The Rossby wave train patterns forced by shallower and deeper Tibetan Plateau atmospheric heat-source in summer in a linear baroclinic model          下载免费PDF全文

ZHU Chuandong  REN Rongcai 《大气和海洋科学快报》2019,(1):35-40

观测结果表明,在夏季青藏高原高层大气热源(TPUHS)的发展和衰减阶段(高原热源由浅向深发展),北半球的环流异常表现出不同的Rossby波列型。本研究利用线性斜压模式LBM来探究深浅TPUHS的波列效应。模拟结果表明,深浅TPUHS能强迫出不同的Rossby波列型,而且波列型与观测结果相似。对应浅的TPUHS,Rossby波列型从青藏高原延伸至美国西海岸;而对应深的TPUHS,Rossby波列型从青藏高原延伸至阿拉斯加。  相似文献   

An Analysis of the Discontinuity in Chinese Radiosonde Temperature Data Using Satellite Observation as a Reference     

Yanjun GUO  Chengzhi ZOU  Panmao ZHAI  Guofu WANG 《Journal of Meteorological Research》2019,(2):289-306

Reconciling upper-air temperature trends derived from radiosonde and satellite observations is a necessary step to confidently determine the global warming rate. This study examines the raw and homogenized radiosonde observations over China and compares them with layer-mean atmospheric temperatures derived from satellite microwave observations for the lower-troposphere(TLT), mid-troposphere(TMT), upper-troposphere(TUT), and lower-stratosphere(TLS) by three research groups. Comparisons are for averages over China, excluding the Tibetan Plateau, and at individual stations where metadata contain information on radiosonde instrument changes. It is found that major differences between the satellite and radiosonde observations are related to artificial systematic changes. The radiosonde system updates in the early 2000 s over China caused significant discontinuities and led the radiosonde temperature trends to exhibit less warming in the middle and upper troposphere and more cooling in the lower stratosphere than satellite temperatures. Homogenized radiosonde data have been further adjusted by using the shift-point adjustment approaches to match with satellite products for China averages. The obtained trends during 1979–2015 from the re-adjusted radiosonde observation are respectively 0.203 ± 0.066, 0.128 ± 0.044, 0.034 ± 0.039, and –0.329 ± 0.135 K decade^–1 for TLT, TMT, TUT, and TLS equivalents. Compared to satellite trends, the re-adjusted radiosonde trends are within 0.01 K decade^–1 for TMT and TUT, 0.054 K decade^–1 warmer for TLT, and 0.051 K decade^–1 cooler for TLS. The results suggest that the use of satellite data as a reference is helpful in identifying and removing inhomogeneities of radiosonde temperatures over China and reconciling their trends to satellite microwave observations. Future efforts are to homogenize radiosonde temperatures at individual stations over China by using similar approaches.  相似文献   

基于SDSM的珠江中上游气候模拟及未来情景预估     

许燕  王世杰  白晓永  李雄耀  史晓明  田义超  吴路华 《中国岩溶》2018,37(2):228-237

预估喀斯特生态脆弱区的未来气候变化对于区域资源的合理开发利用及生态环境保护具有重要参考价值,而目前应用降尺度方法模拟喀斯特地区的未来气候情景仍存在较大的探讨空间。本文依据珠江流域红柳江区13个气象站1961-2001年的实测日气温、日降水量资料和全球大气NCEP再分析资料,采用SDSM模型预测流域在HadCM3模式SRES A2和B2两种排放情景下未来年份气温和降水的变化趋势。结果表明:（1）SDSM模型可以较为准确地模拟研究区的气温和降水变化,确定性系数分别可达99%和65%左右;（2）A2、B2两种情景下,21世纪气温和降水均表现出明显的上升趋势,且随时间推移增幅逐渐增大。截至21世纪末,A2、B2两种情景下的年平均气温变化分别为+3.39 ℃和+2.49 ℃,日均降水将分别增加117.30 %和80.90 %;（3）未来的气温上升以秋季和春季变化最为明显,降水则表现为夏季降水增幅最大。分析成果可为喀斯特区的气候变化影响评价与应对决策提供数据基础和理论依据。   相似文献   

东南沿海早白垩世火山岩的极低级变质作用研究   总被引：1，自引：0，他引：1  

段政  邢光福  余明刚  许乃岑 《岩石学报》2018,34(3):656-668

中国东南沿海广泛分布的白垩纪火山岩中,发育一套具特殊岩相学特征的火山岩地层,以浙江高坞组和福建南园组为代表,其主体为熔结凝灰岩,以深灰色厚层致密块状、含大量长石和石英晶屑、大面积出露但假流动构造模糊为突出特征,而明显区别于其它白垩纪地层组的熔结凝灰岩,表明其具有独特的成岩过程。伊利石结晶度研究表明,高坞组和南园组火山岩特殊的岩相学特征与其成岩后受到极低级变质作用,从而发生一定程度重结晶有关,这一过程使其岩石结构构造趋于均一化。通过对上下火山岩系火山岩的伊利石结晶度、b0值及多型特征对比分析表明,东南沿海这一大范围的火山岩极低级变质作用,可能是早白垩世晚期"闽浙运动"后岩石圈发生强烈伸展,导致区域大规模热隆作用的反映,并与上下火山岩系之间区域性不整合面的形成、长乐-南澳构造带强烈的变质变形事件及东南沿海大规模金铜矿、非金属等成矿作用密切相关,具有重要的研究意义。  相似文献   

神朔铁路寇庄站供水井水质浑浊的处理及防治措施     

陈伟武 《探矿工程》2018,45(3):49-52

神华集团神朔铁路寇庄站供水井由于煤系地层水止水效果不好,对水质影响较大。针对止水封堵出现的问题,提出了在已成井情况下采用上下分隔器封堵注浆工艺技术,很好地解决了煤系水漏水造成供水井水质浑浊的问题。实践证明,该技术施工简单,使用灵活,止水处理事故效果良好。  相似文献   

基于地形起伏度的山区人口密度修正——以岷江上游为例   总被引：4，自引：1，他引：3  

刘颖  邓伟  宋雪茜  周俊 《地理科学》2015,(4):464-470

山区人口承载能力评价是山区国土空间管理的基础之一,而准确的人口密度数据是正确评价人口承载能力的基础。传统的人口密度算法并未考虑地形起伏度对人口分布带来的影响,不能客观反映山区人口聚集程度。引入地形起伏度、海拔高度因子,选择岷江上游作为研究区,首先运用GIS技术提取地形起伏度,再运用SPSS软件对人口密度与地形起伏度相关性进行分析,确定县域不同地形起伏度与海拔人居适宜标准,剔除阈值以外不适宜人口聚居的面积,对人口密度进行修正。研究结果表明:1岷江上游人口分布受地形起伏度的影响显著,二者的对数曲线拟合度为0.89,汶川县、茂县、理县、黑水县与松潘县地形起伏度与人口分布的相关性分别为:0.841、0.773、0.643、0.696和0.730;2应用地形起伏度对岷江上游人口密度修正,为真实反映山区人口密度提供了新的考量依据,剔除了人口密度空间噪音,5县地形起伏度与海拔适宜标准分别为:汶川3.2°和3 693 m,茂县4°和4 033 m,理县4.3°和3 790 m,黑水4.4°和3 853 m、松潘4.2°和3 966 m;地形起伏度高值区面积越大,修正前后的人口密度偏差越大,地形起伏度较大的理县和黑水县修正后的人口密度分别提高了7.8倍和5.6倍;地形起伏度较低的汶川县与茂县修正后人口密度仅分别提高2.3倍与2.4倍;3岷江上游人口潜在压力大,不同区域应因地制宜,汶川和茂县采取重点集约发展战略,理县和黑水县采取适度开发战略,松潘县应采取恢复与保护生态策略。  相似文献   

浙闽相邻区白垩纪上下火山岩系成因与壳幔作用对比研究   总被引：2，自引：0，他引：2  

段政  赵希林  邢光福  杨祝良  余明刚  陈志洪  靳国栋  姜杨  李亚楠 《地质学报》2015,89(2):319-338

浙闽相邻区广泛出露的白垩纪火山岩划分为上下火山岩系。下火山岩系为大面积展布的早白垩世早期长英质火山岩,属弱过铝质高钾钙碱性系列,富集大离子亲石元素Cs、Rb、Ba、Pb等和LREE,无明显Eu异常,亏损高场强元素Nb、Ta、Ti、P等,εHf(t)值较低(-20.43~-6.39),锆石Hf同位素二阶段模式年龄TDM2集中在1.8~2.2Ga之间。上火山岩系为局限于断陷盆地内的早白垩世晚期长英质火山岩,属偏铝质高钾钙碱性系列,相对贫硅贫碱但同样富集LREE和大离子亲石元素,负Eu异常明显,εHf(t)值较高(-10.00~-4.51)。研究表明,上下火山岩系均表现出随时代变新ΣREE和LREE分异程度降低的趋势,均形成于活动大陆边缘环境,主要为幔源岩浆底侵导致古元古代陆壳基底部分熔融形成的低Sr流纹岩类,但上火山岩系成岩过程中经历了更强烈的壳幔作用;例外的是下火山岩系西山头组上部熔岩,属东南沿海罕见的橄榄玄粗岩系列高Sr粗面英安岩,以富集Sr、Ti、Co、Ni和低的εHf(t)为特征,推断由幔源基性岩浆结晶分异形成。区域晚中生代火山岩的综合对比表明,东南沿海深部壳幔作用具有从中—晚侏罗世到早白垩世晚期逐渐增强、自南往北依次减弱的时空演化规律。  相似文献   

Meridional variations of C₂H₂ and C₂H₆ in Jupiter's atmosphere from Cassini CIRS infrared spectra     

C.A. Nixon  R.K. Achterberg  P.G.J. Irwin  T. Fouchet  P.N. Romani  A. LeClair  A.A. Simon-Miller  F.M. Flasar 《Icarus》2007,188(1):47-71

Hydrocarbons such as acetylene (C₂H₂) and ethane (C₂H₆) are important tracers in Jupiter's atmosphere, constraining our models of the chemical and dynamical processes. However, our knowledge of the vertical and meridional variations of their abundances has remained sparse. During the flyby of the Cassini spacecraft in December 2000, the Composite Infrared Spectrometer (CIRS) instrument was used to map the spatial variation of emissions from 10 to 1400 cm⁻¹ (1000-7 μm). In this paper we analyze a zonally averaged set of CIRS spectra taken at the highest (0.48 cm⁻¹) resolution, firstly to infer atmospheric temperatures in the stratosphere at 0.5-20 mbar via the ν₄ band of CH₄, and in the troposphere at 150-400 mbar, via the H₂ absorption at 600-800 cm⁻¹. Stratospheric temperatures at 5 mbar are generally warmer in the north than the south by 7-8 K, while tropospheric temperatures show no such asymmetry. Both latitudinal temperature profiles however do show a pattern of maxima and minima which are largely anti-correlated between the two levels. We then use the derived temperature profiles to infer the vertical abundances of C₂H₂ and C₂H₆ by modeling tropospheric absorption (∼200 mbar) and stratospheric emission (∼5 mbar) in the C₂H₂ν₅ and C₂H₆ν₉ bands, and also emission of the acetylene (ν₄+ν₅)−ν₄ hotband (∼0.1 mbar). Acetylene shows a distinct north-south asymmetry in the stratosphere, with 5 mbar abundances greatest close to 20° N and decreasing from there towards both poles by a factor of ∼4. At 200 mbar in contrast, acetylene is nearly flat at a level of ∼3×¹⁰⁻⁹. Additionally, the abundance gradient of C₂H₂ between 10 and 0.1 mbar is derived, based on interpolated temperatures at 0.1 mbar, and is found to be positive and uniform with latitude to within errors. Ethane at both 5 and 200 mbar shows increasing VMR towards polar regions of ∼1.75 towards 70° N and ∼2.0 towards 70° S. An explanation for the meridional trends is proposed in terms of a combination of photochemistry and dynamics. Poleward, the decreasing UV flux is predicted to decrease the abundances of C₂H₂ and C₂H₆ by factors of 2.7 and 3.5, respectively, at latitude 70°. However, the lifetime of C₂H₆ in the stratosphere (3×¹⁰¹⁰ s at 5 mbar) is much longer than the dynamical timescale for meridional mixing inferred from Comet SL-9 debris (5-50×¹⁰⁸ s), and therefore the rising abundance towards high latitudes likely indicates that meridional mixing dominates over photochemical effects. For C₂H₂, the opposite occurs, with the relatively short photochemical lifetime (3×¹⁰⁷ s), compared to meridional mixing times, ensuring that the expected photochemical trends are visible.  相似文献   

计算机地图制图教学方法改革研究     

王延亮  杨金玲  张贺 《测绘与空间地理信息》2013,(10):73-74,78

计算机地图制图课程的教学多数采用传统的知识驱动式教学法,该教学法的特点是先理论后实践．理论讲授比重较大。在计算机地图制图单纯使用“案例教学法”或“任务驱动教学法”都存在不足。笔者将二者相结合,设计了“案例引导的任务驱动教学法”,以案例为模板,以任务为目标,有效地激发了学生的积极性,使其较好地掌握计算机地图制图的知识和技术。  相似文献   

柴达木-祁连山地块内部震间上地壳块体运动特征与变形模式研究   总被引：1，自引：1，他引：0       下载免费PDF全文

葛伟鹏  王敏  沈正康  袁道阳  郑文俊 《地球物理学报》2013,56(9):2994-3010

以青藏高原北缘及东北缘的柴达木-祁连山地块内的活动断裂、由断裂所围限的微小块体为研究对象,系统收集整理区内活动断裂定量参数和GPS速度场等资料,使用球面应变率计算方法分析研究区内GPS 速度场得到现今构造应变率场,讨论区内最大剪应变率、面膨胀率与旋转率等参数与区域构造变形之间的关系;同时,依据区内详实的活动断裂资料建立精细的微小活动块体模型,利用Backslip模型反演断裂所围限的各个块体边界断裂的滑动速率、块体内部统一应变率及块体欧拉运动学参数等,并与活动构造方法获得的滑动速率做对比;最后,讨论研究区内由GPS速度场所揭示的地壳运动变形模式.结果表明:(1)柴达木-祁连山地区地壳运动,在沿着山脉走向上具有带状区域分块运动特征,大范围内具有弥散变形特征;(2)青藏高原北部变形场应是通过不同断裂差异性相对运动、区域内部逆冲挤压和块体旋转共同作用的结果.从鄂拉山到古浪民勤一带具有强烈的逆冲活动,其两侧地壳块体分别具有逆向旋转的运动性质;(3)在研究区东部GPS速度场所呈现顺时针旋转的形态,应是处于不同地块边界处的中下地壳与地幔介质差异驱动机制对上地壳块体所产生的作用,并以近地表断层应变率积累形式表现的结果,是祁连山地块、阿拉善块体、鄂尔多斯地块等大型块体推挤旋转影响下的复杂运动学形态.  相似文献