ENSO循环与亚、澳季风和南、北方涛动的关系

文中从研究 ENSO循环的成因出发 ,分析了厄尔尼诺 ( El Nino)和拉尼娜 ( La Nina)的产生与西太平洋暖池地区西风异常的关系 ;在此基础上 ,探讨了西太平洋西风异常的形成和变化与亚洲和澳大利亚冬季风的关系 ;最后 ,分析了亚、澳冬季风的活动 ,西太平洋西风异常的形成和东传 ,以及厄尔尼诺和拉尼娜的交替出现等现象与南方涛动和北方涛动传播波的联系。     

Effects of Random Negative Training Samples on Mineral Prospectivity Mapping

Natural Resources Research - Supervised data-driven mineral prospectivity mapping (MPM) usually employs both positive and negative training datasets. Positive training datasets are typically...     

东南沿海3月连阴雨中的地面陆-海高压

利用１９９３～１９９６年３月份欧洲中心数值预报资料、天气图资料及东南沿海９站地面天气实况资料,对连阴雨部分物理量场的分布、降水的日变化、降水落区等因素进行综合分析。结果表明,陆－海高压是连阴雨天气中最直接、最直观、最重要的天气系统。     

Responses of global monsoon and seasonal cycle of precipitation to precession and obliquity forcing

In this paper, the response of global monsoon to changes in orbital forcing is investigated using a coupled atmosphere–ocean general circulation model with an emphasis on relative roles of precession and obliquity changes. When precession decreases, there are inter-hemispheric asymmetric responses in monsoonal precipitation, featuring a significant increase over most parts of the Northern Hemisphere (NH) monsoon regions and a decrease over the Southern Hemisphere (SH) monsoon regions. In contrast, when obliquity increases, global monsoon is enhanced except for the American monsoon. Dynamic effects (caused by changes in winds with humidity unchanged) dominate the monsoonal precipitation response to both precession and obliquity forcing, while thermodynamic effects (caused by changes in humidity with winds unchanged) is related to the northward extension of the North African summer monsoon. During minimum precession, the seasonal cycle of tropical precipitation is advanced with respect to the maximum precession. The rainfall increase in the transitional season (April-June in the NH and October-December in the SH) is dominated by the dynamic component. From an energetics perspective, the southward (northward) cross-equatorial energy transport during April-June (October-December) corresponds to a northward (southward) shift of tropical precipitation, which results in a seasonal advance in the migration of tropical precipitation. Nonetheless, there is no significant change in the seasonal cycle in response to obliquity forcing.

     

Mapping Mineral Prospectivity via Semi-supervised Random Forest

Natural Resources Research - The majority of machine learning algorithms that have been applied in data-driven predictive mapping of mineral prospectivity require a sufficient number of training...     

Fractal characterization of the spatial distribution of geological point processes

Geological point processes can be used to model point patterns occurring frequently in a wide variety of geoscience fields, including the study of mineral deposits, oil producing wells, earthquakes, and landslides. Characterization of the spatial distribution of GPP has implications for understanding the properties of the underlying geological processes and events. Three examples of GPP dealing with (1) metallic mineral deposits, (2) oil producing wells, and (3) aftershocks of the Wenchuan earthquake (on 12 May 2008, magnitude 8.0) are presented to illustrate that (1) the spatial distribution of geological point processes generally shows clustering implying rejection of the Poisson model because L(r) > L_Pois(r); (2) the clustering statistics of the underlying geological processes are fractal; and (3) the size distribution of geological point processes is scale invariant. These results indicate existence of a fundamental law concerning the fractal nature of the point distributions generated by geological point processes.     

Cooperative effects of tropical Pacific and Atlantic SST forcing in southern China winter precipitation variability

Climate Dynamics - This study investigates the variability of winter precipitation over southern China (SC) and the impacts of sea surface temperature (SST) forcing in the tropical Pacific and...     

Robust Feature Extraction for Geochemical Anomaly Recognition Using a Stacked Convolutional Denoising Autoencoder

Mathematical Geosciences - Deep neural networks perform very well in learning high-level representations in support of multivariate geochemical anomaly recognition. Geochemical exploration data...     

Propagation and influence on tropical precipitation of intraseasonal variation over mid-latitude East Asia in boreal winter

本文研究冬季东亚中纬度地区9–29天季节内变化的传播特征和其对热带降水的影响。分析发现风场的季节内信号既可以向东传播,也可以向南传播。向东传播时,风场的季节内信号主要限于中纬度地区,表现为气旋和反气旋的向东移动。向南传播时,源于中纬度的经向风扰动可以深入到低纬度地区,甚至到达赤道附近。伴随的辐合辐散引起赤道附近地区降水异常,形成南海南部和中国东部-日本之间一个南北向偶极型降水异常。一个异常经向翻转环流在连接热带和中纬度季节内风场和降水变化中起着重要作用。     

Geological Features and Formation Processes of the Makeng Fe Deposit,China

Recent studies have revealed that the Makeng Fe deposit is a skarn type deposit. However, the skarns in Makeng, occurring primarily between limestone and sandstone, are not typically associated with limestone and plutons. Different periods of intrusions, e.7. Hercynian mafic intrusions and Yanshanian (i.e. early Cretaceous) Dayang–Juzhou granitic intrusion, occurred in the Makeng deposit district. In this study, the formation processes of the skarns and Fe mineralization are constrained by detailed fieldwork, petrology, geochronology, and geochemistry. Skarns and Fe mineralization intersecting the Hercynian mafic intrusions are observed in consecutive specimens from the 106# tunnel. They suggest that the skarn formation and Fe mineralization occurred after the Hercynian mafic intrusions and are related to the later Yanshanian Dayang–Juzhou granitic intrusion. The geochronological characteristics of weakly skarn‐altered diabases, the decreasing nature of Fe contents in altered diabase, and the major element compositions of pyroxenes and garnets also support that Hercynian mafic intrusions are strongly reformed by Yanshanian granitic magmas and the Fe migrated from mafic intrusion was responsible for formation of iron ore.