伴随对流层中低层气温持续下降的雪转雨过程分析   总被引：2，自引：0，他引：2  

李海军  张雪慧  潘士雄 《气象科技》2015,43(6):1164-1169

利用欧洲中期天气预报中心（ECMWF）0.25°×0.25°分辨率细网格模式产品、探空观测资料和风廓线雷达等资料,对2014年2月18日浙江嘉兴雨雪天气过程中降水相态先由雨转雪、再由雪转雨的变化条件进行了分析,并对ECMWF细网格模式产品进行了预报性能检验,结果表明：模式形势预报准确,但未能预报出雪转雨过程。在对流层中低层气温持续降低的情况下,水汽凝结高度不同是造成两次相态转换的主要原因。上午垂直运动加强,水汽充沛,降水粒子的凝结高度高,足以形成大的雪花,在较低的零度层高度以下降落时不至于融化;下午垂直运动减弱,水汽集中在低层,尽管这一高度层的气温在-3～-2 ℃,但是不足以凝结成固态降水,同时地面气温受海上暖平流影响而回升,因此降水相态由雪转雨。  相似文献   

基于CCD星图的空间目标精确光学定位方法研究     

谌钊  罗成  华卫红 《天文研究与技术》2010,7(3)

通过光学定位方法来确定空间目标的轨道是实现空间目标监测的重要手段之一。介绍一套小型的空间目标光学定位系统,针对该系统获取的CCD星图,提出Top-hat变换和中值滤波相结合的算法去除星图噪声,并提出基于梯度Hough变换的算法完成对CCD星图星点和轨迹的同时精确定位,最后利用星角距的旋转不变性和球面几何原理,实现对空间目标的精确定位。对分辨率为752×580的CCD实拍星图的应用研究结果表明,星图去噪算法和星点、轨迹同时精确定位算法是有效的,且空间目标的定位精度也可达到角秒量级。  相似文献   

Climate change transformation: A definition and typology to guide decision making in urban environments     

Anna C. Hurlimann  Sareh Moosavi  Geoffrey R. Browne 《Chemie der Erde / Geochemistry》2010

Climate change presents a threat to the sustainability of cities and their societies, and must be adequately addressed. Urban environments (cities) are responsible for the creation of a significant amount of greenhouse gas emissions which are the source of climate change. Cities have been increasingly the focus of action to address climate change, yet emissions are not significantly reducing. Additionally, there a lack of integration between adaptation and mitigation. This prevents responses adequate to limit global warming to 1.5^OC, and to be well adapted to anticipated changes. This paper critically analyses existing definitions and typologies of climate change actions. A definition of ‘climate change transformation’ is proposed which includes the integration of adaptation and mitigation goals to enable a new regime in which global warming is limited to 1.5^OC. A new three-part typology: ‘coping, malaction and transformation,’ is presented for categorising climate change actions by the extent to which they integrate adaptation and mitigation, and define a new regime. The typology is accompanied by illustrations to demonstrate the relationship between adaptation and mitigation. The definition, typology and illustration serve to guide effective climate change decision making, and provides principles to guide application in urban environments.  相似文献   

添加剂对KAlSi_3O_8-CaSO_4-CaCO_3体系反应表观活化能的影响   总被引：2，自引：0，他引：2  

石林  曾小平  柴妮  杨国友 《岩石矿物学杂志》2010,29(1):90-94

首先测定了KAlSi3O8-CaSO4-CaCO3体系在不同焙烧条件下钾长石转化成可溶性氧化钾的转化率,进而通过模拟计算表明:KAlSi3O8-CaSO4-CaCO3体系的固相扩散动力学过程符合金斯特林格动力学方程,反应表观活化能Ea为128.92kJ/mol。并着重考察了4种添加剂Na2SO4、Na2SO3、NaCl和NaF对KAlSi3O8-CaSO4-CaCO3体系的影响,结果表明:向体系中分别加入占反应物总质量3%的Na2SO4、Na2SO3、NaCl和1%的NaF后,体系的反应表观活化能Ea从原来的128.92kJ/mol依次下降至87.15、98.71、117.38和126.14kJ/mol,这表明4种添加剂中Na2SO4的效果最好,它能较大程度上降低反应表观活化能,从而降低反应温度和提高固相反应速率。  相似文献   

利用VB实现手持GPS航点航线输入     

蔡足根  陆柏树 《物探化探计算技术》2010,32(1):99-103

手持GPS是目前地质工作中常用的工具,它具有导航方便,高精度,高效率等特点,已赢得广大地质工作者的热爱。但GPS航点航线的输入工作一般是采用手工方式完成,对于大量坐标数据的输入是一个相当繁琐的工作,且容易出错,这样大大限制了GPS的应用。为了解决这个问题,这里利用VB成功地实现了坐标投影转换和批量数据输入GPS,极大地提高了室内和野外工作效率。  相似文献   

辽河西部凹陷欢喜岭地区沙河街组层序界面的识别   总被引：1，自引：1，他引：0  

杨俊生  陈世悦  袁波 《世界地质》2010,29(2):314-322

对辽河西部凹陷欢喜岭地区层序地层的研究,总结出4种层序界面的识别方法:①钻井、测井资料;②泥砂比曲线;③小波变换;④地震时频分析。方法①表现为在沙河街组各三级层序界面处,岩性、相序、曲线形态和幅值有不同程度的突变;方法②表现为在一个完整的三级层序中,泥砂比曲线由小变大再变小,其中泥砂比值最大处为最大湖泛面(MFS)位置;方法③表现为在一个完整的三级层序中,谱系图从低频到高频再到低频的变化,在系数曲线上表现为一个或近似一个完整的振荡旋回,其中谱系图中高频部分对应着最大湖泛面位置;方法④在剖面上层序界面处为低频部分,高频部分是最大湖泛面位置。通过测井与地震信息相结合,综合运用4种方法识别出7个层序界面和6个最大湖泛面,由此建立了研究区的高精度层序地层格架。  相似文献   

长江中下游转换构造结的特征、属性及其研究意义   总被引：3，自引：0，他引：3  

宋传中  黄文成  Shoufa Lin  任升莲  李加好  涂文传 《安徽地质》2010,20(1):14-19,29

"长江中下游转换构造结"是特提斯构造体制与太平洋构造体制交汇、衔接和转换的焦点部位,主要包括大别造山带、郯庐断裂带、长江中下游成矿带三大著名的构造单元,是中国东部中新生代大陆动力学深部过程与浅表响应的经典地区。将大陆造山带、大型断层、矿集区结合起来,瞄准板内变形、运动学和动力学,建立区内大陆动力学的系统研究框架,研究两大构造体制转换的精细过程,分析陆内构造演化和动力学的深部过程与浅部效应,将有助于大陆动力学理论的新突破,指导"第二成矿空间"的深部找矿。  相似文献   

西霞口龙眼港-4.5m码头加固扩建施工新方法     

李芳  王洪伟 《岩土工程技术》2010,24(1):10-11

以山东西霞口集团龙眼港—4.5m码头的改扩建工程为例,阐述了采用三管法旋喷桩托底置换、加劲旋喷桩配合锚拉支护方法在码头改造施工中的可行性及其施工工艺和施工方法,为同类工程施工积累了经验。  相似文献   

Distribution characteristics of delta reservoirs reshaped by bottom currents: A case study from the second member of the Yinggehai Formation in the DF1-1 gas field,Yinggehai Basin,South China Sea     

Shuo Chen  Renhai Pu  Huiqiong Li  Hongjun Qu  Tianyu Ji  Siyu Su  Yunwen Guan  Hui Zhang 《海洋学报(英文版)》2022,41(9):86-106

The Dongfang1-1 gas field (DF1-1) in the Yinggehai Basin is currently the largest offshore self-developed gas field in China and is rich in oil and gas resources. The second member of the Pliocene Yinggehai Formation (YGHF) is the main gas-producing formation and is composed of various sedimentary types; however, a clear understanding of the sedimentary types and development patterns is lacking. Here, typical lithofacies, logging facies and seismic facies types and characteristics of the YGHF are identified based on high-precision 3D seismic data combined with drilling, logging, analysis and testing data. Based on 3D seismic interpretation and attribute analysis, the origin of high-amplitude reflections is clarified, and the main types and evolution characteristics of sedimentary facies are identified. Taking gas formation upper II (IIU) as an example, the plane distribution of the delta front and bottom current channel is determined; finally, a comprehensive sedimentary model of the YGHF second member is established. This second member is a shallowly buried “bright spot” gas reservoir with weak compaction. The velocity of sandstone is slightly lower than that of mudstone, and the reflection has medium amplitude when there is no gas. The velocity of sandstone decreases considerably after gas accumulation, resulting in an increase in the wave impedance difference and high-amplitude (bright spot) reflection between sandstone and mudstone; the range of high amplitudes is consistent with that of gas-bearing traps. The distribution of gas reservoirs is obviously controlled by dome-shaped diapir structural traps, and diapir faults are channels through which natural gas from underlying Miocene source rocks can enter traps. The study area is a delta front deposit developed on a shallow sea shelf. The lithologies of the reservoir are mainly composed of very fine sand and coarse silt, and a variety of sedimentary structural types reflect a shallow sea delta environment; upward thickening funnel type, strong toothed bell type and toothed funnel type logging facies are developed. In total, 4 stages of delta front sand bodies (corresponding to progradational reflection seismic facies) derived from the Red River and Blue River in Vietnam have developed in the second member of the YGHF; these sand bodies are dated to 1.5 Ma and correspond to four gas formations. During sedimentation, many bottom current channels (corresponding to channel fill seismic facies) formed, which interacted with the superposed progradational reflections. When the provenance supply was strong in the northwest, the area was dominated by a large set of delta front deposits. In the period of relative sea level rise, surface bottom currents parallel to the coastline were dominant, and undercutting erosion was obvious, forming multistage superimposed erosion troughs. Three large bottom current channels that developed in the late sedimentary period of gas formation IIU are the most typical.  相似文献   

半潮堤前的反射形态与时均流速场分析     

徐展  王文进  蒋学炼  杨伟超  刘俊涛 《海洋工程》2022,40(3):75-82

采用模型试验和数值模拟研究了不同水深工况下半潮堤前的反射形态及时均流速场。基于Hilbert变换建立了叠合波的时频分离技术,同时获取了入射波和反射波的波面过程及相位关系,通过试验数据证明其适用于不同反射程度的波浪信号分析。不同水深工况下,半潮堤前形成了部分立波系统,腹点和节点分别以四分之一波长的偶数倍和奇数倍交替增加。半潮堤前底床水质点水平速度包络图与波面包络图相差四分之一周期的相位,水平速度的极大值和极小值分别出现在波面包络图的节点和腹点,意味着节点处易形成冲刷,腹点处易形成淤积。3种工况的周期平均速度场均在迎浪基床上方的堤脚处存在一个小型环流系统,可能引起局部冲刷,此处需加强防护。淹没工况下,半潮堤前的周期平均速度场形成一个大型环流系统,表层水流向堤后,中下层水流向海侧,意味着底床悬起的泥沙很可能向离岸方向流失。  相似文献