吉林松原地区地震前热红外亮温异常研究     

张志宏  焦明若  张丽  李梦莹  黄明威  杨牧萍 《大地测量与地球动力学》2021,41(6):595-599

使用小波变换和功率谱估计法,利用中国静止气象卫星亮温数据研究2017年以来松原地区3次M_S＞4.5地震前的热红外异常。结果表明, 2017-07-23 M_S4.9和2018-05-28 M_S5.7地震前的异常都是沿依兰-伊通断裂和密山-敦化断裂走向逐渐扩展的,即异常存在于松辽盆地的东部边缘,地震震中不在异常区内;2019-05-18 M_S5.1地震前异常不明显,可能是由于盆地内二氧化碳和甲烷等温室气体在前2次地震前后已得到最大量的释放。  相似文献   

Detecting climate change effects on forest ecosystems in Southwestern Romania using Landsat TM NDVI data   总被引：1，自引：0，他引：1  

Remus Pravalie  Igor Sîrodoev  Daniel Peptenatu 《地理学报(英文版)》2014,24(5):815-832

Nowadays, Southwestern Romania faces a large-scale aridization of the climate, revealed by the rise of temperatures and the decline of the amount of precipitations, with negative effects visible, among others, in the desiccation of forest vegetation. The present study means to identify the changes that occurred, quality-wise, in the past two decades （1990-2011） in forest vegetation in Southwestern Romania, and to establish the link between those changes and extant thermal stress in the region, whose particular features are high average annual and seasonal temperatures. In order to capture the evolution in time of cli- mate aridization, a first step consisted in using climate data, the temperature and precipitation parameters from three weather stations; these parameters were analyzed both individually and as aridity indexes （De Martonne and UNEP）. In order to quantify the changes in forest vegetation, NDVI indexes were used and analyzed, starting off from Landsat satellite images, acquired at three distinct moments in time, 1990, 2000 and 2011. In order to identify the link between the changes of NDVI index values and regional thermal stress, a yardstick of climate changes, statistical correlations were established between the peak values of average annual temperatures, represented in space, and negative changes in the NDVI index, as revealed by the change-detection analysis. The results obtained indicated there is an obvious （statistically significant） connection between thermal stress and the desiccation （degradation） of forest species in the analyzed area, with false acacia （Robinia Pseudoacacia） the main species to be impacted.  相似文献   

PN断面黑潮流速垂直分布特征及机制分析   总被引：1，自引：0，他引：1  

邓丽静  魏皓  汪嘉宁 《海洋通报》2014,33(5):519-526

基于全球海洋再分析模拟GLORYS2(Global Ocean Reanalysis Simulation 2)结果,分析了PN断面(126.0°E-128.2°E,1 000 m以浅)黑潮流速垂直结构的季节和年际变化,探讨了黑潮流速垂直结构形成的动力学机制。结果表明:1)PN断面黑潮夏季流量最大,春季次之,秋、冬季节最小;气候态平均的冬、夏季流速最大值都位于次表层,春、秋季节流速最大值位于表层;夏季相对流速较大、最大值深度较浅;等密线在黑潮主轴区下凹,冬季更为明显。流速最大值深度和密度水平梯度为零的深度均表现出了较大的年际差异,该年际变化甚至超过季节差异;2)流速与密度符合热成风关系。黑潮通量由太平洋大尺度风场及中尺度运动两者共同决定,但局地的热通量和环流对温盐的输运共同影响密度场,调节黑潮流速的垂直分布,影响水通量的分配及营养盐输运;3)有些年份夏季流速最大值出现在表层,可能是夏季西南季风诱导陆架水离岸输运进入黑潮上层导致的结果。非线性、非地转物理过程的影响没有考虑在本研究中,热成风关系能够解释黑潮流速垂直分布形成的部分原因。  相似文献   

珠江口盆地文昌A凹陷油气差异分布特征     

王柯 《海洋地质前沿》2014,30(6):40-46

在烃源岩分布特征、有机质丰度、类型和成熟度分析的基础上,运用含油气盆地数值模拟技术,定量恢复了烃源岩热成熟演化史,探讨了油气差异分布特征。研究表明,文昌A凹陷各层系烃源岩分布广,厚度大,有机质丰度高;有机质类型文昌组偏Ⅱ1型,恩平组偏Ⅲ型,二者现今多处于高成熟—过成熟阶段。凹陷内烃源岩成熟时间早(文昌组约45.5Ma),现今成熟度高,以干气生成为主;凹陷边缘烃源岩成熟时间较晚(文昌组约30.0Ma),现今成熟度相对较低,以石油生成为主。凹陷现今油气差异分布的格局受制于有机质类型差异和热演化史不同,且下一步油气勘探方向,凹陷内以天然气为主,凹陷边缘以石油为主。  相似文献   

Dynamic and Numerical Study of Waves in the Tibetan Plateau Vortex简   总被引：3，自引：0，他引：3  

CHEN Gong  LI Guoping 《大气科学进展》2014,31(1):131-138

In terms of its dynamics, The Tibetan Plateau Vortex （TPV） is assumed to be a vortex in the botmdary layer forced by diabatic heating and friction. In order to analyze the basic characteristics of waves in the vortex, the governing equations for the vortex were established in column coordinates with the balance of gradient wind. Based on this, the type of mixed waves and their dispersion characteristics were deduced by solving the linear model. Two numerical simulations with triple-nested domains--one idealized large-eddy simulation and one of a TPV that took place on 14 August 2006---were also carried out. The aim of the simulations was to validate the mixed wave deduced from the governing equations. The high-resolution model output data were analyzed and the results showed that the tangential flow field of the TPV in the form of center heating was cyclonic and convergent in the lower levels and anticyclonic and divergent in the upper levels. The simulations also showed that the vorticity of the vortex is uneven and might have shear flow along the radial direction. The changing vorticity causes the formation and spreading of vortex Rossby （VR） waves, and divergence will cause changes to the n~otion of the excitation and evolution of inertial gravity （IG） waves. Therefore, the vortex may contain what we call mixed ：inertial gravity-vortex Rossby （IG-VR） waves. It is suggested that some strongly developed TPVs should be studied in the future, because of their effects on weather in downstream areas.  相似文献   

夏季越南东北外海暖水的时空变化特征及其机理研究   总被引：1，自引：1，他引：0  

YAN Yunwei  CHEN Changlin  LING Zheng 《海洋学报(英文版)》2014,33(11):55-63

Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observations. The wake of warm water forms in June, continues to mature in July and August, starts to decay in September, and disappears in October. The warm water wake also shows robust diurnal variation – it intensifies during the day and weakens in the night. Warm water wakes can be generated through wind-induced mixing and thermal(latent heat flux) processes. In this paper, a mixed layer model is used to evaluate the relative importance of the two processes on seasonal and diurnal timescales, respectively. The results demonstrate that thermal processes make a greater contribution to the wake than wind-induced mixing processes on a seasonal timescale, while the warm water wake is dominated by wind-induced mixing processes on a diurnal timescale.  相似文献   

地热井井筒热效应研究          下载免费PDF全文

刘志涛  张志胜  胡松涛  吕明荟  谭现锋 《山东国土资源》2014,30(8)

在进行地热研究中需要对水位进行校正以消除井筒热效应,否则可能会形成错误的结论。在简要分析井筒热效应机理的基础上,对现有2种水位校正方法进行了论述,另外还基于积分原理提出了一种新的计算方法,并通过实例对各种方法的校正结果进行了对比分析。  相似文献   

利用低空视频检测道路车辆     

刘慧  李清泉  曾喆  高春仙 《武汉大学学报(信息科学版)》2011,(3):316-320

针对背景像素的移动,提出了SURF特征稳像和光流法向量相结合的新方法来解决低空视频的道路车辆检测。首先,检测两帧图像的SURF特征;再用最近邻匹配得到两幅图像的匹配点对;随后结合RANSAC和最小二乘法计算全局运动参数向量,获得稳定的帧;最后,根据稳定的帧计算光流法向量,并检测出运动车辆。实验结果表明,基于SURF算子的图像稳像算法在不损失稳像精度的前提下,能够提高图像稳像算法的速度,所提方法能够有效地检测出运动车辆。  相似文献   

长三角地区城市用地扩展及城乡热环境的特征分析     

王桂玲  王艳红 《南京气象学院学报》2011,(3):227-231

利用1993年和2004年长三角地区的卫星遥感资料,分析了该地区的3个主要区域南京、上海、苏锡常及其周边的土地利用类型变化,定量地评价城市用地扩展程度.结合2004年地表温度(LST)卫星资料,揭示了城乡LST空间分布特征及其差异.结果表明:上海、苏锡常和南京11a期间城市建设用地动态度K分别为204.0%、354.3%和99.2%,苏锡常城市扩展程度最快;不同土地覆盖类型的LST不同,城市用地LST最高,其次作物地,林地最低;城乡之间平均地表温差具有季节变化,冬季最大,而秋季最小.  相似文献   

南海北缘琼东南盆地热结构与莫霍面温度   总被引：3，自引：1，他引：2       下载免费PDF全文

单竞男  张功成  吴景富  唐晓音  赵长煜  宋阳  胡圣标 《地球物理学报》2011,54(8):2102-2109

相对于大陆地区,洋壳或海陆过渡区目前较缺乏岩石圈热结构方面的研究.本文依据琼东南盆地现有热流数据和相关岩石热物性参数,沿分布于盆地内不同位置的4条地震测线计算了不同圈层的热流分配关系(即热结构)及莫霍面温度.计算时根据最新的P-波速度变化分析将该区地壳分为四层,分别为沉积盖层、上地壳、下地壳及下地壳高速层.结果表明:琼...  相似文献