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陕西富平地区中奥陶统等深流沉积的特征及其地质意义 被引量:27
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作者 屈红军 梅志超 +3 位作者 李文厚 关利群 冯杨伟 范玉海 《地质通报》 CAS CSCD 北大核心 2010年第9期1304-1309,共6页
陕西富平赵老峪地区中奥陶统赵老峪组发育一套与深水碳酸盐岩重力流沉积、放射虫硅质岩、火山凝灰岩伴生的等深流沉积。根据岩性特征可以将该等深流沉积划分为砾屑等深积岩、砂屑等深积岩、粉屑等深积岩和灰泥等深积岩4种类型,识别出较... 陕西富平赵老峪地区中奥陶统赵老峪组发育一套与深水碳酸盐岩重力流沉积、放射虫硅质岩、火山凝灰岩伴生的等深流沉积。根据岩性特征可以将该等深流沉积划分为砾屑等深积岩、砂屑等深积岩、粉屑等深积岩和灰泥等深积岩4种类型,识别出较完整的、由单一灰泥或粉屑或砂屑等深积岩叠置组成的4种等深积岩层序。等深流的流向从东北向西南方向,说明中奥陶世富平地区可能是秦岭北侧弧后盆地伸进浅水台地的一个北东向的深海前槽。富平赵老峪地区下奥陶统马家沟组和华北地块其他地区一样都发育浅水台地相碳酸盐岩,中奥陶统突变为深水斜坡-盆地边缘相的碳酸盐岩重力流及等深流沉积,而同期华北地块主体隆升为陆,反映了在扬子板块向华北板块俯冲的背景下,秦岭北侧早古生代弧后盆地北测的陷落下沉作用。 展开更多
关键词 中奥陶统 赵老峪组 平地区 等深积岩 弧后盆地
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陕西富平地区上奥陶统赵老峪组等深流沉积特征及影响因素 被引量:4
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作者 黄伟 何幼斌 +1 位作者 李华 刘朱睿鸷 《古地理学报》 CAS CSCD 北大核心 2017年第1期161-174,共14页
陕西富平地区上奥陶统赵老峪组发育等深流沉积。以实测剖面、岩石光面、薄片资料以及地球化学资料为基础,结合前人研究成果,对赵老峪组等深积岩类型、层序以及等深流沉积发育的影响因素进行了分析。研究认为:(1)赵老峪组发育灰泥等深积... 陕西富平地区上奥陶统赵老峪组发育等深流沉积。以实测剖面、岩石光面、薄片资料以及地球化学资料为基础,结合前人研究成果,对赵老峪组等深积岩类型、层序以及等深流沉积发育的影响因素进行了分析。研究认为:(1)赵老峪组发育灰泥等深积岩和粉屑等深积岩2种类型,识别出由单一的灰泥等深积岩以及灰泥等深积岩与粉屑等深积岩组成的2种等深积岩层序;(2)等深流水团温度越低,盐度越高,则等深流强度越大;(3)等深流水团水温由高变低、再变高,盐度由低变高、再变低,可能造成了等深积岩层序由细变粗、再变细;(4)古水深变大、古气候变干热、古盐度变低有利于等深流和等深流沉积的发育。 展开更多
关键词 等深流 等深积岩 等深积岩层序 平地区 上奥陶统 赵老峪组
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陕西富平地区晚奥陶世沉积环境研究 被引量:3
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作者 童乐 何幼斌 李华 《矿物岩石地球化学通报》 CAS CSCD 北大核心 2019年第4期748-758,共11页
结合露头剖面、岩石薄片观察、碳氧同位素及微量元素等资料,综合分析了陕西富平地区上奥陶统赵老峪组海相碳酸盐岩沉积时的古水深、古盐度、古温度及氧化还原条件变化规律,以期恢复其沉积环境。研究表明,赵老峪组下部0~12层的δ^13C平... 结合露头剖面、岩石薄片观察、碳氧同位素及微量元素等资料,综合分析了陕西富平地区上奥陶统赵老峪组海相碳酸盐岩沉积时的古水深、古盐度、古温度及氧化还原条件变化规律,以期恢复其沉积环境。研究表明,赵老峪组下部0~12层的δ^13C平均值为-0. 95‰、δ^18O值为-5. 67‰、Sr/Ba值为80. 31、B/Ga值为7. 93、U/Th值为5. 57、V/Cr值为5. 44,主要是以泥晶灰岩为主的深水原地沉积,其沉积环境总体表现为水体较深、离岸较远、水温较高、盐度较高的贫氧-厌氧环境;上部13~35层δ^13C平均值为0. 55‰、δ^18O值为-4. 03‰、Sr/Ba值为19. 05、B/Ga值为9. 17、U/Th值为2. 78、V/Cr值为4. 77,主要发育深水原地沉积、重力流沉积和等深流沉积,但深水原地沉积的发育层数相比于下部大大减少,沉积环境逐渐演变为水深相对较浅、水温较低、盐度较低的贫氧-厌氧环境,这一阶段的整体古水深、古温度和古盐度及氧化还原条件相比于0~12层沉积时较稳定,变化幅度较小。结果表明,用地球化学指标研究深水碳酸盐岩沉积时期的海平面变化、古温度、古盐度及氧化还原条件等环境因素也是可行的。 展开更多
关键词 沉积环境 地球化学 上奥陶统 平地区
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恩平地区成藏条件分析 被引量:5
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作者 李昭伟 《中国海上油气(地质)》 1999年第3期174-180,共7页
EP11-1-1、PY4-2-1、EP20-3-1等3口井油气层的发现,证明恩平地区存在富生油凹陷,特别是PY4-2-1井的钻探成功,揭示了残留文昌组生油凹陷为富生油凹陷。文中结合1997年探井钻前钻后成果,对恩平地区成藏条件进行分析。可以认... EP11-1-1、PY4-2-1、EP20-3-1等3口井油气层的发现,证明恩平地区存在富生油凹陷,特别是PY4-2-1井的钻探成功,揭示了残留文昌组生油凹陷为富生油凹陷。文中结合1997年探井钻前钻后成果,对恩平地区成藏条件进行分析。可以认为,长期活动的大断裂系统对油气藏形成起控制作用,文昌组为主要油源岩,珠江组上段为良好储盖组合层段,T2以前圈闭形成是成藏的关键。 展开更多
关键词 平地区 成藏条件 富生油凹陷 成油体系
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广东台山-恩平地区环境地质问题及其影响因子 被引量:4
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作者 李洪艺 张澄博 +5 位作者 张永定 邱锦安 梁森荣 陈仲如 林涛 彭利群 《地质灾害与环境保护》 2011年第2期9-13,共5页
台山-恩平地区环境地质调查表明:台山市东部和南部丘陵出露酸性侵入岩,受工程影响,滑坡、崩塌和水土流失频发;恩平市东部、南部及开平市南部,岩土松散,隐伏岩溶发育,常见滑坡和地面塌陷;南部沿海软土分布广泛,常见地面不均一沉降和工程... 台山-恩平地区环境地质调查表明:台山市东部和南部丘陵出露酸性侵入岩,受工程影响,滑坡、崩塌和水土流失频发;恩平市东部、南部及开平市南部,岩土松散,隐伏岩溶发育,常见滑坡和地面塌陷;南部沿海软土分布广泛,常见地面不均一沉降和工程构筑开裂;养殖业和城镇化使沿海耕地减少和地表水土严重污染。总的来说,目前该区环境地质条件良好,地质灾害不甚发育,但危害性大。 展开更多
关键词 环境地质 地质灾害 影响因子 台山-恩平地区
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基于布格重力异常研究平陆地区深部构造特征 被引量:2
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作者 郭长辉 王磊 +1 位作者 余大新 乔龙 《山西地震》 2021年第4期8-10,15,共4页
应用平陆地区及周边布格重力资料,对其所揭示的深部构造现象进行研究,结合地形地貌特征分析其与布格重力异常的关系。结果表明,平陆地区布格重力异常总体表现为东高西低,存在重力异常值高低交互出现的特征。再结合地形地貌特征,表现出... 应用平陆地区及周边布格重力资料,对其所揭示的深部构造现象进行研究,结合地形地貌特征分析其与布格重力异常的关系。结果表明,平陆地区布格重力异常总体表现为东高西低,存在重力异常值高低交互出现的特征。再结合地形地貌特征,表现出隆起区为重力异常高值,凹陷及盆地区表现为重力异常低值,同时,中条山北缘断裂等大型的控制性断裂多分布在等值线密集分布的布格重力异常梯度带上。 展开更多
关键词 布格重力异常 深部构造 地区
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低海拔平畈地区杂交稻制种产量与品质不稳定的原因及对策
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作者 李明珠 《杂交水稻》 CSCD 北大核心 2000年第5期12-13,共2页
结合通城制种基地的实际情况 ,分析了平畈地区制种产量不稳定、品质差的主要原因 。
关键词 杂交水稻 制种 地区 产量 品质
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东海平玉春地区含油气远景再分析
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作者 蔡峰 林峰 《海洋地质动态》 1995年第5期1-3,共3页
平玉春地区是目前东海油气勘探的重点地区,以往对该地区的油气资源评价均根据有机质的热降解模型来考虑,无法再现该区的排烃史。本文采用溢流型排烃模型对平玉春地区的排烃量进行定量模拟,通过对排烃过程的动态模拟,直接求取排烃量... 平玉春地区是目前东海油气勘探的重点地区,以往对该地区的油气资源评价均根据有机质的热降解模型来考虑,无法再现该区的排烃史。本文采用溢流型排烃模型对平玉春地区的排烃量进行定量模拟,通过对排烃过程的动态模拟,直接求取排烃量,对提高资源评价的可信度有较现实的意义。 展开更多
关键词 油气勘探 排烃量 资源量 东海玉春地区
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不同回灌补源模式下石川河富平地下水库数值模拟 被引量:3
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作者 张紫瑶 王继玲 +2 位作者 周维博 冯缠利 高建辉 《水资源与水工程学报》 CSCD 北大核心 2022年第2期54-60,共7页
石川河富平地区地下水长期处于采补失衡状态,大范围含水层被疏干,形成区域性降落漏斗,针对拟建的石川河富平地下水库,设置5种开采回灌方案,建立地下水流数值模型模拟不同方案下地下水库水位和蓄水库容变化情况。结果表明:各回灌方案在... 石川河富平地区地下水长期处于采补失衡状态,大范围含水层被疏干,形成区域性降落漏斗,针对拟建的石川河富平地下水库,设置5种开采回灌方案,建立地下水流数值模型模拟不同方案下地下水库水位和蓄水库容变化情况。结果表明:各回灌方案在消除降落漏斗的同时,均能较好地恢复地下水水位,且不超过地下水库的调蓄上限水位;回灌量相同、回灌方式不同时,逐日回灌方式的水位恢复效果优于灌期+非灌期回灌方式,较2018年地下水水位平均抬升13.55 m,蓄水库容增加2.99×10^(8)m^(3);回灌量不同时,较大回灌量对地下水水位的影响大于回灌方式,即泾惠渠水源回灌时,水位抬升程度最大,为19.77 m,蓄水库容相应增加4.36×10^(8)m^(3)。模拟结果可为地下水库的调蓄与运行提供参考。 展开更多
关键词 地下水库 回灌补源模式 地下水流数值模拟 蓄水库容 石川河 平地区
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贫困地区中学英语互动教学的应用
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作者 雷子婧 《中文科技期刊数据库(全文版)教育科学》 2017年第1期280-280,共1页
教育是第一生产力,随着科技的发展、社会的进步。在我国,教育也在发展、在进步。但由于地域差异和经济发展的差异,本着因材施教的教育理念,我们也该对不同地区的学生展开不同的相应的教育教学。平困地区的英语教学是艰难的,尤其是互动... 教育是第一生产力,随着科技的发展、社会的进步。在我国,教育也在发展、在进步。但由于地域差异和经济发展的差异,本着因材施教的教育理念,我们也该对不同地区的学生展开不同的相应的教育教学。平困地区的英语教学是艰难的,尤其是互动式的教育模式应用。 展开更多
关键词 地区 中学英语 互动教学
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低对比度砂岩油层岩石组分核磁与常规测井联合反演方法 被引量:3
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作者 管耀 冯进 +5 位作者 刘君毅 高楚桥 王清辉 李兆平 石磊 潘卫国 《中国海上油气》 CAS CSCD 北大核心 2020年第4期71-77,共7页
南海东部恩平地区浅层分布大量低对比度油层,其颗粒组分以极细砂为主,细粒组分对放射性的高吸附导致这类油层自然伽马高,常规测井特征与泥岩对比度低。本文利用泥岩和低对比度砂岩在核磁测井上的明显差异,从核磁测井T2谱中提取出"... 南海东部恩平地区浅层分布大量低对比度油层,其颗粒组分以极细砂为主,细粒组分对放射性的高吸附导致这类油层自然伽马高,常规测井特征与泥岩对比度低。本文利用泥岩和低对比度砂岩在核磁测井上的明显差异,从核磁测井T2谱中提取出"大孔率"曲线,认为"大孔率"是地层不同粒级砂岩储集空间的综合响应,可表征地层的岩石粒级组分,并进一步推导出"大孔率"的测井响应方程,联合常规测井响应方程共同构建最优测井解释目标函数,对地层岩性进行联合反演,从而获得准确的极细砂组分含量。该方法已在恩平地区浅层得到广泛应用,识别出大量低对比度油层,取得了较好的增储效果。 展开更多
关键词 低对比度砂岩油层 核磁测井 联合反演 “大孔率”曲线 最优化测井解释 平地区
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Driving Analysis on Ecological Security in Vulnerable Transition Areas of Mountain and Plain 被引量:1
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作者 刘欣 赵艳霞 +2 位作者 秦彦杰 张金英 武爱彬 《Agricultural Science & Technology》 CAS 2013年第3期433-435,共3页
[Objective] This study aimed to investigate the driving mechanism of eco- logical security in vulnerable areas in mountain and plain. [Method] The ecological security evaluation index system of Lincheng County was est... [Objective] This study aimed to investigate the driving mechanism of eco- logical security in vulnerable areas in mountain and plain. [Method] The ecological security evaluation index system of Lincheng County was established using PSR model. Driving mechanism was analyzed in total system and subsystems respectively by the principal components. The ecological safety driving factor was calculated through the total system and subsystem respectively. And the intersection was adopt- ed as dominant driving factor. [Result] A total of 10 indices including density index of rivers, land degradation index, farmland drought and flood insurance yield, human in- terference index, population density, the natural population growth rate, per capita GDP, the R&D funds spending accounts for the proportion of GDP, laborer by edu- cation degree and three industry accounted for the proportion of GDP, are the domi- nant driving factors of the regional ecological security. [Conclusion] This study will pro- vide reasonable and feasible advice for the benign development of the area. 展开更多
关键词 Ecological security Driving force Transition areas of mountains and plains
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Livelihood Strategy and Farmland Use in Xinping County of Yuanjiang Dry-hot Valley 被引量:1
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作者 赵文娟 杨世龙 王潇 《Agricultural Science & Technology》 CAS 2016年第4期977-982,共6页
Methods of participatory rural appraisal and mathematical statistics were adopted to study livelihood diversification, livelihood strategy and farmland use of the four types of farmers in Xinping County of Yuanjiang d... Methods of participatory rural appraisal and mathematical statistics were adopted to study livelihood diversification, livelihood strategy and farmland use of the four types of farmers in Xinping County of Yuanjiang dry-hot valley with field survey data. The results showed as follows: firstly, as farmers are transforming from pure agriculture to non-agriculture, their agricultural livelihood diversification index will decrease, while non-agricultural livelihood diversification index will increase. In term of livelihood activities, pure agricultural farmers are exclusively engaged in agricultural activities, agricultural-dominant and non-agricultural-dominant farmers are engaged in both agricultural and non-agricultural ones, while non-agricultural farmers are basically engaged in off-farm activities. Secondly, as for crops planted, pure agricultural and agricultural-dominant farmers tend to choose those crops with more investment,shorter growth period and higher value, meanwhile non-agricultural-dominant farmers tend to choose crops with less investment, simpler management and longer growth period. Thirdly, to cope with current problems in farming, pure agricultural farmers will adopt measures such as changing planting structure, maintaining or expanding planting scale, increasing planting investment and renting in more land to promote the development of farming; agriculture-dominant farmers will adopt measures such as changing planting structure, reducing planting scale, maintaining planting investment, renting in and taking back the leased land as well as engaging in non-agricultural activities to overcome the difficulties faced; while non-agricultural-dominant farmers will adopt measures such as reducing both planting scale and investment,changing planting structure and engaging in farmland transfer as well as various offfarm activities to avoid livelihood risks. 展开更多
关键词 Xinping County of Yuanjiang dry-hot valley Farmers' livelihood activities Farmland use
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Relation between Economic Development Level and Resource and Environment Carrying Capacity of Central Area of Yunnan Province Based on Decoupling Analysis 被引量:4
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作者 程超 童绍玉 +2 位作者 彭海英 闫少凯 刘玲 《Agricultural Science & Technology》 CAS 2015年第12期2829-2832,共4页
Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling ... Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that (i) the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse "N" in temporal changes. (ii) Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse "V" change. (iii) The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod. 展开更多
关键词 The central area of Yunnan Province Economic development level Re- source and environment carrying capacity Decoupling analysis Scissors difference
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Preliminary Studies on the Zoogeographic Divisions of Chinese Ground Spiders(Araneae:Gnaphosidae) 被引量:1
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作者 张超 《Agricultural Science & Technology》 CAS 2010年第6期7-10,共4页
This paper aims to carry out the preliminary study on the zoogeographic distributions of 166 species within Gnaphosidae by clustering method,and analyze and compare the similarities of 15 subregions in seven zoogeogra... This paper aims to carry out the preliminary study on the zoogeographic distributions of 166 species within Gnaphosidae by clustering method,and analyze and compare the similarities of 15 subregions in seven zoogeographic regions in China.The results suggested that the division of Northern China was coincident with the distribution pattern of Chinese ground spiders,but there was subregion recombination between the other regions.There was aggregation between Da Hinggan Mountains subregion in the Northeast,east plain subregion in Mengxin area and west hungriness subregion,between Tianshan mountainous subregion in Mengxin area,Qiangtang altiplano subregion and the southwest mountainous region subregion in Southwest,and between east hill plain subregion in central China,west mountainous region altiplano subregion,Min and Guang coastal subregion in south of China and south Dian mountainous region subregion.The other two subregions in the Northeast formed a region.Qinghai and south Xizang subregion in Qinghai-Xizang Region formed a branch independently. 展开更多
关键词 Gnaphosidae SPIDER Zoogeographic distributions Cluster analysis
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履职尽责敢担当
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作者 彭双喜 柴红旗 《人大建设》 2017年第3期58-59,共2页
在桐柏县城关镇东风桥社区,人们经常可以看到一位身材不高、行走不便却仍不失军人姿态的中年汉子。他走街串巷,不知疲倦,忙着搞调查研究,倾听群众呼声,收集民声民意,默默无闻地履行着“人民选我当代表,我当代表为人民”的诺言。他就是... 在桐柏县城关镇东风桥社区,人们经常可以看到一位身材不高、行走不便却仍不失军人姿态的中年汉子。他走街串巷,不知疲倦,忙着搞调查研究,倾听群众呼声,收集民声民意,默默无闻地履行着“人民选我当代表,我当代表为人民”的诺言。他就是桐柏县人大代表、城关镇东风桥社区党支部书记、主任张传海。 展开更多
关键词 张传海 党支部书记 军人姿态 团结友善 县城居民 几十年如一日 平地区 支柱型产业 伊斯兰教协会 重要交通枢纽
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Agriculture Development-induced Surface Albedo Changes and Climatic Implications Across Northeastern China 被引量:16
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作者 ZHANG Xuezhen WANG Wei-Chyung +2 位作者 FANG Xiuqi YE Yu ZHENG Jingyun 《Chinese Geographical Science》 SCIE CSCD 2012年第3期264-277,共14页
To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeaste... To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far. 展开更多
关键词 surface albedo land cover change climatic effects last 300 years northeastern China
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An Ocean Reanalysis System for the Joining Area of Asia and Indian-Pacific Ocean 被引量:9
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作者 YAN Chang-Xiang ZHU Jiang XIE Ji-Ping 《Atmospheric and Oceanic Science Letters》 2010年第2期81-86,共6页
An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climat... An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climate variation over China in the inter-annual time scale.This system consists of a nested ocean model forced by atmospheric reanalysis,an ensemble-based multivariate ocean data assimilation system and various ocean observations.The following report describes the main components of the data assimilation system in detail.The system adopts an ensemble optimal interpolation scheme that uses a seasonal update from a free running model to estimate the background error covariance matrix.In view of the systematic biases in some observation systems,some treatments were performed on the observations before the assimilation.A coarse resolution reanalysis dataset from the system is preliminarily evaluated to demonstrate the performance of the system for the period 1992 to 2006 by comparing this dataset with other observations or reanalysis data. 展开更多
关键词 reanalysis system data assimilation ensemble optimal interpolation background error covariance
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Skewness of subsurface ocean temperature in the equatorial Pacific based on assimilated data 被引量:2
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作者 苏京志 张人禾 +1 位作者 LI Tim 容新尧 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第3期600-606,共7页
The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while ... The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while the temperature skewness in the western and central Pacific is primarily negative. There is also an asymmetry of the temperature skewness above and below the climatological mean therrnocline in the central and western Pacific. A positive skewness appears below the thermocline, but the skewness is negative above the thermocline. The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure. Because of positive (negative) second derivative of temperature with respect to depth below (above) the thermocline, an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline. In the far eastern equatorial Pacific, the thermocline is close to the base of the mixed layer, the shape of the upper-ocean vertical temperature profile cannot be kept. Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin. Over the central and eastern Pacific, the anomalies of the subsurface waters tend to entrain into the surface mixed layer (by climatological mean upwelling) and then affect the SST. Hence, the positive (negative) subsurface skewness in the far eastern (central) Pacific may favor positive (negative) SST skewness, which is consistent with the observational fact that more La Nina (EI Nino) occur in the central (eastern) Pacific. The present result implies a possible new paradigm for EI Nino and La Nina amplitude asymmetry in the eastern Pacific. 展开更多
关键词 SKEWNESS subsurface temperature equatorial ocean
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Evapotranspiration, Yield and Crop Coefficient of Irrigated Maize Under Straw Mulch 被引量:12
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作者 ZHANG Xi-Ying CHEN Su-Ying PEI Dong LIU Meng-Yu SUN Hong-Yong 《Pedosphere》 SCIE CAS CSCD 2005年第5期576-584,共9页
Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting ... Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting of the winterwheat. In order to improve irrigation efficiency in this region of serious water shortage, field studies in 1999 and 2001, twodry seasons with less than average seasonal rainfall, were conducted with up to five irrigation applications to determineevapotranspiration, calculate the crop coefficient, and optimize the irrigation schedule with maize under mulch, as well asto establish the effects of irrigation timing and the number of applications on grain yield and water use efficiency (WUE)of maize. Results showed that with grain production at about 8 000 kg ha-1 the total evapotranspiration and WUE ofirrigated maize under mulch were about 380-400 mm and 2.0-2.2 kg m-3, respectively. Also in 2001 WUE of maizewith mulch for the treatment with three irrigations was 11.8% better than that without mulch. In the 1999 and 2001seasons, maize yield significantly improved (P = 0.05) with four irrigation applications, however, further increases werenot significant. At the same time there were no significant differences for WUE with two to four irrigation applications.In the 2001 season mulch lead to a decrease of 50 mm in the total soil evaporation, and the maize crop coefficient undermulch varied between 0.3-1.3 with a seasonal average of 1.0. 展开更多
关键词 crop coefficient MAIZE MULCH water use efficiency
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