Atmosphere

11 pages, 363 KiB

Open AccessArticle

Statistics of the Inertial Energy Transfer Range in d-Dimensional Turbulence (2 ≤ d ≤ 3) in a Lagrangian Renormalized Approximation

by Toshiyuki Gotoh and Yukio Kaneda

Atmosphere 2023, 14(6), 1053; https://doi.org/10.3390/atmos14061053 - 20 Jun 2023

Cited by 1 | Viewed by 1366

Abstract

Statistics in the inertial energy transfer range (IETR) of d-dimensional turbulence (

2 \leq d \leq 3

) are studied using a Lagrangian renormalized approximation (LRA). The LRA suggests that the energy spectrum in the IETR is given by [...] Read more.

Statistics in the inertial energy transfer range (IETR) of d-dimensional turbulence (

2 \leq d \leq 3

) are studied using a Lagrangian renormalized approximation (LRA). The LRA suggests that the energy spectrum in the IETR is given by

K_{d} {| \bar{ε} |}^{2 / 3} k^{- 5 / 3}

, where

K_{d}

is a constant and

\bar{ε}

is the energy flux across wave-number k; the energy transfer is forward for

d_{c} < d \leq 3

but inverse for

2 \leq d < d_{c}

, where

d_{c} \approx 2.065

; at

d = d_{c}

,

K_{d}

diverges and the skewness of the longitudinal velocity difference vanishes; and the d-dependence of the two-time Lagrangian velocity correlation spectra under appropriate normalization is weak in the IETR. Full article

(This article belongs to the Special Issue Turbulence from Earth to Planets, Stars and Galaxies—Commemorative Issue Dedicated to the Memory of Jackson Rea Herring)

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25 pages, 7234 KiB

Open AccessArticle

Meteorological Drought Variability over Africa from Multisource Datasets

by Kenny T. C. Lim Kam Sian, Xiefei Zhi, Brian O. Ayugi, Charles Onyutha, Zablon W. Shilenje and Victor Ongoma

Atmosphere 2023, 14(6), 1052; https://doi.org/10.3390/atmos14061052 - 19 Jun 2023

Cited by 5 | Viewed by 2302

Abstract

This study analyses the spatiotemporal variability of meteorological drought over Africa and its nine climate subregions from an ensemble of 19 multisource datasets (gauge-based, satellite-based and reanalysis) over the period 1983–2014. The standardized precipitation index (SPI) is used to represent drought on a [...] Read more.

This study analyses the spatiotemporal variability of meteorological drought over Africa and its nine climate subregions from an ensemble of 19 multisource datasets (gauge-based, satellite-based and reanalysis) over the period 1983–2014. The standardized precipitation index (SPI) is used to represent drought on a 3-month scale. We analyse various drought characteristics (duration, events, frequency, intensity, and severity) for all drought months, and moderate, severe, and extreme drought conditions. The results show that drought occurs across the continent, with the equatorial regions displaying more negative SPI values, especially for moderate and severe droughts. On the other hand, Eastern Sahara and Western Southern Africa portray less negative SPI values. The study also reveals that extreme drought months have the largest interannual variability, followed by all drought months and severe drought months. The trend analysis of SPI shows a significantly increasing trend in drought episodes over most regions of Africa, especially tropical areas. Drought characteristics vary greatly across different regions of Africa, with some areas experiencing longer and more severe droughts than others. The equatorial region has the highest number of drought events, with longer durations for severe and extreme drought months. The Eastern Sahara region has a low number of drought events but with longer durations for moderate, severe, and extreme drought months, leading to an overall higher drought severity over the area. In contrast, Western Southern Africa and Madagascar display a consistently low drought severity for all categories. The study demonstrates the importance of conducting drought analysis for different drought levels instead of using all drought months. Drought management and adaptation strategies need to enhance community resilience to changing drought situations and consider drought variability in order to mitigate different impacts of drought across the continent. Full article

(This article belongs to the Special Issue Prediction, Observation, and Monitoring of Weather and Climate Extremes)

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11 pages, 1662 KiB

Open AccessEditor’s ChoiceCommunication

The Dependence of Gales on Relevant Meteorological Elements in One of the Hottest Regions of China, the Turpan Basin

by Zhiqi Xu, Hao Tang, Xiya Zhang and Haibo Hu

Atmosphere 2023, 14(6), 1051; https://doi.org/10.3390/atmos14061051 - 19 Jun 2023

Viewed by 1348

Abstract

The Turpan Basin is one of the hottest regions in China, with high fire potential. The occurrence of gales could roll over trains as well as spread and expand the fire rapidly, posing adverse effects on traffic and fire protection. Therefore, it is [...] Read more.

The Turpan Basin is one of the hottest regions in China, with high fire potential. The occurrence of gales could roll over trains as well as spread and expand the fire rapidly, posing adverse effects on traffic and fire protection. Therefore, it is important to discuss the frequency and mechanism of gales in Turpan. Based on the observational data of seven stations and ERA5 reanalysis data from 2015 to 2021, this study uses the t-mode principal component analysis using the oblique rotation (T-PCA) method to explore the seasonal differences and related synoptic patterns of gales in the Turpan Basin. The synoptic circulations are divided into nine categories. In types 1, 2, 3, 5, 7 and 9, there are a high-pressure center to the west and a lower-pressure center to the south of Turpan, while in types 4, 6 and 8, there is a strong high-pressure center to the south or northeast of Turpan. When the high-pressure system is located to the west of Turpan, gales are prone to occur, while to the south or northeast, gales seem to be less likely to occur, which is closely related to synoptic patterns and terrain. To the best of our knowledge, this study pioneered the frequency and mechanism of gales in Turpan, which could facilitate gale prevention in the area. Full article

(This article belongs to the Special Issue China Heatwaves)

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18 pages, 2781 KiB

Open AccessArticle

Triggering of an Epidemic Outbreak via Long-Range Atmospheric Transport of Bio-Aerosols—Application to a Hypothetical Case for COVID-19

by Bertrand R. Rowe, J. Brian A. Mitchell, André Canosa and Roland Draxler

Atmosphere 2023, 14(6), 1050; https://doi.org/10.3390/atmos14061050 - 19 Jun 2023

Viewed by 2000

Abstract

In the present work, we investigate the possibility that long-range airborne transport of infectious aerosols could initiate an epidemic outbreak at distances downwind beyond one hundred kilometers. For this, we have developed a simple atmospheric transport box model, which, for a hypothetical case [...] Read more.

In the present work, we investigate the possibility that long-range airborne transport of infectious aerosols could initiate an epidemic outbreak at distances downwind beyond one hundred kilometers. For this, we have developed a simple atmospheric transport box model, which, for a hypothetical case of a COVID-19 outbreak, was compared to a more sophisticated three-dimensional transport-dispersion model (HYSPLIT) calculation. Coupled with an extended Wells–Riley description of infection airborne spread, it shows that the very low probability of outdoor transmission can be compensated for by high numbers and densities of infected and susceptible people in the source upwind and in the target downwind, respectively, such as occur in large urban areas. This may result in the creation of a few primary cases. It is worth pointing out that the probability of being infected remains very small at the individual level. Therefore, this process alone, which depends on population sizes, geography, seasonality, and meteorology, can only “trigger” an epidemic, which could then spread via the standard infection routes. Full article

(This article belongs to the Special Issue Aerobiology and Health Impacts)

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11 pages, 284 KiB

Open AccessArticle

Risk Assessment of the Impact of Heavy Metals in Urban Traffic Dust on Human Health

by Nima Mahmoud, Dana Al-Shahwani, Hanadi Al-Thani and Rima J. Isaifan

Atmosphere 2023, 14(6), 1049; https://doi.org/10.3390/atmos14061049 - 19 Jun 2023

Cited by 16 | Viewed by 3444

Abstract

Excessive exposure to heavy metals induces potential adverse health impacts in humans. More specifically, heavy metals in particulate matter (PM) have a significant impact since PM can penetrate human organs and systems, causing several morbidities. In this work, dust samples were collected from [...] Read more.

Excessive exposure to heavy metals induces potential adverse health impacts in humans. More specifically, heavy metals in particulate matter (PM) have a significant impact since PM can penetrate human organs and systems, causing several morbidities. In this work, dust samples were collected from 20 different types of roads in a busy zone in Doha during the winter of 2016–2017, where a higher human exposure rate occurs due to extensive outdoor activities during this time of the year. The elemental composition in terms of the mass concentration of 30 elements was determined in each sample via an energy-dispersive X-ray fluorescence (XRF) spectrometer. Then, the toxicity of six heavy metals in these airborne traffic dust samples was investigated. The heavy metals reported to have a hazardous impact on human health are As, Pb, Hg, Cd, Cr, Co, Ni, Cu, and Zn. The extent of carcinogenic and non-carcinogenic risk impact was assessed using pollution indices and then determining the health risks associated with exposure to heavy metals through inhalation, ingestion, and dermal contact. The non-carcinogenic hazard index analysis results indicate no toxicity for all metals. However, the carcinogenic risk factor results show that only chromium might induce a slight risk for children and adults. In light of this, further research is recommended to investigate more areas in urban Doha where more samples can be collected and analyzed. Full article

(This article belongs to the Special Issue Air Pollution in Urban and Regional Level: Sources, Sinks and Transportation (2nd Edition))

19 pages, 22393 KiB

Open AccessEditor’s ChoiceArticle

Research on the Influence Mechanism of Outdoor Wind Environment on Indoor Smoke Exhaust Efficiency in the Super-High-Rise Tower Crown Based on Airpak Simulation

by Tongtong Zhang, Xiaojun Zhou, Zhongsheng Zhang and Fei Qu

Atmosphere 2023, 14(6), 1048; https://doi.org/10.3390/atmos14061048 - 19 Jun 2023

Cited by 1 | Viewed by 1534

Abstract

The high wind pressure and velocity of the outdoor environment make super-high-rise tower crown space distinct from general tall through space. This segregation causes the crown space to be particularly prone to smoke short-circuiting influenced by the outside wind environment if a fire [...] Read more.

The high wind pressure and velocity of the outdoor environment make super-high-rise tower crown space distinct from general tall through space. This segregation causes the crown space to be particularly prone to smoke short-circuiting influenced by the outside wind environment if a fire occurs indoors, and causes deficient smoke exhaust efficiency in a fire. The goal of this study was to investigate the general principle regarding the effect of the outdoor wind environment on smoke exhaust efficiency of such spaces under the crown space. We measured external wind direction and wind pressure in the smoke exhaust in the tower crown and developed setting plans for the exhaust outlets and make-up air inlet. Airpak was used to create the external wind environment and compare simulations to see if smoke short-circuiting occurred. We analyzed the causes, summarized solutions that did not result in short-circuiting of smoke flow, and made adjustments. We provide an ideal plan for the setting direction and vent velocity of the make-up air inlet and exhaust outlet in the crown spaces of super-tall towers to improve the design of smoke exhaust systems in such spaces. Full article

(This article belongs to the Special Issue Urban Microclimate: Thermal Comfort, Air Quality and Green Building as Drivers of Healthy Urban Design)

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19 pages, 23320 KiB

Open AccessArticle

Eight-Day Typhoon Quantitative Precipitation Forecasts in Taiwan by the 2.5 km CReSS Model, Part II: Reduced Control of Track Errors on Rainfall Prediction Quality for Typhoons Associated with Southwesterly Flow

by Chung-Chieh Wang, Wei-Kuo Soong, Chih-Wei Chien, Chih-Sheng Chang and Shin-Yi Huang

Atmosphere 2023, 14(6), 1047; https://doi.org/10.3390/atmos14061047 - 18 Jun 2023

Viewed by 1716

Abstract

Due to the enhancement by its steep mesoscale topography, the overall rainfall amount and distribution in Taiwan from typhoons, to a first degree, are determined by the storm track relative to the island. Therefore, the quality of typhoon quantitative precipitation forecasts (QPFs) from [...] Read more.

Due to the enhancement by its steep mesoscale topography, the overall rainfall amount and distribution in Taiwan from typhoons, to a first degree, are determined by the storm track relative to the island. Therefore, the quality of typhoon quantitative precipitation forecasts (QPFs) from numerical models is often controlled by track errors, with better quality from those with smaller track errors. However, the present work demonstrates that in daily QPFs over Taiwan made by a cloud-resolving model during five seasons of 2012–2016, targeted for 84 days during 27 typhoons and at ranges of day one (0–24 h) to day eight (168–192 h), the control of track errors on QPF quality is reduced for typhoons associated with southwesterly flow, compared to those without, and decent QPFs could still be obtained with large track errors in some cases. Subsequently, the circumstances and reasons for good (or bad) QPFs in selected examples are further investigated to deepen our understanding of typhoon QPFs in Taiwan. Some common ingredients are found in three cases where good QPFs were produced at a longer range (day 7 or 8) without a good track: these typhoons passed near northern Taiwan and the southwesterly flow prevailed over much of the island during the accumulation period. Responsible for much of the rainfall in Taiwan, the southwesterly flow was reasonably captured, resulting in good QPFs. In another example where the typhoon moved across southern Taiwan, on the contrary, the rainfall was produced by the storm’s circulation, and the QPF was degraded without a good enough track prediction. Full article

(This article belongs to the Section Meteorology)

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24 pages, 3310 KiB

Open AccessArticle

An Empirical Model of Gross Primary Productivity (GPP) and Relations between GPP and Its Driving Factors, Biogenic Volatile Organic Compounds in a Subtropical Conifer Plantation in China

by Jianhui Bai, Fengting Yang, Huimin Wang and Mingjie Xu

Atmosphere 2023, 14(6), 1046; https://doi.org/10.3390/atmos14061046 - 17 Jun 2023

Cited by 4 | Viewed by 2568

Abstract

Measurements of net ecosystem exchange (NEE), solar global radiation, photosynthetically active radiation (PAR) and meteorological parameters were carried out on a subtropical conifer plantation in China from 2013 to 2016. These observations were used to develop and evaluate an empirical model of gross [...] Read more.

Measurements of net ecosystem exchange (NEE), solar global radiation, photosynthetically active radiation (PAR) and meteorological parameters were carried out on a subtropical conifer plantation in China from 2013 to 2016. These observations were used to develop and evaluate an empirical model of gross primary production (GPP) (EMGPP) with 3-factor and 2-factor models. Using a 3-factor model, the simulated hourly GPP values were consistent with observations with a relative bias of 9.96% and normalized mean square error values of 0.07 mg CO₂ m⁻² s⁻¹ for the scattering factor S/Q (S and Q are diffuse and global solar radiation) < 0.5 and 15.52% and 0.15 mg CO₂ m⁻² s⁻¹ for S/Q ≥ 0.5. Validations of the EMGPP for hourly, daily, monthly, and annual GPP values were carried out and showed that both 3-factor and 2-factor EMGPP models can accurately capture diurnal, seasonal and interannual variations in GPP, but most simulated GPP overestimated the observed value. When the scattering factor is not available, the 2-factor EMGPP can be used. The EMGPP using 3-factor and 2-factor models was applied to simulate GPP under all sky conditions from 2013–2016, and the estimated GPP were in reasonable agreement with the measured values and showed systematic overestimations of 31% and 29% for mean hourly GPP and 41% and 29% for annual amounts, respectively. The sensitivity test demonstrated that GPP values were more sensitive to changes in PAR than to changes in water vapor and scattering factor at low S/Q, but were more sensitive to changes in water vapor than to PAR and S/Q at high S/Q. The sensitivity test revealed some mechanisms of GPP and its related processes, including the relationships between GPP and scattering of PAR, GPP and water vapor, which were in good agreement with other observations and model studies. An empirical model based on PAR energy balance can better describe the multiple interactions between GPP and its driving factors (PAR, water vapor, S/Q). The ratio of the emissions of biogenic volatile organic compounds (BVOCs) to net ecosystem exchange clearly varied between forests in different climate zones. Full article

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

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12 pages, 2019 KiB

Open AccessArticle

Short-Period Variation of the Activity of Atmospheric Turbulence in the MLT Region over Langfang

by Zewei Wang, Cunying Xiao, Xiong Hu, Junfeng Yang, Xuan Cheng, Qingchen Xu, Luo Xiao and Xiaoqi Wu

Atmosphere 2023, 14(6), 1045; https://doi.org/10.3390/atmos14061045 - 17 Jun 2023

Cited by 1 | Viewed by 1250

Abstract

In this paper, we investigate the activity of atmospheric turbulence in the MLT region and the relationship between the activity of atmospheric turbulence and atmospheric wave activity. We use data from the Langfang MF radar (

39 . 4^{\circ} N

, [...] Read more.

In this paper, we investigate the activity of atmospheric turbulence in the MLT region and the relationship between the activity of atmospheric turbulence and atmospheric wave activity. We use data from the Langfang MF radar (

39 . 4^{\circ} N

,

116 . 7^{\circ} E

) from July 2019 to June 2020 and NRLMSIS 2.0 to calculate the parameters of atmospheric wave activity and atmospheric turbulence energy dissipation rate (

ε

). Atmospheric

ε

is modulated by different periods at different altitudes, and while there are 12 h and 24 h periods at all altitudes, the main period is different at different altitudes. A comparison of the

ε

with atmospheric tide activity shows that tides have an effect on

ε

, and the influence of tides on

ε

may be different at different altitudes. The pattern of variation in

ε

is similar to that of the atmospheric activity of the gravity wave, with both

ε

and the atmospheric activity of the gravity wave showing significant semi-annual variation. Full article

(This article belongs to the Section Upper Atmosphere)

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19 pages, 12691 KiB

Open AccessArticle

Underrepresentation of the Linkage between the Barents–Kara Sea Ice and East Asian Rainfall in Early Summer by CMIP6 Models

by Haohan Chen, Jian Rao, Huidi Yang, Jingjia Luo and Gangsen Wu

Atmosphere 2023, 14(6), 1044; https://doi.org/10.3390/atmos14061044 - 17 Jun 2023

Viewed by 1477

Abstract

Our previous study revealed the link between Barents–Kara sea ice and rainfall in eastern China. This study continues evaluating the performance of multiple models from phase 6 of the Coupled Model Intercomparison Project (CMIP6) in simulating this linkage. Most CMIP6 models can simulate [...] Read more.

Our previous study revealed the link between Barents–Kara sea ice and rainfall in eastern China. This study continues evaluating the performance of multiple models from phase 6 of the Coupled Model Intercomparison Project (CMIP6) in simulating this linkage. Most CMIP6 models can simulate Arctic sea ice coverage in the present climate system, although the sea ice extent in the edge areas show some biases. Only a few models can roughly reproduce the observed rainfall dipole pattern associated with Arctic sea ice variability. The linkage between Arctic sea ice variability in winter and eastern China rainfall in early summer is performed through a long memory of the sea ice, the stratospheric variability as the mediator, and downward propagation of stratospheric signals. Very few CMIP6 models can exhibit a realistic interannual relationship between the Arctic sea ice and China rainfall. The selected high-skill models with a more realistic linkage between sea ice and China rainfall present a clear downward impact of the stratospheric circulation anomalies associated with sea ice variability. The reversal of the Northern Hemisphere Annular Mode (NAM) from the negative phase in early winter to the positive phase in spring in the high-skill models and observations denotes the important role of the stratosphere as a mediator to bridge the Arctic sea ice and China rainfall. The long memory of the Arctic sea ice with the stratosphere as the mediator has a deep implication on the seasonal forecasts of East Asian countries. Full article

(This article belongs to the Topic Cryosphere: Changes, Impacts and Adaptation)

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18 pages, 2202 KiB

Open AccessArticle

Assessing the Effects of Environmental Smog Warning Policy on Preventing Traffic Deaths Based on RDD Strategy

by Juan Gao, Cheng Ying, Liyuan Hu, Zixiang Lin and Hao Xie

Atmosphere 2023, 14(6), 1043; https://doi.org/10.3390/atmos14061043 - 17 Jun 2023

Viewed by 1473

Abstract

This paper assessed the impacts of environmental smog early-warning signals on road traffic deaths. For an accurate assessment, we used the daily traffic death data from 2016 to 2020 in 295 Chinese cities and constructed a rigorous Regression Discontinuity Design (RDD) strategy to [...] Read more.

This paper assessed the impacts of environmental smog early-warning signals on road traffic deaths. For an accurate assessment, we used the daily traffic death data from 2016 to 2020 in 295 Chinese cities and constructed a rigorous Regression Discontinuity Design (RDD) strategy to identify the causality and adopted the high-dimensional fixed-effect method to deal with the interference of meteorological factors. The results indicate that light smog and moderate smog early warnings decreased road fatalities by about 3.6% and 4.3%, respectively. Surprisingly, the heavy smog early-warning signal had no significant effect, possibly because of the self-consciousness mechanism instead of the early-warning signal mechanism. Further heterogeneity analysis showed that women drivers, highly-educated drivers, older drivers (over 60 years), two-wheeled vehicle drivers, and drivers on country roads and freeways are more sensitive to smog early-warning signals. Full article

(This article belongs to the Special Issue Recent Advances in Air Quality Management)

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19 pages, 7411 KiB

Open AccessArticle

Diversity and Ranking of ENSO Impacts along the Eastern Seaboard of Subtropical Southern Africa

by Ross C. Blamey and Chris J. C. Reason

Atmosphere 2023, 14(6), 1042; https://doi.org/10.3390/atmos14061042 - 17 Jun 2023

Cited by 6 | Viewed by 2101

Abstract

El Niño–Southern Oscillation (ENSO) is the dominant mode of interannual climate variability over southern Africa during the summer half of the year. It is widely accepted that El Niño (La Niña) core summers (December–February) are typically warmer and drier (cooler and wetter) than [...] Read more.

El Niño–Southern Oscillation (ENSO) is the dominant mode of interannual climate variability over southern Africa during the summer half of the year. It is widely accepted that El Niño (La Niña) core summers (December–February) are typically warmer and drier (cooler and wetter) than average over the region. Although it is recognized that the ENSO impacts are nonlinear and not all events result in the expected impact, little or no work has been carried out to systematically explore the diversity and ranking of these impacts. Here, parameter-space bubble plots involving various rainfall and temperature metrics are used to study how such impacts vary over the eastern seaboard of subtropical southern Africa to determine the ENSO events with the strongest impacts, and to identify the most anomalous ENSO cases. Comparison of neutral summers experiencing the strongest droughts/floods with ENSO impacts is also performed. These metrics are designed to be applicable to the interests of farmers and other user groups. It is found that 1987/1988 (2017/2018) was the most unusual El Niño (La Niña) and neutral 1981/1982 had a severe drought, worse than occurs during most El Niños. These unusual cases are explained in terms of regional circulation and SST anomalies. Implications of the results for seasonal forecasting and for farmers are discussed. Full article

(This article belongs to the Special Issue Effects of Climate Change on Agriculture)

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12 pages, 2616 KiB

Open AccessArticle

Analysis of Carbon Particulate Matter Removal Performance of Dual-Fuel Marine Engine with DOC + CDPF

by Zhiyuan Yang, Zhiwen Tan, Qinming Tan and Shien Tu

Atmosphere 2023, 14(6), 1041; https://doi.org/10.3390/atmos14061041 - 17 Jun 2023

Cited by 1 | Viewed by 1623

Abstract

This study analyzes Diesel Oxidation Catalyst (DOC) and Carbon Diesel Particulate Filter (CDPF) after-treatment systems integrated into a WARTSILA W20DF marine dual-fuel engine. The CDPF was coated with a non-precious metal catalyst whose catalytic redox performance improved with increasing temperature. The carbon particulate [...] Read more.

This study analyzes Diesel Oxidation Catalyst (DOC) and Carbon Diesel Particulate Filter (CDPF) after-treatment systems integrated into a WARTSILA W20DF marine dual-fuel engine. The CDPF was coated with a non-precious metal catalyst whose catalytic redox performance improved with increasing temperature. The carbon particulate matter combustion reached up to 12.5 mg/s at 800 K and over 20 mg/s at 900 K. Then, the W20DF running at 230 kW, 450 kW, 680 kW, and 810 kW with 1000 rpm; a Tisch 10-8xx; and an AVL SPC 478 were used to sample and analyze the carbon particulate matter (CPM) before and after DOC + CDPF. The gaseous emissions (O₂, CO₂, CO, HC, NOx, and NO₂) were analyzed with the flue gas analyzer AVL i60. The results show that the collected carbon particulate matter simultaneously became darker as the load decreased. This study finds that the maximum amount of CPM per unit volume of exhaust gas occurs under 50% working conditions and the lowest amount under 90% working conditions. After DOC + CDPF treatment with a non-precious metal coating, the CPM was reduced by about 50%. Furthermore, this type of catalyst’s efficiency rises with the temperature increase. The CPM combustion efficiency reached up to 20 mg/s at 900 K. The other gas components in the exhaust gas before and after DOC + CDPF also changed. These research results have a significant reference value for DOC + CDPF optimization to decrease the carbon particulate matter in marine engines. Full article

(This article belongs to the Special Issue Advances in Integrated Air Quality Management: Emissions, Monitoring, Modelling (2nd Volume))

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18 pages, 14463 KiB

Open AccessArticle

Removal of Multiple-Radio-Frequency Interference in 1.29 GHz Wind Profiler Spectra

by Kyung Hun Lee and Byung Hyuk Kwon

Atmosphere 2023, 14(6), 1040; https://doi.org/10.3390/atmos14061040 - 16 Jun 2023

Viewed by 1408

Abstract

A 1.29 GHz wind profiler was developed under a private–military–government cooperative wind profiler radar development project in the Republic of Korea. During the test operation period, radio frequency interference (RFI) contamination occurred in the spectrum. In addition to the general shape, with a [...] Read more.

A 1.29 GHz wind profiler was developed under a private–military–government cooperative wind profiler radar development project in the Republic of Korea. During the test operation period, radio frequency interference (RFI) contamination occurred in the spectrum. In addition to the general shape, with a continuous appearance depending on the altitude, the spectrum showed complex shapes, such as discontinuous and overlapping frequencies. The RFI characteristics in the wind profiler spectra were analyzed, and a new algorithm was developed to remove multiple RFI (MRFI). Meteorological and non-meteorological signals were separated by filtering with a spectrum width threshold of 0.1 m/s. A continuity check was performed to determine MRFI in the non-meteorological signal. The number of gates in which the same radial velocity is continuous was determined based on whether the beam was vertical or oblique; a rough continuity test was performed, considering exceptional circumstances for the meteorological signal. For overlapping MRFI, the process was repeated. Spectral contamination by MRFI was removed through filtering and iterated scans; the continuity of wind vectors calculated from the improved spectral radial velocity was verified. Good-quality wind vectors can be produced even in a bad-radio-frequency environment if proper quality control is performed. Full article

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

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19 pages, 12004 KiB

Open AccessArticle

Study on NDVI Periodic Change Characteristics of Inner Mongolia Grassland Based on Variational Mode Decomposition Algorithm

by Deguo Su, Anbing Zhang, Zhixiu Tian, Xinxia Liu and Yikai Hou

Atmosphere 2023, 14(6), 1039; https://doi.org/10.3390/atmos14061039 - 16 Jun 2023

Viewed by 1163

Abstract

Based on the NDVI data of vegetation in Inner Mongolia from 1982 to 2015, the variational mode decomposition (VMD) method, which has been well applied in the field of signal decomposition, is introduced to study the periodicity of vegetation index in Inner Mongolia. [...] Read more.

Based on the NDVI data of vegetation in Inner Mongolia from 1982 to 2015, the variational mode decomposition (VMD) method, which has been well applied in the field of signal decomposition, is introduced to study the periodicity of vegetation index in Inner Mongolia. The VMD method is used to extract the monthly and annual NDVI and the long time series cycle characteristics of temperature and precipitation in the same period from April 1982 to October 2015 in Inner Mongolia. The results show that temperature and precipitation are important factors affecting the growth of vegetation, and there are 6.99 and 3.49 months of the same oscillation cycle for monthly NDVI and temperature and precipitation time series; when the central frequency is the same, the amplitude of the monthly temperature and precipitation time series increases with the increase of the lag period. The annual scale NDVI has the same period of 16.95, 6.8a, and 4.85a with precipitation, and the same period of 6.8a and 4.85a with temperature. The Residue component shows that the overall NDVI and temperature in Inner Mongolia have shown a significant slow growth trend in the past 30 years. Although the precipitation has shown a significant slow decline trend in the same time period (p = 0.000), the grassland is still in the process of continuous improvement. Full article

(This article belongs to the Section Meteorology)

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13 pages, 8893 KiB

Open AccessArticle

Impacts of the Surface Potential Vorticity Circulation over the Tibetan Plateau on the East Asian Monsoon in July

by Yimin Liu, Lulu Luan, Guoxiong Wu and Tingting Ma

Atmosphere 2023, 14(6), 1038; https://doi.org/10.3390/atmos14061038 - 16 Jun 2023

Cited by 2 | Viewed by 1580

Abstract

Based on the definition of potential vorticity substance (W) and its equation, an index “iPV” representing the leading mode of the surface potential vorticity circulation (PVC) over the Tibetan Plateau is defined to characterize the orographic potential vorticity (PV) forcing on the atmospheric [...] Read more.

Based on the definition of potential vorticity substance (W) and its equation, an index “iPV” representing the leading mode of the surface potential vorticity circulation (PVC) over the Tibetan Plateau is defined to characterize the orographic potential vorticity (PV) forcing on the atmospheric general circulation. The relationships between the iPV index and the East Asian monsoon in July, as well as the Silk Road pattern in Eurasia, are investigated on an interannual time scale. Results show that the iPV in July is closely related to the interannual variability of the East Asian monsoon. Corresponding to the positive phase of iPV with negative (positive) PVC over the north (south) of the plateau, strong positive PV anomalies and westerly flows develop in the troposphere over the plateau. Consequently, in the downstream region, the zonal PV advection increases with height just above the Jianghuai Meiyu front, which is conducive to the generation of upward movement. Over the East Asian area, the upper troposphere is controlled by the eastward shifted South Asian High. In the lower troposphere, the southwesterly flow anomaly on the northwestern side of the strengthened western Pacific subtropical high transports abundant water vapor to the north, forming a convergence in the Jianghuai area, leading to the formation of large-scale precipitation along the Meiyu front. Results from partial correlation analysis also demonstrate that the link between the variability of the East Asian monsoon in July and the plateau PV forcing is affected very little by the Silk Road pattern, whereas the plateau PV forcing plays a key “bridging” role in the influence of the Silk Road pattern on the East Asian monsoon. Full article

(This article belongs to the Topic A Themed Issue in Memory of Academician Duzheng Ye (1916–2013))

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26 pages, 5740 KiB

Open AccessArticle

Outdoor Thermal Environment Regulation of Urban Green and Blue Infrastructure on Various Types of Pedestrian Walkways

by Haonan Pan, Yihan Luo, Liyue Zeng, Yurong Shi, Jian Hang, Xuelin Zhang, Jiajia Hua, Bo Zhao, Zhongli Gu and Riccardo Buccolieri

Atmosphere 2023, 14(6), 1037; https://doi.org/10.3390/atmos14061037 - 16 Jun 2023

Cited by 3 | Viewed by 1623

Abstract

Urban green and blue infrastructure (GBI) is effective in urban heat mitigation. However, the diurnal variations in the thermal regulation of GBI on different types of urban pedestrian walkways in the subtropical humid climate zone are unclear. Based on traverse measurements in January [...] Read more.

Urban green and blue infrastructure (GBI) is effective in urban heat mitigation. However, the diurnal variations in the thermal regulation of GBI on different types of urban pedestrian walkways in the subtropical humid climate zone are unclear. Based on traverse measurements in January 2022, this study investigates how outdoor air temperature (Ta) and wet-bulb temperature (Tw) at the pedestrian level are affected by various urban morphology and GBI characteristics in the central urbanized area of Guangzhou (China). Six building-related, three vegetation-related, and three water-related parameters were applied in the analyses. Results show that green infrastructure (GI) has the strongest cooling effect (Pearson’s coefficient r = −0.33~−0.54) on Ta on cloudy evenings and the weakest cooling effect (r = −0.22~−0.32) on clear evenings. Blue infrastructure (BI) exhibits the highest correlations with the cooling effect for Ta on clear afternoons (r = −0.35~−0.51) and weaker, but more consistent, correlations throughout cloudy days (r = −0.23~−0.43). Strong correlations between GI and Tw cooling are observed in the morning and evening on clear days (r = −0.13~−0.48), while BI exhibits the strongest correlation with Tw cooling on clear afternoons (r = −0.13~−0.37). In addition, both GI and BI show a greater cooling effect on both Ta and Tw in low-rise areas compared to high-rise areas. Compared to the individual GI or BI, the integrated GBI has a higher cooling intensity for both Ta and Tw in high-rise areas. However, the cooling potential of integrated GBI is slightly lower for both Ta and Tw during noon and afternoon in low-rise areas. The findings of this study give insights into urban GBI planning and design of specific urban microclimate regulation strategies. Full article

(This article belongs to the Section Biometeorology and Bioclimatology)

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20 pages, 3932 KiB

Open AccessArticle

Evasion of Gaseous Elemental Mercury from Forest and Urban Soils Contaminated by Historical and Modern Ore Roasting Processes (Idrija, Slovenia)

by Federico Floreani, Elena Pavoni, Mateja Gosar and Stefano Covelli

Atmosphere 2023, 14(6), 1036; https://doi.org/10.3390/atmos14061036 - 16 Jun 2023

Cited by 2 | Viewed by 1910

Abstract

Considerable amounts of gaseous elemental mercury (Hg⁰) can be released into the atmosphere from Hg-enriched substrates, such as those from former mining areas, posing a potential environmental threat. In this work, Hg⁰ fluxes at the soil–air interface under natural vegetation [...] Read more.

Considerable amounts of gaseous elemental mercury (Hg⁰) can be released into the atmosphere from Hg-enriched substrates, such as those from former mining areas, posing a potential environmental threat. In this work, Hg⁰ fluxes at the soil–air interface under natural vegetation covers were measured in various locations within the Idrija Hg mining area (Slovenia) and its surroundings. Sites were selected in order to compare Hg⁰ fluxes from both forest soils heavily impacted by historical ore roasting and urban soils characterised by a different degree of Hg enrichment due to the natural occurrence of Hg in rocks or recent mining and roasting processes. Replicate measurements at each site were conducted using a non-steady state flux chamber coupled with a real-time Hg⁰ analyser (Lumex RA-915M). Moreover, topsoil samples (0–2 cm) were analysed for Hg total concentration and speciation. Cinnabar was the predominant Hg form in almost all the sites. Despite Hg⁰ being undetectable in soils using thermo-desorption, substantial emissions were observed (70.7–701.8 ng m⁻² h⁻¹). Urban soils in a naturally enriched area showed on average the highest Hg⁰ fluxes, whereas relatively low emissions were found at the historical roasting site, which is currently forested, despite the significantly high total Hg content in soils (up to 219.0 and 10,400 mg kg⁻¹, respectively). Overall, our findings confirm that shading by trees or litter may effectively limit the amount of Hg⁰ released into the atmosphere even from extremely enriched soils, thus acting as a natural mitigation. Full article

(This article belongs to the Special Issue Mercury in Atmosphere)

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21 pages, 5486 KiB

Open AccessArticle

Characteristics of Marine Heatwaves in the Indonesian Waters during the PDO, ENSO, and IOD Phases and Their Relationships to Net Surface Heat Flux

by Erlin Beliyana, Nining Sari Ningsih, Sekar Ramdanira Gunawan and Ayi Tarya

Atmosphere 2023, 14(6), 1035; https://doi.org/10.3390/atmos14061035 - 16 Jun 2023

Cited by 4 | Viewed by 2672

Abstract

We conducted an investigation into the characteristics of marine heatwaves (MHWs) in Indonesian waters, aiming to understand the underlying mechanisms responsible for their formation, particularly the ones generated by net surface heat flux. To accomplish this, we utilized remote sensing data from the [...] Read more.

We conducted an investigation into the characteristics of marine heatwaves (MHWs) in Indonesian waters, aiming to understand the underlying mechanisms responsible for their formation, particularly the ones generated by net surface heat flux. To accomplish this, we utilized remote sensing data from the National Oceanic and Atmospheric Administration and the European Centre for Medium-Range Weather Forecasts. The dataset covered a 40-year period (1982–2021) encompassing both warm (1982–2007) and cold (2008–2021) phases of the Pacific Decadal Oscillation (PDO). Statistical analysis methods were employed to process the data. Our study reveals significant findings regarding MHWs in Indonesian waters. We observed the highest average frequency and maximum intensity of MHWs, occurring approximately 2–3 times a year and exceeding 1.5 °C, respectively, during the warm phase of PDO (with El Niño events occurring more frequently than La Niña). Conversely, the longest durations of MHWs in Indonesian waters were recorded during the cold phase of PDO (with La Niña events occurring more frequently than El Niño), spanning approximately 7–15 days. We identified local forcing in the form of net surface heat flux as the primary driver of MHW frequency and maximum intensity. During the warm phase of PDO, the net surface heat flux was notably higher, primarily due to increased shortwave radiation (heat gain) and reduced latent heat flux (heat loss) through the evaporation process. These factors collectively contributed to maintaining warmer ocean temperatures. Moreover, our study provides valuable insights into the interannual variability of MHWs through the application of composite calculations. We discovered a strong correlation between the occurrence of El Niño and positive Indian Ocean Dipole (IOD) events during the warm PDO phase and the highest frequency and maximum intensity of MHWs, with approximately 2.52 events and 1.54 °C, respectively. In contrast, we found that MHWs with the longest durations were closely linked to La Niña and negative IOD events during the cold PDO phase, lasting approximately 10.90 days. These findings highlight the complex interplay between climate phenomena and MHW characteristics, further deepening our understanding of their dynamics. Full article

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

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14 pages, 4042 KiB

Open AccessArticle

Intraseasonal Variation in the Mesosphere Observed by the Mengcheng Meteor Radar from 2015 to 2020

by Yihuan Tang, Xiaojing Hao, Shican Qiu, Wenhan Cheng, Chengyun Yang and Jianfei Wu

Atmosphere 2023, 14(6), 1034; https://doi.org/10.3390/atmos14061034 - 15 Jun 2023

Cited by 1 | Viewed by 1193

Abstract

The intraseasonal oscillations (30–100 days, ISO) in the MLT (mesosphere and lower thermosphere) horizontal wind are investigated based on observations from the Mengcheng meteor radar. There is a clear seasonal variation in ISO in the horizontal wind at 80 km, which is strongest [...] Read more.

The intraseasonal oscillations (30–100 days, ISO) in the MLT (mesosphere and lower thermosphere) horizontal wind are investigated based on observations from the Mengcheng meteor radar. There is a clear seasonal variation in ISO in the horizontal wind at 80 km, which is strongest during the winter and weakest during the summer. At 100 km, ISO occurs throughout most of the year except winter, and there are significant differences in periods and amplitudes from year to year. From 2015 to 2016, ISOs with periods of 40–60 days were present in the 100 km horizontal wind, whereas none were simultaneously observed in the 80 km horizontal wind. Cross wavelets were used to study the relationship between ISO in the MLT region and ISO in the lower atmosphere. Some of the ISO activity is linked to tropospheric tropical convective activity, but the ISO connections with that in tropospheric convection are not consistent in the upper mesosphere and in the lower thermosphere. Full article

(This article belongs to the Section Upper Atmosphere)

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21 pages, 4147 KiB

Open AccessArticle

Spatial Analysis of Heavy Metal Pollution in Road-Deposited Sediments Based on the Traffic Intensity of a Megacity

by Angélica Vanessa Goya-Heredia, Carlos Alfonso Zafra-Mejía and Hugo Alexander Rondón-Quintana

Atmosphere 2023, 14(6), 1033; https://doi.org/10.3390/atmos14061033 - 15 Jun 2023

Cited by 4 | Viewed by 3178

Abstract

Population growth has led to the intensification of average daily traffic (ADT), highlighting vehicles as one of the major sources of heavy metal (HM) pollution in cities. The objective of this paper is to conduct a spatial analysis of the HM pollution associated [...] Read more.

Population growth has led to the intensification of average daily traffic (ADT), highlighting vehicles as one of the major sources of heavy metal (HM) pollution in cities. The objective of this paper is to conduct a spatial analysis of the HM pollution associated with road-deposited sediments (RDSs), based on the ADT observed in the main roads of a Latin American megacity (Bogotá, Colombia). The following risk indices were considered: Geoaccumulation Index (Igeo), Integrated Pollution Index (IPI), Ecological Risk Index (ERI), Comprehensive Potential Ecological Risk Index (CERI), Hazard Index (HI), and Carcinogenic Risk Index (CRI). The findings confirm that a size fraction < 250 μm is the most suitable for studying the risk of HMs in the RDS from the indices considered. The best HMs indicative of the relationship with ADT are Ni, Cu, and Pb. The Pb is the HM of most attention, and Cr gains positions for its toxicity level during the evaluation of ecological, non-carcinogenic, and carcinogenic risks, respectively. Finally, the linear regression models developed between ADT and each of the risk indices considered have a better fit (R² > 0.910) compared to the linear regression models developed between ADT and HM concentrations (R² > 0.322). Full article

(This article belongs to the Special Issue Heavy Metals in Atmosphere: Sources, Analysis and Impact on the Environment)

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21 pages, 21826 KiB

Open AccessArticle

A New Progressive EOFs Quality Control Method for Surface Pressure Data Based on the Barometric Height and Biweight Average Correction

by Peiting Liu, Zhifang Xu, Jiandong Gong and Wei Chen

Atmosphere 2023, 14(6), 1032; https://doi.org/10.3390/atmos14061032 - 15 Jun 2023

Viewed by 1145

Abstract

When assimilating surface pressure data in synoptic-scale models, we find the utilization rate of surface pressure data in zones with complex terrains is not high. Therefore, it is particularly important and urgent to carry out quality control of surface pressure data. Numerical weather [...] Read more.

When assimilating surface pressure data in synoptic-scale models, we find the utilization rate of surface pressure data in zones with complex terrains is not high. Therefore, it is particularly important and urgent to carry out quality control of surface pressure data. Numerical weather prediction model analysis and forecasting provide essential data that can be compared with surface observations. The main adverse effects on surface pressure quality control include elevation differences between the model terrain and the observation stations and continuous outliers with the same characteristics in the initiation stage of quality control. Therefore, we propose a progressive empirical orthogonal function (EOF) with simulated observation (EOFs) combining barometric height correction (BHC) and biweight average correction (BAC) methods for the quality control of surface pressure data in this study. From the quality control results of the surface pressure data in regions with complex topography in China during June–August 2013, it was found that the BHC method could effectively reduce the deviations caused by elevation differences between the model terrain and the observation stations, and the BAC method could obviously reduce systematic deviations due to physical processes and the parameterization schemes of the models. The BHC-BAC method integrated the advantages of both methods and had the best correction effect. When continuous outliers with the same characteristics occurred in the initiation stage of quality control, the progressive EOF method might unreasonably eliminate observations. However, the progressive EOFs method could effectively solve this problem and had better performance in data quality control. The progressive EOFs quality control method with the combined BHC-BAC method could obviously reject outliers. The observation increment (deviations between observations and background field) after quality control by the progressive EOFs method was the closest to normal distribution, satisfying the Gaussian distribution assumption of data assimilation. Full article

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

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19 pages, 3817 KiB

Open AccessArticle

Estimating Precipitation Using LSTM-Based Raindrop Spectrum in Guizhou

by Fuzeng Wang, Yaxi Cao, Qiusong Wang, Tong Zhang and Debin Su

Atmosphere 2023, 14(6), 1031; https://doi.org/10.3390/atmos14061031 - 15 Jun 2023

Cited by 3 | Viewed by 1433

Abstract

The change in raindrop spectrum characteristics is an important factor affecting the accuracy of estimations of precipitation. The in-depth study of raindrop spectrum characteristics is of great interest for understanding precipitation process and improving quantitative radar precipitation estimation. In this paper, the raindrop [...] Read more.

The change in raindrop spectrum characteristics is an important factor affecting the accuracy of estimations of precipitation. The in-depth study of raindrop spectrum characteristics is of great interest for understanding precipitation process and improving quantitative radar precipitation estimation. In this paper, the raindrop size distributions at Longli (57913), Puding (57808) and Luodian (57916) stations in Guizhou were analyzed from the perspective of precipitation microphysical characteristics. The results showed that the raindrop size distribution was different among different regions. The correlation coefficients of the mass-weighted average diameter for the rain intensities at these three stations were 46.89%, 49.51%, and 47.03%, respectively, which were slightly lower than the normal correlation coefficients of the average volume diameter for the rain intensities: 67.80%, 71.28%, and 71.46%, respectively. Based on the data from the Guiyang weather radar, raindrop spectrometer, and automatic rain gauge, the dynamic Z-I relationship method and the LSTM neural network method were used to estimate precipitation. The correlation coefficients of the dynamic Z-I relationship method and the LSTM neural network method at the three stations studied were 0.8432, 0.7763, and 0.8658 and 0.8745, 0.9125, and 0.8676, respectively. Regarding the process of stratiform cloud precipitation, the correlation coefficients of the dynamic Z-I relationship method and LSTM neural network method at the three stations were 0.6933, 0.0902, and 0.1409 and 0.7114, 0.4984, and 0.4902, respectively. In the estimation of cumulative precipitation for 45 days from 1 July to 16 August 2020, the relative errors of the neural network estimation at the three stations were −4.25%, −11.35%, and −8.68% and the relative errors of the dynamic Z-I relationship estimation were −2.68%, −7.41%, and −21.23%, respectively. The final relative error of the neural network was slightly worse than that of the dynamic Z-I relationship in the cumulative precipitation estimations of Longli station and Puding station, but the overall correlation coefficients of the LSTM neural network method were better than those of the dynamic Z-I relationship method. Full article

(This article belongs to the Special Issue Hydroclimate in a Changing World: Recent Trends, Current Progress and Future Directions)

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15 pages, 3268 KiB

Open AccessArticle

ENSO Forcing of Rainfall Erosivity in the Wuding River Basin

by Jing Zhao, Jiayang Zhao and Qiang Huang

Atmosphere 2023, 14(6), 1030; https://doi.org/10.3390/atmos14061030 - 15 Jun 2023

Viewed by 1291

Abstract

Rainfall erosivity (RE) is an important indicator of the ability of rainfall to cause soil erosion and is linked to ENSO through the transport of rainfall. Accurate assessment of RE and improved understanding of RE are essential for soil erosion prediction, optimization of [...] Read more.

Rainfall erosivity (RE) is an important indicator of the ability of rainfall to cause soil erosion and is linked to ENSO through the transport of rainfall. Accurate assessment of RE and improved understanding of RE are essential for soil erosion prediction, optimization of soil and water conservation measures, and ecological management and restoration. Therefore, the Wuding River Basin, a typical ecologically fragile area, is selected as the research area. The erosivity model based on daily rainfall was first used to calculate RE, and the temporal and periodic characteristics of RE are studied. Then the effects of the Southern Oscillation Index (SOI), the Surface Temperature of the Central East Equatorial Pacific Ocean (SST), and the Multivariate ENSO Index (MEI) on RE are explored by using cross wavelet technique. Results indicated that: (1) the concentration of rainfall leads to the largest RE values in summer compared with other seasons, accumulating about 69% of the annual RE; (2) The overall trend of increasing RE in the Wuding River basin is not significant, but shows an abrupt change in 2015; (3) the influence of the SOI and SST indices of ENSO events on RE is significant, which is shown to be a statistically significant correlation (95% confidence level), indicating that ENSO has a strong influence on the changing pattern of RE. These findings are helpful in predicting soil erosion and are significant for developing further erosion control measures. Full article

(This article belongs to the Section Meteorology)

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19 pages, 4547 KiB

Open AccessArticle

Characterization of Raindrop Size Distribution over Santa Clara Valley

by Nathan Quinn and Sen Chiao

Atmosphere 2023, 14(6), 1029; https://doi.org/10.3390/atmos14061029 - 15 Jun 2023

Viewed by 1320

Abstract

This study presents a year-long (January 2019–April 2020) analysis of the Z–R relationship and drop size distribution (DSD) scaling parameters for size, concentration, and shape of rain events over Santa Clara Valley, CA. External influences were analyzed based on synoptic variability and seasons. [...] Read more.

This study presents a year-long (January 2019–April 2020) analysis of the Z–R relationship and drop size distribution (DSD) scaling parameters for size, concentration, and shape of rain events over Santa Clara Valley, CA. External influences were analyzed based on synoptic variability and seasons. For the former, 850 hPa winds were separated into groups based on direction and magnitude. Results show that greater drop size, lower concentration, and larger shape parameters for spring, while winter and fall showed smaller drop sizes, higher concentrations, and smaller shape parameters. For synoptic variability, southeasterly-to-southwesterly flow was associated with larger drop sizes, larger concentrations, and smaller shape parameters relative to northwesterly flow. Differences in the DSD scaling parameter values and Z–R relationship were also observed between strong and weak low-level flow. The results of this study suggest that it is beneficial to derive specific microphysical relationships based on seasons and different synoptic events to improve radar rain rate retrieval algorithms using the Z–R relationship. Full article

(This article belongs to the Section Meteorology)

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12 pages, 671 KiB

Open AccessArticle

Tuning Monte Carlo Models to Reproduce Cosmic Radiation Interacting with the Earth’s Atmosphere

by Muhammad Ajaz, Abd Haj Ismail, Muhammad Waqas, Ramoona Shehzadi, Ishrat Asghar, Hannan Younis, Mateen Ullah Mian, Atef AbdelKader, Muhammad Adil Khan and Kashif Safeen

Atmosphere 2023, 14(6), 1028; https://doi.org/10.3390/atmos14061028 - 15 Jun 2023

Viewed by 1400

Abstract

In this work, we performed a comparative study between HIJING, Sibyll, and QGSJET model-based event generators. Such Monte Carlo (MC) models are used to simulate the interaction and propagation of high-energy cosmic radiation (e.g., coming from the sun) with the Earth’s atmosphere. The [...] Read more.

In this work, we performed a comparative study between HIJING, Sibyll, and QGSJET model-based event generators. Such Monte Carlo (MC) models are used to simulate the interaction and propagation of high-energy cosmic radiation (e.g., coming from the sun) with the Earth’s atmosphere. The global event observables selected for the study were the transverse momentum (

p_{T}

) spectra and rapidity density distributions of strange particles (

K_{S}^{0}

,

Λ

, and

Ξ^{-}

). This study was performed in the STAR and CMS fiducial phase spaces by simulating the strange particles in

p p

collisions at

\sqrt{s}

= 200 GeV, 900 GeV, and 7 TeV, and the simulations were then compared to the experimental measurements. It was observed that none of the discussed model-based event generators ultimately predicted the experimental results, except QGSJET, which generally agrees reasonably with the data. However, QGSJET does not produce

Ξ

particles; therefore, it does not provide any predictions for

Ξ

. The other two models reproduced the data only in a limited rapidity or transverse momentum region while mainly underpredicting the data in the rest of the areas. These cosmic radiation simulation models are capable of covering the mid-rapidity regions of density distributions. Utilizing model-based observations, some fundamental parameters can be re-tuned and extrapolations to the highest energies can be investigated. Furthermore, these observations can provide valuable insights that could potentially constrain and improve perturbative- and non-perturbative-based QCD event generators, thereby facilitating a better understanding of the underlying physics. Full article

(This article belongs to the Special Issue Solar Radiation: Measurements and Model Studies—Progress and Perspectives)

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24 pages, 4575 KiB

Open AccessArticle

Impact of Gaseous Pollutants Reduction on Fine Particulate Matter and Its Secondary Inorganic Aerosols in Beijing–Tianjin–Hebei Region

by Zhe Wei and Norhaslinda Mohamed Tahrin

Atmosphere 2023, 14(6), 1027; https://doi.org/10.3390/atmos14061027 - 15 Jun 2023

Cited by 3 | Viewed by 1523

Abstract

A reduction in gaseous pollutants is an important method for mitigating PM_2.5 concentration in the atmosphere, and the reduction in SO₂/NH₃/NO_x is beneficial to control secondary inorganic aerosols in PM_2.5. In this study, the Weather [...] Read more.

A reduction in gaseous pollutants is an important method for mitigating PM_2.5 concentration in the atmosphere, and the reduction in SO₂/NH₃/NO_x is beneficial to control secondary inorganic aerosols in PM_2.5. In this study, the Weather Research and Forecasting model with Chemistry model (WRF-Chem) was applied to study the impact on the PM_2.5 and its secondary inorganic aerosols using the scenario simulation method in the Beijing–Tianjin–Hebei (BTH) region. The results showed that the BTH region is characterized by being NH₃-rich and having a higher [NH₄⁺]/[SO₄²⁻] ratio in southern BTH, with a ratio of more than 6.0. Source contribution to PM_2.5 was highest in the 30%_SO₂_40%_NH₃_40%_NO_x scenario, with a contribution ratio of 6.8%, followed by 3.8% contribution in the 30%_SO₂_40%_NH₃ scenario, and a 3.4% contribution in the 30%_SO₂_60%_NH₃_60%_NO_x scenario. These results indicate that synergistic reduction measures may be suitable for controlling PM_2.5 concentrations. A lower sensitivity factor, β value between PM_2.5 and NH₃ suggests that solely reducing NH₃ emissions is not beneficial for the BTH region. However, this study indicates that the sensitivity of NO₃⁻ would improve significantly if NH₃ emissions are reduced sharply. A slight reduction in NH₃ was found to be beneficial for controlling NO₃⁻ in medium and small cities, while a significant decrease in NH₃ would be more suitable for mega-cities. The study also observed that SO₄²⁻ and its constituents continued to decrease with a consistent β value of approximately 0.14 in the 30%_SO₂_%_NH₃ scenario and between 10.5 and 12.8 in the 30%_SO₂_%_NH₃_%_NO_x scenario. These findings suggest that a synergistic reduction in SO₂-NH₃-NO_x emissions may be more effective in reducing PM_2.5 concentrations and its secondary inorganic aerosols (SIAs). However, it is important to ensure that the reduction in NH₃ and NO_x exceeds 60% in low SO₂ concentration conditions. Full article

(This article belongs to the Special Issue Statistical Methods in Atmospheric Research)

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18 pages, 7771 KiB

Open AccessArticle

Sensitivity of Vegetation Productivity to Extreme Droughts across the Yunnan Plateau, China

by Chen Lin, Yunling He and Zhenyan Wang

Atmosphere 2023, 14(6), 1026; https://doi.org/10.3390/atmos14061026 - 15 Jun 2023

Cited by 4 | Viewed by 1552

Abstract

Extreme drought has negative impacts on the health of vegetation and the stability of ecosystems. In this study, the CASA model was employed to estimate the net primary productivity of vegetation over the Yunnan Plateau. The time-lag effects on vegetation were observed within [...] Read more.

Extreme drought has negative impacts on the health of vegetation and the stability of ecosystems. In this study, the CASA model was employed to estimate the net primary productivity of vegetation over the Yunnan Plateau. The time-lag effects on vegetation were observed within a 0–6 month period of extreme droughts using the Pearson correlation coefficient. The resistance of vegetation during extreme droughts was quantified, and the recovery capability of vegetation following these events was analyzed using the ARIMA model. Moreover, the study investigated the response of vegetation to extreme droughts across diverse altitudinal gradients. The results showed that: (1) This round of extreme drought led to a decrease in the NPP of vegetation in the Yunnan Plateau. (2) Vegetation exhibits a 1–3-month lag period in response to extreme drought, with forests showing slower responses than grasslands and shrubs and higher resistance to the drought. Except for agricultural vegetation, most other vegetation types are able to recover their productivity within a year. (3) Vegetation above 3000 m is less susceptible to the impacts of extreme drought. With increasing elevation, forests exhibit an earlier lag period in response to extreme drought and an increase in resistance, but lower elevation vegetation demonstrates better recovery from extreme drought events. Shrub vegetation shows the highest resistance at elevations between 3000–4000 m, and shrubs at middle to high elevations have better recovery capacity than those at low elevations. Grassland vegetation exhibits increased resistance to extreme drought with higher elevation and shows better recovery. Agricultural vegetation demonstrates higher resistance at middle to high elevations, with no significant elevation differences in recovery capacity. Extreme drought events not only have a lag effect on the vegetation ecosystem, but also affect its stability and resilience to future drought events. To adapt to climate change, future research should emphasize the role of small-scale climate in vegetation’s response to drought. Full article

(This article belongs to the Section Climatology)

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19 pages, 9012 KiB

Open AccessArticle

Consideration of Altered Anthropogenic Behavior during the First Lockdown and Its Effects on Air Pollutants and Land Surface Temperature in European Cities

by Patricia Glocke, Benjamin Bechtel and Panagiotis Sismanidis

Atmosphere 2023, 14(6), 1025; https://doi.org/10.3390/atmos14061025 - 14 Jun 2023

Cited by 2 | Viewed by 1720

Abstract

Substantial reductions in human and economic activities such as road traffic for several months in 2020 were one of the consequences of the Coronavirus pandemic. This unprecedented change in urban metabolism also affected temperature and air pollutants. This study investigates the effects of [...] Read more.

Substantial reductions in human and economic activities such as road traffic for several months in 2020 were one of the consequences of the Coronavirus pandemic. This unprecedented change in urban metabolism also affected temperature and air pollutants. This study investigates the effects of the first COVID-19 lockdown across 43 cities in Europe. It determines the influence of anthropogenic activities on nitrogen dioxide (NO₂), ozone (O₃), and particulate matter (PM_2.5), as well as on land surface temperature (LST) and the surface urban heat island intensity (SUHII) using satellite, modeled, and mobility data. Our findings show that there are great temporal and spatial differences and distinct patterns between the cities regarding the magnitude of change in the variables under study. In general, the results indicate a substantial decrease in NO₂ concentrations in most of the studied cities compared with the reference period of 2015–2019. However, reductions could not be attributed to mobility changes such as less traffic at transit stations, contrary to the results of previous studies. O₃ levels increased during the first lockdown in accordance with the decreasing NO₂ concentrations. The PM pattern was inconsistent over time and space. Similar to the NO₂ results, no relation to the altered mobility behavior was found. No clear signal could be detected for LST and the SUHII, likely due to dominating meteorological influences. Full article

(This article belongs to the Special Issue Road Emission: Recent Trends, Current Progress and Future Direction)

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18 pages, 7361 KiB

Open AccessArticle

A Relationship between Changes of Surface Air and Sea Floor Temperatures at the Arctic Shelf from the Coupled Models Intercomparison Project, Phase 6 Data

by Valentina V. Malakhova and Alexey V. Eliseev

Atmosphere 2023, 14(6), 1024; https://doi.org/10.3390/atmos14061024 - 14 Jun 2023

Cited by 2 | Viewed by 1484

Abstract

The sensitivity of seafloor temperature

T_{B}

to the warming of surface air temperature

T_{a}

is examined for 1850–2300, based on simulations with five models from the Coupled Models Intercomparison Project phase 6 ensemble and driven by a scenario with high anthropogenic [...] Read more.

The sensitivity of seafloor temperature

T_{B}

to the warming of surface air temperature

T_{a}

is examined for 1850–2300, based on simulations with five models from the Coupled Models Intercomparison Project phase 6 ensemble and driven by a scenario with high anthropogenic emissions of greenhouse gases. In this historical period (until 2015), sensitivity coefficients

α = Δ T_{B} / Δ T_{a}

(

Δ

indicates changes relative to the pre-industrial period) were typically ≤0.12 for annual means and up to 0.43 in summer. However, during the same period in the Barents Sea sector, the sensitivity coefficients were as large as 0.6 in summer. For summer, the obtained results are consistent with the limited measurements available for the Siberian shelf. In future, sensitivity coefficients will increase markedly, and

α \geq 0.7

will become common for the part of the Arctic shelf that becomes ice-free in summer. Our results have implications for estimating the future thermal state of subsea sediments, as well as for oceanic biota. Full article

(This article belongs to the Special Issue The Ocean’s Role in Climate Change)

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