Baiu Research Articles

Cooling dehumidification characteristics of two cooling systems applied in natural light plant factory in the rainy summer

In summer, it is easy to cause the plant to die in the natural light plant factory due to high temperature and high humidity. It is studied for the cooling dehumidification characteristics among various ways of cooling and dehumidification - water Energy- saving groundwater source heat pump cooling air treatment unit (ATU), wet curtain fan, mechanical ventilation, etc. in the semi-enclosed natural light plant factory in typical plum rain weather. The results show that, during the rainy season, the external environment is relatively low temperature. On a typical day, the average temperature is 28.10°C from 9:15 to 17:00 in daytime in the natural light plant factory with only mechanical ventilation. The indoor temperature is 31.1°C, and the average relative humidity is 81.61%, which can meet the needs of suitable temperature and humidity for cultivated crops. Compared with the normal opening of ATU, only the A area can save the operating cost of 337.34 yuan per day. Between 0:00 and 6:40 in the morning and 20:40 to 24:00 in the evening, the average relative humidity of the natural light plant with both mechanical and natural ventilation is 87.03%. Only mechanical ventilation is opened, and the relative humidity is 95.44%. Therefore, natural ventilation should be strengthened from night to next morning.

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.

Changes in the summer extreme precipitation in the Jianghuai plum rain area and their relationship with the intensity anomalies of the south Asian high

Based on the daily precipitation data of 66 stations in the Jianghuai plum rain area from 1960 to 2014 and the concurrent reanalysis data of NCEP/NCAR, this study utilized several techniques, including trend analysis, empirical orthogonal function (EOF) analysis and composite analysis, to investigate the spatio-temporal changes of the summer extreme precipitation in the area and their relationship with the intensity anomalies of the south Asian high (SAH). The main results are as follows: (1) The first eigenvector of the summer extreme precipitation indices (EPIs) of PQ90 and PNL90 exhibits a distribution pattern of uniform “+”, and the first principal component (PC1) shows a significant increasing trend. The second eigenvector generally exhibits a dipole pattern of “south +, north –”, and the second principal component (PC2) of PQ90 shows a significant increasing trend. (2) The intensity index of the summer SAH (SAHI) underwent an abrupt change around 1977, with a subsequent increasing trend. The SAHI depicts a significant positive correlation with PC1 of PNL90 and PQ90, thus the EPIs are higher during the years with a strong SAH. (3) When the SAH shifts eastward (westward) and strengthens (weakens) and the location of the western Pacific subtropical high shifts westward (eastward), the mid-latitude region displays the characteristics of a meridional (zonal) circulation pattern, facilitating (hindering) the occurrence of extreme precipitation in the Jianghuai plum rain area. In addition, corresponding to the above-mentioned circulation patterns, vertical movement strengthens (weakens) over the Jianghuai plum rain area, and thus water vapor fluxes enhance and converge (weaken and diverge). Therefore, extreme precipitation is strengthened (weakened) in the study area. (4) The preceding changes in the atmospheric heat source over the eastern Qinghai-Tibet Plateau (one month in advance) affects the changes of the intensity of the following SAH significantly. The changes in the vertically integrated apparent heat sources 〈 Q 1 〉 over the eastern Qinghai-Tibet Plateau and the sea surface to the east of the Philippines and the apparent moisture sink of the Jianghuai plum rain area is an important factor for the above-mentioned adjustment in the circulation structure and the changes in extreme precipitation. • EOF1 of PNL90 and PQ90 present a uniform “+” pattern, and EOF2 present a “south +, north –” pattern. • The intensity of SAH and PC1 of PNL90 and PQ90 show a significant positive correlation. • The circulation patterns facilitate extreme precipitation when SAH shifts eastward and strengthens • The preceding changes in the apparent heat sources over the eastern QTP affect the intensity of the SAH significantly.

Evaluation of TIGGE Daily Accumulated Precipitation Forecasts over the Qu River Basin, China

Quantitative precipitation forecasts (QPFs) provided by three operational global ensemble prediction systems (EPSs) from the THORPEX (The Observing System Research and Predictability Experiment) Interactive Grand Global Ensemble (TIGGE) archive were evaluated over the Qu River basin, China during the plum rain and typhoon seasons of 2009–13. Two post-processing methods, the ensemble model output statistics based on censored shifted gamma distribution (CSGD-EMOS) and quantile mapping (QM), were used to reduce bias and to improve the QPFs. The results were evaluated by using three incremental precipitation thresholds and multiple verification metrics. It is demonstrated that QPFs from NCEP and ECMWF presented similarly skillful forecasts, although the ECMWF QPFs performed more satisfactorily in the typhoon season and the NCEP QPFs were better in the plum rain season. Most of the verification metrics showed evident seasonal discriminations, with more satisfactory behavior in the plum rain season. Lighter precipitation tended to be overestimated, but heavier precipitation was always underestimated. The post-processed QPFs showed a significant improvement from the raw forecasts and the effects of post-processing varied with the lead time, precipitation threshold, and EPS. Precipitation was better corrected at longer lead times and higher thresholds. CSGD-EMOS was more effective for probabilistic metrics and the root-mean-square error. QM had a greater effect on removing bias according to bias and categorical metrics, but was unable to warrant reliabilities. In general, raw forecasts can provide acceptable QPFs eight days in advance. After post-processing, the useful forecasts can be significantly extended beyond 10 days, showing promising prospects for flood forecasting.

Simulation of rainfall runoff based on flood season stage

The staging simulation model is based on the flood season staging, which considering the weather system genesis and rainstorm characteristics. Moreover, the physical mechanism of rainfall runoff can be comprehensively considered, and the physical meaning of the parameter can be better reflected in different stages. In this paper, the Tingxia basins in the humid and semi-humid areas are selected, which the flood season can be divided into in plum rains period and the typhoon period, then the staged simulation model is constructed by the staged rate. Some statistical indicators are introduced to evaluate the effectiveness of the staging rainfall-runoff model in improving simulation accuracy, the simulation results are ideal, and the accuracy is improved.

Flood Risk Analysis of Different Climatic Phenomena during Flood Season Based on Copula-Based Bayesian Network Method: A Case Study of Taihu Basin, China

We propose a flood risk management model for the Taihu Basin, China, that considers the spatial and temporal differences of flood risk caused by the different climatic phenomena. In terms of time, the probability distribution of climatic phenomenon occurrence time was used to divide the flood season into plum rain and the typhoon periods. In terms of space, the Taihu Basin was divided into different sub-regions by the Copula functions. Finally, we constructed a flood risk management model using the Copula-based Bayesian network to analyze the flood risk. The results showed the plum rain period occurs from June 24 to July 21 and the typhoon period from July 22 to September 22. Considering the joint distribution of sub-region precipitation and the water level of Taihu Lake, we divided the Taihu Basin into three sub-regions (P-I, P-II, and P-III) for risk analysis in the plum rain period. However, the Taihu Basin was used as a whole for flood risk analysis in the typhoon period. Risk analysis indicated a probability of 2.4%, and 0.8%, respectively, for future adverse drainage during the plum rain period and the typhoon period, the flood risk increases rapidly with the rising water level in the Taihu Lake.

Analysis of reasons for failure of Meek micro-skin grafting in children with severe burn and treatment measures

Objective: To analyze the reasons for failure of Meek micro-skin grafting in children with severe burns and to observe the clinical effects of the treatment measures. Methods: Thirty children with severe burns hospitalized in the First Affiliated Hospital of Anhui Medical University (hereinafter referred to as the author's affiliation) from January 2012 to January 2018, conforming to the inclusion criteria were included to failed skin graft group. Children in failed skin graft group were performed with Meek micro-skin grafting operation and the operation failed, including 17 males and 13 females aged 1 to 12 year(s). Thirty children with severe burns hospitalized in the author's affiliation during the same period of time, conforming to the inclusion criteria, were included to successful skin graft group. Children in successful skin graft group were performed with Meek micro-skin grafting operation and the operation succeeded, including 16 males and 14 females aged 1 to 12 year(s). Main treatment measures and effects before operation, area and survival rate of Meek micro-skin graft, infected pathogens status, selection status of sensitive antibiotics, preoperative nutrition status, and wound infection status in plum rain season of children in the two groups, and nutritional status before and after strengthening nutritional support of postoperative surviving children in failed skin graft group were analyzed retrospectively. Data were processed with chi-square test and t test. Results: (1) The numbers of children in the two groups performed with main treatment measures of dilatation and anti-shock, tracheotomy intubation, ventilator-assisted respiration, and limb incision decompression after admission were close (χ(2)=0, 0.016, 0.025, 0.009, P>0.05). After taking the above-mentioned main treatment measures, effects of correcting shock, preventing asphyxia, correcting breathing difficulty, and improving peripheral circulation of limb were achieved. (2) The area of Meek micro-skin grafting of children in successful skin graft group was (20.6±2.5)% total body surface area (TBSA), close to (21.2±2.2)% TBSA in failed skin graft group (t=0.534, P>0.05). The survival rate of Meek micro-skin graft of children in successful skin graft group was (79±5)%, significantly higher than (26±3)% in failed skin graft group (t=2.956, P<0.01). (3) The microbial culture of wound secretion of 5 (16.67%) children in 30 patients in successful skin graft group was positive, with Pseudomonas aeruginosa of 2 children, and Escherichia coli, Staphylococcus aureus, and Aspergillus of one patient respectively. As children in successful skin graft group were with no symptom of systemic infection, no blood microbial culture was done. The microbial culture of wound secretion of 30 (100.00%) children in 30 patients in failed skin graft group was positive, and blood microbial culture of 8 (26.67%) children was positive. The main pathogen was Pseudomonas aeruginosa of 11 (36.67%) children in 8 pathogens caused infection with gram-negative bacteria of 22 (73.33%), gram-positive bacteria of 11 (36.67%) children, and fungi of 6 (20.00%) children. (4) Ten kinds of sensitive antibiotics such as cephalosporins, glycopeptides, carbapenems, and tetracyclines antibiotics were used in children in failed skin graft group, of which the use rate of imipenem of 9 (30.00%) was the highest. Only 4 kinds of sensitive antibiotics such as ceftazidime were used in 30 children in successful skin graft group. (5) The preoperative levels of albumin and prealbumin of children in successful skin graft group were (32±4) g/L and (133±41) mg/L respectively, significantly higher than (27±4) g/L and (93±35) mg/L in failed skin graft group (t=5.090, 4.064, P<0.01). The albumin and prealbumin levels of postoperative surviving children in failed skin graft group after nutritional support treatment were (35±4) g/L and (168±49) mg/L, significantly higher than (27±4) g/L and (94±38) mg/L before nutritional support treatment (t=6.911, 6.315, P<0.01). (6) Wound infection of 9 children in 30 children with wound infection in failed skin graft group happened in the plum rain season, and fungi infection of 3 children in 6 children with fungi infection happened in the plum rain season. Wound infection of 2 children in 5 children with wound infection in successful skin graft group happened in the plum rain season, and the only one children with fungi infection happened in the plum rain season. Conclusions: The main reasons for the failure of Meek micro-skin grafting in children with severe burns include infection, nutrition, and season factors, etc. Measures of strengthening wound dressing change, reasonable use of sensitive antibiotics to control infection, internal and external intestinal nutritional support, and reducing disturbance of the plum rain season by enhancing ventilation are effective and worthy of clinical promotion.

Spatiotemporal Change of Plum Rains in the Yangtze River Delta and Its Relation with EASM, ENSO, and PDO During the Period of 1960–2012

The Plum Rains process is a complex process, and its spatiotemporal variations and influencing factors on different time scales still need further study. Based on a dataset on the Plum Rains in the Yangtze River Delta, from 33 meteorological stations during the period of 1960 to 2012, we investigated the spatiotemporal variations of Plum Rains and their relation with the East Asian Summer Monsoon (EASM), the El Niño-Southern Oscillation (ENSO), and the Pacific Decadal Oscillation (PDO) using an integrated approach that combines ensemble empirical mode decomposition (EEMD), empirical orthogonal function (EOF), and correlation analysis. The main conclusions were as follows: (1) the plum rainfall (i.e., the rainfall during the period of Plum Rains) showed a trend of increasing first and then decreasing, and it had a three-year and six-year cycle on the inter-annual scale and a 13-year and 33-year cycle on the inter-decadal scale. The effect of the onset and termination of Plum Rains and the daily intensity of plum rainfall on plum rainfall on the inter-annual scale was greater than the inter-decadal scale, (2) the EOF analysis of plum rainfall revealed a dominant basin-wide in-phase pattern (EOF1) and a north-south out-of-phase pattern (EOF2), and (3) ENSO and EASM were the main influencing factors in the three-year and six-year periods, respectively.

Precipitation on abscised leaves modulates leaf‐mining beetle (Trachys yanoi) survivorship and population dynamics

1. We clarified the effects of early leaf abscission on the survivorship of the leaf‐mining beetle Trachys yanoi Y. Kurosawa (Coleoptera: Buprestidae) and the underlying mechanism in relation to weather conditions in Japan. Trachys yanoi is an insect pest of zelkova trees [Zelkova serrata (Thunb.) Makino (Rosales: Ulmaceae)]. Larvae burrow into zelkova leaves and feed on leaf tissue, causing early leaf abscission.2. This study investigated the relationship between the beetle population and weather conditions over 10 years in a zelkova forest. The effects of moisture and temperature on adult emergence from early abscised leaves were examined in the laboratory and in the field.3. The beetle population in the studied forest was negatively affected by high precipitation levels when the beetles still inhabited early abscised leaves. Fewer adults emerged from early abscised leaves under wet conditions than under dry conditions, in both laboratory and field tests.4. These results demonstrate that early leaf abscission plays an important role in leaf‐mining beetle survivorship and population dynamics, and that the amount of precipitation when leaf‐mining beetles still inhabit early abscised leaves modulates this effect.5. Because precipitation when leaf‐mining beetles still inhabit early abscised leaves was mainly driven by an East Asian rainy season front, the beetle population dynamics were affected by the activity of the front.

Plum Rain-Season-Oriented Modelling and Intervention of Indoor Humidity with and without Human Occupancy

The plum rain season, caused by precipitation along a persistent stationary Mei-Yu front in East Asia, creates favorable temperatures and relative humidity (RH) for mold growth indoors. This paper investigates the effects of human occupancy on indoor humidity and investigates the efficient RH reduction methods to prevent mold growth in moist climates. The research is carried out based on a case study which compares a family-occupied home and another unoccupied one during typical plum rain season in Nanjing. Firstly, by analyzing the factors that can influence the indoor air RH, this paper develops a comprehensive model to evaluate the efficiency of various RH intervention methods. Secondly, this paper collects the meteorological data in Nanjing at different time scales, from days to hours. Thirdly, a specific case study is carried out based on the model and data. The results show that dehumidification and heating can always reduce RH below the critical value under which the mold growth could be inhibited. However, the effects of ventilation are more sophisticated and depend upon the human occupancy, outdoor air temperature, and air change per hour (ACH). In certain unoccupied cases, the ventilation may be inappropriate and may continuously bring moisture outside into the indoor environment, which has adverse effects on mold suppression. In the occupied cases, the condition changes significantly because the human is deemed as an internal source of heat and moist. Special care should be exercised for occupied ventilation in order to determine the optimal ACH and appropriate outdoor temperatures. Finally, some guidance is given to prevent mold growth in the general area that suffers from the plum rain season.

Air Pollution Characteristics and Meteorological Correlates in Lin'an, Hangzhou, China

The concentration and distribution of atmospheric particulate matter depend primarily on the meteorological conditions associated with a fixed pollution source. The effects of meteorological factors on particulate matter have been analyzed on the meteorological seasonal scale, but few researchers have considered the climatic season, which is divided based on the distribution feature of climatic factors. In addition, the hysteresis effect of meteorological factors is easily neglected. Here, we reviewed the characteristics and influential factors of particle pollution based on particle concentration and meteorological data from January 2013 through December 2013. Results from nonparametric tests and Spearman’s nonparametric correlation coefficient showed that particle pollution exhibited a statistically significant seasonal trend. The pollution on workdays was slightly less than that on holidays, but no significant difference was found. The air pressure 1–2 days earlier showed a higher positive correlation with the current particle concentrations (except in winter), and the temperature 2–3 days earlier in summer and fall showed a stronger negative correlation with the particle concentration. Lower moisture and frequent precipitation would significantly reduce the pollution on the current day and the next day (except in summer). The variation of particulate matter concentration in summer exhibited a high-low-high variation, caused mainly by temperature and precipitation; the air quality during the plum rain period was significantly better than that in the period before the plum rain. The fine particle pollution level during the high-temperature and heat wave days was the lowest, after which the concentration increased.

Precipitation effect on surface salinity and temperature in the Yatsushiro Sea

Field observation was carried out during July 2016 in Minamata Bay of Yatsushiro Sea, measured data of temperature and salinity of five stations has been used for comparing the numerical simulation based on Princeton Ocean Model (POM). Simulation results showed deviations existed between simulated and measured data, especially the salinity field, which was probably caused by the increased precipitation during plum rain season. Therefore, a new precipitation module and modified heat flux forcing for POM were built to present the rainfall effect of salinity and temperature. It is indicated that the accuracy of predicted temperature and salinity was improved to some extent. In contrast with the previous simulation, deviations were reduced significantly. Nevertheless, simulation results of new model under rainy and sunny conditions showed the cooling impact of precipitation was slight, which may be caused by the daytime observation and solar radiation was dominated. However, this study has shown that precipitation effect is an important factor for surface numerical simulation during rainy season.

Isotopic Characteristics of Precipitation and Origin of Moisture Sources in Hemuqiao Catchment, a Small Watershed in the Lower Reach of Yangtze River

The stable isotopes of oxygen and hydrogen in the water cycle have become a significant tool to study run-off formation, hydrograph separation, and the origin of precipitation. Precipitation assessment based on isotopic data has a potential implication for moisture sources. In the study, δD and δ18O of precipitation samples collected from six rainfall events were analyzed for stable isotope composition to provide implication of isotopic characteristics as well as moisture sources in Hemuqiao basin within Lake Tai drainage basin, eastern China. In these events, stable oxygen and hydrogen isotopic composition of precipitation had strong variations. Models of the meteoric water line and deuterium excess for different rainfall types (typhoon and plum rain, which is caused by precipitation along a persistent stationary front known as the Meiyu front for nearly two months during the late spring and early summer between eastern Russia, China, Taiwan, Korea and Japan) were established. Compared with plum rain, the moisture source of typhoon events had higher relative humidity and temperature. Moisture transport pathways were traced using the Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT Model, developed by NOAA, Washington DC, U.S.) to verify the linkage with isotopic composition and moisture source. The moisture sources of typhoon events mostly derived from tropical ocean air with higher isotopic value, while that of plum rain events came from near-source local air with lower isotopic value.

How will the onset and retreat of rainy season over East Asia change in future?

Future change of the rainy season over East Asia region is investigated using the high horizontal resolution global atmospheric model called the Meteorological Research Institute‐Atmospheric General Circulation Model (MRI‐AGCM) version 3.2S (20‐km grid) and 3.2H (60 km). Higher reproducibility of precipitation during East Asian rainy season gives reliability of future projections. For the present‐day simulations (1983–2003, 21 years), the models are forced with observed historical sea surface temperature (SST). For the future simulations (1979–2099, 21 years), the models are forced with future SST projected by Atmosphere–Ocean General Circulation Models (AOGCMs) participated to the fifth phase of the Coupled Model Intercomparison Project (CMIP5). In order to estimate the uncertainty of future change, we execute ensemble simulations with three kinds of cumulus convection schemes and four kinds of SST distributions using 60‐km version to meet the limitation of computer resources. For each grid point, the onset and retreat of rainy season are defined from time evolution of pentad mean precipitation. The onset of rainy season becomes earlier in most regions over East Asia, but onset will delay in some area of western Japan. Retreat delays over China and Korea. Duration increases in most part of East Asia especially over China and Korea. This can be caused by enhanced water vapor transport from the tropics. The delay of onset over western Japan can be attributed to the decrease of water vapor transport associated with the southward shift of the subtropical high. Future change presented in higher horizontal resolution compared with previous studies is useful for impact, adaptation and mitigation studies of global warming.

Seismically Detected Ground Tilts Induced by Precipitation and Fluvial Processes: An Example From Taiwan

AbstractShear strains, among other ground motions, can be induced by weather‐related processes. As a result, broadband seismic data offer a unique tool for understanding these natural weather events. Here we used continuous seismic, meteorological, and stream data to analyze weather‐related ground motions during typhoons and rainy seasons in Taiwan. In addition to high‐frequency signals, we detected ultralong period seismic signals at the station Mahsi (MASB) during three meteorological events: Typhoon Kalmaegi in 2008, Typhoon Morakot in 2009, and the East Asian rainy season in 2012. Seismic velocity signals with frequencies lower than 0.3 mHz correlate with precipitation and with the time derivative of the water level in a nearby river. We converted the seismic signals to ground tilt and found that the tilt correlates with the time history of river water level, which fluctuates with precipitation. The seismically derived tilt ranges from 10−8 to 10−7 radians, consistent with an analytic circular loading model, indicating water level fluctuations of higher than 1 m in the small river 30 m away from MASB. To quantify precipitation using seismic data, we successfully modeled seismic waveforms using an empirical Green's function method, which gives good fits to both main event seismic waveforms and precipitation time history. This work demonstrates that continuous recordings from broadband seismometers may help determine local fluvial water load and could be useful for decadal rainfall change research.

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.

Wet depositions of mercury during plum rain season in Taiwan.

The plum rain season in Taiwan is in May and June. The severest plum rain season over the last 21years was in 2017. This study involves the collection of mercury wet depositions in the plum rain season of May-June in 2017. A DMA-80 (Direct Mercury Analyzer) was used to analyze the precipitated mercury concentrations and calculate the wet depositions of mercury in the plum rain season. The results indicate that the highest wet depositions of mercury in the aqueous phase were on 6/16, reaching 209.04μg/m2*day, while the lowest were on 5/15, at 0.18μg/m2*day. The mercury wet depositions in the particulate phase were highest on 6/17, when it exceeded 100μg/kg, and lowest on particulate phase were occurred in 6/11, when it was 3.64μg/m2*day. The relationship between the wet depositions of mercury in the aqueous phase and rainfall was insignificant, while that between the wet depositions of mercury in the particulate phase and rainfall was significant. The wet depositions of mercury in this study were second highest (30.73μg/m2day) when compared with those in studies in the years 2007-2017. Although the rainfall in this study was only 564mm H2O, high mercury concentrations obtained from the plum rain season result in the high wet depositions of mercury in Taichung, Taiwan.

Assessing membrane biofouling and its gel layer of anoxic/oxic membrane bioreactor for megacity municipal wastewater treatment during plum rain season in Yangtze River Delta, China

This study assessed membrane biofouling and its gel layer of anoxic/oxic membrane bioreactor (A/O-MBR) for megacity municipal wastewater treatment during plum rain season, which was continuous rainy weather, in Yangtze River Delta, China. A laboratory-scale A/O-MBR was operated to treat the municipal wastewater from Quyang wastewater treatment plant, which located at the typical megacity of Shanghai in Yangtze River Delta, from April to July accompanying with plum rain season. As reactor performance showed, CODCr, NH4+-N, TN, TP of the influent gradually decreased during plum rain season, and inhibited pollutant removal due to organic carbon shortage. However, dissolve inorganic carbon and inorganic components in mixed liquid had an obvious increase under rainy weather. Membrane filtration results indicated that plum rain season enhanced pore blocking behavior, further leading to the serious membrane biofouling but inhibiting gel layer formation. Additionally, gel layer analysis predicted that plum rain season led to plenty of inorganic components and precipitate flew into A/O-MBR reactor. Inorganic components with elements of Ca, Mg Ba, Fe, Al and Si seriously blocked membrane pores. Those components also accumulated into gel layer in the form of SiO2, CaCO3, CaSiO3, MgNH4PO4, BaCO3, AlPO4, etc. Consequently, plum rain season enhanced pore blocking behavior and led to severe membrane biofouling but with the inhibition of gel layer formation.

The pioneering works of Professor Duzheng Ye on atmospheric dispersion, Tibetan Plateau meteorology, and air–sea interaction

This paper provides an overview of the impacts of the original works of Professor Duzheng YE on a selected set of observational and model studies with which the present author has been associated over the past several decades. The main themes of these works include atmospheric energy dispersion, air–land interactions over the Tibetan Plateau, and El Ni˜norelated air–sea coupling over East Asia. The dispersive behavior of observed atmospheric fluctuations accompanying cold surge events in East Asia is demonstrated. Cold air outbreaks over Korea and southern China are coincident with the successive downstream development of troughs and ridges, with the group velocity of such wave packets being notably faster than the phase propagation speed of individual troughs and ridges. In a more general context, dispersive features are also discernible from lagged teleconnection charts and cross-spectra of observed and model-simulated geopotential height variations on 10–30-day time scales. Using the output from a high-resolution general circulation model, the relative contributions of condensational, sensible, and radiative heating to the atmospheric energy budget over the Tibetan Plateau are documented. The rapid changes of the upper tropospheric Tibetan anticyclone and East Asian mei-yu (“plum rain”) precipitation band associated with the development of the Asian monsoon system are described. The principal anomalies in sea level pressure, surface wind, precipitation and sea surface temperature over southeastern China and the Philippine Sea region during El Ni˜no events are presented. The contributions of remote El Ni˜no-related forcing and local air–sea interaction to the occurrence of these anomalies are assessed.

Assessment of environmental effects in scour monitoring of a cable-stayed bridge simply based on pier vibration measurements

A recent work by the authors has demonstrated the feasibility of scour evaluation for Kao-Ping-Hsi Cable-Stayed Bridge simply based on ambient vibration measurements. To further attain the goal of scour monitoring, a key challenge comes from the interference of several environmental factors that may also significantly alter the pier frequencies without the change of scour depth. Consequently, this study attempts to investigate the variation in certain modal frequencies of this bridge induced by several environmental factors. Four sets of pier vibration measurements were taken either during the season of plum rains, under regular summer days without rain, or in a period of typhoon. These signals are analyzed with the stochastic subspace identification and empirical mode decomposition techniques. The variations of the identified modal frequencies are then compared with those of the corresponding traffic load, air temperature, and water level. Comparison of the analyzed results elucidates that both the traffic load and the environmental temperature are negatively correlated with the bridge frequencies. However, the traffic load is clearly a more dominant factor to alternate the identified bridge deck frequency than the environmental temperature. The pier modes are also influenced by the passing traffic on the bridge deck, even though with a weaker correlation. In addition, the variation of air temperature follows a similar tendency as that of the passing traffic, but its effect on changing the bridge frequencies is obviously not as significant. As for the effect from the alternation of water level, it is observed that the frequency baselines of the pier modes may positively correlate with the water level during the seasons of plum rains and typhoon.