Salinity changes in the World Ocean since 1950 in relation to changing surface freshwater fluxes   总被引：1，自引：0，他引：1  

Nikolaos Skliris  Robert Marsh  Simon A. Josey  Simon A. Good  Chunlei Liu  Richard P. Allan 《Climate Dynamics》2014,43(3-4):709-736

Global hydrographic and air–sea freshwater flux datasets are used to investigate ocean salinity changes over 1950–2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic–Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E–P are examined for 1950–2010 (using two reanalyses) and 1979–2010 (using four reanalyses and two blended products). Large differences in the 1950–2010 E–P trend patterns are evident in several regions, particularly the North Atlantic. For 1979–2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E–P products. However, a robust pattern of increased E–P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E–P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E–P over 1950–2010 amount to an increase of 1 ± 0.6 % in net evaporation across the subtropics and an increase of 4.2 ± 2 % in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979–2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period.  相似文献   

Spatio-temporal variation prediction on Cd content in the rice grains from Northern Zhejiang Plain during 2014–2019 based on high-precision soil geochemical data     

Yin  Hanqin  Lu  Xinzhe  Sun  Rui  Huang  Chunlei  Kang  Zhanjun  Xu  Mingxing  Wei  Yingchun  Cai  ZiHua 《地理学报(英文版)》2023,33(2):413-426

Journal of Geographical Sciences - In recent years, Cadmium (Cd) pollution has been found in many soil geochemical surveys in Northern Zhejiang Plain, a crucial rice production area in East China,...  相似文献   

疏松砂岩储层窜流通道平面分布规律研究     

于春磊  王硕亮  张媛  王娟 《现代地质》2016,30(5):1134-1140

国内大部分高含水油田,注入水窜流现象较为严重,已成为影响油田高效开发的主要矛盾,对窜流通道形成后渗透率场的计算与描述显得尤为迫切和重要。目前窜流通道参数计算方法,只能计算得到注采井点的渗透率数值,不能计算得到注采井间的渗透率分布状况,并且目前窜流通道渗透率计算方法没有将室内实验结果、数值模拟结果和油藏工程方法结果有效结合起来。以国内某高含水油田为例,通过长期注水冲刷实验,模拟了窜流通道的动态形成过程,归纳出了储层岩石注水冲刷倍数与渗透率之间的关系式。在常规数值模拟计算方法的基础上,将渗透率变化规律模型引入到数值模拟计算中,建立了计算窜流通道平面分布的新方法。以海上某油田的地质模型为基础,计算得到了该油田目前状态的窜流通道渗透率平面二维分布规律。综合对比动态数据法、概率密度模型法、经验公式法和示踪剂测试结果,证明本方法得到的结果真实可靠。  相似文献   

新疆新一代天气雷达加装带通滤波器后激励信号频谱分析   总被引：2，自引：2，他引：0  

安克武  黄晓  周长江  张春雷 《气象科技》2009,37(3):341-344

对新一代天气雷达加装了带通滤波器前后激励信号的频谱特性进行了探讨,通过对带通滤波器的组成结构及阻抗转移函数的分析,分别对激励信号函数和响应信号函数进行傅立叶变换,求出对应的频谱函数,再与实际测量结果进行比较,发现实际带通滤波效果达到预期的目的,避免了雷达微波信号由于带宽的因素对当地其它微波设备的信号干扰。  相似文献   

Study of the Shear Strength of Sediments in Main Sedimentation Stages     

Liang Wang  Wei Zhu  Jian Xie  Lei Li  Chunlei Zhang 《Marine Georesources & Geotechnology》2013,31(6):556-566

The shear strength properties of sediments are relevant to many practical problems, including those related to predicting the bearing capacity of the man-made crust lying over dredged disposal sites and those associated with estimating the erosion resistance and the bearing capacity of sediments. In this study, an experimental apparatus and method is developed for sedimentation. This apparatus consists of a settling column, pore measurement apparatus, shear vane apparatus, and multilayer extraction sampling apparatus. The change regulation of interface height, density, excess pore pressure, peak undrained shear strength, residual undrained shear strength, and sensitivity varies before and after the excess pore pressure dissipates to zero in the self-weight consolidation stage. The higher the water content, the greater the particle segregation degree. Particles are mainly segregated in the settling stage, and they are not segregated further in the self-weight consolidation stage. Before excess pore pressure dissipates to zero in the self-weight consolidation stage, shear strength is related to water content, effective stress, and the formed structure of sediments. After excess pore pressure dissipates to zero, peak undrained shear strength is mainly associated with the structure (thixotropy) of sediments. Residual undrained shear strength increases because of the slight decrease in water content. The mechanisms of thixotropy can be expressed as the increase in the original and curing cohesions of sediments with time as determined from microscopic aspects.  相似文献   

Estimation of age,growth and maturation of purpleback flying squid, <Emphasis Type="Italic">Sthenoteuthis oualaniensis</Emphasis>, in Bashi Channel,central Pacific Ocean     

Bilin Liu  Jingyuan Lin  Chunlei Feng  Jianhua Li  Hang Su 《中国海洋大学学报(英文版)》2017,16(3):525-531

The age, growth and maturation of Sthenoteuthis oualaniensis were determined with statolith data collected with a light purse seine from the Bashi Channel of central Pacific Ocean. The estimated longevity of the squid was no more than 6 months for females, and no more than 5 months for males. Growth in mantle length (ML) was best described by logistic models for both females and males, while growth in body weight (BW) was best fitted by power curves. The maximum absolute growth rate (AGR) and instantaneous growth rate (IGR) in ML or BW both occurred at 91–105 days for females and 76–90 days for males. Back calculated hatching dates were from October to January, with a peak in December, although the short duration of sampling date might have had an influence on the result. The lower percentage of mature females (37.2%) suggested that the study area during the sampling date was not a spawning ground for the species. Size and age at first maturity were 183 mm ML and 136 days for females, whereas they were 156 mm ML and 85 days for males.  相似文献   

山西娘子关泉水及污染成因再分析   总被引：2，自引：2，他引：0  

梁永平  赵春红  唐春雷  申豪勇  王志恒  郭芳芳 《中国岩溶》2017,36(5):633-640

山西娘子关泉水是我国北方最大的岩溶泉水之一,也是世界著名大泉,上世纪80年代前多年平均天然流量12.6 m3/s。文章利用1∶5万娘子关泉域岩溶水文地质环境地质调查项目勘探调查成果,对以下2个问题开展再分析:（1）娘子关泉水的成因,勘探等资料表明绵河南岸五龙泉、苇泽关等泉组主要接收下部中、上寒武统含水岩组岩溶水的补给,而非前人研究来源于上部中奥陶至下奥陶含水岩组补给;（2）结合水文地质条件,采用同位素等方法分析,认为部分地区煤矿老窑水的出流是导致娘子关泉水近年来加速污染的主要原因。   相似文献   

煤炭开采条件下三姑泉域岩溶含水层保护评价   总被引：1，自引：1，他引：0  

王振兴  李向全  侯新伟  张春潮  桂春雷  左雪峰 《中国岩溶》2019,38(1):28-39

三姑泉域是我国典型的北方岩溶区,同时位于国家规划的晋东大型煤炭基地,煤炭开采与水资源保护之间的问题较为突出。多年来区内煤炭资源的大规模开采造成了区域地下水位下降、水质恶化等现象。因此开展北方岩溶区煤炭基地含水层保护评价对水资源保护及经济可持续发展具有十分重要的意义。本文从含水层脆弱性、含水层功能和煤炭开采影响力三方面建立综合评价指标体系,采用APH法进行三姑泉域岩溶含水层综合保护评价。针对煤炭基地特征,采用增加了煤炭采空区指标的COP修正模型评价了含水层的脆弱性。含水层功能评价分别从供水能力与生态、大泉维持能力开展;煤炭开采影响力评价从开采活动及煤炭地质结构两方面开展。综合评价结果显示需要重点保护的区段为岩溶大泉、水源地及地表渗漏段,其次为岩溶强径流带及煤炭剧烈开采区,与实际情况相符。   相似文献   

树轮稳定碳同位素研究的应用现状与发展趋势   总被引：2，自引：0，他引：2  

刘广深  米家榕 《世界地质》1996,15(4):42-48

获取历史时期环境气候变迁资料是研究环境气候变迁的基础，在各种获取资料的方法中，树轮同位素方法是较为新颖，准确，定量的一种高分辨率方法。本文较为系统，深入地评述了树轮稳定碳同位素方法的原理及其在环境气候变迁研究的应用现状，并简要归纳了研究工作中的发展趋势。  相似文献   

Calculation of Ice Crystal Diffraction     

Liu Chunlei  Yao Keya 《大气科学进展》1996,13(3):340-348

The diffraction angular distributions are calculated for different ice crystals (e.g,solid and hollow hexagonal columns,solid plates and single hexagonal bullet) randomly oriented in space,based on the theory of Cai and Liou.Results of solid column and plate are compared with those from formulas of Wendling et al and Liou.The resull comparison shows that all three procedures discussed in this paper have good agreement.After considering the coin putation time and comparison results,it is suggested that the formula of Wendling et al.can be used to calculate the solid column diffraction,and the formula of Liou can be used to calculate the plate diffraction.The comparison also shows that the diffraction results of solid columu,hollow column and single bullet ice particles randomly oriented in space are very close.  相似文献