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 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 Comparison of modelled and monitored deposition fluxes of sulphur and nitrogen to ICP-forest sites in Europe

2006 ◽  
Vol 3 (3) ◽  
pp. 337-355 ◽  
Author(s):  
D. Simpson ◽  
H. Fagerli ◽  
S. Hellsten ◽  
J. C. Knulst ◽  
O. Westling
Keyword(s):  
Wet Deposition ◽  
Transport Model ◽  
Control Strategies ◽  
Precipitation Amount ◽  
Monitoring Network ◽  
N Deposition ◽  
Small Range ◽  
The European Union ◽  
Chemical Transport Model ◽  
Mean Values

Abstract. The EMEP MSC-W Eulerian chemical transport model, and its predictions of deposition of acidifying and eutrophying pollutants over Europe, play a key role in the development of emission control strategies for Europe. It is important that this model is tested against observational data. Here we compare the results of the EMEP model with measured data from 160 sites of the European Union/ICP Forest (Level II) monitoring network, for the years 1997 and 2000. This comparison comprises: (a) Precipitation amount, (b) Total deposition of SO2−4 to coniferous and deciduous forests, (c) Wet deposition of SO2−4, NO3− and NH4+ in open field sites, and (d) Concentrations of SO2−4, NO3− and NH4+ in precipitation. Concerning precipitation, the EMEP model and ICP network showed very similar overall levels (within 4% for 1997 and 11% for 2000). The correlation was, however, poor (r2=0.15–0.23). This can be attributed largely to the influence of a few outliers, combined with a small range of rainfall amounts for most points. Correlations between modelled and observed deposition values in this study were rather high (r2 values between 0.4–0.8 for most components and years), with mean values across all sites being within 30%. The EMEP model tends to give somewhat lower values for SO2−4, NO3− and NH4+ wet deposition to ICP, but differences in mean values were within 20% in 1997 and 30% in 2000. Modelled and observed concentrations of SO2−4, NO3− and NH4+ in precipitation are very similar on average (differences of 0–14%), with good correlation between modelled and observed data (r2=0.50–0.78). Differences between the EMEP model and ICP measurements are thought to arise from a mixture of problems with both the observations and model. However, the overall conclusion is that the EMEP model performs rather well in reproducing patterns of S and N deposition to European forests.

scholarly journals Model Inter-Comparison Study for Asia (MICS-Asia) phase III: multimodel comparison of reactive nitrogen deposition over China

2020 ◽  
Vol 20 (17) ◽  
pp. 10587-10610
Author(s):  
Baozhu Ge ◽  
Syuichi Itahashi ◽  
Keiichi Sato ◽  
Danhui Xu ◽  
Junhua Wang ◽  
...  
Keyword(s):  
Air Quality ◽  
Nitrogen Deposition ◽  
Acid Deposition ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Monitoring Network ◽  
Phase Iii ◽  
Reactive Nitrogen ◽  
Comparison Study ◽  
Deposition Monitoring

Abstract. Atmospheric nitrogen deposition in China has attracted public attention in recent years due to the increasing anthropogenic emission of reactive nitrogen (Nr) and its impacts on the terrestrial and aquatic ecosystems. However, limited long-term and multisite measurements have restrained the understanding of the mechanism of the Nr deposition and the chemical transport model (CTM) improvement. In this study, the performance of the simulated wet and dry deposition for different Nr species, i.e., particulate NO3- and NH4+, gaseous NOx, HNO3 and NH3 have been conducted using the framework of Model Inter-Comparison Study for Asia (MICS-Asia) phase III. A total of nine models, including five Weather Research and Forecasting models coupled with the Community Multiscale Air Quality (WRF-CMAQ) models, two self-developed regional models, a global model and a Regional Atmospheric Modeling System coupled with the Community Multiscale Air Quality (RAMS-CMAQ) model have been selected for the comparison. For wet deposition, observation data from 83 measurement sites from the East Asia Acid Deposition Monitoring Network (EANET), Chinese Ecosystem Research Network (CERN), China Agricultural University Deposition Network (CAUDN), National Acid Deposition Monitoring Network (NADMN) and Department of Ecological Environment (DEE) of China have been collected and normalized for comparison with model results. In general, most models show the consistent spatial and temporal variation of both oxidized N (Nox) and reduced N (Nrd) wet deposition in China, with the normalized mean error (NME) at around 50 %, which is lower than the value of 70 % based on EANET observation over Asia. Both the ratio of wet or dry deposition to the total inorganic N (TIN) deposition and the ratios of TIN to their emissions have shown consistent results with the Nationwide Nitrogen Deposition Monitoring Network (NNDMN) estimates. The performance of ensemble results (ENMs) was further assessed with satellite measurements. In different regions of China, the results show that the simulated Nox wet deposition was overestimated in northeastern China (NE) but underestimated in the south of China, namely southeastern (SE) and southwestern (SW) China, while the Nrd wet deposition was underestimated in all regions by all models. The deposition of Nox has larger uncertainties than the Nrd, especially in northern China (NC), indicating the chemical reaction process is one of the most important factors affecting the model performance. Compared to the critical load (CL) value, the Nr deposition in NC, SE and SW reached or exceeded reported CL values and resulted in serious ecological impacts. The control of Nrd in NC and SW and Nox in SE would be an effective mitigation measure for TIN deposition in these regions. The Nr deposition in the Tibetan Plateau (TP) with a high ratio of TIN ∕ emission (∼3.0), indicates a significant transmission from outside. Efforts to reduce these transmissions ought to be paramount due the climatic importance of the Tibetan region to the sensitive ecosystems throughout China.

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 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.

scholarly journals Weather forecast in north-western Greece: RISKMED warnings and verification of MM5 model

2010 ◽  
Vol 10 (2) ◽  
pp. 383-394 ◽  
Author(s):  
A. Bartzokas ◽  
V. Kotroni ◽  
K. Lagouvardos ◽  
C. J. Lolis ◽  
A. Gkikas ◽  
...  
Keyword(s):  
Air Temperature ◽  
Weather Forecasting ◽  
Precipitation Amount ◽  
Warning System ◽  
Weather Forecast ◽  
Early Morning ◽  
Meteorological Model ◽  
Adverse Weather ◽  
North Western ◽  
Western Greece

Abstract. The meteorological model MM5 is applied operationally for the area of north-western Greece for one-year period (1 June 2007–31 May 2008). The model output is used for daily weather forecasting over the area. An early warning system is developed, by dividing the study area in 16 sub-regions and defining specific thresholds for issuing alerts for adverse weather phenomena. The verification of the model is carried out by comparing the model results with observations from three automatic meteorological stations. For air temperature and wind speed, correlation coefficients and biases are calculated, revealing that there is a significant overestimation of the early morning air temperature. For precipitation amount, yes/no contingency tables are constructed for 4 specific thresholds and some categorical statistics are applied, showing that the prediction of precipitation in the area under study is generally satisfactory. Finally, the thunderstorm warnings issued by the system are verified against the observed lightning activity.

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