Effects of climate variability on the distribution and fishing conditions of yellowfin tuna (Thunnus albacares) in the western Indian Ocean     

Kuo-Wei Lan  Karen Evans  Ming-An Lee 《Climatic change》2013,119(1):63-77

Variations in the abundance and distribution of pelagic tuna populations have been associated with large-scale climate indices such as the Southern Oscillation Index in the Pacific Ocean and the North Atlantic Oscillation in the Atlantic Ocean. Similarly to the Pacific and Atlantic, variability in the distribution and catch rates of tuna species have also been observed in association with the Indian Ocean Dipole (IOD), a basin-scale pattern of sea surface and subsurface temperatures that affect climate in the Indian Ocean. The environmental processes associated with the IOD that drive variability in tuna populations, however, are largely unexplored. To better understand these processes, we investigated longline catch rates of yellowfin tuna and their distributions in the western Indian Ocean in relation to IOD events, sea surface water temperatures (SST) and estimates of net primary productivity (NPP). Catch per unit effort (CPUE) was observed to be negatively correlated to the IOD with a periodicity centred around 4 years. During positive IOD events, SSTs were relatively higher, NPP was lower, CPUE decreased and catch distributions were restricted to the northern and western margins of the western Indian Ocean. During negative IOD events, lower SSTs and higher NPP were associated with increasing CPUE, particularly in the Arabian Sea and seas surrounding Madagascar, and catches expanded into central regions of the western Indian Ocean. These findings provide preliminary insights into some of the key environmental features driving the distribution of yellowfin tuna in the western Indian Ocean and associated variability in fisheries catches.  相似文献   

ENVIRONMENTAL CHANGES SINCE LATE PLEISTOCENE IN ESTUARINE PLAIN OF JIULONG RIVER, FUJIAN PROVINCE     

陈文瑞  蓝东兆  陈承惠  朱大奎 《中国地理科学(英文版)》1997,7(4):375-382

TheestuarineplainoftheJiulongRiver,whichisthesecondlargestrivernexttotheMinjiangRiverinFujianPrc)vince,intervenesbetweenXi~enandZhangzhoucitiesinthesouthoftheprovince.'I'heplainconsistsofthreeparts:thenorthernplain,thesouthernPlainandZiniIsles.Withsoutllcrn--Subtr<)picoceanicm(>nasexinclimate,itdevelol>saregionalvegetationtypeofeveTgreen13r(Jad--lcav(3dfores[,ofwhicll,however,mosthasbeendestroyedbyhumanbeing.Nowaday-s.shruborgrasslandvegetationcanbeseenonthehillsintheviciTlily'ofthisarea…  相似文献   

浅谈我国高校开设民俗类公共选修课的意义     

刘岚 《广东海洋大学学报》2006,26(5):130-133

在分析民俗类公共选修课在高校中受欢迎的原因的基础上,探讨了高校开设民俗类公共选修课的意义:(1)学习民俗文化是高校毕业生参与未来国际竞争的需要;(2)让学生了解民俗文化潜在的强制性、规范性和宣泄性;(3)增强学生的民族自豪感和荣誉感;(4)培养高校学生的“和合”观念;(5)帮助学生形成正确的世界观、人生观和价值观等。  相似文献   

Composition and exhalation flux of gases from mud volcanoes in Taiwan   总被引：3，自引：0，他引：3  

Tsanyao?Frank?YangEmail author  Gao-Hua?Yeh  Ching-Chou?Fu  Cheng-Chen?Wang  Te-Fang?Lan  Hsiao-Fen?Lee  Cheng-Hong?Chen  Vivek?Walia  Quo-Cheng?Sung 《Environmental Geology》2004,46(8):1003-1011

Many mud volcanoes are distributed along the tectonic sutures in southern Taiwan and can be divided into five zones based on their relative positions in different tectonic domains. Most active mud volcanoes are exhaling methane-dominated gases. Nevertheless, some gases show unusual carbon dioxide-dominated and/or nitrogen-excess compositions. This implies that there are multiple sources for the gas compositions of mud volcanoes in Taiwan.For better understanding the total amount of exhalation gases and its flux, the gas flow and compositions were continuously measured in the interval of two minutes at Chung-lun (CL) bubbling mud pool for a few months. The major compositions of gases exhaling from this site were 75~90% of CO₂ and 5~12% of CH₄. The amount of gases exhaling from the mud pool can be estimated to be about 1.4 ton/year for CH₄ and 28 ton/year for CO₂, respectively. The preliminary results of exhaling gas flux from the major vents of representative active mud volcanoes, yielded an estimated total CH₄ output of the mud volcanoes in Taiwan of ca. 29 ton/year during quiescent period.  相似文献   

信息技术对海道测量发展的影响分析     

马兰  孔毅  宋海英  庞云  郭思海 《现代测绘》2012,35(1):15-16,26

介绍分析了现代信息技术——ECDIS、3S技术、Internet技术在海道测量领域的应用与发展现状,旨在对未来海道测量领域的信息化建设进行探索。  相似文献   

第二次土地调查数据库成果在土地勘测定界中的应用     

余兰 《测绘与空间地理信息》2012,(7):210-211

介绍了第二次土地调查数据库成果在勘测定界中的应用,进一步规范了土地勘测定界成果资料,确保了成果质量,真正做到了图、数与实地一致,并通过生产实际探讨了县级土地勘测定界内外业工作方法。  相似文献   

浅谈全数字摄影测量从业人员的培训     

李学清  范兰 《测绘标准化》2012,(4):46-47

随着计算机技术的发展和性能的提高以及全数字摄影测量工作站功能的完善,数字摄影测量的应用领域已远远超出传统的摄影测量范围。通过对测绘生产单位目前从事全数字摄影测量工作的人员的年龄、文化及专业知识结构的分析,提出相应的培训方法、时间与培养目标,为各测绘生产单位在培训全数字摄影测量从业人员时提供参考。  相似文献   

一次罕见飑前强降雹超级单体风暴特征分析   总被引：29，自引：14，他引：15  

戴建华  陶岚  丁杨  王元  陈雷 《气象学报》2012,70(4):609-627

2009年6月5日,受一个飑线前超级单体雷暴的影响,上海部分地区出现了直径25—30mm的冰雹,随后,飑线尾随该超级单体扫过上海,造成大风、雷电和强降水天气。基于常规天气观测、多普勒天气雷达、风廓线仪和自动气象站等资料分析发现,该超级单体发生在东北冷涡西南侧的高空强冷平流与低空暖平流形成的强不稳定层结背景下,超级单体风暴发生、发展在飑线前的暖区中,经过由"热岛效应"和海陆风锋共同形成的低空辐合线时明显加强发展;该风暴呈现出"指"状、"楔"状、弱回波区(WER)等超级单体雷达反射率特征,"指"状回波处出现了中气旋的径向速度特征,具有标志大冰雹的三体散射长钉(TBSS)特征回波,通过三体散射长钉多普勒速度发现了大冰雹的下降区和增长区。分析还表明:东北冷涡西南侧横槽南摆导致中空降温,0℃层和-20℃层高度明显下降,为冰雹的空中增长提供较好的温度环境条件,较低的0℃层也保证冰雹在空中下落中融化较少。双风廓线仪对比观测表明,超级单体发展的低空风场环境中具有较大的垂直风切变和风暴相对螺旋度,中尺度对流系统与环境场的相互作用形成了有利于风暴发展和维持的正反馈机制。飑线前超级单体雷暴与飑线主体关系密切,起到类似"箭"与"弓"的引导作用,飑线主体的一部分进入超级单体所遗留下的"冷"区后明显减弱,东侧入海后也逐渐减弱,其余部分仍在发展加强;最终,强风暴逐渐减弱,超级单体特征也开始消失,飑线与之合并形成新的"人"字型中尺度对流系统,新的"弓"形回波带与原回波带相比移动方向发生右偏,因此,飑前超级单体在飑线主体移动和演变的临近预报中有重要指示意义。  相似文献   

新疆新一代区域数值预报业务系统客观检验分析     

蓝俊  高华  张祖熠  张海亮  马玉芬  窦刚 《沙漠与绿洲气象(新疆气象)》2022,16(2):69-77

运用MET检验工具,对新一代乌鲁木齐区域数值预报业务系统(RMAPS-CA)和目前业务运行系统(DOGRAFS)各季节业务模式预报性能进行对比检验分析.结果表明,相较于DOGRAFS系统,RMAPS-CA系统具有更高的空间分辨率和预报检验评分,预报能力明显提高.具体表现为:(1)对于高空要素预报,RMAPS-CA系统温...  相似文献   

Relationship of the interannual variability of the Indonesian Throughflow with the IOD over the tropical Indian Ocean   总被引：1，自引：0，他引：1  

Jian Lan  Jieli Hong  Yi Wang 《Theoretical and Applied Climatology》2009,97(1-2):75-79

Based on the Simple Ocean Data Assimilation (SODA) reanalysis product, the interannual variability of the upper-ocean ITF volume transport from 1958 to 2001 is investigated. The wavelet analysis shows a second prominent interannual oscillation with a period of about 2–4 years. To reveal any relationship between this band-scale oscillation of the upper-ocean ITF and Indian Ocean Dipole (IOD), correlation and wavelet analyses are used. The correlation coefficient between the upper-ocean ITF and IOD reaches –0.35 with the upper-ocean ITF lagging the IOD index by 8 months. The dipole structure of IOD event is reproduced by the correlation with the upper-ocean ITF lagging the SST anomaly over the tropical Indian Ocean by 8 months from 1958 to 2001. The upper-ocean ITF and IOD show high coherency from about 1975 to 2001. The fact that the wavelet power spectrum of the upper-ocean ITF shows similar structure to that of IOD index supports this high coherency. These analyses suggest that the 2–4-year band-scale oscillation of the upper-ocean ITF is uniquely related to IOD over the tropical Indian Ocean.  相似文献