Impacts of the annual cycle of background SST in the tropical Pacific on the phase and amplitude of ENSO

The dominant annual cycle of sea surface temperature(SST)in the tropical Pacific exhibits an antisymmetric mode,which explains 83.4%total variance,and serves as a background of El Niño-Southern Oscillation(ENSO).However,there is no consensus yet on its anomalous impacts on the phase and amplitude of ENSO.Based on data during 1982-2022,results show that anomalies of the antisymmetric mode can affect the evolution of ENSO on the interannual scale via Bjerknes feedback,in which the positive(negative)phase of the antisymmetric mode can strengthen El Niño(La Niña)in boreal winter via an earlier(delayed)seasonal cycle transition and larger(smaller)annual mean.The magnitude of the SST anomalies in the equatorial eastern Pacific can reach more than±0.3◦C,regulated by the changes in the antisymmetric mode based on random sensitivity analysis.Results reveal the spatial pattern of the annual cycle associated with the seasonal phase-locking of ENSO evolution and provide new insight into the impact of the annual cycle of background SST on ENSO,which possibly carries important implications for forecasting ENSO.

Study of Dynamics of Floodwater Nitrogen and Regulation of Its Runoff Loss in Paddy Field-Based Two-Cropping Rice with Urea and Controlled Release Nitrogen Fertilizer Application

The article deals with the effects of urea and controlled release nitrogen fertilizer （CRNF） on dynamics of pH, electronic conductivity （EC）, total nitrogen （TN）, NH4^＋-N and NO3 -N in floodwater, and the regulation of runoff TN loss from paddy field-based two-cropping rice in Dongting Lake, China, and probes the best fertilization management for controlling N loss. Studies were conducted through modeling alluvial sandy loamy paddy soil （ASP） and purple calcareous clayey paddy soil （PCP） using lysimeter, following the sequence of the soil profiles identified by investigating soil profile. After application of urea in paddy field-based two-cropping rice, TN and NHa＋-N concentrations in floodwater reached peak on the 1st and the 3rd day, respectively, and then decreased rapidly over time; all the floodwater NO3--N concentrations were very low; the pH of floodwater gradually rose in case of early rice within 15 d （late rice within 3 d） after application of urea, and EC remained consistent with the dynamics of NH4^＋-N. The applied CRNF, especially 70% CRNF, led to significantly lower floodwater TN and NH4^＋ concentrations, pH, and EC values compared with urea within 15 d after application. The monitoring result for N loss due to natural rainfall runoff indicated that the amount of TN lost in runoff from paddy field- based two-cropping rice with urea application in Dongting Lake area was 7.47 kg ha^-1, which accounted for 2.49% of urea- N applied, and that with CRNF and 70% CRNF application decreased 24.5 and 27.2% compared with urea application, respectively. The two runoff events, which occurred within 20 d after application, contributed significantly to TN loss from paddy field. TN loss due to the two runoffs in urea, CRNF, and 70% CRNF treatments accounted for 72, 70, and 58% of the total TN loss due to runoff over the whole rice growth season, respectively. And the TN loss in these two CRNF treatments due to the first run-off event at the 10th day after application to early rice decreased 44.9 and 44.2% compared with urea, respectively. In conclusion, the 15-d period after application of urea was the critical time during which N loss occurred due to high floodwater N concentrations. But CRNF decreased N concentrations greatly in floodwater and runoff water during this period. As a result, it obviously reduced TN loss in runoff over the whole rice growth season.

THE IMPACT OF DIFFERENT PHYSICAL PROCESSES AND THEIR PARAMETERIZATIONS ON FORECAST OF A HEAVY RAINFALL IN SOUTH CHINA IN ANNUALLY FIRST RAINING SEASON

An ensemble prediction system based on the GRAPES model, using multi-physics, is used to discuss the influence of different physical processes in numerical models on forecast of heavy rainfall in South China in the annually first raining season(AFRS). Pattern, magnitude and area of precipitation, evolution of synoptic situation, as well as apparent heat source and apparent moisture sink between different ensemble members are comparatively analyzed. The choice of parameterization scheme for land-surface processes gives rise to the largest influence on the precipitation prediction. The influences of cumulus-convection and cloud-microphysics processes are mainly focused on heavy rainfall;the use of cumulus-convection parameterization tends to produce large-area and light rainfall. Change in parameterization schemes for land-surface and cumulus-convection processes both will cause prominent change in forecast of both dynamic and thermodynamic variables, while change in cloud-microphysics processes show primary impact on dynamic variables. Comparing simplified Arakawa-Schubert and Kain-Fritsch with Betts-Miller-Janjic schemes, SLAB with NOAH schemes, as well as both WRF single moment 6-class and NCEP 3-class with simplified explicit schemes of phase-mixed cloud and precipitation shows that the former predicts stronger low-level jets and high humidity concentration, more convective rainfall and local heavy rainfall, and have better performance in precipitation forecast. Appropriate parameterization schemes can reasonably describe the physical process related to heavy rainfall in South China in the AFRS, such as low-level convergence, latent heat release, vertical transport of heat and water vapor, thereby depicting the multi-scale interactions of low-level jet and meso-scale convective systems in heavy rainfall suitably, and improving the prediction of heavy rainfall in South China in the AFRS as a result.

APPLICATION EXPERIMENT OF ASSIMILATING RADAR-RETRIEVED WATER VAPOR IN SHORT-RANGE FORECAST OF RAINFALL IN THE ANNUALLY FIRST RAINY SEASON OVER SOUTH CHINA

A scheme of assimilating radar-retrieved water vapor is adopted to improve the quality of NWP initial field for improvement of the accuracy of short-range precipitation prediction. To reveal the impact of the assimilation of radar-retrieved water vapor on short-term precipitation forecast, three parallel experiments, cold start, hot start and hot start plus the assimilation of radar-retrieved water vapor, are designed to simulate the 31 days of May, 2013 with a fine numerical model for South China. Furthermore, a case of heavy rain that occurred from 8-9 May 2013 over the region from the southwest of Guangdong province to Pearl River Delta is analyzed in detail. Results show that the cold start experiment is not conducive to precipitation 12 hours ahead; the hot start experiment is able to reproduce well the first6 hours of precipitation, but badly for subsequent prediction; the experiment of assimilating radar-retrieved water vapor is not only able to simulate well the precipitation 6 hours ahead, but also able to correctly predict the evolution of rain bands from 6 to 12 hours in advance.

INFLUENCES OF LOW-FREQUENCY MOISTURE TRANSPORTATION ON LOW FREQUENCY PRECIPITATION ANOMALIES IN THE ANNUALLY FIRST RAINY SEASON OF SOUTH CHINA IN 2010

85-station daily precipitation data from 1961-2010 provided by the National Meteorological Information Center and the NCEP/NCAR 2010 daily reanalysis data are used to investigate the low-frequency variability on the precipitation of the first rain season and its relationships with moisture transport in South China,and channels of low-frequency water vapor transport and sources of low-frequency precipitation are revealed.The annually first raining season precipitation in 2010 is mainly controlled by 10-20 d and 30-60 d oscillation.The rainfall is more(interrupted) when the two low-frequency components are in the same peak(valley) phase,and the rainfall is less when they are superposed in the inverse phase.The 10-20 d low-frequency component of the moisture transport is more active than the 30-60 d.The10-20 d water vapor sources lie in the South India Ocean near 30° S,the area between Sumatra and Kalimantan Island(the southwest source),and the equatorial middle Pacific region(the southeast source),and there are corresponding southwest and southeast moisture transport channels.By using the characteristics of 10-20 d water vapor transport anomalous circulation,the corresponding low-frequency precipitation can be predicted 6 d ahead.

ANALYSES OF INTRASEASONAL OSCILLATION CHARACTERISTICS OF FLOOD-CAUSING RAINSTORMS IN XIJIANG RIVER VALLEY DURING THE ANNUALLY FIRST RAINING SEASON IN THE PAST YEARS

Based on the daily precipitation data of nine stations representing the Xijiang River valley and the National Center for Environmental Prediction/National Center for Atmospheric Research (USA) reanalysis data, this study uses the wavelet analysis and band-pass filter methods to investigate the atmospheric intraseasonal oscillation characteristics of flood-causing rainstorms in the valley during the annually first raining seasons in 1968, 1994, 1998, 2002 and 2005. Results show that the daily precipitation in the valley exhibits significant quasi-biweekly (10 to 20 days) oscillations. The flood-causing rainstorms in the valley were mainly associated with the confluence of low-frequency warm and humid airflow in the lower latitudes and cold and dry airflow in the higher latitudes. The low-frequency vortexes were propagating or in control when this type of rainstorms took place over the valley, being favorable for the convergence of moisture at lower levels and thus vital to the formation of the rainstorms.

STUDY ON THE RELATIONSHIP BETWEEN THE DECADAL VARIATIONS OF ANNUALLY FIRST RAINY SEASON PRECIPITATION OF GUANGXI AND SEA SURFACE TEMPERATURE OF INDIAN OCEAN IN SOUTHERN HEMISPHERE

Decadal circulation differences between more and less rainfall periods in the annually first rainy season of Guangxi and their association with sea surface temperature (SST) of the austral Indian Ocean are investigated by using the NCEP/NCAR reanalysis data. The results are shown as follows. A pattern in which there is uniform change of the Guangxi precipitation shows a 20-year decadal oscillation and a 3-year interannual change. In contrast, a pattern of reversed-phase change between the north and the south of Guangxi has a 6-year interannual periodicity and quasi-biennial oscillation. In the period of more precipitation, the surface temperature in Eurasia is positively anomalous so as to lead to stronger low pressure systems on land and larger thermal contrast between land and ocean. Therefore, the air column is more unstable and ascending flows over Guangxi are intensified while the Hadley cell is weakened. Furthermore, the weaker western Pacific subtropical high and South Asia High, together with a stronger cross-equatorial flow, result in the transportation of more humidity and the appearance of more precipitation. The correlation analysis indicates that the Indian Ocean SST in Southern Hemisphere is closely associated with the variation of the seasonal precipitation of Guangxi on the decadal scale by influencing the Asian monsoon through the cross-equatorial flow.

Annual variation of adult survival of a south-temperate House Wren population in Argentina

Identifying factors affecting the survival of individuals is essential for understanding the evolution of life-history traits and population dynamics.Despite numerous studies on this subject in north-temperate environments,there is a lack of equivalent studies at similar latitudes in the south.Here,we used a 14-year dataset of capture,banding,and resighting to estimate the annual variation in the apparent adult survival probability of a south-temperate population of House Wrens(Troglodytes aedon bonariae).We evaluated temporal variation in sur-vival and the effect of environmental(climatic)and demographic variables(adult abundance,total number of fledglings produced during each breeding season)on survival estimators.We found that the probability of adult survival decreased as the abundance of breeding adults increased.This density-dependent effect could be related to the resident lifestyle of southern House Wrens,which could determine an intense competition for territories and resources that ultimately would affect their survival.

The changes in the annual distribution of mountain runoff during the period of 1965-2018 in Hexi Corridor,Northwest China

The annual distribution characteristics of river runoff in arid regions have significant implications for water resource stability and management.Based on the mountain runoff data from 1965 to 2018,this study examines the annual change characteristics of monthly runoff of the Shiyang River Basin,Heihe River Basin,and Shule River Basin in the Hexi Corridor,Northwest China.Many indexes are used and analyzed,including the coefficient of variance,the complete regulation coefficient,the concentration degree and concentration period,the magnitude of change,the skewness coefficient,and the kurtosis coefficient of the annual distribution curves.The results reveal the following:(1)The inhomogeneity of annual runoff distribution in the Taolai River and the rivers to the west of it,except the Shiyou River,show an increasing trend.Conversely,the inhomogeneity of the rivers to the east of the Taolai River generally show a downward trend,but the coefficient of variance value is still very high.(2)In the Shiyang River Basin,the annual distribution of the concentration period is characterized by a relatively discrete pattern.Conversely,the Heihe River Basin exhibits a relatively concentrated pattern,and the distribution pattern of the Shule River Basin is quite different.Notably,all concentration periods in the three basins have shifted backward after the 2000s.(3)The Shiyang River Basin exhibits disordered annual distribution curves of runoff in different years.In contrast,the Heihe River Basin presents a typical‘single-peak’pattern with a prominent right-skewed.The Shule River Basin has regular distribution curves,with a gradually significant‘double-peak’pattern from east to west.Overall,there has been a slight change in runoff in the Shiyang River Basin,while the Heihe River Basin and Shule River Basin have experienced significant increases in runoff.The annual distribution curves of runoff in the Liyuan River and the rivers to the east of it exhibit a gentle peak pattern,and the appearance probability of extreme runoff during the year is low.Conversely,the rivers to the west of the Liyuan River,excluding the Danghe River,display a sharp peak and thick tail pattern,indicating that the appearance probability of extreme runoff during the year is high.These findings have practical implications for the planning and management of water resources in the Hexi Corridor.Moreover,they provide a solid foundation for predicting future changes in regional water resources.

Fragipan Horizon Changes Using Annual Ryegrass and Other Admendments

A greenhouse experiment was conducted involving intact fragipan soil cores of 50 cm thickness after removing the topsoil horizons. The cores were maintained in moist condition throughout the experiment and received several treatments with various amendments for different periods ranging from 9 to 17 months. The amendments included annual ryegrass or Festulolium residues, powder limestone and various humate compounds alone or in combination with the grass residues. The results suggested a significant effect of ryegrass and Festulolium in reducing penetration resistance into the top 10 cm of the fragipan within 9 - 17 months, particularly when used in combination with certain humate materials such as Leonardite. Apparently, this is the result of the release of certain soluble organic compounds from the plant residues or the humate amendments that increase the solubility of Si and Al associated with the fragipan brittleness, thus decreasing the density of the compacted fragipan material.

Wind risk and mitigation calculator framework for determining the wind annualized risk for single- and multi-family homes to support resilient community decision-making

Communicating risks and mitigation benefits associated with natural hazards such as wind to the general public is challenging given the location-dependency of parameters and the complexity of the problem.Web tools play a crucial role in educating residents,decision-makers,and stakeholders regarding potential wind hazard losses to,for example,residential buildings.However,a notable gap exists on the practical incorporation of mitigation actions within these tools.This gap hampers the collective awareness and understanding among stakeholders,communities,and citizens regarding the tangible advantages of mitigation strategies in reducing wind-related risks.Furthermore,there exists a need to elucidate the functionality and objectives of these tools in a more accessible manner.This study aims to present and outline the wind risk and mitigation calculator tool(WRMCT)within the Hazardaware platform,which is an address-based risk assessment tool.This tool,developed for 196 counties in the Gulf of Mexico coastal area,facilitates users’education of potential risks and benefits associated with mitigation strategies.WRMCT enables users to access location-specific wind risk and interactively suggests potential mitigation actions along with economic savings to support informed decisions and residential risk reduction.WRMCT intends to enhance users’ability to make informed decisions,take proactive measures in mitigating wind hazards,and contribute to the development of resilient,residential communities.

Analysis on the Variations of Annual Runoff Distribution in the Weihe Basin

With the impact of climate change and the increasing intensity of human activities,the hydrological regime had changed,including annual runoff distribution,which was related with water resources management and ecological construction. Based on the monthly runoff data for more than 40 years of the Beidao,Xianyang,Huaxian station on Weihe Basin,the annual distribution characteristics of runoff were studied. Several indices related to attributes of uneven,concentrate degree and variation amplitude were calculated,and the results showed that there had obvious fresh and drought seasonal changes in 1990s. The annual runoff distribution had changed a lot,mainly because of runoff decrease in the wet season. The Huaxian station,which locates at the upper reaches,had a higher unevenness,concentration and relative variation rate than that of the Beidao and Xianyang station.

河龙区间典型流域径流年内分配对水土保持生态建设的响应

[目的]揭示河龙区间不同地貌区下典型流域的多年径流变化特征,明晰水土保持生态建设对其径流年内分配均匀程度的影响。[方法]选取河龙区间风沙区、土石山区和黄土丘陵沟壑区的秃尾河、三川河及延河流域,在收集各流域1960-2019年径流观测和水土保持措施数据的基础上,构建基尼系数指标,量化径流年内分配均匀度,分析了流域径流年内分配的演变趋势与空间差异,探究了河龙区间流域径流年内分配对不同类型水土保持措施的响应特征。[结果](1)1960-2019年,3个典型流域径流量极显著减少,秃尾河、三川河和延河的年径流量减少幅度分别为-0.05亿m^(3)/a,-0.03亿m^(3)/a,-0.02亿m^(3)/a;(2)3个典型流域径流年内分配特征显著差异,风沙区的秃尾河流域径流年内分配最为均匀,土石山区次之,黄土丘陵沟壑区的延河流域年内分配最不均匀,各流域的径流基尼系数分别为0.2,0.35,0.6;(3)不同地貌区径流基尼系数均呈下降趋势,径流年内分配趋向均匀;(4)水土保持林草植被、梯田和淤地坝建设与径流基尼系数具有显著负相关关系。[结论]水土保持生态建设具有调节径流年内分配,促进河川径流年内分配更加均匀的作用。

Horizontal Distribution and Annual Variations of Fecal Coliform Bacteria in Luoyuan Bay

Fecal Coliform Bacteria （FCB） of marine waters was monitored in Luoyuan Bay from January, 2003 to December, 2005. The results showed that number of FCB in marine water samples ranged from no detection （ 〈2 cfu/100 mL） to 540 cfu/100 mL in Luoyuan Bay. Values of FCB during August to October were significantly higher than those during January to April during three year period. Monthly changes of FCB values at each year period were mainly due to monthly precipitation. In addition, compared with FCB values in difference sample sites, values of FCB in Bay-heed were significantly higher than those in middle of bay and Bay-mouth, Luoyuan Bay. However, values of FCB in Bay-mouth were significantly less than those in middle of bay. The ratios to the par of FCB in 2003, 2004, and 2005 years were 100%, 98.0%, and 97.9%, respectively. Therefore, we considered that the pollution of FCB of surface marine water in Luoyuan Bay was not serious.

国家级大连刺参原种场核心区生态环境质量和微生物群落结构周年变化及其相关性分析

水产原种是良种培育的种质基础和保护生物多样性的核心,为全面掌握我国首家国家级刺参(Apostichopus japonicus)原种场核心保种区状况,本研究于2022年7月至2023年5月对该核心保种区的水环境、沉积物环境进行了周年检测,同时利用高通量测序方法分析了海水和沉积物微生物群落结构周年变化,进一步完成生态环境因子与微生物群落结构相关性分析。结果显示,海水水质良好,除春季活性磷酸盐,夏、秋、冬季铅元素和秋季镍元素含量符合Ⅱ类水质标准外,其他水质指标均符合Ⅰ类水质标准,保种区水体属于贫营养级;沉积物中除了秋季铬元素含量未达到Ⅰ类沉积物标准外,其他全部指标均符合Ⅰ类沉积物标准,表明保种区生态环境保护良好。对海水和沉积物四季微生物群落结构分析结果显示,核心区水体共获得3796个OTUs,4个季节水体中的Shannon指数在5.90±0.04~6.84±0.01之间,秋季最高,夏季最低;沉积物中共获得4151个OTUs,四个季节沉积物的Shannon指数在6.06±1.44~7.88±0.22之间,夏季最高,春季最低。PcoA分析显示,水体和沉积物在四季的菌群结构存在差异,且水体的菌群结构受季节影响变化相对于沉积物而言更为显著。对不同季节的水体和沉积物菌群LEfSe分析结果显示,在不同季节的水体和沉积物样品中分别筛选到73和66个显著差异菌群(P<0.05),其中冬季沉积物中的代表性差异菌群包含弧菌科(Vibrionaceae)、冷单胞菌科(Psychromonadaceae),需要警惕冬季弧菌对刺参健康的潜在威胁。环境因子与菌群结构的相关性分析结果表明,温度、pH、盐度是影响水体菌群结构的主要环境因子,有机碳、硫化物、重金属(铜、铅)是影响沉积物菌群结构的主要环境因子。上述研究结果为评估保种核心区生态环境、解析其风险因子和影响因素提供支撑,为我国刺参原种的高效保种提供科学依据。

围氏马尾藻(Sargassum wightii)周年生长及有性生殖的早期发育研究

围氏马尾藻(Sargassum wightii)是广西涠洲岛、广东徐闻等海域的习见物种,为大型经济海藻。了解大型藻类的周年生长情况及其早期发育过程,可以推测藻体成熟时间并为其人工育苗和栽培等提供科学依据。本文报道了广东徐闻海域生活的围氏马尾藻的周年生长特点、温度对其排卵的影响及其有性生殖的早期发育过程,围氏马尾藻周年生长情况可分为快速生长期、成熟期、衰退期和休止期4个时期,藻体平均长度在4月初达到最长(188.32±43.77)cm, 4月和5月的藻体月平均长度均超过180cm,而在7月下旬至11月上旬不超过5cm;围氏马尾藻为雌雄同托,卵细胞发育属8核1卵型;培养温度对其排卵过程至关重要,生殖托在15、27、30℃培养下无法排卵,在18~24℃培养下均可排卵, 24℃培养下排卵时间最短,仅需3d便可排卵;受精卵在24℃下培养24h左右发育形成有假根的幼孢子体,幼苗培养30d便发育出第四片叶片。本研究结果为围氏马尾藻的生物学、生态学研究提供了基础资料,为其人工育苗和栽培提供了科学依据。

Circle of Friends

CISCE brings together partners on the global industrial chain to collaborate and enhance global competitiveness.LOCATED in South Yorkshire in north-central England,British Steel,originally founded in 1967,is the U.K.’s only manufacturer of rail.It now produces three million tons of crude steel annually and has the distinction of maintaining stable production even during the COVID-19 pandemic,with its ironmaking,steelmaking and all rolling mills in full operation.

海绵城市年径流总量控制率制定策略研究

在中国海绵城市建设不断推进的当下,优化海绵城市建设核心指标年径流总量控制率的制定策略对于平衡海绵城市建设的合理性与成本效益具有重要意义。采用传统工程策略叠加年径流总量控制率一阶变化率曲线进行经济性分析,并通过径流污染控制及排水管道设计目标进行验证,形成了一套年径流总量控制率“3+2”指标制定策略,即综合考虑年径流总量控制率分区图、年径流总量控制率与其一阶变化率曲线关系图、城市开发后自然水文条件接近开发前的原则,以及年径流总量控制率与排水管道设计目标的关系、与径流污染控制目标的关系;最后在宁波市海绵城市建设中付诸应用。结果表明:该策略提升了年径流总量控制率指标的合理性与经济性;根据该策略,宁波市年径流总量控制率制定为75%时,可实现工程合理前提下的海绵城市建设成本效益最大化。研究成果可为海绵城市建设提供参考。

海上油气生产设施变压器维护保养质量提升策略

变压器是海上油气生产设施供配电系统中的关键设备,因变压器故障导致设施停电停产时有发生,其主要原因在于变压器维护保养(以下简称“维保”)工作不到位,因海上生产设施的变压器维保工作缺乏系统全面的标准,致使施工质量参差不齐,变压器故障频出。为改变这一现状,明确提出了海洋环境使用的变压器年度维保工作范围与技术要求,规范维保项目和深度,将变压器在线监测系统和变压器上下游开关柜纳入变压器维保范围,并制定相应维保技术要求,以提高变压器维保工作的完整性、规范性和整体质量。对当前变压器维保过程中的常见问题提出解决方案。

基于SWMM模型的海绵城市建设效果评估

为定量评估广州市荔湖片区海绵城市建设成效,研究通过本底分析、资料收集等构建了片区排水分区尺度上的SWMM模型,并从年径流总量控制率、管网过流能力和内涝风险方面对广州市荔湖片区海绵城市建设效果进行了模拟分析,以期验证该区域按照海绵城市建设实施方案开发建设后,片区防灾减灾能力,同时本研究成果可为南方高密度地区海绵城市建设对缓解城市内涝提供理论参考。通过对广州市荔湖片区模拟计算得出主要结论如下:(1)广州市荔湖片区低影响开发建设后,年径流总量控制率显著提升,2022年片区年径流总量控制率为81.46%,较2019年低影响开发建设前提升了15.37%;(2)对广州市荔湖片区低影响开发建设前后排水管网过流能力模拟分析,结果表明片区在低影响开发建设前,在不同重现期降雨条件下,管网均出现溢流情况,且随着设计重现期的增大,管网溢流比例增加。片区低影响开发建设后,在不同重现期降雨条件下,管网溢流情况均明显降低;(3)对广州市荔湖片区低影响开发建设后内涝风险模拟分析,结果显示在发生百年一遇24 h降雨(累计降雨量322 mm)时,片区基本为无风险区域,极少部分为低风险区域,荔湖片区海绵城市建设后能有效应对百年一遇暴雨。广州市荔湖片区通过海绵城市建设可有效降低雨水外排,提升了片区防灾减灾能力。