Storm surges in the northern part of the Sea of Japan

All the available historic records of sea level and appropriate weather charts have been used to study storm surges in the northern part of the Sea of Japan. The generation of surges in this area was investigated by means of a two-dimensional numerical model. Computed sea levels were compared with hourly observed residual sea levels in De-Kastri. The agreement between computed and observed storm surges is quite satisfactory. The relative importance of various meteorological parameters and bottom topography in formation of the strong storm surge on 20–21 September 1975 was studied numerically.     

新疆北天山地区中强震前单台地震波参数异常特征研究

强地震的孕育过程也是孕震介质的形成过程,在强震前震源附近小地震的地震波运动学,动力学特征的变化过程,则反映了孕震介质的变化过程,为研究地震的孕育,发展和发生的过程,采用单台地震波振幅比,尾波持续时间比,尾波衰减系数这３项地震波参数作为地震学短期前兆指标,分析其震兆特征,从而达到监测孕震介质变化的目的,研究结果表明,单台地震波参数能够有效地发现地震的前兆,但地震波参数的前兆图像复杂多变,不具有统一的     

Determining short-term changes in the hydraulic properties of a sandy-loam soil by a three-run infiltration experiment

ABSTRACT

Soil structure-dependent parameters can vary rapidly as a consequence of perturbing events such as intense rainfall. Investigating their short-term changes is therefore essential to understand the general behaviour of a porous medium. The aim of this study is to gain insight into the effects of wetting, perturbation and recovery processes through different sequences of Beerkan infiltration experiments performed on a sandy-loam soil. Two different three-run infiltration experiments (LHL and LLL) were carried out by pouring water at low (L, non-perturbing) and high (H, perturbing) heights above the soil surface and at short time intervals (hours, days). The results demonstrate that the proposed method allows one to capture short-term variations in soil structure-dependent parameters. The developed methodology is expected to simplify the parameterization of hydrological models with temporally variable soil hydraulic properties.     

Detecting patterns of climate change in long-term forecasts of marine environmental parameters

ABSTRACT

Forecasting environmental parameters in the distant future requires complex modelling and large computational resources. Due to the sensitivity and complexity of forecast models, long-term parameter forecasts (e.g. up to 2100) are uncommon and only produced by a few organisations, in heterogeneous formats and based on different assumptions of greenhouse gases emissions. However, data mining techniques can be used to coerce the data to a uniform time and spatial representation, which facilitates their use in many applications. In this paper, streams of big data coming from AquaMaps and NASA collections of 126 long-term forecasts of nine types of environmental parameters are processed through a cloud computing platform in order to (i) standardise and harmonise the data representations, (ii) produce intermediate scenarios and new informative parameters, and (iii) align all sets on a common time and spatial resolution. Time series cross-correlation applied to these aligned datasets reveals patterns of climate change and similarities between parameter trends in 10 marine areas. Our results highlight that (i) the Mediterranean Sea may have a standalone ‘response’ to climate change with respect to other areas, (ii) the Poles are most representative of global forecasted change, and (iii) the trends are generally alarming for most oceans.     

副高异常偏西背景下西北一次漏报的雷暴大风中尺度分析*

摘要：利用西安多普勒天气雷达、L波段风廓线雷达和加密自动站探测资料，结合天气实况，对2018年7月26日发生在陕西一次副热带高压影响下的的强风暴过程进行了中尺度分析。结果表明：（1）本次强风暴伴随的阵风锋共维持了4h，其中有3h出现7级以上的大风，且最大风力10级。（2）在副热带高压影响下，陕西处于高温、高湿气团中，大气层结极不稳定。（3）此次强风暴在高的对流有效位能环境下（CAPE）下，抬升触发的关键因子是关中地区中尺度辐合线，当初生的对流云团下山后，中尺度辐合线触发的对流风暴形成小范围冷池出流与环境风场形成新的辐合线，加强对流风暴发展。（4）当阵风锋移动过程中遇到前方的对流云团时，将低层暖湿空气抬升，并随着上升气流输送到主体对流风暴中，迅速补充了主体风暴的能量，使得主体风暴再次强烈发展，延长了阵风锋的生命史。     

Relationships between moment magnitude and fault parameters: theoretical and semi-empirical relationships

Fault parameters are important in earthquake hazard analysis. In this paper, theoretical relationships between moment magnitude and fault parameters including subsurface rupture length, downdip rupture width, rupture area, and average slip over the fault surface are deduced based on seismological theory. These theoretical relationships are further simplified by applying similarity conditions and an unique form is established. Then, combining thc simplified theoretical relationships between moment magnitude and fault parameters with seismic source data selected in this study, a practical semi-empirical relationship is established. The seismic source data selected is also to used to derive empirical relationships between moment magnitude and fault parameters by the ordinary least square regression method. Comparisons between semi-empirical relationships and empirical relationships show that the former depict distribution trends of data better than the latter. It is also observed that downdip rupture widths of strike slip faults are saturated when moment magnitude is more than 7.0, but downdip rupture widths of dip slip faults are not saturated in the moment magnitude ranges of this study.     

测井资料在碳酸盐岩洞—裂缝型储层产能评价中的应用

介绍了一种基于测井资料来预测双孔结构碳酸盐岩储层产能的新方法。首先根据碳酸盐岩剖面中双孔结构储层的地质和测井特征,提取与储层产能密切相关的多个测井和地质参数,考虑到这些参数与产能的非线性相关关系以及产能数据的变化特点,采用BP神经网络技术建立其储层产能的预测模型,由此处理了轮南地区的多口井测井资料。所预测的储层段产能与试油产能较为一致,效果良好。     

Two attempts of study of seismic source from teleseismic data by simulated annealing non-linear inversion

Two seismic source studies usingteleseismic data are performed by Simulated Annealing(SA), a non-linear inversion method. The Very FastSimulated Annealing (VFSA) algorithm is used and onlyteleseismic data are inverted. We have designed a fastand efficient way of multiple direct problemevaluation, which is based on pre-calculating theelementary Green's function. During the process we setthe values of the inversion control parameters(temperature, number of iterations) and modified thecooling schedule. In the current version, theinversion seeks for the point source mechanism, thedepth of the source, the scalar moment and the sourcetime function (STF). The method is applied to twoearthquakes: 18 Nov. 1992 in Greece, M 5.9 and 14 Sep.1995 in Mexico, M7.3. The calculation is performed ona simple 1D model of the structure. For the firstearthquake the inversion recovered the solution fairlywell; for the second the solution was less acceptable.However, we do not consider this fact to be a failureof the method, but a consequence of an inadequatemodel of the source and of the medium structure. Acasual attempt of reliability determination was alsoperformed; the obtained values of errors arereasonable, except for a few cases when the methodfailed.     

A modified ISBA surface scheme for modeling the hydrology of Athabasca River Basin with GCM-scale data

A soil–vegetation–atmosphere transfer model (SVAT), interactions between the soil–biosphere–atmosphere (ISBA) of Météo France, is modified and applied to the Athabasca River Basin (ARB) to model its water and energy fluxes. Two meteorological datasets are used: the archived forecasts from the Meteorological Survey of Canada’s Global Environmental Multiscale Model (GEM) and the European Centre for Mid-range Weather Forecasts global re-analysis (ERA-40), representing spatial scales typical of a weather forecasting model and a global circulation model (GCM), respectively. The original treatment of soil moisture and rainfall in ISBA (OISBA) is modified to statistically account for sub-grid heterogeneity of soil moisture and rainfall to produce new, highly non-linear formulations for surface and sub-surface runoff (MISBA). These new formulations can be readily applied to most existing SVATs. Stand alone mode simulations using the GEM data demonstrate that MISBA significantly improves streamflow predictions despite requiring two fewer parameters than OISBA. Simulations using the ERA-40 data show that it is possible to reproduce the annual variation in monthly, mean annual, and annual minimum flows at GCM scales without using downscaling techniques. Finally, simulations using a simple downscaling scheme show that the better performance of higher resolution datasets can be primarily attributed to improved representation of local variation of land cover, topography, and climate.