大伙房和柴河两水库的环境因子同鲢、鳙生长和产量变动的关系   总被引：2，自引：1，他引：2  

史为良  夏德昌  董双林  王立柱  刘兴河 《海洋与湖沼》1994,25(1):77-86

对辽宁省大伙房水库（１９８０－１９８７）和柴河水库（１９８１－１９８７）的水文、理化和生物数据，与这两座库同时间的不投饵网箱养殖的鲢、鳙鱼种的生长和产量进行回归分析。结果表明，７－８月的入库水量和出库水量、９月与６月间的水位差等参数同鲢，鳙均重及产量相关显著，用它们来估测大体鲢、鳙的生长与产量是可行的。  相似文献   

南极冰藻极端环境适应性的研究进展   总被引：1，自引：0，他引：1  

王守强  缪锦来  郑洲  王波  李光友 《海洋科学进展》2005,23(Z1):95-100

南极冰藻对南极海冰生态系统初级生产力的直接贡献率超过20%,是地球上能够在海冰中旺盛生长的罕见的生物群落.单细胞的南极冰藻,在低温、低光照和高盐度的海冰盐囊中能够生存是其在生理、代谢和遗传上进行了复杂的适应性改变,通过产生特殊的冰活性物质、不饱和脂肪酸、色素蛋白复合物等来适应这种极端环境.同时,尽管南极臭氧层被破坏甚至出现巨大空洞,紫外线辐射显著增强,但对南极冰藻的影响并不明显.南极冰藻中的抗辐射活性物质可能起着重要作用,这些抗辐射物质往往结构新颖且活性强,能消除或减轻紫外线的伤害.  相似文献   

Analytical Research on Wave Diffraction on Arc-Shaped Bottom-Mounted Perforated Breakwaters     

程建生缪国平  王景全 《中国海洋工程》2007,21(3):417-428

An analytical method is developed to study wave diffraction on arc-shaped and bottom-mounted perforated breakwaters.The breakwater is assumed to be rigid,thin,vertical,immovable and located in water of constant depth.The fluid domain is divided into two regions by imaginary interface.The velocity potential in each region is expanded by eigenfunctions.By satisfying the continuity of pressure and normal velocity across the imaginary fluid interface,a set of linear algebraic equations can be obtained to determine the unknown coefficients of eigenfunctions.Numerical results,in the form of contour maps of the relative wave amplitude around the breakwater,are presented for a range of wave and breakwater parameters.Results show that the wave diffraction on the arc-shaped and bottom-mounted perforated breakwater is related to the incident wavelength and the porosity of the breakwater.The porosity of the perforated breakwater may have great effect on the diffracted field.  相似文献   

4种南极冰藻的生化组成对UV - B辐射增强的响应   总被引：4，自引：1，他引：4  

缪锦来  阚光锋  姜英辉  张波涛  李灏  侯旭光  李光友 《海洋科学》2004,28(9):26-31

实验室人工模拟南极UV—B辐射环境，对南极冰藻的生化组成变化进行了测定和分析，结果表明．UV—B辐射增强(70μW／cm^2)后，4种南极冰藻的总蛋白含量显著减少，其中脯氨酸、羟脯氨酸等6种氨基酸增加，谷氨酸、缬氨酸等减少；总脂含量明显增加，绿藻增加30％以上，硅藻增加超过15％；饱和脂肪酸含量降低，不饱和脂肪酸含量增加，并且产生了一些新的不饱和脂肪酸；Mg、Na和Al元素的含量显著降低，而Fe、Ca、Zn、Mn等含量却明显增加。总体来说，4种南极冰藻的灰分含量显著下降，有机成分明显增加。表明了南极冰藻对UV—B增强的积极响应．能调整自身对强辐射环境的适应性，这为深入研究冰藻对南极强辐射环境的适应性提供了科学依据。  相似文献   

地方院校应用技术型专业本硕一体化培养模式探讨——以广西师范学院地理信息科学专业为例     

赵银军  苗亚琼  邓青 《测绘与空间地理信息》2017,(3)

地方院校应用技术型专业构建"本硕一体化"人才培养模式,是适应新时期地方院校教育改革和促进学生自我能力发展的有效探索。本文从应用技术型专业特征入手,以广西师范学院地理信息科学专业为例,探索了地方院校应用技术型专业"本硕一体化"培养的可行性,并从生源选择、培养方式等方面解析了"本硕一体"培养模式,以期为地方院校的教育改革提供思路及参考。  相似文献   

Evaluation of NTCM-BC and a proposed modification for single-frequency positioning   总被引：1，自引：0，他引：1  

Xiaohong Zhang  Fujian Ma  Xiaodong Ren  Weiliang Xie  Feng Zhu  Xin Li 《GPS Solutions》2017,21(4):1535-1548

Ionospheric delay is a dominant factor that affects the accuracy of single-frequency positioning. Thus, an empirical ionospheric model with high accuracy is very important for single-frequency users. This study proposes a modified empirical broadcast ionospheric model, called MNTCM-BC, based on the Neustrelitz Total Electron Content (TEC) broadcast model NTCM-BC. Nine daily ionospheric coefficients of these models are estimated using datasets of the previous day from 30 globally distributed Global Navigation Satellite System monitor stations, and the prediction performance of the MNTCM-BC is evaluated with the datasets of the current day from all 300 verification stations. The results show that the complex behavior of the ionosphere is well described by the MNTCM-BC, including the visibility of two ionization crests on both sides of the geomagnetic equator and the TEC variations that depend on the local time and geomagnetic latitude. In terms of the prediction accuracy, compared with the NTCM-BC, the main improvement in the MNTCM-BC is achieved in summer, whereas the accuracy is comparable in other seasons. Hence, the following analyses are focused on summer. In the low-solar activity year of 2009, the prediction accuracy of the MNTCM-BC is improved by 0.11 TECU compared with that of the NTCM-BC. As to the high-solar activity year of 2014, the corresponding improvement is 0.35 TECU. In addition, when the number of monitor stations is increased from 30 to 300, the prediction accuracy of two models can be slightly improved by 0.06 TECU in 2009 and 0.13 TECU in 2014, respectively, while reliability enhances. Furthermore, the average three-dimensional positioning accuracy of 160 globally distributed stations for single-frequency point positioning using the Klobuchar model, the NTCM-BC and the MNTCM-BC is 1.83, 1.21 and 1.20 m during quiet day and 3.15, 2.31 and 2.21 m during perturbed day, respectively. Relative to the Klobuchar model and the NTCM-BC, the average accuracy improvements in the MNTCM-BC are about 30 and 3%, respectively.  相似文献   

关于自然资源资产负债表改革试点工作的几点思考     

苗强  张建军 《国土资源情报》2017,(6)

自然资源资产负债表是我国生态文明建设中的重大理论创新和积极探索.目前,全国8个试点地区总体进展情况良好,但自然资源资产负债表整体设计上侧重于资源存量和流量的统计核算,基本未与领导干部自然资源资产离任审计等重大制度有效衔接,无法全面反映地方各级政府的工作量和成效,资源资产变化也无法准确全面地反映生态环境的变化.建议对资源调查统计标准进行改进和对接,并将自然资源资产负债表与各类资源保护制度相衔接,开展价值量核算.  相似文献   

Evaluation of the trend uncertainty in summer ozone valley over the Tibetan Plateau in three reanalysis datasets   总被引：3，自引：0，他引：3       下载免费PDF全文

Dong Guo  Yucheng Su  Xiuji Zhou  Jianjun Xu  Chunhua Shi  Yu Liu  Weiliang Li  Zhenkun Li 《Acta Meteorologica Sinica》2017,31(2):431-437

Trend uncertainty in the ozone valley over the Tibetan Plateau (OVTP) and the South Asian high (SAH) during 1979–2009 in ERA-Interim (interim reanalysis data from the ECMWF), JRA-55 (55-yr reanalysis data from the Japan Meteorological Agency), and NCEP-CFSR (Climate Forecast System Reanalysis) datasets was evaluated. The results showed that the NCEP-CFSR OVTP became strong in the summers of 1979–2009, whereas it became weak according to ERA-Interim and JRA-55. Satellite data merged with TOMS (Total Ozone Mapping Spectrometer) and OMI (Ozone Monitoring Instrument) agreed with the OVTP trend of NCEP-CFSR. The OVTP strengthening in NCEP-CFSR may have been caused by SAH intensification, a rising tropopause, and increasing ozone over non-TP (non-Tibetan Plateau) areas (27°–37°N, < 75°E and > 105°E). Analogously, the OVTP weakening in ERA-Interim and JRA-55 may have been affected by weakening SAH, descending tropopause, and decreasing non-TP ozone.  相似文献   

FY-3A水汽资料在江淮梅雨强降水系统湿动力诊断中的应用          下载免费PDF全文

苗春生  刘春  王坚红  薛峰 《大气科学学报》2017,40(1):36-47

中国卫星FY-3A水汽产品为大气水汽混合比,对大气各层水汽条件具有精细化描述能力。将卫星水汽混合比空间分布与区域流场对应叠加,进行综合量化分析,是目前卫星监测反演数据研究分析与业务应用的形式之一。由于卫星数据与流场数据为非同源数据,具有各自的坐标系,综合分析需要将坐标系统一,卫星坐标系随时间变化,因此向固定的流场坐标系转化。整个数据预处理过程,包括卫星数据插值至标准等压面层,卫星轨道网格转为经纬等距标准网格;双权重法异常数据剔除;平滑滤除高分辨率"噪音";十折交叉相关检验确认卫星资料精细化特征保持良好。对流场分析首先选择关键系统,江淮梅雨强降水系统主要为浅薄低涡和辐合线,近5 a的统计显示3/5的低涡活跃在江南,2/3的辐合线活跃在淮北。诊断分析合成的江淮梅雨强降水典型系统,获得辐合线系统纬向湿度锋区更强,低涡系统湿舌经向度大,显示更多干湿气团混合。进而将预处理后的FY-3A水汽分布与强降水系统低层流场对应时刻综合比对,结果显示:与流场气旋性辐合区对应的卫星湿区对强降水落区具有精细化指示性。同时FY-3A湿度产品计算的大气低层(1 000~850 h Pa)可降水量、以及降水区对应的假相当位温高能区及高能锋区,均与降水强度呈正比关系。将卫星水汽资料诊断方法应用于近海海域,可估测系统强降水落区以及降水强度,有利于改善海上缺乏降水观测站的问题。  相似文献   

中国南部沿海暴雨东风波特征及SST影响机制研究   总被引：1，自引：1，他引：0       下载免费PDF全文

王坚红  曾喻  彭模  苗春生 《大气科学学报》2017,40(3):333-345

分析1999—2013年影响我国南部沿海的东风波,可分为3类:偏南东风波、西行东风波以及近海东风波。太平洋副热带高压是影响3类东风波特征的关键系统,其西伸与北进直接引导东风波路径及活动位置。东风波的分类合成结构特征显示:强涡度中心指示东风波槽中心,强涡度中心通常位于850 h Pa及以下。东风波低层为强辐合场,槽后有整层的垂直上升区。偏南东风波波槽轴线随高度向西倾斜,西行东风波和近海东风波波槽轴线近乎垂直。合成诊断还显示,东风波的海上移动有向SST(Sea Surface Temperature,海表温度)大值趋暖的趋势。数值模拟证实,增强东风波槽前SST暖中心的强度,将引起槽区低层和槽后中层出现负变高中心,同时SST的增温将通过感热与潜热促使东风波槽强度加强,将进一步地增强东风波暴雨强度和雨带的北移。并增强中低层流场的气旋式气流成分,增强低层辐合场,维持深厚垂直上升运动层。典型西行东风波个例分析显示,螺旋度与东风波强度成正比,东风波纬向位温偏差显示东风波在热力场上具有"上暖下冷"的不稳定垂直结构。东风波涡度增强时,扰动动能向分层扰动位能转化。东风波强度减弱时,分层扰动位能向扰动动能转化。  相似文献