基于Landsat 8劈窗算法与混合光谱分解的城市热岛空间格局分析——以兰州市中心城区为例

在ENVI和GIS支持下,提出了基于Landsat 8遥感影像的地温反演劈窗算法,提取兰州市中心城区地表温度。利用FNEA和混合光谱分解法确定了兰州市中心城区的城市热岛中心、不透水面和植被盖度,分析了城市热岛空间分布格局以及地表温度与下垫面之间的关系。结果显示:基于Landsat 8数据地温反演的劈窗算法是可行的。兰州中心城区的高温区分布较集中,地表温度与植被呈较强的负相关,与不透水面呈不显著的正相关,与其他非光合物质呈正相关。     

Experimental research on physical properties of saline soil subgrade filler in Chaerhan region

In order to improve the engineering stability of saline soil of high chloride content in the Chaerhan salt lake region, six typical characteristics saline soil samples were selected, and tests on their...     

鄂尔多斯盆地志靖——安塞地区延长组首次湖侵期沉积特征及其石油地质意义

通过沉积物岩石学特征、粒度分布特征、沉积构造与生物化石特征、单井分析等综合方法,对志靖—安塞地区长9油层组沉积相发育及分布特征进行了研究。结果表明,鄂尔多斯盆地志靖—安塞地区在首次湖侵期长9期发育三角洲-湖泊沉积体系,主要发育三角洲前缘亚相和浅湖亚相。长92期研究区北部大面积发育三角洲前缘沉积,西南部发育小面积三角洲前缘沉积,浅湖面积较小,呈喇叭状向东南方向开口。长91期沉积格局基本上继承了长92期的特点,但浅湖的范围有所加大。三角洲前缘水下分流河道砂体整体上呈北东—南西向条带状展布。长9期湖侵过程形成了具生烃潜力的泥岩,主要分布在吴起—志丹—安塞一带,在志丹东南部区域最厚,可达20m,并呈现向东南方向继续变厚延伸的趋势。储集空间的存在和烃源岩的发育使得研究区长9储层具有较好的勘探前景。     

Optical observations of the broad-lined type Ic supernova SN 2012ap

The optical observations of the type Ic supernova(SN Ic) SN 2012 ap in NGC 1729 are presented. A comparison with other SNe Ic indicates that SN 2012 ap is highly reddened(with E(B- V)host～0.8 mag) and may represent one of the most luminous SNe Ic ever observed, with an absolute V-band peak magnitude of ～-19.3±0.5 mag after extinction correction. The near-maximum-light spectrum shows wide spectral features that are typical of broad-lined SNe Ic. One interesting feature in the spectrum is the appearance of some narrow absorption features that can be attributed to the diffuse interstellar bands, consistent with the large reddening inferred from the photometric method. Based on the light curves and the spectral data, we estimate that SN 2012 ap produced a56 Ni mass of ～ 0.3 ± 0.1M in the explosion, with an ejecta mass of 2.4+0.7-0.7M and a kinetic energy of E5K= 1.1+0.4-0.4× 102 erg. The properties of its progenitor are also briefly discussed.     

Midlatitude unstable air-sea interaction with atmospheric transient eddy dynamical forcing in an analytical coupled model

While recent observational studies have shown the critical role of atmospheric transient eddy (TE) activities in midlatitude unstable air-sea interaction, there is still a lack of a theoretical framework characterizing such an interaction. In this study, an analytical coupled air-sea model with inclusion of the TE dynamical forcing is developed to investigate the role of such a forcing in midlatitude unstable air-sea interaction. In this model, the atmosphere is governed by a barotropic quasi-geostrophic potential vorticity equation forced by surface diabatic heating and TE vorticity forcing. The ocean is governed by a baroclinic Rossby wave equation driven by wind stress. Sea surface temperature (SST) is determined by mixing layer physics. Based on detailed observational analyses, a parameterized linear relationship between TE vorticity forcing and meridional second-order derivative of SST is proposed to close the equations. Analytical solutions of the coupled model show that the midlatitude air-sea interaction with atmospheric TE dynamical forcing can destabilize the oceanic Rossby wave within a wide range of wavelengths. For the most unstable growing mode, characteristic atmospheric streamfunction anomalies are nearly in phase with their oceanic counterparts and both have a northeastward phase shift relative to SST anomalies, as the observed. Although both surface diabatic heating and TE vorticity forcing can lead to unstable air-sea interaction, the latter has a dominant contribution to the unstable growth. Sensitivity analyses further show that the growth rate of the unstable coupled mode is also influenced by the background zonal wind and the air–sea coupling strength. Such an unstable air-sea interaction provides a key positive feedback mechanism for midlatitude coupled climate variabilities.

     

基于COM组件的单站数值预报结果提取与网络动态发布方法

为实现对海量数值预报产品的高效应用和对单站数值预报结果的网络共享,针对ECMWF、T639等数值预报产品特点,创建了一种单站数值预报结果的提取方法,并基于COM组件实现其结果的网络动态发布.本文给出了网络服务器端单站数值预报结果提取COM组件设计的一般思路和关键程序代码,解决了单站数值预报结果的快速提取、直观显示和网络动态实时发布问题.     

2017年3月江苏北部一次雷雨大风天气过程分析

利用多种常规观测资料和NCEP／NCAR再分析资料,分析了2017年3月1日江苏北部出现的一次罕见冷空气雷雨大风天气过程的发生背景、地面要素和云团演变特征,同时从大气动力、热力和水汽条件出发分析了午后对流的成因。结果表明：此次过程发生前,江苏地区位于高空槽前,对流层中低层有冷式切变线伴随两股冷空气南下,受江苏省北部地面气旋阻挡,冷空气在上游堆积,当气旋东移入海冷空气爆发式南下时,造成严重的大风灾害。此次过程中,对流层中高层大气降温而低层回温使大气温度直减率增大,为对流发生提供不稳定条件,但水汽输送主要集中在低层,且高层大气无明显抽吸作用,导致此次过程未发生强对流性降水,主要以大风灾害性天气为主。     

Influence of Vertical Shear of Basic Tangential Wind on the Development and Maintenance of Typhoon

By using a linear symmetric Conditional Instability of Second Kind (CISK) model containing basic flow, we study the interactions between basic flow and mesoscale disturbances in typhoon. The result shows that in the early stage of typhoon formation, the combined action of vertical shear of basic flow at low level and CISK impels the disturbances to grow rapidly and to move toward the center of typhoon. The development of disturbances, likewise, influences on typhoon’s development and structure. Analysis of the mesoscale disturbances’ development and propagation indicates that the maximum wind region moves toward the center, wind velocity increases, and circulation features of an eye appear. Similarly, when a typhoon decays, the increase of low-level vertical wind shear facilitates the development of mesoscale disturbances. In turn, these mesoscale disturbances will provide typhoon with energy and make the typhoon intensify again. Therefore, it can be said that typhoon has the renewable or self-repair function.