Detecting primary precursors of January surface air temperature anomalies in China

This study aims to detect the primary precursors and impact mechanisms for January surface temperature anomaly (JSTA) events in China against the background of global warming, by comparing the causes of two extreme JSTA events occurring in 2008 and 2011 with the common mechanisms inferred from all typical episodes during 1979–2008. The results show that these two extreme events exhibit atmospheric circulation patterns in the mid–high latitudes of Eurasia, with a positive anomaly center over the Ural Mountains and a negative one to the south of Lake Baikal (UMLB), which is a pattern quite similar to that for all the typical events. However, the Eurasian teleconnection patterns in the 2011 event, which are accompanied by a negative phase of the North Atlantic Oscillation, are different to those of the typical events and the 2008 event. We further find that a common anomalous signal appearing in early summer over the tropical Indian Ocean may be responsible for the following late-winter Eurasian teleconnections and the associated JSTA events in China. We show that sea surface temperature anomalies (SSTAs) in the preceding summer over the western Indian Ocean (WIO) are intimately related to the UMLB-like circulation pattern in the following January. Positive WIOSSTAs in early summer tend to induce strong UMLB-like circulation anomalies in January, which may result in anomalously or extremely cold events in China, which can also be successfully reproduced in model experiments. Our results suggest that the WIOSSTAs may be a useful precursor for predicting JSTA events in China.     

昆明静止锋下的云南强倒春寒天气分析

利用NCEP1°×1°的6小时再分析资料和常规观测资料,对2005年3月云南出现强倒春寒天气过程的环流特征和物理量场特征进行了分析,探讨了在无南支槽的配合下,由昆明静止锋和高空切变线引发的大范围降雪和降温的强倒春寒天气发生前后中低层环流的演变、热力学和动力学物理因子与倒春寒天气的关系及其形成条件,为今后预测这类天气提供参考依据。     

锡林郭勒盟草原火险气象等级预报方法的研究

依据国家草原火险等级划分标准,针对锡林郭勒盟的具体情况对指标体系进行逐月调整,运用多个气象因子和综合因子之间相关来确定草原火险天气等级标准,建立草原火险气象等级预报方程,并开发研制了草原火险气象等级预报服务系统,经过近1年的试运行,能够对草原火险天气进行很好的预报预测,同时指导草原火险的遥感监测业务.     

基于回复电压法的ZnO压敏电阻冲击老化诊断

针对如何准确诊断ZnO压敏电阻老化的问题,提出了一种新的诊断方法——回复电压法,通过对ZnO压敏电阻试样进行不同程度的冲击老化试验,并采用多种诊断方法对试样在冲击前后的老化状态进行测量,发现回复电压法同传统的压敏电压以及放电残压变化率法所得的结论相吻合,且回复电压法的主要参数回复电压最大值以及中心时间常数在冲击后呈现下降趋势,这与SEM电镜扫描试验得出的压敏电阻晶粒平均尺寸下降,电导率上升的结论相一致,进一步证明了回复电压法诊断的及时有效性,这对提高ZnO压敏电阻的老化诊断准确度具有一定的参考价值。     

全球、中国及云南近百年气温变化的层次结构和突变特征

用文献［１］建立的自适应多分辨数据波滤器进行了全球、中国及云南近百年气温变化的层次结构和突变特征分析。结果表明：（１）全球近百年来的气温变化对于较大时间尺度的演化来说主要特征是变暖,并为３个层次：即１９１９年以前的偏冷期;１９２０－１９７８年偏暖期和１９７９年以后的更暖期。对应于这种较大时间尺度的层次演变,全球的气温变化表现出十分明显的突变特征,两上最明显增暖的突变点分别发生在１９２０年和１９７９     

用滤膜法观测大气冰核的静力扩散云室

介绍了经过改进的用滤膜法观测冰核的静力扩散云室及其取样装置。叙述了其各组成部分的原理、结构、达到的性能指标，分析了各系统的工作对冰核活化条件的影响。给出了对相对稳定的人工ＡｇＩ冰核源作不同体积的取样和不同温度下的处理结果，同时也给出了用该设备对北京市海淀区冬季冰核浓度的日变化所做的初步观测结果。     

Spectroscopic and photometric observations of unidentified ultraviolet variable objects in the GUVV-2 Catalog

An NUV-optical diagram composed from sources from the second Galaxy Evolution Explorer(GALEX) Ultraviolet Variability(GUVV-2) Catalog provides us with a method to tentatively classify the unknown GUVV-2 sources by their NUV-optical magnitudes.For the purpose of testing the correctness and generality of the method,we carry out a program on the spectroscopic observations of the unidentified GUVV-2 sources.The spectroscopic identification of these 37 sources are 19 type-A to-F stars,10 type-G to-K stars and 7 ...     

基于地震观测数据的结构损伤水平表征参数研究

为了能在震后更好地利用测得的结构动力响应参数快速对结构损伤程度进行评估,文中挑选了最大层间位移角、自振频率相对改变量和顶层加速度放大系数3个参数,分析结构损伤指数与3个参数之间的相关性,并且提出了一种组合结构体系参数.结果表明,结构损伤指数与最大层间位移角的相关性为高度相关,与自振频率相对改变量和顶层加速度放大系数的相...     

长春万达广场抗浮锚杆的设计与试验研究

以长春万达广场地下室抗浮锚索工程为例,研究了扩体拉力型锚杆支护在宏观上和微观上的力学作用机理、扩体型锚固体的设计计算、所采用的锚杆扩体部分的扩孔器的内部结构等。在实验结果基础上,得出在土层中采用扩体型锚杆不仅能充分利用土体自身的强度,提高其承载力,改变其锚固体的应力状态,而且能减少锚杆锚固体长度、缩短施工工期、降低工程成本、节约自然资源等结论。最后对扩体型锚索影响承载力的因素、地层适用条件以及它的应用前景进行了探讨和展望。     

Determining air permeability in reclaimed coastal land based on tidal fluctuations

Coastal land reclamation is a common practice in many regions around the World. A reclaimed coastal land often has a two-layer system: a highly permeable layer consisting of crushed rock fragments underneath a less permeable layer. This study deals with vertical airflow in a reclaimed coastal land induced by the periodic variations of water table elevation due to tide fluctuations. The influence of atmospheric pressure fluctuations can be easily dealt with through a simple superposition procedure reported by Li and Jiao, thus is not considered here. A time-series Fourier analysis method is developed to determine air permeability based on a tide-induced airflow model reported by Li and Jiao for the reclaimed coastal land. This method employs the amplitude attenuations of subsurface air pressure to search for values of dimensionless air-leaking-resistance which can be subsequently used to calculate air permeability. Two types of data, the air pressure data in the upper less permeable layer and the tidal fluctuation data, are required to calculate the air permeability. Type curves relating to the amplitude attenuations and the relative depth can also be used to determine the values of air permeability. A field site in Hong Kong International Airport is used to demonstrate the applicability of this method for reclaimed coastal land consisting of a marine sand layer above a layer of crushed rock fragments. The application shows that the amplitude attenuations of diurnal and semi-diurnal components in the Fourier series are most reliable for determining the value of air permeability.