On the problem of active longitudes of sunspots and flares

The active longitudes of indices for sunspot activity and solar flares were detected and investigated by the method of isoline for the period July 1, 1957 to December 31, 1962. In the most active hemisphere of the sun the active longitudes of sunspot and flares appear to coincide. It is shown that the rate of concentration in the active longitudes is the highest for more important formations. Arguments for the reality of the active longitudes of sunspot areas are advanced. In conclusion the question of the influence of the uncertainty of the solar rotation period on the detection of active longitudes of flares is considered.     

Predictive landslide susceptibility mapping using spatial information in the Pechabun area of Thailand

For predictive landslide susceptibility mapping, this study applied and verified probability model, the frequency ratio and statistical model, logistic regression at Pechabun, Thailand, using a geographic information system (GIS) and remote sensing. Landslide locations were identified in the study area from interpretation of aerial photographs and field surveys, and maps of the topography, geology and land cover were constructed to spatial database. The factors that influence landslide occurrence, such as slope gradient, slope aspect and curvature of topography and distance from drainage were calculated from the topographic database. Lithology and distance from fault were extracted and calculated from the geology database. Land cover was classified from Landsat TM satellite image. The frequency ratio and logistic regression coefficient were overlaid for landslide susceptibility mapping as each factor’s ratings. Then the landslide susceptibility map was verified and compared using the existing landslide location. As the verification results, the frequency ratio model showed 76.39% and logistic regression model showed 70.42% in prediction accuracy. The method can be used to reduce hazards associated with landslides and to plan land cover.     

Analytical theory of motion of phoebe,the ninth satellite of saturn

The literal solution of the restricted three body problem obtained by the authors up to the eleventh order with respect to the minor parameter is applied to the investigation of the motion of Phoebe, the ninth satellite of Saturn. As distinct from the existing analytical theories of the motion of the satellite, in the present paper the planetary perturbations are taken into account. A comparison with the modern numerical theory of the motion of Phoebe has shown that the new analytical theory of the satellite motion represents observations with the same degree of accuracy.     

长江中游砂山沉积物磁组构特征及其指示的古风场

本文通过对新发现的江西九江新港砂山剖面沉积物磁化率各向异性测量和磁化率椭球体主轴的统计分析,揭示了该风成砂剖面磁组构参数在不同层位的变化特征,获得了古风向特征及其演变规律.(1)整个时期内该区的主导风向为NW-SE和NNW-SSE向,但在不同时期风向和风力强度又有所不同,变化最为剧烈的时期是砂2层,风向发生了根本性的改变,由原来的NW-SE为主,变为NE-SW向为主,且该阶段沉积环境相对比较稳定;(2)砂2、砂5、砂6层具有较大P、F、L和较小的q值,说明在其形成时气候最为寒冷,冬季风的风力最强、风速比较稳定,这与野外观察到的在这几层中大型板状斜层理发育,砂层粒度较粗,黏土含量较少的结果一致;(3)晚更新世末期长江中游的风成沙丘广泛发育,表明该时段是长江中下游地区气候最干冷、风力作用最强的时期,有着与北方沙漠—黄土区相类似的气候环境;(4)研究表明,AMS主轴的等面积赤平投影法和玫瑰花图,可以用来分析古风向的变化规律,是一种简易有效的方法.     

一种附加尺度因子的电离层层析新方法

用乘法代数重构方法反演电离层电子密度时,没有GPS测量射线穿过的电离层网格的反演精度依赖于迭代初值。就此,提出一种改进的代数重构算法--附加尺度因子的代数重构算法（Scaling-ART）。将实测STEC与迭代中当前电子密度计算的STEC的比值作为基本尺度,依据电子密度的空间相关性和网格中心到观测射线的距离,对没有信号穿过的网格也计算出对应尺度进行调整,使其向真值逐渐逼近,提高反演精度。实验证实,改进的新算法相比于原有的乘法代数重构算法能够取得更好的反演精度。     

Agricultural opportunity costs assessment based on planting suitability: a case study in a mountain county in southwest China

Payment for ecosystem services (PES) has become an increasingly popular means of ecosystem conservation. Opportunity cost is an important factor to increase the investment efficiency of PES projects. However, the distribution of opportunity cost is usually unclear in mountainous regions due to the obvious environment changes. In this study, we developed a framework to assess the distribution of agricultural opportunity costs in mountainous regions and applied this method to Baoxing County, a typical mountainous county in Sichuan Province of southwest China. Planting suitability of 17 crops was assessed based on agricultural statistics and natural conditions data within a GIS environment. Agricultural opportunity cost was quantified with a weighted summation of farmers’ willingness to cultivate and each crop’s opportunity cost. Finally, specific agricultural opportunity cost was obtained according to the spatial areas of the protection programs and land use status. The results showed that agricultural opportunity costs of PES in Baoxing County were estimated to be more than $30 million, with a mean of 400.85 $/ha. Agricultural opportunity costs in mountainous regions displayed some obvious spatial variation and areas with lower agricultural opportunity costs could be selected as priority areas for PES. Our findings revealed that the planting suitability evaluation can make agricultural opportunity costs mapping more reasonable. It will be helpful for the PES programs implementation in mountainous regions.     

不规则波中半潜式平台及其系泊系统动力响应分析

采用时域分析方法,研究某半潜式平台在不规则波作用下的动力响应特性。重点分析在不同浪向角情况下,平台系统有1根锚链缆发生断裂时,其运动谱与锚链缆张力谱的变化特性。研究表明,在该半潜平台遭遇恶劣海况时,一旦有某1根锚链缆发生断裂,则对整个平台系统的动力响应特性将是有很大影响的。     

Impact of climate change on potential evapotranspiration under a historical and future climate scenario in the Huang-Huai-Hai Plain,China

Theoretical and Applied Climatology - Climate change is widely accepted to be one of the most critical problems faced by the Huang-Huai-Hai Plain (3H Plain), which is a region in which there is an...     

Geochronology and Genesis of the Tiegelongnan Porphyry Cu(Au) Deposit in Tibet: Evidence from U–Pb,Re–Os Dating and Hf,S, and H–O Isotopes

The Tiegelongnan Cu (Au) deposit is the largest copper deposit newly discovered in the Bangong–Nujiang metallogenic belt. The deposit has a clear alteration zoning consisting of, from core to margin, potassic to propylitic, superimposed by phyllic and advanced argillic alteration. The shallow part of the deposit consists of a high sulphidation‐state overprint, mainly comprising disseminated pyrite and Cu–S minerals such as bornite, covellite, digenite, and enargite. At depth porphyry‐type mineralization mainly comprises disseminated chalcopyrite, bornite, pyrite, and a minor vein molybdenite. Mineralization is disseminated and associated with veins contained within the porphyry intrusions and their surrounding rocks. The zircon U–Pb ages of the mineralized diorite porphyry and granodiorite porphyry are 123.1 ± 1.7 Ma (2σ) and 121.5 ± 1.5 Ma (2σ), respectively. The molybdenite Re–Os age is 121.2 ± 1.2 Ma, suggesting that mineralization was closely associated with magmatism. Andesite lava (zircon U–Pb age of 111.7 ± 1.6 Ma, 2σ) overlies the ore‐bodies and is the product of post‐mineralization volcanic activity that played a critical role in preserving the ore‐bodies. Values of ?4.6 ‰ to + 0.8 ‰ δ³⁴S for the metal sulfides (mean ? 1.55 ‰) suggest that S mainly has a deep magmatic source. The H and O isotopic composition is (δD = ?87 ‰ to ?64 ‰; δ¹⁸O_H2O = 5.5 ‰ to 9.0 ‰), indicating that the ore‐forming fluids are mostly magmatic‐hydrothermal, possibly mixed with a small amount of meteoric water. The zircon ε_Hf(t) of the diorite porphyry is 3.7 to 8.3, and the granodiorite porphyry is 1.8 to 7.5. Molybdenite has a high Re from 382.2 × 10^?6 to 1600 × 10^?6. Re and Hf isotope composition show that Tiegelongnan has some mantle source, maybe the juvenile lower crust from crust–mantle mixed source. Metallogenesis of the Tiegelongnan giant porphyry system was associated with intermediate to acidic magma in the Early Cretaceous (~120 Ma). The magma provenance of the Tiegelongnan deposit has some mantle‐derived composition, possibly mixed with the crust‐derived materials.     

Assessing precipitation variations in the Yangtze River Basin during 1979–2019 by vertically integrated moisture flux divergence

Natural Hazards - Spatiotemporal variations in precipitation are closely related to vertically integrated moisture flux divergence (VIMD), where the extremes further cause natural disasters. Based...