青藏高原不同地区夏季近地层能量输送与微气象特征比较分析   总被引：1，自引：0，他引：1  

赵兴炳  彭斌  秦宁生  王伟 《四川气象》2011,(1):6-11

利用2009年7月在青藏高原理塘、林芝、海北、拉萨获得的气象观测资料,对比分析了这些地区近地层气象要素、辐射收支及湍流通量日变化特征。结果表明：无论是高原东部、中部还是北部,无论是高原台地还是高山峡谷区,7月份近地层各气象要素、湍流通量、辐射收支都有明显的日变化。各地区的地表辐射、感热、潜热等最高值都出现在中午,最低值出现在早晨。地表反照率日变化均呈早晚高中午低的＂U＂型分布。地面热源强度在白天均为热源,正午为强热源,在夜间表现为弱的冷、热源交替出现。7月份近地层地气热量交换中,感热输送作用小,潜热输送占主导地位。动量通量和摩擦速度均在风速较大的下午较大,风速小的早晨小。  相似文献   

藏北丁固—加措地区中-上更新统高台阶砾石层的厘定及其意义          下载免费PDF全文

易成兴  曾昌兴  陈仁 《贵州地质》2014,31(2):96-98,88

西藏北部丁固-加措地区,分布一套零星出露的、固结—半固结状态的砂砾岩层,在综合研究其岩石组合、沉积特征、地质时代、区域地质特征的基础上,将其厘定为一个非正式岩石地层单位——高台阶砾石层,该砾石层对研究区内第四系地质演化具有重要意义。  相似文献   

远震作用下软弱土层的震害影响     

黄志东  何萍  杜鹏 《华南地震》2014,(3):65-68

软弱土层在地震作用下,容易发生水平永久变形和不均匀沉陷,是发生震害的主要因素之一。特别是在远震作用下,软弱土层地区的破坏烈度高于其他较坚硬岩土地区,软弱土层上部的中高层建筑物和构筑物更易遭受破坏。通过回顾和分析1994年9月16日台湾海峡7.3级地震在汕头市的地震反应特征及震害影响,指出应加强软弱土层地区的工程抗震设计,提高防灾抗震能力。  相似文献   

The CIRES Tethered Lifting System: a survey of the system, past results and future capabilities     

Ben B. Balsley 《Acta Geophysica》2008,56(1):21-57

This paper presents a survey of the Tethered Lifting System (TLS) being developed for atmospheric research by the Cooperative Institute for Research in Environmental Sciences (CIRES) at University of Colorado. Basic elements of the system are described, and examples of both published results and work in progress are presented.  相似文献   

Sub aerial random wave pressure and layer thickness on impermeable sea walls     

S Neelamani 《Ocean Engineering》2004,31(13):1601-1621

Investigations on sub aerial wave pressures and layer thickness on plane impermeable and non-overtopping seawallns were carried out by using physical model studies. Seawalls with slopes of 1:3, 1:4 and 1:6 were used. JONSWAP spectrum with significant wave height, H_s from 0.08 to 0.2 m and peak periods, T_p from 1.5 to 6.0 s and a constant water depth of 0.7 m is used. Based on extensive measurements, empirical formulas for practical applications are proposed to predict the maximum, significant and mean sub aerial random wave pressure and layer thickness (thickness of water layer perpendicular to the still water level on the run-up zone) by using the surf similarity parameter, significant wave height and elevation on the sub aerial region as inputs. It is found that the maximum layer thickness is 1.11 times the significant layer thickness and maximum sub Arial wave pressure is 1.06 times the significant wave pressures. The predictive equations based on extensive measurements can be used for the design of non-overtopping seawalls.  相似文献   

A Coupled Ice-Ocean Model in the Pan-Arctic and North Atlantic Ocean: Simulation of Seasonal Cycles     

Jia?WangEmail author  Qinzheng?Liu  Meibing?Jin  Motoyoshi?Ikeda  Francois?J.?Saucier 《Journal of Oceanography》2005,61(2):213-233

A coupled ice-ocean model is configured for the pan-Arctic and northern North Atlantic Ocean with a 27.5 km resolution. The model is driven by the daily atmospheric climatology averaged from the 40-year NCEP reanalysis (1958–1997). The ocean model is the Princeton Ocean Model (POM), while the sea ice model is based on a full thermodynamical and dynamical model with plastic-viscous rheology. A sea ice model with multiple categories of thickness is utilized. A systematic model-data comparison was conducted. This model reasonably reproduces seasonal cycles of both the sea ice and the ocean. Climatological sea ice areas derived from historical data are used to validate the ice model performance. The simulated sea ice cover reaches a maximum of 14 × 10⁶ km² in winter and a minimum of 6.7 × 10⁶ km² in summer. This is close to the 95-year climatology with a maximum of 13.3 × 10⁶ km² in winter and a minimum of 7 × 10⁶ km² in summer. The simulated general circulation in the Arctic Ocean, the GIN (Greenland, Iceland, and Norwegian) seas, and northern North Atlantic Ocean are qualitatively consistent with historical mapping. It is found that the low winter salinity or freshwater in the Canada Basin tends to converge due to the strong anticyclonic atmospheric circulation that drives the anticyclonic ocean surface current, while low summer salinity or freshwater tends to spread inside the Arctic and exports out of the Arctic due to the relaxing wind field. It is also found that the warm, saline Atlantic Water has little seasonal variation, based on both simulation and observations. Seasonal cycles of temperature and salinity at several representative locations reveals regional features that characterize different water mass properties.  相似文献   

边界层湍流参数化改进对雾的模拟影响     

黄翊  彭新东 《大气科学》2017,41(3):533-543

为了提高边界层参数化在我国复杂下垫面上的描述能力,改善边界层能量和物质输送计算和检验其数值模拟效果,本文选取WRF三维模式,采用基于我国不同下垫面上的边界层观测资料改进的新MYNN（Mellor-Yamada-Nakanishi-Niino）参数化方案对2009年3月17日黄海海雾以及2011年12月4日华北地区两次大雾过程进行模拟检验,探讨边界层参数化方案对雾和边界层结构模拟的影响。参照卫星云图和探空资料,边界层内云水混合比垂直积分的水平分布的模拟能力明显提高,反映了改进的MYNN方案能够更好地模拟出两次雾过程的发生、移动和雾区空间分布,更精确的云水混合比和温度的垂直分布能更好地给出雾区的垂直结构和稳定层结,同时可改善雾区低层位温以及比湿垂直分布的模拟。  相似文献   

海藻中植物生长素组成的初步研究   总被引：1，自引：0，他引：1       下载免费PDF全文

韩丽君 《海洋科学》2003,27(3):70-72

海藻样品在经过提取、分离和纯化等前处理步骤后，以薄层色谱（TLC）法定性检测了16种海藻中的植物生长素（IAA）以及提取和分离纯化的效果。结果表明，大部分海藻样品经过提取、脱色、萃取、柱层析纯化过程后都发现含有IAA的显色斑点而其它生长素的显色斑点很少。这些结果说明了16种海藻样品中都含有IAA以及定性检测方法的准确性和前处理方法的必要性。  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987112000254   总被引：1，自引：0，他引：1  

Y.Srinivas  A.Stanley Raj  D.Hudson Oliver  D.Muthuraj  N.Chandrasekar 《地学前缘(英文版)》2012,3(5):729-736

The applications of intelligent techniques have increased exponentially in recent days to study most of the non-linear parameters.In particular,the behavior of earth resembles the non-linearity applications.An efficient tool is needed for the interpretation of geophysical parameters to study the subsurface of the earth.Artificial Neural Networks(ANN) perform certain tasks if the structure of the network is modified accordingly for the purpose it has been used.The three most robust networks were taken and comparatively analyzed for their performance to choose the appropriate network.The single-layer feed-forward neural network with the back propagation algorithm is chosen as one of the well-suited networks after comparing the results.Initially,certain synthetic data sets of all three-layer curves have been taken for training the network,and the network is validated by the Held datasets collected from Tuticorin Coastal Region(78°7′30″E and 8°48′45″N),Tamil Nadu.India.The interpretation has been done successfully using the corresponding learning algorithm in the present study.With proper training of back propagation networks,it tends to give the resistivity and thickness of the subsurface layer model of the field resistivity data concerning the synthetic data trained earlier in the appropriate network.The network is trained with more Vertical Electrical Sounding(VES) data,and this trained network is demonstrated by the field data.Groundwater table depth also has been modeled.  相似文献   

东天山卡瓦布拉克前寒武纪地块填图方法思考——以大黑山幅1:25万区调为例     

吴玉门  郭华春  吴羿辰 《新疆地质》2012,(Z1):6-9

东天山卡瓦布拉克地区前寒武纪地块为古克拉通构造区,物质构成非常复杂。以大陆层圈构造为理论基础,运用形变地层学和变质构造解析方法为主的岩石地层调查方法,在东天山大黑山地区的1:25万区调中重新选择技术路线和工作方法,提高了区内中深变质岩系研究程度及构造-岩石地层单位划分和填图精度。  相似文献