2008年6月26日锡林浩特暴雨天气过程分析及服务情况     

闫淑清  郝艳霞  巴特尔  谢东  孙喜明 《内蒙古气象》2011,(4):32-34

受高空冷涡和鄂海高压的共同影响,2008年6月26日锡林浩特市出现了一次暴雨过程。通过分析表明:(1)700、850hPa的切变线,为降雨提供了辐合条件和触发条件。(2)地面冷暖锋维持少动,T-logP图中的不稳定能量和充沛的水汽,使降雨量增大。(3)雷达回波显示为絮状,东北移的过程中有气旋性运动,且有最大速度模糊,风向随高度顺转,对强降雨的发生有很好的指示意义。同时,根据分析结果,及时、到位的做好服务工作,有效减少了人民群众的财产损失。  相似文献   

鄂尔多斯地区降水天气过程预报方法     

郝利平  许彦慧  巴根 《内蒙古气象》2010,(2):15-17

鄂尔多斯素有"十年九旱、年年春旱"之称,降水量是影响当地工农牧业生产的主要因素,根据鄂尔多斯多年的降水资料,找出其降水的季节分布规律,尽可能作准降水预报,为工农牧业生产及党政决策提供参考。  相似文献   

A multi-model comparison of Atlantic multidecadal variability     

Jin Ba  Noel S. Keenlyside  Mojib Latif  Wonsun Park  Hui Ding  Katja Lohmann  Juliette Mignot  Matthew Menary  Odd Helge Otterå  Bert Wouters  David Salas y Melia  Akira Oka  Alessio Bellucci  Evgeny Volodin 《Climate Dynamics》2014,43(9-10):2333-2348

A multi-model analysis of Atlantic multidecadal variability is performed with the following aims: to investigate the similarities to observations; to assess the strength and relative importance of the different elements of the mechanism proposed by Delworth et al. (J Clim 6:1993–2011, 1993) (hereafter D93) among coupled general circulation models (CGCMs); and to relate model differences to mean systematic error. The analysis is performed with long control simulations from ten CGCMs, with lengths ranging between 500 and 3600 years. In most models the variations of sea surface temperature (SST) averaged over North Atlantic show considerable power on multidecadal time scales, but with different periodicity. The SST variations are largest in the mid-latitude region, consistent with the short instrumental record. Despite large differences in model configurations, we find quite some consistency among the models in terms of processes. In eight of the ten models the mid-latitude SST variations are significantly correlated with fluctuations in the Atlantic meridional overturning circulation (AMOC), suggesting a link to northward heat transport changes. Consistent with this link, the three models with the weakest AMOC have the largest cold SST bias in the North Atlantic. There is no linear relationship on decadal timescales between AMOC and North Atlantic Oscillation in the models. Analysis of the key elements of the D93 mechanisms revealed the following: Most models present strong evidence that high-latitude winter mixing precede AMOC changes. However, the regions of wintertime convection differ among models. In most models salinity-induced density anomalies in the convective region tend to lead AMOC, while temperature-induced density anomalies lead AMOC only in one model. However, analysis shows that salinity may play an overly important role in most models, because of cold temperature biases in their relevant convective regions. In most models subpolar gyre variations tend to lead AMOC changes, and this relation is strong in more than half of the models.  相似文献   

1988—2018年那曲市其香错水域面积变化及原因分析     

拉巴  边多  顿玉多吉  央美  张伟华  白玛仁增 《气象与环境学报》2021,37(5):72-77

基于Landsat卫星遥感数据,采用水体指数法和相关分析法,分析1988—2018年那曲市双湖县其香错湖泊水域面积变化及原因。结果表明：该湖泊近31 a内水域面积呈显著增长趋势（R²=0.88,P < 0.001）,31 a内增长了33.37 km²,增长率为18.03%;从空间上分析,其香错在近31 a内湖泊面积不断向四周扩展,其中在东、西方向和北部变化尤为显著。湖泊所在区域年平均气温呈增加趋势,蒸发量显著减小,冻土深度也明显减小。在上述因素的共同作用下,引起湖泊补给水源的增加和湖泊水容量的增大,最终导致湖泊面积持续上涨。  相似文献   

Effect of stress interactions on anisotropic P-SV-wave dispersion and attenuation for closely spaced cracks in saturated porous media     

Chenghao Cao  Fangyuan Chen  Li-Yun Fu  Jing Ba  Tongcheng Han 《Geophysical Prospecting》2020,68(8):2536-2556

Generally, local stress induced by individual crack hardly disturbs their neighbours for small crack densities, which, however, could not be neglected as the crack density increases. The disturbance becomes rather complex in saturated porous rocks due to the wave-induced diffusion of fluid pressures. The problem is addressed in this study by the comparison of two solutions: the analytical solution without stress interactions and the numerical method with stress interactions. The resultant difference of effective properties can be used to estimate the effect of stress interactions quantitatively. Numerical experiments demonstrate that the spatial distribution pattern of cracks strongly affects stress interactions. For regularly distributed cracks, the resulting stress interaction (shielding or amplification) shows strong anisotropy, depending on the arrangement and density of cracks. It has an important role in the estimation of effective anisotropic parameters as well as the incident-angle-dependency of P- and SV-wave velocities. Contrarily, randomly distributed cracks with a relative small crack density generally lead to a strong cancellation of stress interactions across cracks, where both the numerical and analytical solutions show a good agreement for the estimation of effective parameters. However, for a higher crack density, the incomplete cancellation of stress interactions is expected, exhibiting an incidence-angle dependency, slightly affecting effective parameters, and differentiating the numerical and analytical solutions.  相似文献   

Seismotectonic database of Turkey     

Tamer Y. Duman  Tolga Çan  Ömer Emre  F. Tuba Kadirioğlu  Nilay Başarır Baştürk  Tuğbay Kılıç  Selim Arslan  Selim Özalp  Recai F. Kartal  Doğan Kalafat  Ferdane Karakaya  Tuba Eroğlu Azak  Nurcan M. Özel  Semih Ergintav  Sinan Akkar  Yıldız Altınok  Senem Tekin  Ayhan Cingöz  A. İhsan Kurt 《Bulletin of Earthquake Engineering》2018,16(8):3277-3316

Turkey is located in one of the most seismically active regions in the world. Characterizing seismic source zones in this region requires evaluation and integration of geological, geophysical, seismological and geodetical data. This first seismotectonic database for Turkey presented herein was prepared, under the framework of the National Earthquake Strategy and Action Plan—2023. The geographic information system (GIS)-based database includes maps of active faults, catalogues of instrumental and historical earthquakes, moment tensor solutions and data on crustal thickness. On the basis of these data, 18 major seismotectonic zones were delineated for Turkey and the surrounding region. The compilation and storage of the seismotectonic data sets in a digital GIS will allow analyses and systematic updates as new data accrete over time.  相似文献   

Crosslinked Egg White as Eco‐Friendly,Reusable, and Cost‐Effective Biosorbent for Rapid Removal of Indigo Carmine          下载免费PDF全文

Tulay Oymak  Esra Bağda 《洁净——土壤、空气、水》2018,46(6)

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转型期测绘复合创新、知识服务型人才培养模式创新与质量保障     

柯福阳  赵显富  丁海勇  孙景领  祝善友  缪启龙 《测绘通报》2019,(4):138-142

审视分析当前测绘工程专业人才培养存在的问题,以"测绘4.0"与智能测绘对测绘人才的新要求为导向,南京信息工程大学遥感与测绘工程学院结合实际情况,依托优势特色,在培养方案制定、课程体系构建、教学手段和模式、评价方式、工程实训等人才培养方面进行一系列的创新与实践,构建了闭环的人才培养质量保证体系,人才培养成效和社会声誉显著,为测绘高校复合创新、知识服务型高级人才的培养提供了重要参考。  相似文献   

Keplerian integrals,elimination theory and identification of very short arcs in a large database of optical observations     

G. F. Gronchi  G. Baù  A. Milani 《Celestial Mechanics and Dynamical Astronomy》2017,127(2):211-232

Modern asteroid surveys produce an increasingly large number of observations, which are grouped into very short arcs (VSAs) each containing a few observations of the same object in one single night. To decide whether two VSAs collected in different nights correspond to the same observed object we can attempt to compute an orbit with the observations of both arcs: this is called the linkage problem. Since the number of linkages to be attempted is very large, we need efficient methods of orbit determination. Using the first integrals of Kepler’s motion we can write algebraic equations for the linkage problem, which can be put in polynomial form. In Gronchi et al. (Celest Mech Dyn Astron 123(2):105–122, 2015) these equations are reduced to a polynomial equation of degree 9: the unknown is the topocentric distance of the observed body at the mean epoch of one VSA. Here we derive the same equations in a more concise way, and show that the degree 9 is optimal in a sense that will be specified in Sect. 3.3. We also introduce a procedure to join three VSAs: from the conservation of angular momentum we obtain a polynomial equation of degree 8 in the topocentric distance at the mean epoch of the second VSA. For both identification methods, with two and three VSAs, we discuss how to discard solutions. Finally, we present some numerical tests showing that the new methods give satisfactory results and can be used also when the time separation between the VSAs is large. The low polynomial degree of the new methods makes them well suited to deal with the very large number of asteroid observations collected by the modern surveys.  相似文献   

粤北石土岭铀矿床同位素地球化学研究   总被引：15，自引：2，他引：13  

朱捌  凌洪飞  沈渭洲  高剑峰  邓平  黄国龙  谭正中 《矿床地质》2006,25(1):71-82

石土岭铀矿床位于贵东岩体东南部与寒武纪浅变质岩接触带的内带,矿区内NWW向和NNE向基性岩脉十分发育。矿体主要赋存于帽峰岩体中,呈脉状产出,并受近EW向裂隙构造控制。沥青铀矿的U-Pb年龄(135Ma)与帽峰岩体的年龄(220Ma)相差明显,但与NWW向辉绿岩脉的年龄(143Ma)十分接近。矿石中黄铁矿的初始87Sr/86Sr值(0.71315~0.72579)介于成矿期间辉绿岩的值(0.70449~0.70632)与帽峰和下庄岩体演化至成矿时期(135Ma)的值(0.75058~0.99507)之间;黄铁矿的铅同位素组成呈线性分布,为基底变质岩铅与帽峰岩体铅及辉绿岩铅之间不同程度的混合。Sr、Pb同位素组成显示出成矿组分具多来源特征;成矿流体的δ18OH2O=2.0‰~8.1‰,δDH2O=-63‰~-51‰,反映出成矿流体主要由幔源流体组成;方解石的δ13C=-8.3‰,表明矿化剂∑CO2也来自地幔。因此,幔源流体在石土岭铀矿床的形成中具有十分重要的意义。  相似文献