青鱼(Mylopharyngodon piceus)新发病病原类志贺邻单胞菌(Plesiomonas shigelloides)的分离鉴定     

叶键  刘晓宁  王晓  徐慧  沈文英  高敏杰  章晓栋 《海洋与湖沼》2016,47(3):633-639

为研究青鱼暴发性死亡原因,从病症典型青鱼(Mylopharyngodon piceus)肌肉、肝脏和肾脏处进行细菌接种,分离获得一株细菌(HZ2015),对其进行了形态观察、生化特性检测和16S r RNA序列分析,通过动物回归实验、毒力检测和药敏试验了解其对青鱼的致病性、毒力及药物敏感性。所得菌株为类志贺邻单胞菌(Plesiomonas shigelloides),动物回归实验能复制出类似症状,且能从体内再次分离到该菌株;分离株对小鼠的半数致死量(LD50)为106.6 CFU;对头孢呋辛、头孢哌酮、庆大霉素、卡那霉素、复达欣高度敏感。研究表明,菌株HZ2015为青鱼体表溃烂病病原,本研究系类志贺邻单胞菌致青鱼体表溃烂病的首次报道。  相似文献   

秋季南黄海浮游动物分布及其影响因素   总被引：3，自引：1，他引：2  

王晓  姜美洁  刘萍  张学雷  王燕  王宗灵 《海洋学报》2016,38(10):125-134

基于2007年秋季在南黄海（32°20'~37°00'N;124°E以西）进行的浮游动物及环境因子大面调查;分析了秋季南黄海浮游动物种类组成、分布特征及其影响因素;主要结果如下:共鉴定浮游动物113种（不包括25种浮游幼体）;中华哲水蚤（Calanus sinicus）、强壮滨箭虫（Aidanosagitta crassa）、磷虾幼体（Euphausia larvae）和小齿海樽（Doliolum denticulatum）是秋季优势种;浮游动物丰度为（156.37±12.04）ind/m3;生物量为（172.57±10.41）mg/m3;与历史调查数据相比;本航次浮游动物丰度和生物量相对处于较高水平;磷虾幼体分布趋势与中华假磷虾（Psudeuphausia sinica）一致;说明秋季是中华假磷虾种群的一个重要的补充时期;小齿海樽在南黄海的大量出现系自身种群补充的结果;精致真刺水蚤（Euchaeta concinna）和肥胖软箭虫（Flaccisagitta enflata）主要分布在深水区;在近岸海区很少出现。中华哲水蚤、强壮滨箭虫丰度高值区倾向分布于海洋锋附近;进一步佐证了海洋锋对浮游动物的积聚作用。  相似文献   

南海上层经向翻转环流的低频变化     

杨志通  罗义勇 《海洋学报(英文版)》2016,35(3):10-20

The low-frequency variability of the shallow meridional overturning circulation(MOC) in the South China Sea(SCS) is investigated using a Simple Ocean Data Assimilation(SODA) product for the period of 1900–2010. A dynamical decomposition method is used in which the MOC is decomposed into the Ekman, external mode, and vertical shear components. Results show that all the three dynamical components contribute to the formation of the seasonal and annual mean shallow MOC in the SCS. The shallow MOC in the SCS consists of two cells: a clockwise cell in the south and an anticlockwise cell in the north; the former is controlled by the Ekman flow and the latter is dominated by the external barotropic flow, with the contribution of the vertical shear being to reduce the magnitude of both cells. In addition, the strength of the MOC in the south is found to have a falling trend over the past century, due mainly to a weakening of the Luzon Strait transport(LST) that reduces the transport of the external component. Further analysis suggests that the weakening of the LST is closely related to a weakening of the westerly wind anomalies over the equatorial Pacific, which leads to a southward shift of the North Equatorial Current(NEC) bifurcation and thus a stronger transport of the Kuroshio east of Luzon.  相似文献   

星载SAR对雨团催生海面风场的观测研究   总被引：2，自引：1，他引：1  

叶小敏  林明森  袁新哲  丁静  解学通  张毅  徐莹 《海洋学报(英文版)》2016,35(9):80-85

雨团或对流雨是热带与亚热带地区的主要降雨形式,较易被高分辨率星载合成孔径雷达（SAR）探测到。SAR图像上的雨团足印是由大气中雨滴的散射与吸收、下沉气流等共同导致形成的。本文以RADARSAT-2卫星100 m分辨率的SAR图像上雨团引起的海面风场及其结构反演与解译作为实例进行分析。使用CMOD4地球物理模式函数,分别以NCEP再分析数据、欧洲MetOp-A卫星先进散射计（ASCAT）和中国HY-2卫星微波散射计的风向为外部风向,进行了SAR图像的海面风场反演。反演的海面风速相对于NCEP、ASCAT和HY-2的均方根误差（RMSE）分别为1.48 m/s,1.64 m/s和2.14 m/s。SAR图像上一侧明亮另一侧昏暗的圆形信号图斑被解译为雨团携带的下沉气流对海面风场（海面粗糙度）的改变所致。平行于海面背景风场其通过雨团圆形足印中心的剖面上的风速变化可拟合为正弦或余弦曲线,其拟合线性相关系数均不低于0.80。背景风场的风速大小、雨团引起的风速大小以及雨团足印的直径可利用拟合曲线获得,雨团足印的直径大小一般为数千米或数十千米,本文的8例个例解译与分析均验证了该结论。  相似文献   

阿尔金北缘岩石变形机制——来自X光组构分析的证据     

何江涛  陈柏林  王永  孟令通  吴玉  韩梅梅  王斌 《地质通报》2016,35(1):123-129

对阿尔金北缘地区变形蚀变花岗岩、花岗质糜棱岩、变形酸性火山岩和变形英安质凝灰岩中石英和绢云母2种矿物进行X光岩石组构分析,认为本区岩石变形比较明显,宏观面理近于东西向展布,绢云母变形较强,平行于面理定向排列;而石英以底面或近底面滑移为主,部分样品兼有柱面Ⅰ型滑移和柱面Ⅱ型滑移,反映本区岩石变形机制为中浅层次的脆-韧性变形(10~15km、250~350℃、0.25~0.40GPa)。通过岩石组构特征与宏观面理产状,推断本区韧性变形以右行运动为主,与板块碰撞在阿尔金北缘大平沟地区产生的韧性变形带特征一致。  相似文献   

高压超高压变泥质岩适用的地质温压计评述     

王晓赛  杜瑾雪  田野 《岩石矿物学杂志》2018,37(2):325-341

高压超高压变泥质岩形成温压条件及p-T演化轨迹是高压超高压变质作用研究的重要内容。本文介绍了高压超高压变泥质岩适用的几种地质温压计,包括石榴子石-多硅白云母Fe~(2+)-Mg交换温度计、石榴子石-绿泥石Fe~(2+)-Mg交换温度计、硬绿泥石-绿泥石Fe~(2+)-Mg交换温度计、多硅白云母Si含量压力计、金红石Zr含量温度计、榍石Zr含量温压计、锆石Ti含量温度计、石英Ti含量温度计以及氧同位素温度计,并对上述温压计的适用条件及使用时的注意事项做了简要评述。  相似文献   

四川马边、雷波地区峨眉山玄武岩地球化学特征及其成因     

杨辉  马继跃  朱兵  张芹贵  伏国通  田野 《四川地质学报》2018,(1)

对马边、雷波地区峨眉山玄武岩岩石学,岩石地球化学特征等研究表明,玄武岩浆可能来源于富集型下地幔、地幔石榴子石二辉橄榄岩低程度部分熔融区;马边沙腔玄武岩源区的部分熔融程度略微低于雷波地区玄武岩。峨眉山玄武岩地壳混染程度较低,在岩浆上升演化过程中经历了早期以单斜辉石为主的分离结晶作用,晚期存在不同程度的斜长石结晶;马边沙腔地区则具有较为强烈的橄榄石分离结晶。  相似文献   

华南区域高分辨率数值模式前汛期预报初步评估     

林晓霞  冯业荣  陈子通  简云韬 《热带气象学报》2021,37(4):656-668

基于华南地区自动站逐小时观测资料, 采用传统站点评分、邻域法等评估华南区域高分辨率数值模式(包括GRAPES_GZ_R 1 km模式和GRAPES_GZ 3 km模式)对降水、地面温度和风场等要素的预报能力。结果表明: GRAPES_GZ_R 1 km模式的降水预报技巧优于GRAPES_GZ 3 km模式, 模式预报以正偏差为主。对于不同起报时间的预报, 00时(世界时, 下同)起报的预报效果优于12时。GRAPES_GZ_R 1 km模式的TS评分是GRAPES_GZ 3 km模式的两倍以上, 对不同降水阈值的评分均较高。分数技巧评分(FSS)显示GRAPES_GZ_R 1 km模式6 h累计降水预报在0.1 mm、1 mm及5 mm以上的降水均可达到最低预报技巧尺度, 对所检验降水对象的空间位置把握能力更好。2 m气温和10 m风速检验结果表明两个模式均能较好把握广东省温度的分布特征, GRAPES_GZ_R 1 km模式对2 m气温预报结果优于GRAPES_GZ 3 km模式, 预报绝对误差更小; 两个模式对风速的预报整体偏强, 预报偏差在1~4 m/s之间, 但相比之下GRAPES_GZ 3 km模式在风场预报上表现更好。GRAPES_GZ_R 1 km模式的2 m气温和10 m风速预报偏差随降水过程存在明显波动, 强降水过后温度预报整体偏低, 风速预报偏强, 在模式产品订正、使用等需要考虑模式对主要天气系统的预报情况。总的来说, GRAPES_GZ_R 1 km模式的预报产品具有较好的参考价值。   相似文献   

Verification and Assessment of Real-time Forecasts of Two Extreme Heavy Rain Events in Zhengzhou by Operational NWP Models     

钟水新  庄妍  胡胜  陈子通  丁伟钰  冯业荣  邓涛  刘显通  张艳霞  徐道生  戴光丰  蒙伟光 《热带气象学报(英文版)》2021,27(4):406-417

In the present study, the performances of the NWP models on two heavy rainfalls on 20 July and 22 August 2021 over Henan Province were investigated. The impacts of the water vapor transport to the extreme rainfall were further discussed. The results showed that the regional model system in the Guangzhou Meteorological Service generally showed high scores on the extreme rainfall over Henan. The maximum 24h accumulative rainfall by the 24h forecasts by the CMA-GD reached 556 mm over Henan Province. The 24-h and 48-h Threat Score (TS) of heavy rainfall reached 0.56 and 0.64. The comparisons of the Fraction Skill Score (FSS) verifications of the heavy rainfall by CMA-GD and CMA-TRAMS at the radium of 40km reached 0.96 and 0.87. The water vapor transport to the extreme rainfall showed that the vertically integrated water vapor transport (IVT) of the whole layer before the occurrence of the heavy rainfall exhibited a double-eyes distribution in case 7 · 20. The north eye over Henan reached the same magnitude of IVT as the typhoon eye (Cempaka) over south China. The IVT over the lower troposphere (<500 hPa) showed an overwhelming magnitude than the upper level, especially in the planetary boundary layer (<700 hPa). More practical technical needs to be developed to improve its performances on the forecasting of extreme rainfall, as well as more experiments need to be conducted to examine the effects of the specific terrain and physical schemes on the extreme rainfall.  相似文献   

Assimilation of Polarimetric Radar Data Using an Ensemble Kalman Filter for the Analysis and Forecast of Tropical Storm Ewiniar     

黎慧琦  刘显通  肖辉  万齐林 《热带气象学报(英文版)》2021,27(2):94-108

This study explores the potential for directly assimilating polarimetric radar data (including reflectivity Z and differential reflectivity ZDR) using an ensemble Kalman filter (EnKF) based on the Weather Research and Forecasting (WRF) model to improve analysis and forecast of Tropical Storm Ewiniar (2018). Ewiniar weakened but brought about heavy rainfall over Guangdong, China after its final landfall. Two experiments are performed, one assimilating only Z and the other assimilating both Z and ZDR. Assimilation of ZDR together with Z effectively modifies hydrometeor fields, and improves the intensity, shape and position of rainbands. Forecast of 24-hour extraordinary rainfall ≥250 mm is significantly improved. Improvement can also be seen in the wind fields because of cross-variable covariance. The current study shows the possibility of applying polarimetric radar data to improve forecasting of tropical cyclones, which deserves more researches in the future.  相似文献