Typhoon Rain Research Articles

Hysteresis analysis reveals how phytoplankton assemblage shifts with the nutrient dynamics during and between precipitation patterns

The escalation of global eutrophication has significantly increased due to the impact of climate change, particularly the increased frequency of extreme rainfall events. Predicting and managing eutrophication requires understanding the consequences of precipitation events on algal dynamics. Here, we assessed the influence of precipitation events throughout the year on nutrient and phytoplankton dynamics in a drinking water reservoir from January 2020 to January 2022. Four distinct precipitation patterns, namely early spring flood rain (THX), Plum rain (MY), Typhoon rain (TF), and Dry season (DS), were identified based on rainfall intensity, duration time, and cumulative rainfall. The study findings indicate that rainfall is the primary driver of algal dynamics by altering nutrient levels and TN:TP ratios during wet seasons, while water temperature becomes more critical during the Dry season. Combining precipitation characteristics with the lag periods between algal proliferation and rainfall occurrence is essential for accurately assessing the impact of rainfall on algal blooms. The highest algae proliferation occurred approximately 20 and 30 days after the peak rainfall during the MY and DS periods, respectively. This was influenced by the intensity and cumulative precipitation. The reservoir exhibited two distinct TN/TP ratio stages, with average values of 52 and 19, respectively. These stages were determined by various forms of nitrogen and phosphorus in rainfall-driven inflows and were associated with shifts from Bacillariophyta-dominated to Cyanophyta-dominated blooms during the MY and DS seasons. Our findings underscore the interconnected effects of nutrients, temperature, and hydrological conditions driven by diverse rainfall patterns in shaping algal dynamics. This study provides valuable insights into forecasting algal bloom risks in the context of climate change and developing sustainable strategies for lake or reservoir restoration.

Investigation of microplastics in urban rivers of Eastern China in summer: abundance, characteristics and ecological risk assessment.

Microplastics (MPs) are increasingly becoming recognized as worldwide environmental contaminants, exerting a substantial impact on the safety of city rivers. This study explored the abundance and characteristics of MPs in summer 2023, including June and August, representing plum rain and typhoon rain seasons. The Qinhuai River exhibits more spatial fluctuations in six sampling sites with average concentrations of 470 ± 119.56 items per L, and the abundance increases with the water flows in the river. Downstream had the highest MP abundance of 484 ± 121.34 items per L, which were positive with the concentration of suspended solids (SS). Transparent and green MPs were more even in the sampling sites, and the shapes of fragments were predominant in the summer. Interestingly, the proportion of fiber and small-sized (38-75 μm) microplastics was predominant in the plum rain seasons, while the percentage of large-sized (270-5000 μm) and polymers of PE occurred in the typhoon rain seasons. The index of hazard scores of plastic polymers (H) revealed that the studied river had a severe pollution level (IV), which was highly influenced by PVC and PC. Besides, the pollution load index PLI value of different rain seasons was slightly polluted (I), while the PLI in autumn rain seasons was relatively higher than that in other seasons due to the higher variance of MPs. Therefore, the ecological risk of microplastics of PVC and PC in the Qinhuai River during varying seasons should be seriously considered. Our research is expected to provide valuable assistance in improving the management of urban rivers.

Water environment response of urban water networks in the Pearl River Delta (China) under the influence of typhoon rain events

Abstract Identifying water quality parameter concentrations and their drivers is important for the prevention and control of water environment pollution. In this study, we constructed an inverse model of water quality parameters based on measured water quality parameters and remote sensing spectral data for this study area using artificial neural networks. We investigated the water environment response of the urban water network in the Pearl River Delta under the influence of typhoon rain events and explored their spatial heterogeneity using a multiscale geographically weighted regression model. The results indicate that in regions with a high level of urbanization, the dissolved oxygen (DO) concentration in river water is lower, and the ammonia nitrogen (NH3-N) concentration is higher. Under the influence of typhoon rain events of varying intensities, the response of water quality parameters in the urban water network of Zhongshan City varies. The intensity of rainfall determines the impact of typhoon rain events on water quality parameter concentrations. Our results are expected to improve the understanding of water quality trends under the influence of typhoon rain events and help policymakers and planners better develop water environment control strategies during typhoon transit.

Analyzing the response distribution of DO concentration and its environmental factors under the influence of typhoon rain events with remote sensing

Typhoon rain events are important factors that trigger changes in dissolved oxygen concentrations in watersheds. The direction of the typhoon driving force is clear, but the mode of action and mechanism are complex. Moreover, quantifying the relationship between these actions and dissolved oxygen is challenging. This study collected measured data from water quality monitoring and remote sensing during the 2022 typhoon rain events. By analyzing the changes in typhoon driving factors and dissolved oxygen (DO) concentrations in water under various typhoon storms, extended MOORA plus the full multiplicative form (MULTIMOORA), Multiscale Geographic Weighted Regression (MGWR), and spatial autocorrelation analysis were used to evaluate the response of DO concentration. Furthermore, the effects of the atmospheric environment under the influence of human activities on the response distribution of the urban water environment were analyzed. The results of the study showed that under the effect of a typhoon with higher rainfall intensity, the response of DO concentration in the water body of the river in the center of the city was better. However, the response of DO concentration in the water body at the mouth of the sea had a tendency to become worse. Under the influence of typhoon rain events with smaller intensity, the scouring effect of rainwater dominated, and the DO concentration response in the water body had a tendency to become worse. The analysis of spatial heterogeneity under the influence of human activities showed that the ranking values of DO concentration response in rivers in the city area of Zhongshan, under the influence of typhoon rain events, were positively correlated with the distribution of ozone (O3) concentration and sulfur dioxide (SO2) concentration in the eastern, central, and western parts of Zhongshan. Conversely, it was negatively correlated with the distribution of O3 concentration and SO2 concentration in the northern and southern parts of Zhongshan. Based on the research results, we constructed a technique to evaluate the response of dissolved oxygen concentration during the typhoon transit period, which can provide an indicator reference for urban managers in water environment management.

Dynamic Coupling Model of Water Environment of Urban Water Network in Pearl River Delta Driven by Typhoon Rain Events

Typhoon rain dominates meteorology-rainfall-runoff-environmental factor changes at the regional scale and regulates water resources in the river network area by means of multi-field coupled meteorological, hydrological, and geographic models, shaping complex water resources and water environment scenarios in the Pearl River Delta. Because of limitations in the monitoring capacity of the typhoon process, quantifying the ephemeral processes and spatial heterogeneity information of typhoon rain events is difficult, which makes the degree of research on typhoon rainfall-runoff transformation processes low and the progress in regional water resources and water environment evaluations based on typhoon events slow. In this study, typhoon rain event data, namely, remote-sensing spectra, measured water quality parameters, and meteorological factors, in the Pearl River Delta during 2022 were first collected. Next, a dynamic coupling model between typhoon rain events and the water network environment was established to simulate and predict the water environment conditions of the Zhongshan City water network controlled by the regulation of typhoon rain events. By inputting the quantitative data of the typhoon rain events, the water environment conditions of the river network in Zhongshan City after the typhoon rain events were simulated and output. The results showed that the distribution of dissolved oxygen concentrations and ammonia nitrogen concentrations were consistent: the concentration was highest in the central urban area, which is more urbanised than other areas, and it was lowest in the area far from the urban centre. Moreover, under the influence of Typhoon Ma-on, the water environment of the Zhongshan City water network changed over time: dissolved oxygen concentrations decreased and then increased, and ammonia nitrogen concentrations increased and then decreased. The water quality prediction model proposed in this study helps to improve the understanding of the dynamic impact of typhoon rain on the water quality of an urban water network in the Pearl River Delta and is conducive to improving the formulation of water environment control strategies during typhoon transit.

Combining soil macropore flow with formation mechanism to the development of shallow landslide warning threshold in South China

Because of the physical character of soil from granite weathering and the typhoon rains in South China, the model for early warnings of existing shallow landslides cannot be well applied in that area. This study developed a new shallow landslide model based on the effect of soil macropores for determining the rainfall threshold to post an early warning of the possibility of a shallow landslide in South China. We studied the hydrological effects of macropore flow and proposed a mechanistic model of the formation of shallow landslides by introducing the macropore coefficient of granite residual soil. The rainfall threshold of each slope unit was calculated by combining the hydrological model with the proposed shallow landslide model. Lastly, we tested the calculated result in the Maguihe watershed, Guangdong province, South China, which experienced a group of massive shallow landslides on 21 September 2010. The study results showed that the macropores of vegetation roots had a significant effect by increasing the permeability of granite residual soil. Coniferous forest land has the highest initial infiltration rate and stable infiltration rate, followed by shrub forest land, and then bare land. Statistical verification showed that the accurate prediction rate of the proposed model was 80.65%, which is adequate for early warning of shallow landslides in South China. We discuss the application conditions and parameter calibrations of the proposed model, and offer recommendations for future research.

A Statistical-Based Model for Typhoon Rain Hazard Assessment

Extreme typhoon rainfall can lead to damaging floods near the coastal region in mainland China. In the present study, we calibrate the parameters for a parametric hurricane rain model by using the precipitation radar (PR) data from the Tropical Rainfall Measuring Mission (TRMM) (i.e., PR-TRMM) and the TRMM microwave imager (TMI) data (i.e., TMI-TRMM). To show the applicability of the model for the tropical cyclone (TC) rain hazard assessment, we combine the developed rainfall intensity model with historical and synthetic TC tracks to estimate the T-year return period value of the accumulated rainfall in 24 h, QA24-T. We map QA24-100 for part of the coastal region in mainland China, showing that the spatial variation of QA24-100 is relatively smooth. It was found that the estimated QA24-100 using the model developed, based on the snapshots from PR-TRMM, is about 60% of that obtained using the model developed based on the snapshots from TMI-TRMM. This reflects the differences in the rainfall intensities reported in TMI-TRMM and PR-TRMM. As part of verification, we compare the estimated return period value to that obtained by using the record from surface meteorological stations at a few locations. The comparison indicates that, on average, QA24-100 based on gauge data is about 1.4 and 2.3 times that obtained using the model developed based on the snapshots from PR-TRMM and TRM-TRMM, respectively. This suggests that, for TC rain hazard estimation, one may consider the empirical scaling factor of 1.4 and 2.4 for the rainfall intensity models developed based on snapshots from PR-TRMM and TMI-TRMM, respectively.

Study on the construction of underground reservoirs on Zhoushan Island and related environmental issues based on the use of typhoon rain

Water resources in the island area vary greatly from year to year and are unevenly distributed within the year, especially during typhoon and rainstorm periods when the lack of reservoirs leads to a large loss of rainfall and flood resources. In order to improve the water resources supply capacity of the island, this paper takes the excavated underground reservoir on Zhoushan Island as the research object to solve the problem of abundant rainfall and flood resources but lack of saving space during the plum and typhoon floods, and to enhance the self-sufficiency of water resources on the island. The study focuses on three environmental issues in the construction of underground reservoirs, and analyses the actual effect of the resourceful use of rainwater floods using the actual measurement data of Typhoon 2106 (In fa) to prove the feasibility of the construction of underground reservoirs. It makes a useful exploration for the future planning and construction of underground reservoirs on Zhoushan Island using underground space resources to solve water shortage.

Applicability of Difference in Oxygen-18 and Deuterium of Water Sources and Isotopic Hydrograph Separation in a Bamboo Catchment during Different Rainfall Types

Typhoon storm and plum rain are two typical rainfall types in the lower regions of the Yangtze River Basin, which frequently cause flood disasters in China. New information in stable water isotopes offers the opportunity to advance understanding of runoff mechanisms and water source dynamics in response to these two typical rainfall types. We intensively monitored two representative rainfall events in a small bamboo forestry watershed in 2016. Results showed that precipitation isotopic variations during the event were generally larger than those of other monitored compartments (including throughfall, surface overland water, groundwater and river water) and also larger for the plum rain than for the typhoon event (δ18O varied in 5.2‰ and 3.7‰, respectively). Importantly, the differences of isotopic temporal variation between rainfall and throughfall showed significant impacts on the two-component hydrograph separation for both rainfall types (e.g., if not considered, the pre-event water fractions were 26.6% and 15.3% higher for the typhoon and plum rain events, respectively). Furthermore, we evaluated the role of soil water on the three-component isotopic hydrograph separation model; results revealed that soil water accounted for 10.9% and 28.3% of the total discharge in typhoon and plum rain events, respectively. This underpins the important role of soil water dynamics during the rainy season in this humid region.

Badland landscape response to individual geomorphic events

Landscapes form by the erosion and deposition of sediment, driven by tectonic and climatic forcing. The principal geomorphic processes of badland – landsliding, debris flow and runoff erosion – are similar to those in full scale mountain topography, but operate faster. Here, we show that in the badlands of SW Taiwan, individual rainfall events cause quantifiable landscape change, distinct for the type of rainfall. Typhoon rain reduced hillslope gradients, while lower-intensity precipitation either steepened or flattened the landscape, depending on its initial topography. The steep topography observed in our first survey is inconsistent with the effects of any of the rainfall events. We suggest that it is due to the 2016 Mw 6.4 Meinong earthquake. The observed pattern in the badlands was mirrored in the response of the Taiwan mountain topography to typhoon Morakot in 2009, confirming that badlands offer special opportunities to quantify natural landscape dynamics on observational time scales.

Water quality characteristics and health risk assessment of main water supply reservoirs in Taizhou City, East China

Taizhou is a typical coastal area in East China where drinking water is mainly supplied by reservoir water. The water quality of the reservoirs may be affected to some extent by human activities and climate. Therefore, the purpose of this study is to evaluate the water quality characteristics of the main water supply reservoirs in Taizhou City, Zhejiang Province, and to study the influence of the two rainy periods, the plum rains period and the typhoon rains period, on the water quality of the reservoirs using the entropy water quality index evaluation method. Total non-carcinogenic and carcinogenic health risks from different exposure pathways were assessed for people at different ages. It is found that the water quality of the main water supply reservoirs in Taizhou City is generally good and suitable for drinking, but the water quality of the reservoirs will deteriorate during the rainy seasons. Non-carcinogenic health risks are at acceptable levels for all age groups, but unacceptable high carcinogenic health risks are observed for both children and adults, which is mainly caused by As. Through this study, local decision-makers can be better informed for a better management of surface water resources in this area.

Engineering on the precipice: the performance of mountain road rehabilitation in the Central Cordillera of the Philippines

Parts of the Central Cordillera of Luzon are among the most challenging locations on Earth in which to build and maintain transport infrastructure, a situation perhaps most epitomized by the Halsema Highway. Since its original construction in the 1920s, the highway has undergone phased improvement and has become a socio-economic lifeline to the rural communities it serves. Unfortunately, in 1990, continuing road improvement works had to be abandoned owing to the outcome of a 7.8 M s earthquake and the effects of subsequent typhoon damage. Earthquake reinstatement works were designed in 1998 and constructed between 2001 and 2006. The engineering geological challenge this posed was compounded by the effects of severe typhoon rains during the reconstruction period, requiring continual assessment of changing slope and drainage conditions. Since construction, the road has been affected by several new typhoons including, most notably, Typhoons Pepeng and Ompong in 2009 and 2018 respectively. Field inspections in 2010 and 2018, combined with the interpretation of satellite imagery available in Google Earth, have allowed the performance of the works implemented between 2001 and 2006 to be assessed and the outcome has been largely favourable. Very little of the recorded damage has occurred in the locations of earthquake reinstatement. Instead, several new areas of slope failure and subsequent blockage and damage to the road have developed. Many of these areas can be explained with respect to their underlying engineering geology and geomorphology. However, there are just as many that owe their origin to the pattern of rainfall and runoff arising during the passage of individual and successive typhoons, modified significantly by drainage management practices in the road corridor, where engineering serviceability and land use practices sometimes have conflicting objectives.

Flood risk analysis in the Taihu Basin during flood periods based on Copula function

太湖流域位于长江入海口，地处中国沿海经济带和长江沿线内陆经济带的交汇处，是中国高度城镇化地区之一.流域汛期降水受到多重天气系统的影响，不同的天气系统带来时空分布各异的降水，给该地区城镇防洪排涝工作造成了巨大的挑战.本文基于Copula理论对太湖流域汛期洪涝风险进行研究，考虑了因降水主导因素不同所造成的流域洪涝风险的时空差异性.在时间角度，采用降水主导因素发生时间的概率分布，将汛期划分为梅汛期和台汛期；在空间角度，通过Copula函数，对研究区进行聚类划分；在此基础上，根据太湖流域防洪规划，对流域梅汛期和台汛期的洪涝风险进行分析.研究结果表明：①太湖流域的汛期划分为：6月24日-7月21日为梅汛期，7月22日-9月22日为台汛期；②根据各分区降水和太湖水位的联合分布函数拟合效果的优劣，在梅汛期，太湖流域被划分为P-Ⅰ区、P-Ⅱ区和P-Ⅲ区；在台汛期，整个流域的降水作为一个整体，不分区；③到2025年，太湖流域在梅汛期和台汛期出现排涝不利情境的风险概率分别为2.4%和1.1%.本文的研究方法可以为太湖流域设计暴雨的调整、洪水资源的利用以及防洪排涝实时调度的决策提供科学参考.;The Taihu Basin is located at the estuary of the Yangtze River, belonging to the intersection of China coastal economic belt and the inland economic belt along the Yangtze River. It is one of China's highly urbanized areas. Under the influence of continental polar air masses, maritime tropical air masses and tropical cyclones, the types of precipitation in the Taihu Basin are divided into plum rain and typhoon rain. Different weather systems lead to the different heterogeneous precipitation, which brings great challenges to flood management in the basin. Taking the spatial and temporal differences of flood risk caused by different weather systems into consideration, this paper analyzed the flood risk based on Copula theory. In terms of time, the probability distribution of the precipitation dominant factors was used to divide the flood period into the plum rain period and the typhoon period. In terms of space, we clustered the study areas in the plum rain period and the typhoon period respectively by the Archimedean copula function. Finally, the flood disaster risk during the plum rain period and the typhoon period was analyzed. The results indicate that the flood period of the Taihu Basin is divided into the plum rain period (June 24 to July 21) and the typhoon period (July 22 to September 22). According to the joint distribution of sub-region precipitation and the Taihu Lake water level, the Taihu Basin is divided into three sub-regions (P-Ⅰ sub-region, P-Ⅱ sub-region and P-Ⅲ sub-region) in the plum rain period, while the Taihu Basin as a whole for flood risk analysis in the typhoon period. In the future, the probability of the drainage adverse in the Taihu Basin during the plum rain periods and the typhoon period is 2.4% and 1.1%, respectively. It is of great significance for the Taihu Basin to adjust the schemes of design storm and utilize flood resource and make the decision of real-time scheduling for flood control and drainage.

Stable isotope ratios of typhoon rains in Fuzhou, Southeast China, during 2013–2017

Stable isotope ratios (δ2H and δ18O) in precipitation not only show a certain response to climate change at different time scales, but also have strong linkages to extreme weather events such as tropical cyclones (hurricanes/typhoons). Typhoon activity in the coastal region of Southeast China is quite intense, bringing huge amounts of moisture; thus, contributing to extreme rainfall in this region. The existing isotope data in Southeast China is available on a monthly or daily temporal resolution, which is inadequate to study 1–2-day-long typhoon rainfall events at a particular location. In this study, hourly rainfall δ2H and δ18O data are collected for eight typhoon events from 2013 to 2017 in Fuzhou, Southeast China. The total correlation between δ2H and δ18O is obtained as δ2H = 7.41 δ18O + 0.81 (R2 = 0.96, N = 220). All the eight typhoon events reveal a similar variability pattern in δ18O values which can be divided into three stages. More positive δ18O values occur in the first and third stages, while the second stage is dominated by most negative δ18O values, exhibiting an inverted U-shaped pattern. The positive δ18O values during the first and third stages are governed by re-evaporation. The precipitation during the second stage has distinctly lower δ18O values than the weighted average δ18O of summer precipitation in Fuzhou. Some of these values are slightly lower than those of the water vapor over the Pacific Ocean’s surface. No significant relationship is observed between precipitation δ18O and temperature as well as the amount of precipitation during the second stage. We hypothesize that the significant 18O-depletion is mainly caused by the ‘rain shield effect’, which refers to combination of large-scale convection, high condensation efficiency, and recycling of isotopically depleted vapor in rain shield areas leading to very negative δ18O values during typhoon system. These findings suggest the use of stable isotope ratios as important tracers of typhoon water.

Application of Stable Isotope Tracer to Study Runoff Generation during Different Types of Rainfall Events

The main purpose of this study is to explore the runoff generation mechanism and isotopic variation of precipitation during typhoon and plum rain events in the mountainous region mainly covered with bamboo in southeastern China. The isotopic value of precipitation in plum rain events is more depleted than that of precipitation in typhoon events and has a larger range of d-excess. Typhoon events are affected by frequent temperate and tropical cyclones, the ocean evaporationis expected to be very intenseand marine air parcels move very quickly. As for plum rain events, marine air parcel moves slowly due to the blocking effect of the cold front and air moisture evaporated from the continent plays a significant role in the isotope of precipitation depletion process. The difference of stable isotope values in various water sources allows the two-component hydrological separation to quantify the contribution of the event and pre-event water. The results indicate that the pre-event water accounts for at least 60% of the discharge and the difference in proportion of pre-event water between different types of rain events suggests that the initial state of watershed, rainfall intensity and macropore flow are major control factors of the runoff production mechanism.

Bacterial community composition in rainwater associated with synoptic weather in an area downwind of the Asian continent

Bacteria are abundant in atmospheric waters and can be disseminated by precipitation to the surface of the Earth, potentially influencing ecosystems, public health and climate. However, data on bacterial communities in rainwater, especially on the association with weather, are very limited. In this study, rainwater was collected at the coastal city Kumamoto, southwestern Japan, in 2015. The bacterial communities in fourteen samples were identified using 16S rRNA sequencing and compared according to the rain types at the synoptic scale, i.e., cyclones, Meiyu and non-Meiyu stationary fronts, and typhoons. Diverse bacterial communities were present in all four types of rainwater and were dominated by the phyla Proteobacteria (37%), Bacteroidetes (16%), Cyanobacteria (14%), Actinobacteria (9%), Acidobacteria (8%) and Firmicutes (5%). Approximately half of the phyla (16 out of 33) were common among the rain types. The operational taxonomic units (OTUs) common among the four types of rainwater represented the majority (averagely 74%) of the sequences, indicating the predominance of common bacterial OTUs regardless of rain type. On the other hand, the synoptic weather systems and the origins of air masses associated with the rain likely resulted in distinct bacterial communities. High fractions of bacterial soil indicator taxa signified the large contribution of bacteria from soils. Genera containing ice nucleation-active bacteria were identified in all samples except one typhoon rain sample. Marine bacterial taxa, e.g., Pseudoalteromonas, Synechococcus and Marinobacter, were detected in several samples, indicating the dispersal of marine bacteria via clouds and rainwater. Fecal indicator bacteria were also detected in all samples. Thus, the bacteria in the four types of rainwater were characterized by largely overlapping communities with some differences in community composition, indicating that rain is an efficient pathway for the dissemination of bacterial communities in nature and links continental, marine and island ecosystems.

Analysis of the Positive Effect from the Typhoon Saomai to the Hydrothermal Environment of Shanghai

Northwestern Pacific is the only ocean which has the most typhoon formation. The study of typhoon has far reaching significance today. Typhoon can relieve drought and make temperature drop substantially. Even we were suffering continuous high temperature in summer, the temperature would decrease immediately accompanied with typhoon. By using MODIS and weather station data to calculate the vegetation index, we analyze the drought characteristics of Shanghai during Saomai period, so that we can show the changes from the two aspects of the vegetation growth and the surface temperature. On the other hand, through the relative humidity data of Typhoon Saomai, we can find that the vegetation index and the relative humidity have been increased significantly. Typhoon rain also has its beneficial agricultural production side. It can lift the drought or ease the drought. It also provides abundant water resources for the growth of crops. In addition, the typhoon for the adjustment of the Earth’s heat, is contributed to maintain heat balance. Therefore, the typhoon to bring the changes in hydrothermal environment on the objective assessment of its impact and timely use of typhoon resources are of great significance.

Using Hydraulic Engineering Model Experiment to Study the Sediment Trapping Efficiency of Adjustable Check Dam

The construction of fully closed check dam (CD) is a conventional flood prevention mechanism implemented on rivers. Fully closed CDs trap large amounts of sediments in rivers to stabilize the river slopes and control erosion. However, fully closed CDs cannot selectively trap sediment and may easily overflow, causing them to losing their ability to mediate and hold sediments. Previous studies proposed the concept of “breathable CDs”. The researcher introduced metal slit dam (SD) that could be assembled and disassembled quickly and conveniently. Once a CD reaches maximum capacity, operators must ensure that the water channels of the dam are free from blockage. Moreover, they must inspect the internal accumulation conditions of the dam periodically or immediately following heavy typhoon rains. When necessary, either the sediment buildup in the upriver blockage must be cleared, or the transverse structure of the dam must be removed to allow fine particles to be discharged along with a moderate amount of water. These actions can free up the sediment-storing capacity of the dam for the next heavy typhoon rains. In addition, operators should also inspect the damages inflicted on the dam, such as erosion, wear and tear, and deformation conditions. Damaged components should be disassembled and repaired if possible, or recycled and reused. The present study performed channel tests to simulate closed CDs, SDs, steel pipe dam (SPDs), and steel pipe plus slit dam (SPSDs) for 50-year and 100-year frequency floods. Results were then analyzed to determine the sediment trapping (ST) effects of various CDs, the effects of “adjustable CDs”, and the changes of moderated riverbeds.

Importance of Oceanian small mountainous rivers (SMRs) in global land-to-ocean output of lignin and modern biospheric carbon.

The land-to-ocean export of particulate organic carbon (POC) connects carbon flow from the atmosphere through land to the ocean, of which the contemporary fraction that reaches the deep sea for burial may effectively affect atmospheric CO2. In this regard, small mountainous rivers (SMRs) in Oceania, a global erosion hotspot driven by torrential typhoon rain and active earthquakes are potentially important. Here we measured typhoon lignin discharges for Taiwan SMRs. We found that the particulate lignin export in 96 hours by a single SMR amounting to ~20% of the annual export by Mississippi River. The yearly particulate lignin discharge from Taiwan Island (35,980 km2) is governed by the frequency and magnitude of typhoon; thus, the historical lignin export ranged widely from 1.5 to 99.7 Gg yr−1, which resulted in a 10–100 times higher areal yield relative to non-Oceanian rivers. The lignin-derived modern POC output from Oceania region is 37 ± 21 Tg C yr−1, account for approximately 20% of the annual modern POC export from global rivers. Coupled with the hyperpycnal pathway, the forested watersheds of SMRs in Oceania may serve as a giant factory to rapidly produce and efficiently convey modern POC into deep sea for sequestration.

도로 침수영역의 탐색을 위한 빅데이터 분석 시스템 연구

The frequency of natural disasters because of global warming is gradually increasing, risks of flooding due to typhoon and torrential rain have also increased. Among these causes, the roads are flooded by suddenly torrential rain, and then vehicle and personal injury are happening. In this respect, because of the possibility that immersion of a road may occur in a second, it is necessary to study the rapid data collection and quick response system. Our research proposes a big data analysis system based on the collected information and a variety of system information collection methods for searching flooded road areas by torrential rains. The data related flooded roads are utilized the SNS data, meteorological data and the road link data, etc. And the big data analysis system is implemented the distributed processing system based on the Hadoop platform.