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HABITAT SUITABILITY MODELING FOR ORANGE (CITRUS) CULTIVATION WITH AN ORGANIC AGRICULTURE ORIENTATION UNDER THE IMPACT OF CLIMATE CHANGE IN PHU THO PROVINCE Nguyen Thi Huyen Trang(1), Pham Quang Hiep(1), Tran Dang Hung(1), Nguyen Thi Minh Hang(1), Le Phuong Ha(1), Dao Thi My Linh(1), Nguyen Van Ha(1), Nguyen Thi Kim Thanh(2) Received: 10 August 2026; Accepted: 21 September 2026 Abstract: Orange is a fruit crop of high economic value in the midland and mountainous region of Northern Viet Nam. In the context of climate change and the orientation toward organic agriculture, identifying areas suitable for orange cultivation is of major importance for sustainable production planning. This study applies the Random Forest (RF) algorithm within the biomod2 platform to assess and predict habitat suitability for orange cultivation in Phu Tho province under CMIP6 climate change scenarios. The dataset comprises 14 variables in three groups: climate (WorldClim 2), soil-terrain (SoilGrids, DEM), and anthropogenic factors reflecting production development conditions. The model was trained using RF (ntree = 200, mtry = 2), evaluated by 5-fold cross-validation, and combined into an ensemble model (EMwmean). Future climate data were derived from the MPI-ESM1-2-HR model under two scenarios, SSP2-4.5 and SSP3-7.0, for the periods 2021-2040 and 2041-2060. The results show that the model achieved high accuracy (AUC = 0.959; TSS = 0.886). Residential density, annual rainfall, and elevation were the factors with the greatest influence on habitat suitability. Under current conditions, 373,445.7 ha (39.89% of the natural area) were classified as suitable or highly suitable. Under the impact of climate change, the suitable area expands under both scenarios but to differing degrees: the expansion is larger and more stable under SSP2-4.5, whereas under SSP3-7.0 the gain is smaller in the early period (2021-2040) and the suitable area subsequently shifts toward higher-elevation areas. The findings provide a scientific basis for planning orange-growing areas oriented toward organic agriculture that are adapted to climate change. Keywords: Random Forest, habitat suitability, organic agriculture, CMIP6, Phu Tho. Download file: Here |
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VULNERABILITY ASSESSMENT OF HOUSEHOLDS TO NATURAL HAZARDS: A CASE STUDY OF AN ETHNIC COMMUNITY IN LAO CAI PROVINCE, VIET NAM Doan Minh Hoang(1), Nguyen Thi Hai(2*), Ta Thi Hoai(2), Received: 22 July 2026; Accepted: 24 August 2026 Abstract: This study presents an indicator-based assessment of household vulnerability to natural hazards among H’Mong communities in Lao Cai Province, Viet Nam. The assessment used the IPCC AR4 framework with three components: Exposure (E), Sensitivity (S), and Adaptive Capacity (AC), and a set of 19 indicators was used to assess the vulnerability. Household data were collected through in-depth and semi-structured interviews with 70 H’Mong households in 2026. Flash floods and landslides are the most frequently experienced hazards in the study area, with percentages of 67% and 80%, respectively. 100% of interviewed households rely on agriculture. Approximately 73% of households reported having no savings or access to credit and 68.5% lived in wooden, grade-IV (lowest-grade) houses. The calculated assessment results for E, S, and AC were 0.46, 0.57, and 0.44, respectively, resulting in an overall vulnerability index of 0.59. Financial limitations, inadequate housing, and weak institutional support were identified as the main constraints to household resilience. These findings provide evidence to support targeted disaster risk reduction and climate change adaptation policies for ethnic minority communities in mountainous regions. Keywords: Vulnerability, household vulnerability, indicator-based assessment, natural hazards, mountainous areas, Viet Nam. Download file: Here |
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DESIGNING VIET NAM’S CARBON MARKET FOR THE ENERGY SECTOR: INTERACTIONS AMONG THE CARBON PRICE, FREE ALLOCATION, AND NET ETS VALUE PASS-THROUGH INTO ELECTRICITY PRICES Nguyen Thanh Cong(1), Tran Thuc(2) Received: 7 August 2026; Accepted: 24 September 2026 Abstract: The design of an emissions trading system (ETS) for the energy sector depends jointly on the carbon price, the free allocation rate, and the extent to which the electricity sector’s net ETS value is reflected through the electricity-price channel. This study extends the static PEP-1-1 computable general equilibrium (CGE) model, calibrated to a 37-account Social Accounting Matrix (SAM) constructed for Viet Nam for 2019, by incorporating sectoral emissions accounting, free allocation, and an ETS accounting balance for a regulated electricity sector. A grid of 126 scenarios combines seven carbon prices (50,000-2,500,000 VND/tCO₂), three free-allocation rates (100%, 90%, and 80%), and six pass-through coefficients (0.1-1.0), with each scenario solved independently around the 2019 base equilibrium. Across the grid, real GDP falls by 0.0048%-5.3104%, the consumer price index (CPI) rises by 0.0058%-6.4877%, household consumption falls by 0.0077%-8.6294%, aggregate output falls by 0.4154%-10.6984%, and modelled emissions fall by 0.6793%-16.9257% relative to the baseline. The sensitivity results indicate a diminishing incremental emission response as the carbon price rises. In the specified local slices, reducing α from 100% to 80% produces larger changes in aggregate outcomes than varying θ from 0.1 to 1.0; because the parameters have different units and ranges, this comparison is not an absolute ranking of parameter importance. FIN_GAP_ELEC, which represents the share of the electricity sector’s net ETS value not reflected through the price channel, is zero when pass-through is complete (θ = 1) and ranges from -VND 48,447 billion to +VND 4,552 billion on the model’s accounting scale. It is not an observed corporate cash flow or government fiscal flow. The analysis is confined to the comparative-static grid; the three-period quasi-dynamic extension is excluded because it lacks a period-specific non-ETS baseline. The study does not identify an optimal policy configuration or make legal recommendations; the findings are conditional on the model’s data, structure, closure, and assumptions. Keywords: Carbon market, emissions trading system, free allocation, net ETS value, electricity-price pass-through, computable general equilibrium model. Download file: Here |
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SPATIAL CONSISTENCY QUALITY CONTROL OF DAILY SURFACE AIR TEMPERATURE OBSERVATIONS IN VIET NAM USING INVERSE DISTANCE WEIGHTING AND RANDOM FOREST Bui Thi Khanh Hoa, Do Thi Anh Huyen, Nguyen Vinh Thu, Nguyen Viet Hung Received: 18 August 2026; Accepted: 17 September 2026 Abstract: This study developed and evaluated a spatial consistency quality control (QC) method for daily surface air temperature observations from 186 SYNOP stations across Viet Nam during 1961-2023. The variables examined included daily mean (Tavg), minimum (Tmin), and maximum (Tmax) temperatures. The proposed framework combines inverse distance weighting (IDW) with a machine learning (ML) model. IDW serves as the baseline reference, whereas ML is employed to better capture nonlinear relationships associated with spatial location, elevation, seasonality, and climatic region. Final QC flags were derived from the combined outputs of both models, allowing alerts to be stratified into method-specific detections, concurrent detections by IDW and ML, and high-suspicion cases. The ML model consistently outperformed IDW for all three variables. Its mean absolute error was 0.47°C for Tavg, 0.59°C for Tmin, and 0.73°C for Tmax, compared with 0.58°C, 0.74°C, and 1.00°C, respectively, for IDW. Under the IDW-ML framework, 98.87-99.10% of the evaluated observations were classified as good quality, while alert rates ranged from 0.90% to 1.13% and high-suspicion cases accounted for only 0.05-0.13%. Approximately one-third of all alerts were detected concurrently by both methods, thereby narrowing the subset of stations requiring priority manual review. These findings demonstrate that the combined IDW-ML approach provides an effective framework for spatial QC of daily temperature observations, particularly in networks characterized by complex terrain, uneven station distribution, and island stations, as in Viet Nam. Keywords: Quality control (QC), spatial consistency checking (SCC), Viet Nam, inverse distance weighting (IDW), machine learning (ML). Download file: Here |
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IOT-ENABLED HYDROMETEOROLOGICAL MONITORING NETWORKS: ARCHITECTURE, PERFORMANCE ASSESSMENT AND IMPLEMENTATION CHALLENGES IN VIET NAM Le Ngoc Quyen(1), Pham Ho Quoc Tuan(2), Doan Thi Truc Man(2), Received: 18 May 2026; Accepted: 16 July 2026 Abstract: Climate change, the rising frequency and intensity of extreme weather events, and sustainable development imperatives have created an urgent need to modernize meteorological and hydrological (MH) monitoring systems. Traditional monitoring networks in Viet Nam and many developing countries still face constraints in station density, data transmission latency, scalability, and operational costs. The Internet of Things (IoT) has emerged as a breakthrough solution owing to its ability to connect distributed sensors, enable real-time data processing, and integrate artificial intelligence. This paper investigates the application of IoT in MH monitoring networks, focusing on system architecture analysis, technical performance evaluation, and identification of implementation challenges within the context of implementing Resolution 57-NQ/TW of the Party Central Committee on breakthroughs in science, technology, innovation, and national digital transformation. The study employs a systematic literature review and network simulation based on empirical data from pilot stations in Viet Nam. The results propose an optimized layered IoT architecture for MH monitoring, integrating multi-parameter sensors, LPWAN communication protocols (LoRaWAN/NB-IoT), edge computing, and cloud platforms supporting digital twin modeling. The study also identifies challenges related to protocol standardization, data security, operational sustainability in remote areas, inter-sectoral data sharing mechanisms, and digital workforce capacity. The paper concludes that integrating IoT into MH monitoring networks is not merely a technical upgrade but a strategic driver for implementing Resolution 57-NQ/TW, promoting digital transformation in the natural resources and environment sector, and enhancing forecasting capacity, early warning systems, and climate change adaptation decision-making. Key policy, technical, and institutional recommendations are proposed to guide synchronized, secure, and sustainable implementation in Viet Nam. Keywords: Internet of Things (IoT), meteorological and hydrological monitoring, system architecture, network performance, edge computing, digital transformation, Resolution 57-NQ/TW, data quality, LoRaWAN, SensorThings API. Download file: Here |
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QUANTIFYING NATURALIZED STREAMFLOW ENTERING VIET NAM FROM THE UPPER RED RIVER BASIN USING THE VIC-3L MODEL Dang Tran Duc Minh(1), Nguyen Tien Giang(1), Khuong Van Hai(2*), Do Thi Ngoc Bich(3)(1)Faculty of Meteorology, Hydrology and Oceanography; VNU University of Science Received: 22 June 2026; Accepted: 24 July 2026 Abstract: The Red River Basin is an important transboundary river system, with the upstream area in China contributing substantially to water resources in Viet Nam. However, quantifying natural transboundary inflows remains challenging because of limited observations and increasing human impacts on water resources. This study applied the VIC-3L model to reconstruct naturalized streamflow in the main tributaries of the Red River Basin flowing into Viet Nam during 1981-2020. The model was calibrated and validated at the Muong Lay, Lao Cai, Dao Duc, and Bac Me stations using the SCE-UA optimization algorithm. Results show that the model accurately reproduced monthly streamflow, with Nash-Sutcliffe efficiency (NSE) values ranging from 0.91 to 0.95. Total annual runoff from the three upstream catchments in China (the Yuanjiang, Lixian, and Panlong rivers) decreased from 53.67 km³ during 1981-2004 to 48.14 km³ during 2005-2020, representing a decline of approximately 10.3%. At Lao Cai station, the naturalized streamflow was 19.62 km³/year, whereas the observed streamflow was only 13.07 km³/year, indicating a difference of about 6.55 km³/year. The larger reduction in observed streamflow compared with naturalized streamflow suggests that, in addition to reduced precipitation, upstream reservoir regulation, inter-basin water diversion, and water usage may have contributed to changes in streamflow entering Viet Nam. The study demonstrates the applicability of the VIC-3L model for reconstructing naturalized streamflow and assessing transboundary water resources, providing a scientific basis for sustainable water resources management in the Red River Basin. Keywords: VIC-3L, Red River basin, naturalized streamflow, transboundary water resources, streamflow variation. Download file: Here |
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APPLICATION OF MULTI-CRITERIA DECISION-MAKING (MCDM) TO SUPPORT EFFECTIVE FLOOD-SEASON OPERATION OF THE MULTI-RESERVOIR SYSTEM IN THE MA RIVER BASIN Nguyen Thi My Linh(1), Tran Duc Thien(1), Le Trung Kien(2), Trinh Nhu Trang(1) Received: 3 August 2026; Accepted: 14 September 2026 Abstract: Flood-season operation of multi-reservoir systems requires the simultaneous consideration of multiple objectives, including dam safety, downstream flood mitigation, carryover storage for the dry season, and hydropower generation. This study integrates HEC-ResSim simulation with the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) to compare five operational alternatives for the Ma River Basin during the period from 1 July to 30 November 2025. The alternatives were developed by reducing the maximum pre-flood water levels at the Hua Na, Cua Dat, and Trung Son reservoirs by 0-2.0 m and were evaluated using nine quantitative criteria under eight weighting schemes representing different management priorities. The results show that the alternative involving a 2.0 m reduction in the maximum pre-flood water level provides the greatest downstream flood-mitigation effectiveness, but at the expense of reduced carryover storage for the dry season and hydropower generation. In contrast, the 0.5 m reduction alternative provides a relatively stable compromise and is more suitable when a balance among operational objectives is required. Overall, integrating MCDM with reservoir-operation simulation enables the trade-offs among competing objectives to be quantified, thereby directly supporting context-specific operational decision-making rather than prescribing a single fixed operating rule. Keywords: MCDM, TOPSIS, Ma River Basin, multi-reservoir system operation. Download file: Here |
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DERIVING SHORT-DURATION DESIGN RAINFALL FROM DAILY RAINFALL FOR URBAN DRAINAGE ASSESSMENT IN A DATA-SCARCE AREA Nguyen Thao Hien, Pham Thanh Long, Nguyen Van Hong, Chau Thanh Hai Received: 10 July 2026; Accepted: 23 September 2026 Abstract: Upgrading and improving urban drainage systems to prevent and mitigate urban flooding under the impacts of climate change and urbanization has become an urgent priority. The design of drainage systems should be based on appropriate design standards. Accordingly, this study develops design rainfall hyetographs based on intensity-duration-frequency (IDF) curves and the Alternating Block Method (ABM), combined with the Storm Water Management Model (EPA-SWMM), to assess the drainage capacity of an urban catchment. While typical urban areas generally have sufficient rainfall monitoring stations providing short-duration rainfall observations for drainage system design, newly developed urban areas often lack such data. Therefore, this study focuses on analyzing the correlation between daily and short-duration rainfall, using Tan Son Hoa (TSH) station as the reference station and Xi Mang Ha Tien (XMHT) station as the representative station for the data-scarce Thu Duc Canal catchment. The results show a strong correlation in maximum daily rainfall between the two stations, with R2=0.996, while the relationships between daily and short-duration rainfall exhibit R2 values ranging from 0.9047 to 0.9813, all of which are statistically significant at the 5% significance level. Based on the regression equations between ZdayP and ZdurationP, IDF curves and design rainfall hyetographs were developed for return periods of N=2-50 years, using a peak position coefficient of r=0.45. The subsequent EPA-SWMM simulations provide a preliminary assessment indicating that the drainage capacity of the Thu Duc Canal catchment is limited, with several drainage pipes and manholes exceeding their design capacity thresholds in areas including Kha Van Can Street, Vo Van Ngan Street, and the Thu Duc Post Office area. Keywords: Maximum daily rainfall, Short-duration rainfall, Rainfall correlation, Design rainfall, IDF. Download file: Here |
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ASSESSING THE PERFORMANCE OF THE COUPLED SCHISM-WWM MODEL IN TOTAL WATER LEVEL FORECASTING ALONG THE THANH HOA – NGHE AN COAST IN 2025 Pham Van Tien, Le Quoc Huy, Phung Dang Hieu, Dang Minh Hoang, Nguyen Hong Hanh, Nguyen Thi Lan, Nguyen Van Khanh Received: 18 August 2026; Accepted: 24 September 2026 Abstract: The open-source SCHISM model, with its advantages of a high-performance numerical solver and unstructured-grid framework, provides an effective tool for simulating complex hydrodynamic processes in estuarine and coastal areas. In 2025, SCHISM was applied for the first time in Viet Nam to experimentally forecast total water levels along the coast. This study evaluates the results of 24 independent forecast cycles during two strong typhoons, Kajiki (August 2025) and Bualoi (September 2025), using observed water-level data from Hon Dau, Sam Son, Hon Ngu, Quang Chau, and Cua Hoi stations. The results show that the model achieved relatively good forecasting performance, with Skill values ranging from 0.72 to 0.97. Most forecasts satisfy the QCVN 84 quality requirements, with total-water-level errors below 20%; the exception is the 30-hour lead-time forecast during Typhoon Kajiki (August 2025), for which errors at Hon Ngu and Cua Hoi exceed 40%. The study also indicates that total-water-level forecast performance along the Thanh Hoa-Nghe An coast is strongly affected by variations in forecast meteorological forcing. The spatial distribution of maximum total water level in the coastal zone is closely related to storm structure, particularly the distribution of strong winds within the typhoon. Keywords: Total water level forecasting, storm surge, forecast lead time, meteorological forcing, coupled SCHISM model. Download file: Here |
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EVALUATION OF NEAR-SURFACE POTENTIAL TEMPERATURE (GLORYS12V1) AGAINST IN SITU OBSERVATIONS IN THE VIET NAM EAST SEA Tran Thi My Hong(1), Le Duc Quyen(2) Received: 7 July 2026; Accepted: 21 September 2026 Abstract: This study evaluates the performance of the GLORYS12V1 ocean reanalysis data against in situ near-surface seawater temperature observations at eight hydrographic stations in Vietnamese coastal and offshore waters during 2003-2022. The evaluated GLORYS12V1 field is seawater potential temperature at the uppermost standard level, approximately 0.494 m depth. Monthly matched observation-reanalysis pairs were assessed using the Pearson correlation coefficient, Nash-Sutcliffe efficiency coefficient, mean absolute error, mean bias, and root-mean-square error. The analysis also examined characteristic monthly and annual mean temperature values, trends during 2003-2022, and ENSO-stratified deseasonalized anomaly errors. The results indicate that GLORYS12V1 reproduced the observed monthly temperature variability and seasonal cycle reasonably well at the eight evaluated stations, with correlation coefficients ranging from 0.869 to 0.984 and NSE values from 0.738 to 0.954. Performance varied among stations, with larger absolute errors at some Northern and North-central coastal stations and generally smaller errors at Southern and offshore stations. The regional annual mean near-surface temperature fields showed a persistent North-South thermal contrast and an increasing tendency during 2003-2022. ENSO-stratified analysis indicated differences in deseasonalized anomaly errors among La Niña, neutral, and El Niño conditions. Overall, the results provide a station-based assessment of GLORYS12V1 uppermost-level seawater potential temperature and support its use as a near-surface SST proxy at the evaluated locations, while highlighting the need for caution in coastal areas with strong seasonal and local variability. Keywords: Sea surface temperature, hydrographic stations, Viet Nam East Sea, GLORYS12V1, ENSO. Download file: Here |
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SURFACE-WATER-QUALITY DYNAMICS IN THE MEKONG DELTA UNDER POLLUTION PRESSURES AND ALTERED FLOW REGIMES Vu Thi Hoai Thu(1,2*) Received: 11 May 2026; Accepted: 16 June 2026 Abstract: Surface-water quality in the Vietnamese Mekong Delta is deteriorating under combined pollution pressures and altered hydrological conditions. This study synthesizes 2016-2024 monitoring records, a 3,117-sample water-quality database, supplementary surveys conducted in 2022-2024, source-apportionment outputs, and hydrodynamic-salinity-morphological evidence to clarify how pollution loads and changes in assimilative capacity jointly shape water quality index (WQI) dynamics. WQI ranges from 2.376 to 85.314, with a regional mean of 47.486, indicating widespread fair-to-poor conditions in coastal, peri-urban, aquaculture-intensive, and poorly flushed canal areas. Principal component analysis (PCA), factor analysis (FA), and agglomerative hierarchical clustering (AHC) identify five pollution components: organic wastewater, agricultural runoff and pesticides, microbial contamination associated with Zn/Cu, salinity-related mobilization of As and Cr, and combined nutrient-microbial pollution. Source apportionment shows domestic/industrial dominance in urban and estuarine corridors, while agriculture and aquaculture are more influential in inner-delta and coastal settings. The main scientific contribution is an integrated mechanism showing that altered flow regimes do not generate pollutants directly but reduce dilution, increase residence time, deepen salinity intrusion, and lower assimilative capacity, thereby amplifying water-quality decline. Keywords: Surface water quality, Mekong Delta, pollution sources, altered flow, salinity intrusion. Download file: Here |
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HYDROCHEMICAL AND STABLE-ISOTOPE SIGNATURES OF GROUNDWATER IN THE VietNamESE MEKONG DELTA: AQUIFER-SCALE DIFFERENTIATION, UNCERTAINTY AND MANAGEMENT ORIENTATIONS Le Van Tien Hung(¹), Trieu Anh Ngoc(¹), Vu Thi Hoai Thu(²*) Received: 17 May 2026; Accepted: 24 June 2026 Abstract: Groundwater is a strategic water source in the Vietnamese Mekong Delta (VMD), especially during dry-season drought and salinity intrusion. The delta, however, is a multilayered aquifer system rather than a homogeneous groundwater reservoir. The working dataset was compiled from the national project DTDL.CN-54/22 and related hydrogeological records; it includes precipitation, surface-water and groundwater samples collected during 2023-2025 and earlier monitoring records where explicitly stated. After quality screening, the groundwater dataset used for isotope-hydrochemical interpretation comprises 132 stable-isotope records, 132 hydrochemical records, 65 ³H records and 44 paired ¹⁴C/¹³C records, classified by aquifer and checked against well metadata. Stable isotopes were reported relative to VSMOW; repeated laser analyses were accepted only when the standard deviation of the final injections was below 0.05‰ for δ¹⁸O and 0.5‰ for δ²H. The local meteoric water line is δ²H = 6.80δ¹⁸O + 2.23, whereas the optimal regional groundwater line is δ²H = 4.92δ¹⁸O – 13.46 (R² = 0.85; RMSE = 0.34; AICc = -299.69). The lower groundwater slope is interpreted cautiously as the combined result of pre-recharge evaporation, mixed recharge histories, paleo-brackish/saline components, diffusion and water-sediment interaction, rather than as a single diagnostic mechanism. Hydrochemical facies, Cl⁻, EC/TDS, Na⁺/Cl⁻, Cl⁻/Br⁻ and HCO₃⁻ were used as independent checks on the isotope interpretation. The results demonstrate aquifer-scale differentiation: the Holocene aquifer (qh) is surface-sensitive and affected by modern recharge; the Upper Pleistocene (qp₃), Middle-Upper Pleistocene (qp₂₋₃) and Lower Pleistocene (qp₁) aquifers form a transitional domain; the Upper/Middle Pliocene (n₂²) and Lower Pliocene (n₂¹) aquifers preserve stronger paleo-salinity and older-water signals; and the Upper Miocene aquifer (n₁³) behaves as a deeper strategic reserve. These findings support aquifer-specific monitoring, controlled deep pumping and adaptive groundwater management under climate-change stress. Keywords: Groundwater, stable isotopes, hydrochemistry, Vietnamese Mekong Delta, uncertainty, salinization. Download file: Here |
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ASSESSMENT OF BEACH PLASTIC WASTE POLLUTION USING THE CLEAN COAST INDEX: EVIDENCE FROM THANH HOA PROVINCE, VIET NAM Vu Dinh Hieu(1), Nguyen Thi Thuy (1), Nghiem Van Tuan(2), Nguyen Cao Van(1) Received: 5 August 2026; Accepted: 25 September 2026 Abstract: Marine plastic pollution is an increasingly important environmental and socio-economic challenge for coastal provinces of Viet Nam. Thanh Hoa Province represents a typical coastal setting of the North Central Coast of Viet Nam, where diverse coastal activities, including tourism, industry, capture fisheries and aquaculture, coexist with major river systems such as the Ma, Len and Chu rivers. The presence of these river systems, together with diverse coastal activities and geomorphological settings, contributes to substantial spatial variation in beach litter accumulation. A preliminary assessment using a litter transport model identified three major areas of litter accumulation in Sam Son, Hau Loc and Nghi Son which were subsequently selected for detailed field investigation. This study assesses visible beach litter (>5 mm) across 22 transects in Sam Son, Hau Loc and Nghi Son, Thanh Hoa Province, using material classification and the Clean Coast Index (CCI). Four sampling cells per transect in each of two campaigns yield 176 cell observations (22 × 4 × 2). The national project report dates its winter field campaign to 21 October 2021-13 February 2022 and its later beach campaign to 31 March-23 July 2024; according to the authors, COVID-19 disrupted the planned sampling sequence. The source manuscript reports 15,649 debris items (0.560 items/m²) and 235.69 kg (0.008 kg/m²), of which plastics account for 61.97% of items and 67.51% of mass. Reported area-by-campaign plastic densities range from 0.139 to 1.390 items/m². The project gives also reports an overall CCI of 11.2, with a separate CCI value of 6.9 for plastic litter across the three survey locations; this value cannot be reproduced from the published density summaries and is retained as a source-reported value pending cell-level reconciliation. Hau Loc had the highest reported area-level CCI in both survey campaigns, with values of 27.83 in Season 1 and 15.06 in Season 2. The comparison describes conditions during two seasonal windows in different years and does not isolate a causal monsoon effect. Keywords: Beach litter, Clean Coast Index, plastic pollution, coastal monitoring, Viet Nam. Download file: Here |
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