoli Wang and Chengguang Lai
Atmosphere 2020, 11(9), 990; https://doi.org/10.3390/atmos11090990 - 16 Sep 2020
Cited by 5 | Viewed by 2695
Abstract
In recent decades, the severe drought across agricultural regions of China has had significant impact on agriculture. The standardized precipitation evapotranspiration index (SPEI) has been widely used for drought analyses; however, SPEI is prone to be affected by potential evapotranspiration (PET). We thus [...] Read more.
In recent decades, the severe drought across agricultural regions of China has had significant impact on agriculture. The standardized precipitation evapotranspiration index (SPEI) has been widely used for drought analyses; however, SPEI is prone to be affected by potential evapotranspiration (PET). We thus examined the correlations between soil moisture anomalies and the SPEI calculated by the Thornthwaite, Hargreaves, and Penman–Monteith (PM) equations to select the most suitable for drought research. Additionally, the Mann–Kendall and wavelet analysis were used to investigate drought trends and to analyze and the impact of atmospheric circulation on drought in China from 1961 to 2018. The results showed that (1) PET obtained from the PM equation is the most suitable for SPEI calculation; (2) there were significant wetting trends in Northern China and the whole Chinese mainland and most of the wetting mutation points occurred in the 1970s and 1980s and the significant inter-annual oscillations period in the Chinese mainland was 2–4 years; (3) the Chinese mainland and Northern China are strongly influenced by West Pacific Trade Wind, while Western Pacific Subtropical High Intensity and Pacific Subtropical High Area have primary impact on Southern China. Full article
(This article belongs to the Section Climatology)
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