Applying the relative hypocentre location approach: where was the 1980 November 23 Irpinia earthquake?

The purpose of this work is to evaluate under what conditions it is feasible and with what accuracy it is possible to locate the nucleation point of a large earthquake, given the availability of aftershocks located with high precision by the deployment of a local network. We experiment with several approaches and apply them lo the location of the epicentre of the 1980 November 23 Irpinia earthquake ( M ^w= 6.9).
First we use local P ^g phases selected to optimize the azimuthal coverage, obtaining a well-constrained location with a small statistical error, which typically underestimates the true hypocentre uncertainty.
We then exploit the relative location technique, obtaining stable, almost coincident solutions under three conditions: (1) using multiple independent master events to derive an average epicentre; (2) fitting simultaneously the larger data set for all available master events, using a forward approach; (3) conducting an a priori evaluation of the statistics of station and master events to separate model uncertainties and improve the statistical accuracy of the relative locations. Moreover, only by introducing station statistics can we achieve the desired accuracy of ≅ 1 km in constraining the rupture nucleation point of this large earthquake, and we show that the application of the relative location technique to uncleaned, unweighted data for a single master event provides only a crude epicentre with a confidence ellipse deceivingly smaller than the true hypocentre uncertainty.
The revised epicentre for the 1980 November 23 Irpinia earthquake (48.803 °N-15.302°E) validates the class of multidisciplinary reconstructions of the source process such as the model of Valensise et al. (1989), based on the hypocentre of Westaway & Jackson (1987), and is shifted by almost 13 km to the NW of the epicentre recently proposed by Westaway (1992).     

唐山地震深浅构造关系研究

地表观察和浅层高分辨率地震探测表明 ,唐山断裂与地震地表主破裂带的位置、产状均一致 ,且具有高角度西倾的逆冲走滑性质 ,发生过右旋水平错动和向东逆冲的垂直活动 ,而次破裂带与褶皱构造活动引起的其他断裂直接相关。根据瞬变磁场和深地震探测结果分析 ,唐山地区存在莫霍面斜坡和地壳“背斜”、中地壳水平滑脱和扩展断裂、上地壳高角度逆冲走滑断裂和背向斜构造 ,它们组成 1幅多层次、多级序的复式逆断裂 -扩展背斜构造图像 ,控制了唐山地震的孕育和发生     

Correction of CMPAS Precipitation Products over Complex Terrain Areas with Machine Learning Models

Machine learning models were used to improve the accuracy of China Meteorological Administration Multisource Precipitation Analysis System (CMPAS) in complex terrain areas by combining rain gauge precipitation with topographic factors like altitude, slope, slope direction, slope variability, surface roughness, and meteorological factors like temperature and wind speed. The results of the correction demonstrated that the ensemble learning method has a considerably corrective effect and the three methods (Random Forest, AdaBoost, and Bagging) adopted in the study had similar results. The mean bias between CMPAS and 85% of automatic weather stations has dropped by more than 30%. The plateau region displays the largest accuracy increase, the winter season shows the greatest error reduction, and decreasing precipitation improves the correction outcome. Additionally, the heavy precipitation process’precision has improved to some degree. For individual stations, the revised CMPAS error fluctuation range is significantly reduced.     

基于高分辨率城区遥感影像的道路半自动提取方法研究

遥感影像上人工地物的自动化和智能化采集一直是摄影测量与遥感技术长期探索的一个主要课题。道路是重要的基础地理信息,随着遥感影像分辨率的提高,道路特征的复杂化对道路提取方法形成了挑战。针对高分辨率城区遥感影像道路提取中存在的问题,结合多分辨率分析思想、模板匹配原理和LSB-Snake模型,综合提出了一种适用于城区高分辨率遥感影像的道路半自动提取方法。实验表明该方法可以在很大程度上弥补LSB-Snake模型的不足,同时具有良好的抗噪声能力,可作为一种有效手段应用在城区高分辨率遥感影像的道路提取中,具有很好的交互性、可靠性和高效性。     

The complex decision-making of climate-induced relocation: adaptation and loss and damage

Climate change is increasingly challenging the ability of millions of people to sustain livelihoods as the places where they live become uninhabitable. The relocation of populations as individuals, households, and communities within countries and across international borders demonstrates the complexity of climate change impacts. Looking at the literature, some researchers argue that relocation caused by climate change can be an effective strategy to adapt to localized changes, whereas others argue that the movement away from ones' homeland is more neatly captured in the climate change lexicon as ‘loss and damage’. We argue here that the relocation of people as a result of the impacts of climate change can be both adaptation and loss and damage. Drawing on examples from Alaska and Kiribati, we show that dividing this issue between the two concepts is unhelpful in resolving key issues around the types of appropriate support for these transitions to sustain and protect livelihoods and to open up possibilities for self-determined futures.

Policy Relevance

Climate-induced relocation poses a significant challenge for the populations affected as well as the government agencies tasked with providing technical assistance and funding. At present, policies and institutional frameworks have not yet been developed to accommodate these challenges, despite the urgent need to do so. When the relocation of populations can be planned, participatory, and people centred, then it can be an adaptation strategy that will protect people from the permanent loss of land and livelihoods. If these movements are decided, driven, managed, and undertaken by those affected, then there is the potential for the relocation to also be a transformative opportunity for people to respond to the impacts of climate change, and sustain their livelihoods and possibly even improve certain livelihood outcomes. However, these relocations also cause significant loss and damage. The extent of the loss and damage will partly depend on the ability to have these relocations planned and ensure that human rights protections are embedded in institutional frameworks. The article shares a series of lessons and learnings that are of policy relevance at a variety of scales.     

极干旱区域台站迁徙前后资料的差异分析——以东疆托克逊站为例

采用新疆托克逊站和参考站(尉犁、东坎两站)1974—2014年观测资料,分析了城市化对托克逊站气候资料的影响,结果表明:地处极干旱区域的托克逊站气温、相对湿度和平均风速与参考站一致性较差,其中,由于城市化发展造成托克逊县的升温率为0.44℃·(10 a)~(-1);均一性检测发现,由于城市化的影响,平均气温、相对湿度、风速均产生了断点。新站与旧站观测资料对比分析发现,由于新旧站环境差异大,使得年相对湿度新站比旧站低4.0%;年平均风速新站偏大1.3 m·s~(-1),年风向相符率低只有49.01%,平均风速全年各月在显著性水平0.05的条件下资料不连续。     

A High-resolution Simulation of Supertyphoon Rammasun (2014) —— Part I: Model Verification and Surface Energetics Analysis

A 72-h high-resolution simulation of Supertyphoon Rammasun (2014) is performed using the Advanced Research Weather Research and Forecasting model. The model covers an initial 18-h spin-up, the 36-h rapid intensification (RI) period in the northern South China Sea, and the 18-h period of weakening after landfall. The results show that the model reproduces the track, intensity, structure of the storm, and environmental circulations reasonably well. Analysis of the surface energetics under the storm indicates that the storm's intensification is closely related to the net energy gain rate (ε g), defined as the difference between the energy production (P D) due to surface entropy flux and the energy dissipation (D S) due to surface friction near the radius of maximum wind (RMW). Before and during the RI stage, the ε g is high, indicating sufficient energy supply for the storm to intensify. However, the ε g decreases rapidly as the storm quickly intensifies, because the D S increases more rapidly than the P D near the RMW. By the time the storm reaches its peak intensity, the D S is about 20% larger than the P D near the RMW, leading to a local energetics deficit under the eyewall. During the mature stage, the P D and D S can reach a balance within a radius of 86 km from the storm center (about 2.3 times the RMW). This implies that the local P D under the eyewall is not large enough to balance the D S, and the radially inward energy transport from outside the eyewall must play an important role in maintaining the storm's intensity, as well as its intensification.     

Case study on the three-dimensional structure of meso-scale eddy in the South China Sea based on a high-resolution model

Meso-scale eddies are important features in the South China Sea(SCS). The eddies with diameters of 50–200 km can greatly impact the transport of heat, momentum, and tracers. A high-resolution wave-tide-circulation coupled model was developed to simulate the meso-scale eddy in the SCS in this study. The aim of this study is to examine the model ability to simulate the meso-scale eddy in the SCS without data assimilations The simulated Sea Surface Height(SSH) anomalies agree with the observed the AVISO SSH anomalies well. The simulated subsurface temperature profiles agree with the CTD observation data from the ROSE(Responses of Marine Hazards to climate change in the Western Pacific) project. The simulated upper-ocean currents also agree with the main circulation based on observations. A warm eddy is identified in winter in the northern SCS. The position and domain of the simulated eddy are confirmed by the observed sea surface height data from the AVISO. The result shows that the model has the ability to simulate the meso-scale eddy in the SCS without data assimilation.The three-dimensional structure of the meso-scale eddy in the SCS is analyzed using the model result. It is found that the eddy center is tilted vertically, which agrees with the observation. It is also found that the velocity center of the eddy does not coincide with the temperature center of the eddy. The result shows that the model has the ability to simulate the meso-scale eddy in the SCS without data assimilations. Further study on the forming mechanism and the three-dimensional structure of the meso-scale eddies will be carried out using the model result and cruise observation data in the near future.     

鄂尔多斯盆地南部上三叠统层序地层学研究

高分辨率层序地层学是对地层记录中反映基准面变化旋回的时间地层单元的二级划分。鄂尔多斯盆地南部上三叠统成油体系可明显的划分为1个中期地层层序和10个短期地层层序，它们在时空上的演变反映基准面、可容纳空间变化对沉积物沉积厚度、堆积方式有明显的控制作用。三角洲水下分流河道砂体的储集物性变化也明显受基准面、可容纳空间变化的影响。上升旋回的水下分流河道砂体物性随基准面上升变差，下降旋回的水下分流河道砂体物性随基准面下降变好，且下降旋回砂体物性好于上升旋回的砂体物性。     

鄂尔多斯盆地中部延安地区中侏罗统延安组高分辨率层序地层研究

利用高分辨率层序地层学方法,以延水河剖面研究为重点,详细剖析了中侏罗统延安组不同级次基准面旋回划分,建立了鄂尔多斯盆地延安地区延安组高分辨率层序地层格架。共识别出了36个短期、8个中期和3个长期基准面旋回。讨论了不同级次基准面旋回叠加式样与沉积相、沉积作用和构造作用等的响应关系,进一步通过基准面旋回层序研究了盆地的充填演化史。