关于大气涡动热通量参数化问题研究     

戴新刚  汪萍 《气候与环境研究》2002,7(4):465-473

用NCEP/NCAR等再分析资料计算和分析表明,月平均瞬变涡动热通量和月平均温度梯度的局域相关性很低,甚至在一些纬度是负相关,更严重的是二者之间存在非线性的多值对应函数关系.如果用非局域参数化,参数化水平将有所提高,但改进并不明显.通过与分子运动论输运理论进行数学、特别是物理类比提出了考虑"风暴路径"效应的瞬变涡动热通量的参数化方案,经再分析资料的检验,结果表明它能大大提高参数化的水平.其次,还证实采用空间非局域参数化仍然是进一步提高瞬变涡动热通量参数化水平的方法之一.此外,资料分析显示中高纬度纬向平均温度梯度和纬偏涡动温度通量之间也存在负相关及多值函数关系,说明仅用温度梯度去参数化纬向平均涡动热通量难以得到好的结果,需要考虑多元参数化或非同步参数化等.  相似文献   

2009年4月19日阿合奇Ms5.5级地震的前兆异常初步分析     

于桂春  刘辉  潘振生  王新刚  海仁尼沙 《高原地震》2010,22(4):30-34

2009年4月19日在新疆阿图什市阿合奇县（41.1°N,78.3°E）发生了Ms5.5级地震。此次地震前,阿合奇台地倾斜资料、乌什台水管倾斜资料和二氧化碳、巴楚台地应力均出现了明显的震前异常。趋势异常表现为年变畸变;短临异常表现在矢量加速和减速。  相似文献   

Influence of the Moho surface distribution on the oil and gas basins in China seas and adjacent areas     

Yimi Zhang  Wanyin Wang  Linzhi Li  Xingang Luo  Dingding Wang  Tao He  Feifei Zhang  Jing Ma 《海洋学报(英文版)》2023,42(3):167-188

Owing to the strategic significance of national oil and gas resources, their exploration and production must be prioritized in China. Oil and gas resources are closely related to deep crustal structures, and Moho characteristics influence oil and gas distribution. Therefore, it is important to study the relationship between the variation of the Moho surface depth undulation and hydrocarbon basins for the future prediction of their locations. The Moho depth in the study area can be inverted using the Moho depth control information, the Moho gravity anomaly, and the variable density distribution calculated by the infinite plate. Based on these results, the influences of Moho characteristics on petroleum basins were studied. We found that the Moho surface depth undulation deviation and crustal thickness undulation deviation in the hydrocarbon-rich basins are large, and the horizontal gradient deviation of the Moho surface shows a positive linear relationship with oil and gas resources in the basin. The oil-bearing mechanism of the Moho basin is further discussed herein. The Moho uplift area and the slope zone correspond to the distribution of oil and gas fields. The tensile stress produced by the Moho uplift can form tensile fractures or cause tensile fractures on the surface, further developing into a fault or depression basin that receives deposits. The organic matter can become oil and natural gas under suitable chemical and structural conditions. Under the action of groundwater or other dynamic forces, oil and natural gas are gradually transported to the uplift or the buried hill in the depression zone, and oil and gas fields are formed under the condition of good caprock. The research results can provide new insights into the relationship between deep structures and oil and gas basins as well as assist in the strategic planning of oil and gas exploration activities.  相似文献   

集合预报方法的全局研究   总被引：9，自引：4，他引：5  

范新岗 《气象学报》1999,57(1):74-83

应用一个最大简化的６变量非线性模式,引入胞映射全局分析方法,研究初值误差范围内不同扰动对预报结果的影响。在获得对其全局认识的基础上,再通过理论研究与预报实践证明,集合预报方法确能改进预报。理论研究表明,可以求出最佳集合样本数,而且由模式预报试验得到的最佳集合样本数与理论结果是一致的。另外,观测精度、预报精度以及模式状态变量的个数对最佳集合样本数有着不同的影响。  相似文献   

POM模式边界条件的数值试验及其在环台湾岛海域风生流模拟中的应用   总被引：3，自引：0，他引：3  

吕新刚  沙文钰 《海洋通报》2003,22(1):17-23

通过一个数值试验，对运用POM模式做风生流模拟时边界条件的选取方案做了初步的讨论。试验表明，POM“外模式”采用辐射边条件、“内模式”采用辐射方案的改进形式是一种可行的方法：如果用水位作为控制条件，也可以使用辐射边条件。文章同时给出了环台湾岛海域冬、夏风季生流的模拟结果。  相似文献   

Integrated gravity and magnetic study on patterns of petroleum basin occurrence in the China seas and adjacent areas     

Tao He  Wanyin Wang  Zhizhao Bai  Xingang Luo  Jing Ma  Yimi Zhang 《海洋学报(英文版)》2023,42(3):201-214

The China seas and adjacent areas contain numerous petroleum basins. One of the main challenges for future oil and gas exploration is to identify the inherent patterns of petroleum basin distribution. The formation and evolution of petroleum basins along with the migration and accumulation of oil and gas are often closely related to the tectonic environment. The gravity and magnetic fields with high lateral resolution and wide coverage provide important data for regional tectonic research. Based on the gravity data in the Global Satellite Gravity Anomaly Database (V31.1) and magnetic data from the Earth Magnetic Anomaly Grid (2-arc-minute resolution) (V2), this study uses integrated gravity and magnetic field technique to obtain integrated gravity and magnetic field result for the China seas and adjacent areas, and then adopts the normalized vertical derivative of the total horizontal derivative technique to conduct partition. Finally, it identifies the relationship between the partition characteristics and tectonics as well as the patterns of petroleum basin occurrence. The research shows that the partition of gravity and magnetic field integrated result has a good correlation with the Neo-Cathaysian tectonic system and tectonic units. The petroleum basins are characterized according to three blocks arranged from north to south and four zones arranged from east to west. The north?south block structure causes the uneven distribution of oil and gas resources in the mainland area and the differences in the hydrocarbon-bearing strata. Petroleum basins are more abundant in the north than in the south. The ages of the main oil- and gas-bearing strata are “Paleozoic–Mesozoic, Paleozoic–Mesozoic–Cenozoic, and Paleozoic–Mesozoic”, in order from north to south. The difference in the overall type of oil and gas resources in all basins is controlled by the east–west zonation. From east to west, the oil and gas resource type exhibits a wave-like pattern of “oil and gas, gas, oil and gas, gas”. The vertical distribution is characterized by an upper oil (Mesozoic–Cenozoic) and lower gas (Mesozoic–Paleozoic) structure. Within the study area, the Paleozoic marine strata should be the main strata of future natural gas exploration.  相似文献   

Evaluating the Algorithm for Correction of the Bright Band Effects in QPEs with S-, C-and X-Band Dual-Polarized Radars     

Yang CAO  Debin SU  Xingang FAN  Hongbin CHEN 《大气科学进展》2019,36(1):41-54

The bright band, a layer of enhanced radar reflectivity associated with melting ice particles, is a major source of significant overestimation in quantitative precipitation estimation(QPE) based on the Z–R(reflectivity factor–rain rate) relationship.The effects of the bright band on radar-based QPE can be eliminated by vertical profile of reflectivity(VPR) correction. In this study, we applied bright-band correction algorithms to evaluate three different bands(S-, C-and X-band) of dual-polarized radars and to reduce overestimation errors in Z–R relationship–based QPEs. After the reflectivity was corrected by the algorithms using average VPR(AVPR) alone and a combination of average VPR and the vertical profile of the copolar correlation coefficient(AVPR+CC), the QPEs were derived. The bright-band correction and resulting QPEs were evaluated in eight precipitation events by comparing to the uncorrected reflectivity and rain-gauge observations, separately. The overestimation of Z–R relationship–based QPEs associated with the bright band was reduced after correction by the two schemes for which hourly rainfall was less than 5 mm. For the verification metrics of RMSE(root-mean-square error), RMAE(relative mean absolute error) and RMB(relative mean bias) of QPEs, averaged over all eight cases, the AVPR method improved from 2.28,0.94 and 0.78 to 1.55, 0.60 and 0.40, respectively, while the AVPR+CC method improved to 1.44, 0.55 and 0.30, respectively.The QPEs after AVPR+CC correction had less overestimation than those after AVPR correction, and similar conclusions were drawn for all three different bands of dual-polarized radars.  相似文献   

节理控制的降雨入渗通道对黄土开挖边坡稳定性的影响   总被引：1，自引：0，他引：1  

王新刚  余宏明  胡斌  连宝琴 《山地学报》2013,31(4)

黄土节理控制着黄土开挖边坡地表径流的主要入渗通道,在降雨作用下黄土节理将逐步发育成大的入渗通道,加剧了黄土开挖边坡的破坏.通过野外现场地质调查,统计黄土开挖边坡的节理裂隙、入渗贯穿通道分布状况,得出不同开挖边坡高度的入渗通道间距与开挖边坡高度高斯拟合关系式;根据入渗通道分布关系式,概化建立降雨入渗通道的演化数值分析模型,利用岩土工程软件Flac3D模拟分析山西忻州河曲运煤大道黄土开挖边坡在降雨状况下入渗通道发育过程,分析了40mm/d、80mm/d、120mm/d三种降雨工况下降雨24h的入渗通道演化过程及开挖边坡破坏程度,以及降雨对黄土开挖边坡的影响;指出在降雨作用下入渗通道在坡高60m左右破坏严重,坡高高于此高度应注意入渗通道的剧烈扩展并加以防治.借用野外统计、调查结果概化建立入渗通道扩展演化数值模型,可以为工程地质条件相同黄土开挖边坡地区降雨作用下稳定破坏分析以及防治提供一种有效分析方法.  相似文献   

一种用于DEM数据认证与篡改定位的感知哈希算法     

张鑫港  闫浩文  张黎明 《地球信息科学学报》2020,22(3):379-388

DEM数据作为重要的基础地理信息数据,其数据完整性问题不容忽视。基于DEM数据完整性认证的要求,以及相关认证算法的欠缺,本文运用感知哈希技术设计了一种DEM数据认证算法,并可实现篡改定位。因DEM数据具有数据量大、细节丰富的特点,首先对其进行规则格网划分,将其划分为互不重叠的格网单元;然后对格网单元数据进行DCT分解,提取数据的特征信息以生成特征向量矩阵,并对特征向量矩阵进行摘要化处理;随后,使用Logistic混沌系统对简化后的特征向量矩阵进行置乱;对置乱矩阵进行量化、编码后,便可生成感知哈希序列。在数据认证时,首先计算原始数据与待验证数据的高程相对中误差,再将二者的感知哈希序列进行归一化汉明距离度量,结合判定阈值,即可对DEM数据进行数据认证与篡改定位。该算法对DEM数据的格式转换、水印嵌入等攻击有较强的鲁棒性,对各类改变内容的操作具有敏感性,并可实现DEM数据微小篡改的识别与定位。与已有的DEM完整性认证方法相比,将DEM数据的"内容"作为完整性度量的重要标准,在具体应用中更具有实用价值。  相似文献   

基于气象监测网络的森林火险快速预警模型   总被引：1，自引：0，他引：1  

李玉  张黎明  张兴国  王昊  张鑫港 《地球信息科学学报》2020,22(12):2317-2325

森林火灾发生频繁且突发性强,进行森林火险快速预警对于减小森林火灾损失和促进森林资源可持续发展至关重要。本文基于GIS空间分析和可视化技术,利用地面气象站构建实时气象监测网络,设计了运用气象监测网络的森林火险预警模型,可实现森林火险及时、快速预警。模型应用层次分析法建立了预警因子重要性层次结构并确定预警因子的权重;运用Voronoi图技术,基于气象站点和实时气象数据,构建气象监测网络;利用叠置分析技术计算得出预警结果。基于该模型设计的森林火灾快速预警系统应用于青海省林业局,验证了系统可行性与适用性,该模型可全面、准确、快速地实现对森林火险的预警。结果表明：① 根据预警模型及实时气象监测数据,可及时发出预警信号,快速实现县级、林场级别的森林火险早期预警和及时响应;② 运用GIS可视化技术,可快速生成相关区域森林火险的空间分布专题图,直观地观察预警等级的变化情况。实践表明,森林火险快速预警对森林火灾进行有效预防、中断管理和制定扑救措施具有重要的指导作用,并对森林防火工作、保护森林资源和人类生命财产安全具有重大意义。  相似文献