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41.
青岛局地风特征的分析 总被引:8,自引:0,他引:8
本文根据位于胶州湾东岸的青岛沧口和流亭两机场气象台和唠山区气象台资料及现场实验资料对胶州湾东岸的海陆风气候特征,来自胶州湾与来自南面黄海水域的两支海陆风相互作用及其对沧口地区的影响,崂山西坡下坡风的气候特征及影响进行了分析。文中还提出了一种根据常规气象观测资料估算海陆风发生频率的方法。 相似文献
42.
Observations of the countercurrent on the inshore side of the Kuroshio northeast of Taiwan 总被引:4,自引:0,他引:4
Intensive current measurements in the area northeast of Taiwan indicate subsurface, southwestward flow existed between the inshore edge of the Kuroshio and the East China Sea continental slope. At 70 km away from Taiwan, this countercurrent has a mean speed about 30 cm s–1 at mid-depth. Closer to Taiwan, the flow turns along with the topography, and subjects to sidewall and bottom friction. Both the magnitude and the vertical shear of this countercurrent are comparable with that inferred from hydrographic survey. The wind field features short-period (a few days) fluctuations associated with the cold front passages, however, this is not reflected on the current records. It appears that the countercurrent is fairly steady. Together with similar reversing flow found at places much further to the north, the overall pattern seems to be a general quasi-steady feature along most part of the shelf edge of the East China Sea. 相似文献
43.
A geomorphological and statistical analysis of slope canyons from the northern KwaZulu-Natal continental margin is documented
and compared with submarine canyons from the Atlantic margin of the USA. The northern KwaZulu-Natal margin is characterized
by increasing upslope relief, concave slope-gradient profiles and features related to upslope growth of the canyon forms.
Discounting slope-gradient profile, this morphology is strikingly similar to canyon systems of the New Jersey slope. Several
phases of canyon incision indicate that downslope erosion is also an important factor in the evolution of the northern KwaZulu-Natal
canyon systems. Despite the strong similarities between the northern KwaZulu-Natal and New Jersey slope-canyon systems, key
differences are evident: (1) the concavity of the northern KwaZulu-Natal slope, contrasting with the ∼linear New Jersey slope;
(2) the relative isolation of the northern KwaZulu-Natal canyons, rather than the dense clustering of the New Jersey canyons;
and (3) the absence of strongly shelf-breaching canyons along the northern KwaZulu-Natal margin. In comparison with the New
Jersey margin, we surmise a more youthful stage of canyon evolution, a result of either the canyons themselves being younger
or the formative processes being less active. Less complicated patterns of erosion resulting from reduced sediment availability
have developed in northern KwaZulu-Natal. The reduction in slope concavity on the New Jersey margin may be the result of grading
of the upper slope by intensive headward erosion, a process more subdued—or less evident—on the KwaZulu-Natal margin. 相似文献
44.
浙江近海大黄鱼 Pseudosciaena crocea( Richardson )的性成熟特性 总被引:2,自引:0,他引:2
鱼类性成熟的开始是鱼类生命周期中转入繁衍后代的一个重要阶段。同一世代的个体开始性成熟的年龄、大小,以及延续期限与速度,是种和种内种群对水域生活条件的适应属性之一。
研究鱼类性成熟过程的特点,不仅在解决鱼类种群数量的预测与控制问题中,对补充过程的了解具有重大的意义,而且也为制订合理的渔业经营管理措施提供必要的生物学依据。
本文主要在于探讨浙江近海大黄鱼种群的性成熟特点及其影响因子;其次,讨论该特点在这一种群数量上的意义;并对捕捞规格(法定许可捕捞的鱼体大小和年龄等生物学指标)问题提出初步意见。
在这项工作中,单才根、滕文法和蓝志满等同志曾协助搜集资料、耳石制片和计算工作。在资料的收集中,得到洞头公社和温州地方水产部同的大力支持;本文承张孝威教授热情指导,井承成庆泰副教授等提出宝贵意见,均此谨表谢忱。 相似文献
45.
An experimental set-up is developed and proved to be effective for laboratory study of an underwater towed system. The experimental technique gives a practical method for monitoring the kinematic and dynamic performance of an underwater towed system in a ship towing tank. Both the theoretical and experimental results in the investigation indicate that the hydrodynamic response of a towed vehicle to the wave induced motion of a towing ship can be significantly reduced by applying a two-part tow method. A comparison of the numerical and experimental results in the investigation demonstrates that the numerical simulation results are close to the experimental data, overall agreement between experimental and theoretical results is satisfactory. The results qualitatively verify the mathematical model of a two-part underwater towed system proposed by Wu and Chwang [Wu, J., Chwang, A.T., 2000. A hydrodynamic model of a two-part underwater towed system. Ocean Engineering 27 (5), 455–472]. 相似文献
46.
Based on the ray theory and Longuet-Higgins’s linear model of sea waves, the joint distribution of wave envelope and apparent wave number vector is established. From the joint distribution, we define a new concept, namely the outer wave number spectrum, to describe the outer characteristics of ocean waves. The analytical form of the outer wave number spectrum, the probability distributions of the apparent wave number vector and its components are then derived. The outer wave number spectrum is compared with the inner wave number spectrum for the average status of wind-wave development corresponding to a peakness factor P = 3. Discussions on the similarity and difference between the outer wave number spectrum and inner one are also presented in the paper. 相似文献
47.
48.
胶州湾是我囻黄海南部对虾的重要产卵场之一,每年4月中国对虾(Penaeus chinensis)亲体陆续进人胶州湾,进行产卵活动。繁殖的幼对虾生长迅速,至8月下旬虾群平均体长可达13cm左右,成为秋汛渔业的重要捕捞对象。近年由于捕捞力量加强等诸多因素,湾内对虾的年渔获量由70年代的2-5t,减至80年代的1-2t。虽然1984年以来有关部门实施对虾增殖放流,对虾资源量有所回升,但是因春季洄游的亲体(雌虾)数量锐减,7-8月间又使用各种网具违捕幼虾,因而极大地损害了幼虾资源。刘瑞玉等(1992)曾调查研究了胶州湾对虾生物资源。本文根据作者1991年以来5月和8月的对虾拖网调査资料,对胶州湾对虾资源的生态分布及其变动原因进行了分析研究,对加强管理和保护幼虾资源,以及提高对虾产量有极其重要的意义。 相似文献
49.
Numerical analysis of the sea (lake) breeze dynamics and initialization of the model 总被引:1,自引:0,他引:1
Wu Zengmao 《海洋学报(英文版)》1989,8(4):535-547
In this paper, analysed are the effects of synoptic wind, earth-rotation inertia and land surface roughness on sea (lake) breeze process, on the basis of the calculated results of a 2-D primitive equation model with turbulent energy closure. The results show that a moderate background wind field acts as a trigger for sea (lake) breeze onset, and presents prominent effect on the breeze intensity, inland advance rate and structure feature. The effects of Coriolis force not only make the breeze veering round, but also damp the development of the breeze component normal to shore.The paper also discussed the dynamic method of wind field initialization based on one-site radiosonde. Three approaches of initialization have been tested. In comparison, it was found that the approach of one-dimensional dynamic initialization with nudging term was preferable to the others. 相似文献
50.
随着石油化学工业的发展,由石油裂解产物制成的合成洗涤剂的产量正在飞速增长。1960年到1972年,我国合成洗涤剂产量增长了16倍,1984年年产量已达70多万吨,而且近年来有更大的增长趋势。一般的洗衣粉约含20%的表面活性物质,其余主要是增净剂(如磷酸盐、硅酸盐、硫酸盐、碳酸盐)等。表面活性剂根据其在水溶液中显示出的离子特性,可分为阴离子表面活性剂、阳离子表面活性剂、两性表面活性剂和非离子表面活性剂等四类。我国生产的合成洗涤剂以阴离子型为主,占总产量的70%以上。
合成洗涤剂的广泛应用产生了一系列环境污染问题,特别是对水生生物的影响和危害已引起人们的关注。目前,国内外对此问题正从以下几方面开展研究:(1)大量洗涤剂排入水体产生泡沫层并消耗溶解氧而引起的水质和底质的恶化;(2)表面活性剂本身对生物的急性和慢性的致毒效应;(3)表面活性剂的界面活性作用所引起的水环境中污染物界面交换过程的变化,以及由此而产生的生物效应;(4)洗涤剂中的增净剂等成分所引起的水质富营养化等。
另一方面,我们也注意到,不仅大量生活和工业用洗涤剂随废水进入河口浅海区后对生态环境的影响值得重视,而且研究其在河口区的地球化学特征,显然能为河口海域环境特征及污染状况的研究提供重要的信息。然而国内尚未见有我国河口海域阴离子洗涤剂含量分布的任何资料。在国外虽然有过这方面工作的某些报道(Ambe, 1973; Gagnon,1983),但以河口水体、底泥及其诸环境因素作为一个整体来考察阴离子表面活性剂的行为及其环境意义的工作还属罕见。为此,我们研究拟定了简便快速测定阴离子表面活性剂的方法,结合海河口有机污染的调查,进行了这方面的研究工作。 相似文献