河流功能区划方法及实例研究

河流功能区划是规范和引导各类河流功能开发利用行为的基础工作。按照中国河流功能属性特点并考虑流域管理的需求,分析了河流功能区划的理论依据和区划原则,构建了由属性层、区划层、指标层和管理层4个层面构成的河流功能区划体系,给出了河流功能区的区划方法和具体的操作步骤。以太浦河为例进行了河流功能区划实例研究,提出了太浦河河流功能区划成果及其管理目标与对策。结果表明,提出的河流功能区划的方法是合理、可行的,能够为河流管理提供一个新途径。     

正交曲线坐标系二维浅水方程ELADI有限差分方法

N-S方程数值模拟的精度和效率一直是计算流体力学的重要研究课题.结合欧拉-拉格朗日方法(ELM)和交替方向隐式方法( ADI)建立正交曲线坐标系二维浅水方程的ELADI (Eulerian-Lagrangian alternating direction implicit method)有限差分方法,详细阐述了基本原理...     

海洋微型底栖生物调查方法与操作规程

海洋微型底栖生物包括底栖细菌、底栖微藻及底栖原生动物等单细胞原核和真核生物,是底栖微食物网中能量传递的基础和关键环节,在海洋生物地球化学循环过程中起着重要作用.然而我国现有的<海洋调查规范>国家标准中有关底栖生物的研究仅涉及利用网筛分选的大型和小型底栖动物,缺少微型底栖生物调查的方法与规程,严重制约了对海洋整体食物网能...     

High-frequency atmospheric variability over South China Sea as depicted by TRMM and QuikSCAT

By using the TRMM and QuikSCAT datathe characteristics of the 2–8 day high frequency atmospheric variability over the South China Sea are studied in this paper.It’s found that: (1) the 2–8 day high frequency signals are significant not only during the periods of the South China Sea Summer Monsoon (SCSSM),but also after the retreat of the SCSSM.It reaches its peak around July to August;(2) the 2–8 day high frequency signals exhibit strong intermittent features;(3) During El Nino years,the 2–8 day high freque...     

半滑舌鳎（Cynoglossus semilaevis）野生与养殖群体遗传多样性的比较研究

采用扩增片段长度多态性技术（AFLP技术）对2个野生和2个养殖的半滑舌鳎群体进行了遗传多样性的比较研究。实验采用8对AFLP引物组合,在四个群体的120个个体中共扩增出498个位点。结果表明,半滑舌鳎养殖群体的遗传多样性降低：河北唐山野生群体和江苏连云港野生群体的多态位点百分数分别为45．18％和39．96％,Nei遗...     

Investigation of the thermodynamic processes of a floe-lead system in the central Arctic during later summer

Thermodynamic processes of a system involving a floe and a small lead in the central Arctic were investigated during the ice-camp period of the third Chinese National Arctic Research Expedition from 20 to 28 August, 2008. The measurements included surface air temperatures above the floe, spectral albedo of the lead, seawater temperatures in the lead and under the ice cover, and the lateral and bottom mass balance of the floe. The surface air temperature at 1.15 m remained below 0℃ throughout the observation period and sea ice had commenced its annual cycle of growth in response to autumn cooling during the study. The surface of the lead was frozen by 23 August, after which the spectral albedo of the thin-ice-covered lead in the band of 320-950 nm was 0.46 ±0.03, the seawater temperatures both in the lead and under the ice cover, as well as the vertical seawater-temperature gradient in the lead decreased gradually, and the oceanic heat under the ice was maintained at a low level approaching 0 W/m2. By the end of the measurement, the thickness of the investigated floe had reached its annual minimum, while the lateral of the floe was still in the melting phase, with a mean melting rate of 1.0 ±0.3 cm/d during the measurement, responding to an equivalent latent heat flux of 21 ±6 W/m2. The lateral melting of the floe had made a more significant contribution to the sea-ice mass balance than the surface and bottom melting in the end of August.     

Comparison of Ozone and PM2.5 Concentrations over Urban,Suburban, and Background Sites in China

Surface ozone (O₃) and fine particulate matter (PM_2.5) are dominant air pollutants in China. Concentrations of these pollutants can show significant differences between urban and nonurban areas. However, such contrast has never been explored on the country level. This study investigates the spatiotemporal characteristics of urban-to-suburban and urban-to-background difference for O₃ (Δ[O₃]) and PM_2.5 (Δ[PM_2.5]) concentrations in China using monitoring data from 1171 urban, 110 suburban, and 15 background sites built by the China National Environmental Monitoring Center (CNEMC). On the annual mean basis, the urban-to-suburban Δ[O₃] is ?3.7 ppbv in Beijing–Tianjin–Hebei, 1.0 ppbv in the Yangtze River Delta, ?3.5 ppbv in the Pearl River Delta, and ?3.8 ppbv in the Sichuan Basin. On the contrary, the urban-to-suburban Δ[PM_2.5] is 15.8, ?0.3, 3.5 and 2.4 μg m^?3 in those areas, respectively. The urban-to-suburban contrast is more significant in winter for both Δ[O₃] and Δ[PM_2.5]. In eastern China, urban-to-background differences are also moderate during summer, with ?5.1 to 6.8 ppbv for Δ[O₃] and ?0.1 to 22.5 μg m^?3 for Δ[PM_2.5]. However, such contrasts are much larger in winter, with ?22.2 to 5.5 ppbv for Δ[O₃] and 3.1 to 82.3 μg m^?3 for Δ[PM_2.5]. Since the urban region accounts for only 2% of the whole country’s area, the urban-dominant air quality data from the CNEMC network may overestimate winter [PM_2.5] but underestimate winter [O₃] over the vast domain of China. The study suggests that the CNEMC monitoring data should be used with caution for evaluating chemical models and assessing ecosystem health, which require more data outside urban areas.     

基于分位数映射法的黑河上游气候模式降水误差订正

区域气候模式降水弥补了高寒山区气象站点稀少的缺陷,是水文模拟的重要驱动变量。然而,高寒山区模式输出降水的总量和频率都存在较大不确定性。因此,改进了用于降水频率纠正的分位数映射法(Quantile Mapping,QM),对中尺度数值预报模式(Weather Research and Forecasting model,WRF)模拟的黑河上游日降水输出数据进行误差订正。选取第95分位和第98分位降水量为阈值,选择2004-2009年为建模时段,2010-2013年为验证时段,使用分段拟合的方法建立传递函数,侧重于对极端降水进行单独订正。研究结果表明:该方法不仅对降水空间分布有明显的改善,对极端降水也有很好的订正效果。订正前模式模拟日降水与台站之间的均方根误差为3.41 mm·d^-1,绝对偏差为115.67 mm·y^-1,订正后均方根误差减少为3.11 mm·d^-1,绝对偏差有明显改善,为60.3 mm·y^-1。订正后流域内年降水空间分布更加合理,年降水量也更接近于观测降水插值结果,其空间相关系数由0.74改善为0.94。春、夏季订正效果优于秋、冬季,其中夏季订正效果较为明显,订正前降水偏差百分比在-0.1~0.1以内的区域面积仅占流域总面积的28%,而订正后占比增加至66%。同时,该方法对极端降水有较好的订正效果,减小了日降水强度(SDII)和极强降水量(R99p)的模拟偏差,订正后的第95分位模拟降水与观测降水插值的相关系数由0.15提高到0.48。本研究为站点稀少的黑河上游提供了一种更有效的误差订正方案,有利于为寒区水文研究获取更精确的降水数据。     

春季西南热低压的发生发展与结构特征

通过普查1997-2006年3-5月典型西南热低压天气过程,分析其气候特征,归纳热低压的生命史,将其分为4个不同的发展阶段:初生、成熟、相持和填塞.利用台站观测资料和NCEP 1°×1°及2.5°×2.5°再分析资料,对7次典型的春季西南热低压过程进行合成分析,揭示了成熟阶段和填塞阶段热低压结构特征.分析结果表明:在春季西南热低压系统控制下,气压降幅显著,气温升高、相对湿度降低,午后偏南风加大,气象要素具有明显的日变化特征;68％的热低压会给西南地区造成35℃以上的高温,32％的热低压给贵州造成高温.热低压系统为浅薄暖性低压,干区深厚,低压区为辐合区、正涡度区,以上升运动为主,并且是对流性不稳定.热低压填塞阶段,受冷空气侵入,低压北侧偏北风加大,近地层气旋的辐合增强,低压内为高能区,在冷空气的向南推进过程中,易出现强对流天气.     

基于遥感水质的夏季东海鲐鱼渔情预报研究

根据2007~2009年7~9月渔汛期间我国鲐鱼灯光围网在东海的生产数据,利用海表温、叶绿素浓度、悬浮物浓度和透明度等遥感水质数据,分别将作业网次比例和单网次产量(CPUE)作为适应性指数,利用算术平均数(AM)和几何平均数(GM)分别建立基于海表温、叶绿素浓度、悬浮物浓度和透明度的综合栖息地指数模型。结果表明,AM栖息地指数模型和GM栖息地指数模型拟合效果较好(P<0.01),在HSI大于0.5的海域,2007~2009年7~9月平均作业网次比例在65%以上,各月平均CPUE均高于19.82 t/net。研究认为,AM模型稍优于GM模型。利用2010年7~9月生产数据及遥感水质数据对AM模型进行验证,分析认为,87%以上的作业网次和产量分布在HSI高于0.5的海域,CPUE为14~17 t/net,且较稳定,波动较小。研究认为,基于遥感水质数据的AM栖息地指数模型能较好地预测东海鲐鱼渔场。