scholarly journals Insights into seasonal variation of wet deposition over southeast Asia via precipitation adjustment from the findings of MICS-Asia III

2021 ◽  
Vol 21 (11) ◽  
pp. 8709-8734
Author(s):  
Syuichi Itahashi ◽  
Baozhu Ge ◽  
Keiichi Sato ◽  
Zhe Wang ◽  
Junichi Kurokawa ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Southeast Asia ◽  
Wet Deposition ◽  
Precipitation Amount ◽  
Model Performance ◽  
The Philippines ◽  
Dry Season ◽  
Phase Iii ◽  
Satellite Measurements ◽  
Research Attention

Abstract. Asia has attracted research attention because it has the highest anthropogenic emissions in the world, and the Model Inter-Comparison Study for Asia (MICS-Asia) phase III was carried out to foster our understanding of the status of air quality over Asia. This study analyzed wet deposition in southeast Asian countries (Myanmar, Thailand, Lao People's Democratic Republic (PDR), Cambodia, Vietnam, the Philippines, Malaysia, and Indonesia) with the aim of providing insights into the seasonal variation of wet deposition. Southeast Asia was not fully considered in MICS-Asia phase II due to a lack of observational data; however, the analysis period of MICS-Asia III, namely the year 2010, is covered by ground observations of the Acid Deposition Monitoring Network in East Asia (EANET), and the coordinated simulation domain was extended to cover these observation sites. The analyzed species are wet depositions of S (sulfate aerosol, sulfur dioxide (SO2), and sulfuric acid (H2SO4)), N (nitrate aerosol, nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitric acid (HNO3)), and A (ammonium aerosol and ammonia (NH3)). The wet deposition simulated with seven models driven by a unified meteorological model in MICS-Asia III was used with the ensemble approach, which effectively modulates the differences in performance among models. By comparison with EANET observations, although the seven models generally captured the wet depositions of S, N, and A, there were difficulties capturing these in some cases. Considering the model performance for ambient aerosol concentrations over southeast Asia, this failure of models is considered to be related to the difficulty in capturing the precipitation in southeast Asia, especially during the dry and wet seasons. Generally, meteorological fields overestimate the precipitation during the dry season, which leads to the overestimation of wet deposition during this season. To overcome this, a precipitation-adjusted approach that scaled the modeled precipitation to the observed value was applied, and it was demonstrated that the model performance was improved. Satellite measurements were also used to adjust for precipitation data, which adequately accounted for the spatiotemporal precipitation patterns, especially in the dry season. As the statistical scores were mostly improved by this adjustment, the estimation of wet deposition with precipitation adjustment was considered to be superior. To utilize satellite measurements, the spatial distribution of wet deposition was revised. Based on this revision, it was found that Vietnam, Malaysia, and Indonesia were upward corrected, and Myanmar, Thailand, Lao PDR, Cambodia, and the Philippines were downward-corrected; these corrections were up to ±40 %. The improved accuracy of precipitation amount was key to estimating wet deposition in this study. These results suggest that the precipitation-adjusted approach has the potential to obtain accurate estimates of wet deposition through the fusion of models and observations.

scholarly journals Insights into seasonal variation of wet deposition over Southeast Asia via precipitation adjustment from the findings of MICS-Asia III

2020 ◽  
Author(s):  
Syuichi Itahashi ◽  
Baozhu Ge ◽  
Keiichi Sato ◽  
Zhe Wang ◽  
Junichi Kurokawa ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Southeast Asia ◽  
Wet Deposition ◽  
Precipitation Amount ◽  
Monitoring Network ◽  
The Philippines ◽  
Phase Iii ◽  
Satellite Measurements ◽  
Meteorological Model ◽  
Research Attention

Abstract. Asia has attracted research attention because it has the highest anthropogenic emissions in the world, and the Model Inter-Comparison Study for Asia (MICS-Asia) Phase III was carried out to foster our understanding on the status of air quality over Asia. This study analyzed wet deposition in Southeast Asian countries (Myanmar, Thailand, Lao People's Democratic Republic (PDR), Cambodia, Vietnam, the Philippines, Malaysia, and Indonesia) with the aim of providing insights into the seasonal variation of wet deposition. Southeast Asia was not fully considered in MICS-Asia Phase II due to a lack of observational data; however, the analysis period of MICS-Asia III, namely, the year 2010, is covered by ground observations of the Acid Deposition Monitoring Network in East Asia (EANET), and the coordinated simulation domain was extended to cover these observation sites. The analyzed species are wet depositions of S (sulfate aerosol, sulfur dioxide (SO2), and sulfuric acid (H2SO4)), N (nitrate aerosol, nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitric acid (HNO3)), and A (ammonium aerosol and ammonia (NH3)). The wet deposition simulated with seven models driven by unified meteorological model in MICS-Asia III was used with the ensemble approach, which effectively modulates the differences in performance among models. By comparison with EANET observations, although the seven models generally captured the wet depositions of S, N, and A, there were difficulties capturing these in some cases. This failure of models is considered to be related to the difficulty in capturing the precipitation in Southeast Asia, especially during the dry and wet seasons. To overcome this, a precipitation-adjusted approach which scaling the modeled precipitation to the observed value was applied, and it was demonstrated that the model performance was improved. Satellite measurements were also used to adjust for precipitation data, which worked well to account for spatio-and-temporal precipitation patterns, especially in the dry season. As the statistical scores were mostly improved by this adjustment, the estimation of wet deposition with precipitation adjustment was considered to be superior. To utilize satellite measurements, the spatial distribution of wet deposition was revised. Based on this revision, it was found that Vietnam, Malaysia, and Indonesia were upward-corrected and Myanmar, Thailand, Lao PDR, Cambodia, and the Philippines were downward-corrected; these corrections were up to ±40 %. The improved accuracy of precipitation amount was key to estimating wet deposition in this study. These results suggest that the precipitation-adjusted approach has the potential to obtain accurate estimates of wet deposition through the fusion of models and observations.

scholarly journals Investigation of global nitrate from the AeroCom Phase III experiment

2017 ◽  
Author(s):  
Huisheng Bian ◽  
Mian Chin ◽  
Didier A. Hauglustaine ◽  
Michael Schulz ◽  
Gunnar Myhre ◽  
...  
Keyword(s):  
Wet Deposition ◽  
Model Performance ◽  
Sea Salt ◽  
Phase Iii ◽  
Chemical Production ◽  
Magnitude Distribution ◽  
Ground Station ◽  
Vertical Distributions ◽  
Atmospheric Nitrate ◽  
Deposition Processes

Abstract. An assessment of global nitrate and ammonium aerosol based on simulations from nine models participating in the AeroCom Phase III study is presented. A budget analyses was conducted to understand the typical magnitude, distribution, and diversity of the aerosols and their precursors among the models. To gain confidence on model performance, the model results were evaluated with various observations globally, including ground station measurements over North America, Europe, and East Asia for tracer concentrations and dry and wet depositions, as well as with aircraft measurements in the Northern Hemisphere mid-high latitudes for tracer vertical distributions. Given the unique chemical and physical features of the nitrate occurrence, we further investigated the similarity and differentiation among the models by examining: (1) the pH-dependent NH3 wet deposition; (2) the nitrate formation via heterogeneous chemistry on the surface of dust and sea-salt particles; and (3) the nitrate coarse mode fraction (i.e., coarse/total). It is found that HNO3, which is simulated explicitly based on full O3–HOx–NOx–aerosol chemistry by all models, differs by up to a factor of 9 among the models in its global tropospheric burden. This partially contributes to a large difference in NO3−, whose atmospheric burden differs by up to a factor of 13. Analyses at the process level show that the large diversity in atmospheric burdens of NO3−, NH3, and NH4+ is also related to deposition processes. Wet deposition seems to be the dominant process in determining the diversity in NH3 and NH4+ lifetimes. It is critical to correctly account for contributions of heterogeneous chemical production of nitrate on dust and sea-salt, because this process overwhelmingly controls atmospheric nitrate production (typically > 80 %) and determines the coarse and fine mode distribution of nitrate aerosol.

scholarly journals Investigation of global particulate nitrate from the AeroCom phase III experiment

2017 ◽  
Vol 17 (21) ◽  
pp. 12911-12940 ◽  
Author(s):  
Huisheng Bian ◽  
Mian Chin ◽  
Didier A. Hauglustaine ◽  
Michael Schulz ◽  
Gunnar Myhre ◽  
...  
Keyword(s):  
Wet Deposition ◽  
Model Performance ◽  
Sea Salt ◽  
Phase Iii ◽  
Chemical Production ◽  
Magnitude Distribution ◽  
Budget Analysis ◽  
Vertical Distributions ◽  
Atmospheric Nitrate ◽  
Deposition Processes

Abstract. An assessment of global particulate nitrate and ammonium aerosol based on simulations from nine models participating in the Aerosol Comparisons between Observations and Models (AeroCom) phase III study is presented. A budget analysis was conducted to understand the typical magnitude, distribution, and diversity of the aerosols and their precursors among the models. To gain confidence regarding model performance, the model results were evaluated with various observations globally, including ground station measurements over North America, Europe, and east Asia for tracer concentrations and dry and wet depositions, as well as with aircraft measurements in the Northern Hemisphere mid-to-high latitudes for tracer vertical distributions. Given the unique chemical and physical features of the nitrate occurrence, we further investigated the similarity and differentiation among the models by examining (1) the pH-dependent NH3 wet deposition; (2) the nitrate formation via heterogeneous chemistry on the surface of dust and sea salt particles or thermodynamic equilibrium calculation including dust and sea salt ions; and (3) the nitrate coarse-mode fraction (i.e., coarse/total). It is found that HNO3, which is simulated explicitly based on full O3-HOx-NOx-aerosol chemistry by all models, differs by up to a factor of 9 among the models in its global tropospheric burden. This partially contributes to a large difference in NO3−, whose atmospheric burden differs by up to a factor of 13. The atmospheric burdens of NH3 and NH4+ differ by 17 and 4, respectively. Analyses at the process level show that the large diversity in atmospheric burdens of NO3−, NH3, and NH4+ is also related to deposition processes. Wet deposition seems to be the dominant process in determining the diversity in NH3 and NH4+ lifetimes. It is critical to correctly account for contributions of heterogeneous chemical production of nitrate on dust and sea salt, because this process overwhelmingly controls atmospheric nitrate production (typically > 80 %) and determines the coarse- and fine-mode distribution of nitrate aerosol.

New and little-known species of the genus Zhengitettix (Orthoptera: Tetrigidae: Scelimeninae) from Southeast Asia

2013 ◽  
Vol 22 (2) ◽  
pp. 204-223
Author(s):  
S.Yu. Storozhenko
Keyword(s):  
New Species ◽  
Southeast Asia ◽  
The Philippines ◽  
Check List ◽  
Key To Species ◽  
The Family

Seven new species of the genus Zhengitettix Liang, 1994 are described: Z. hosticus sp. nov., Z. mucronatus sp. nov. and Z. spinulentus sp. nov. from Vietnam; Z. albitarsus sp. nov. and Z. extraneus sp. nov. from Thailand; Z. palawanensis sp. nov. and Z. taytayensis sp. nov. from the Philippines. Two species, Z. curvispinus Liang, Jiang et Liu, 2007 and Z. obliquespicula Zheng et Jiang, 2005 are firstly recorded from Vietnam. An annotated check-list and key to species of the genus Zhengitettix are given. Position of Zhengitettix within the family Tetrigidae is briefly discussed.

scholarly journals Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

2021 ◽  
Author(s):  
Mayara P. Neves ◽  
Pavel Kratina ◽  
Rosilene L. Delariva ◽  
J. Iwan Jones ◽  
Clarice B. Fialho
Keyword(s):  
Seasonal Variation ◽  
Fish Species ◽  
Resource Availability ◽  
Seasonal Changes ◽  
Dry Season ◽  
Diet Overlap ◽  
Isotopic Niche ◽  
Neotropical Streams ◽  
Feeding Plasticity ◽  
The Impact

AbstractCoexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.

scholarly journals Seasonal Variation of Rainy and Dry Season Per Capita Water Consumption in Freetown City Sierra Leone

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 499
Author(s):  
Salmatta Ibrahim A ◽  
Fayyaz Ali Memon ◽  
David Butler
Keyword(s):  
Seasonal Variation ◽  
Water Use ◽  
Water Consumption ◽  
Low Income ◽  
Rainy Season ◽  
Predictor Variable ◽  
Dry Season ◽  
Data Set ◽  
Per Capita ◽  
End Use

Ensuring a sustainable urban water supply for developing/low-income countries requires an understanding of the factors affecting water consumption and technical evidence of individual consumption which can be used to design an improved water demand projection. This paper compared dry and rainy season water sources available for consumption and the end-use volume by each person in the different income groups. The study used a questionnaire survey to gather household data for a total of 398 households, which was analysed to develop the relationship between per capita water consumption characteristics: Socio-economic status, demographics, water use behaviour around indoor and outdoor water use activities. In the per capita water consumption patterns of Freetown, a seasonal variation was found: In the rainy season, per capita water consumption was found to be about 7% higher than the consumption for the full sample, whilst in the dry season, per capita water consumption was almost 14% lower than the full survey. The statistical analysis of the data shows that the average per capita water consumption for both households increases with income for informal slum-, low-, middle- and high-income households without piped connection (73, 78, 94 and 112 L/capita/day) and with connection (91, 97, 113 and 133 L/capita/day), respectively. The collected data have been used to develop 20 statistical models using the multiple linear stepwise regression method for selecting the best predictor variable from the data set. It can be seen from the values that the strongest significant relationships of per capita consumption are with the number of occupants (R = −0.728) in the household and time spent to fetch water for use (R = −0.711). Furthermore, the results reveal that the highest fraction of end use is showering (18%), then bathing (16%), followed by toilet use (14%). This is not in agreement with many developing countries where toilet use represents the largest component of indoor end use.

scholarly journals The Effect of the Characteristics and Activities of the Board of Directors on Sustainable Development Goal (SDG) Disclosures: Empirical Evidence from Southeast Asia

2021 ◽  
Vol 13 (14) ◽  
pp. 8007
Author(s):  
Lintang D. Sekarlangit ◽  
Ratna Wardhani
Keyword(s):  
Sustainable Development ◽  
Southeast Asia ◽  
Board Of Directors ◽  
Research Work ◽  
The Philippines ◽  
Public Companies ◽  
The Sustainable Development ◽  
The Board Of Directors ◽  
Development Goals ◽  
One Year

This study aimed to analyze the board of directors’ commitment to the Sustainable Development Goals (SDGs) by looking at the influence of the characteristics and activities of the board of directors and the existence of Corporate Social Responsibility (CSR) committees on disclosures regarding the SDGs. The directors’ characteristics that were analyzed in this research included the board size, the proportion of independent directors, the presence of female directors, and the presence of foreign directors. The activities analyzed included the number of board meetings held in one year and the percentage of directors in meetings. The context of this study was companies in five Southeast Asian countries—Indonesia, Malaysia, Singapore, Thailand, and the Philippines—during the 2016 and 2017 reporting years. This study was an initial research work aiming to empirically examine the effect of the board of directors on SDG disclosures in public companies from five countries in Southeast Asia. The study shows that the percentage of attendance of board directors’ meetings and the existence of CSR committees positively affected SDG disclosures. It also indicates that the presence of the board at the meeting can encourage more intensive SDG disclosures. Companies with a high commitment to sustainability, as shown by their forming of CSR committees, also tended to have a higher level of SDG disclosures.

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