长江-淮河流域短时暴雨洪涝灾害危险性预警评估及验证

洪涝灾害危险性预警分析是防灾减灾的重要基础,在灾害发生前进行预警,可以有效减轻灾害带来的影响。本文以2020年6—8月长江-淮河流域洪涝灾害为研究案例,首次利用前3天累计降水量(前期状态),当前时次土壤湿度(当前状态)和预测日降水量(未来状态)作为致灾因子,基于改进的层次分析法建立危险性预警分析模型。通过县域灾情信息验证表明,评估正确率达74.46%,遗漏率仅5.59%,评估结果与实际灾情吻合性好;同时对预警准确性和时相一致性进行评价,最大值(县内最高指数)的预警率达到81.6%;“特大型”暴雨洪涝灾害中的预警达到77.3%以上,且灾害在前3~5天危险性指数普遍提升,存在有效预警。本文方法对于长江—淮河流域短时暴雨洪涝灾害危险性预警有较好的准确性和可靠性,可提供防灾减灾决策依据。     

Isolation and identification of bacteria associated with the surfaces of several algal species

We conducted this study to assess the diversity of bacteria associated with the surfaces of algae based on 16S rDNA sequence analyses.Twelve strains of bacteria were obtained from the surfaces of the following four species of algae:Gracilaria textorii,Ulva pertusa,Laminaria japonica,and Polysiphonia urceolata.The isolated strains of bacteria can be divided into two groups:Halomonas and Vibrio,in physiology,biochemical characteristics and 16S rDNA sequence analyses.The phylogenetic tree constructed based on ...     

Impacts of soil fauna on litter decomposition at different succession stages of wetland in Sanjiang Plain, China

Litter decomposition is the key process in nutrient recycling and energy flow. The present study examined the impacts of soil fauna on decomposition rates and nutrient fluxes at three succession stages of wetland in the Sanjiang Plain, China using different mesh litterbags. The results show that in each succession stage of wetland, soil fauna can obviously increase litter decomposition rates. The average contribution of whole soil fauna to litter mass loss was 35.35%. The more complex the soil fauna group, the more significant the role of soil fauna. The average loss of three types of litter in the 4mm mesh litterbags was 0.3–4.1 times that in 0.058mm ones. The decomposition function of soil fauna to litter mass changed with the wetland succession. The average contribution of soil fauna to litter loss firstly decreased from 34.96% (Carex lasiocapa) to 32.94% (Carex meyeriana), then increased to 38.16% (Calamagrostics angustifolia). The contributions of soil fauna to litter decomposition rates vary according to the litter substrata, soil fauna communities and seasons. Significant effects were respectively found in August and July on C. angustifolia and C. lasiocapa, while in June and August on C. meyeriana. Total carbon (TC), total nitrogen (TN) and total phosphorus (TP) contents and the C/N and C/P ratios of decaying litter can be influenced by soil fauna. At different wetland succession stages, the effects of soil fauna on nutrient elements also differ greatly, which shows the significant difference of influencing element types and degrees. Soil fauna communities strongly influenced the TC and TP concentrations of C. meyeriana litter, and TP content of C. lasiocapa. Our results indicate that soil fauna have important effects on litter decomposition and this influence will vary with the wetland succession and seasonal variation. Foundation item: Under the auspices of State Key Development Program for Basic Research of China (No. 2009CB421103), Key Program of National Natural Science Foundation of China (No. 40830535/D0101), Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX2-YW-BR-16, KSCX2-YW-N-46-06)     

基于基础地理信息数据库的制图设计与实现

辽宁省测绘局于2007年开始正式启动辽宁省基础地理信息数据库建设工程,该建设工程的目标之一是实现了图库一体化功能.本文详细介绍了基于辽宁省基础地理信息数据库的制图设计与实现.     

Crystallographic and NMR studies on sterols from green alga Chaetomorpha basiretorsa Setchell

Chemical investigation of the ethanol extract of the marine green alga Chaetomorpha basiretorsa Setchell led to the isolation of a new sterol stigmast-4,28-dien-3α,6β-diol 1 in addition to the five known sterols of β-lawsaritol 2, saringosterol 3, 24-hydroperoxy-24-vinyl - cholesterol 4, β-stigmasterol 5, 29-hydroxystigmasta-5, 24 （28） -dien-3β-ol 6. Compounds were isolated by normal phase silica gel and Sephadex LH - 20 gel colum chromatography, reverse phase HPLC and recrystalization. Their structures were elucidated by spectroscopic methods including MS, IR 1D/2D NMR and X-ray analysis. Cytotoxicity of compounds was screened by using the standard MTF method. All these compounds were isolated from the green alga Chaetomorpha basiretorsa Setchell for the first time and they were inactive （50% inhibitory concentration was greater than 10 μg/cm^3） against KB, Bel -7402, PC - 3M, Ketr 3 and MCF-7 cell lines.     

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Effects of diet and body size on phosphorus utilization of Liza haematocheila T. ＆ S.

A 21-d laboratory experiment was conducted to study, the phosphorus （P） utilization of two different diets by redlip mullet Liza haematocheila T. ＆ S. Sand-filtered water in salinity 30 and temperatare 25℃ was used. Twenty-nine fish individuals were divided into three groups： 11 to group 1 （G1） fed on diet 1, 11 to group 2 （G2） fed on diet 2, and 7 to contrast group. Diet 1 was a commercial feed, more valuable in nutrition than diet 2 that similar to natural detritus. The results show the intake phosphorus （IP） of G1 was significantly higher than that of G2, and both increased linearly with body size at a certain amount of diet. The retention phosphorus （RP） in fish of G1 was lower than G2. The relationship between retention phosphorus and body size was positive and stronger in G2. Significant difference in faecal phosphorus （FP） was found between G1 and G2. Body size significantly impacted the excretion phosphorus （EP） in G1 but G2. The loss of intake phosphorus in G1 was 10.83-20.27 mg per g fish weight gain, higher than that in G2 for 6.63-9.56. Of the phosphorus, about 10% was allocated into growth, 50% in faeces, and the rest lost in excretion. The main part of phosphorus was lost in faeces but excretion. The phosphorus budget of the fish could be described as 100IP = 7.40RP ＋ 47.39FP ＋ 36.63EP （Diet 1） or 100IP = 11.93RP ＋ 56.64FP ＋ 21.76EP （Diet 2）.     

夏半年川西高原600 hPa低涡活动特征

600 hPa天气系统能够分析川西高原低涡变化的主要特征,并能识别低涡的发展移动和川西高原强降水落区的关系。利用1979—2020年逐3 h的ERA5再分析资料(0.25°×0.25°)和2011—2020年逐小时降水资料,对夏半年川西高原600 hPa低涡活动特征、低涡与降水的关系及致雨低涡动力和热力特征进行统计分析,结果表明：(1)42年间低涡年均80个,持续时间1 d以内占总数的95.7%;在川西高原本地生成、移入和移出低涡年均61.5个、18个和5.3个;低涡源地和消散地分别在甘孜州白玉县和理塘县为中心的区域。(2)生命史大于12 h的低涡占比36.4%,都会带来降水,其中超83.7%会造成中雨以上降水;低涡伴随的日降水强度最大值中心位置随月份先由川西高原东部与南部地区北移到中部,之后逐渐移回到东部与南部地区,相对应7—8月多低涡从北部南移到中部摆动消亡,其余月份多低涡从中部生成影响到东部和南部地区或在南部生成并停滞或摆动。(3)强烈垂直上升运动和正涡度区的耦合发展以及深厚不稳定层结的形成和加强是致雨低涡发生发展并产生强降水的动力特征和热力层结条件。     

海水养殖生态环境压力评价及压力点侦测——以北部湾为例

文章以广西北部湾海水养殖区为例,采用模糊数学灰色统计方法与熵权法设置权重,采用TOPSIS建立广西北部湾海水养殖生态环境压力评价体系,并采用Arc GIS软件对广西北部湾海水养殖生态环境进行定量评价。研究结果显示：(1)海水养殖生态环境压力受养殖模式与时间的影响。(2)陆基池塘养殖模式对生态环境压力影响最大;浅海筏式养殖模式和浅海网箱养殖模式生态压力居中,浅海养殖模式对生态环境压力影响较小;(3)滩涂底播养殖模式对生态环境压力全年平均分布,无关键时期。珍珠港湾地区是压力最大分布区,也是生态环境压力的关键点;茅尾海和湾外鹿耳环江至乌雷为次压力分布区,也是养殖对生态环境压力的次关键点;西村到彬塘为三级压力分布区和关键点。     

Understanding the dynamical-microphysical-electrical processes associated with severe thunderstorms over the Beijing metropolitan region

The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan region(BMR)during the warm season from 2014 to 2018.The aim of the project was to understand how dynamical,microphysical and electrical processes interact in severe thunderstorms in the BMR,and how to assimilate lightning data in numerical weather prediction models to improve severe thunderstorm forecasts.The platforms used in the field campaign included the Beijing Lightning Network(BLNET,consisting of 16 stations),2 X-band dual linear polarimetric Doppler radars,and 4 laser raindrop spectrometers.The collaboration also made use of the China Meteorological Administration’s mesoscale meteorological observation network in the Beijing-Tianjin-Hebei region.Although diverse thunderstorm types were documented,it was found that squall lines and multicell storms were the two major categories of severe thunderstorms with frequent lightning activity and extreme rainfall or unexpected local short-duration heavy rainfall resulting in inundations in the central urban area,influenced by the terrain and environmental conditions.The flash density maximums were found in eastern Changping District,central and eastern Shunyi District,and the central urban area of Beijing,suggesting that the urban heat island effect has a crucial role in the intensification of thunderstorms over Beijing.In addition,the flash rate associated with super thunderstorms can reach hundreds of flashes per minute in the central city regions.The super(5%of the total),strong(35%),and weak(60%)thunderstorms contributed about 37%,56%,and 7%to the total flashes in the BMR,respectively.Owing to the close connection between lightning activity and the thermodynamic and microphysical characteristics of the thunderstorms,the lightning flash rate can be used as an indicator of severe weather events,such as hail and short-duration heavy rainfall.Lightning data can also be assimilated into numerical weather prediction models to help improve the forecasting of severe convection and precipitation at the cloud-resolved scale,through adjusting or correcting the thermodynamic and microphysical parameters of the model.