Seasonal stability of snow cover in Poland in relation to the atmospheric circulation

The seasonal stability of snow cover (ISS) was defined as a percentage ratio of the real and the potential snow cover duration in a winter season. Main results of the study are as follows: (1) alternately occurring periods of high and low values of the index of snow cover stability did not appeared simultaneously in mountainous and non-mountainous areas; (2) in the majority of Poland area both zonal and meridional components of the atmospheric circulation influence the ISS; however, in south the meridional air flow reveals the stronger impact, mostly due to the intensification of the southern advection by the foehn effect; and (3) changes of two or three indices describing atmospheric circulation explain up to 50 % of the ISS in Poland. The diminishing stability of snow cover in Poland corresponds with an increasing intensity of the advection from the western sector in winter in the second half of the twentieth century in Europe.     

Timing of glacier advances and climate in the High Tatra Mountains (Western Carpathians) during the Last Glacial Maximum

During the Last Glacial Maximum (LGM), long valley glaciers developed on the northern and southern sides of the High Tatra Mountains, Poland and Slovakia. Chlorine-36 exposure dating of moraine boulders suggests two major phases of moraine stabilization, at 26–21 ka (LGM I — maximum) and at 18 ka (LGM II). The dates suggest a significantly earlier maximum advance on the southern side of the range. Reconstructing the geometry of four glaciers in the Sucha Woda, Pańszczyca, Mlynicka and Velicka valleys allowed determining their equilibrium-line altitudes (ELAs) at 1460, 1460, 1650 and 1700 m asl, respectively. Based on a positive degree-day model, the mass balance and climatic parameter anomaly (temperature and precipitation) has been constrained for LGM I advance. Modeling results indicate slightly different conditions between northern and southern slopes. The N–S ELA gradient finds confirmation in slightly higher temperature (at least 1 °C) or lower precipitation (15%) on the south-facing glaciers during LGM I. The precipitation distribution over the High Tatra Mountains indicates potentially different LGM atmospheric circulation than at the present day, with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses.     

An attempt to dendroclimatic reconstruction of winter temperature based on multispecies tree-ring widths and extreme years chronologies (example of Upper Silesia, Southern Poland)

This study aims at investigating pre-instrumental tree-ring based winter thermal conditions from Upper Silesia, southern Poland. The Scots pine, pedunculate oak and sessile oak ring widths and the extreme index were used to reconstruct winter mean temperature back to A.D. 1770. The climate response analysis showed that the pine is the most sensitive to February (0.36) and March (0.41) temperature, the oaks were found to be sensitive to the previous December (0.27) and January (0.23) temperature. It was found out that the combination of temperature sensitive species and an additional extreme index in regression can improve the reconstruction, with an emphasis on more reliable reconstruction of extreme values. The elimination of variance reduction and precise reconstruction of actual values of temperature is possible by scaling. The obtained calibration/verification results suggest that, through the application of the long-term composite chronologies a detailed study of the climate variability in Upper Silesia in past centuries can be provided.     

标准化气象数据服务接口设计与实现

为统一气象应用系统数据对接方式,规范气象数据使用环境,以国省两级气象信息化行动方案为纲领,采用Spring Boot和Spring Cloud微服务框架,设计和开发了标准化气象数据服务接口。标准化气象数据服务接口遵循气象信息化标准体系,采集和加工各类气象数据后汇入气象数据资源池,统一通过RESTful API发布数据,为全宁波市气象应用系统提供标准化数据对接服务。该接口改变了应用程序直接读取数据库的旧模式,降低了应用系统的开发成本,同时加强了运维部门对各类气象数据访问的监控和管理。文章主要介绍了气象数据服务接口的设计和开发过程,并详细描述了开发过程中涉及的接口规范、业务流程和关键技术。     

黔中隆起及其周缘地区海相下组合与油气勘探前景

黔中隆起及其周缘地区,主要包括黔西北地区及其东部相邻的麻江古油藏地区,均属扬子台地的一部分,具有相似的构造及盆地演化历史。海相下组合主要是指震旦系、寒武系、奥陶系和志留系。黔中隆起褶皱平缓,断裂活动弱,利于印支期及以前所形成的原生油气藏的保存。黔中隆起的下寒武统烃源岩特别是牛蹄塘组烃源岩比麻江地区古油藏烃源岩发育程度高,震旦系和寒武系白云岩为良好储层,下寒武统泥岩及中上寒武统的膏盐岩可作为直接盖层及区域盖层;再加上该区相对稳定的构造保存条件,只要现今地表淡水下渗的深度不足以沟通深层原生油气藏并使之遭受完全破坏,该区就可能成为中国南方海相下组合石油和天然气勘探的重要地区之一。     

The correlations and anticorrelations in QPO data

Double peak kHz QPO frequencies in neutron star sources varies in time by a factor of hundreds Hz while in microquasar sources the frequencies are fixed and located at the line ν ₂ = 1.5ν ₁ in the frequency‐frequency plot. The crucial question in the theory of twin HFQPOs is whether or not those observed in neutron‐star systems are essentially different from those observed in black holes. In black hole systems the twin HFQPOs are known to be in a 3:2 ratio for each source. At first sight, this seems not to be the case for neutron stars. For each individual neutron star, the upper and lower kHz QPO frequencies, ν ₂ and ν ₁, are linearly correlated, ν ₂ = Aν ₁ + B , with the slope A < 1.5, i.e., the frequencies definitely are not in a 1.5 ratio. In this contribution we show that when considered jointly on a frequency‐frequency plot, the data for the twin kHz QPO frequencies in several (as opposed to one) neutron stars uniquely pick out a certain preferred frequency ratio that is equal to 1.5 for the six sources examined so far. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Modelling hydraulic and capillary-driven two-phase fluid flow in unsaturated concretes at the meso-scale with a unique coupled DEM-CFD technique

The goal of the research was to demonstrate the impact of thin porous interfacial transition zones (ITZs) between aggregates and cement matrix on fluid flow in unsaturated concrete caused by hydraulic/capillary pressure. To demonstrate this impact, a novel coupled approach to simulate the two-phase (water and moist air) flow of hydraulically and capillary-driven fluid in unsaturated concrete was developed. By merging the discrete element method (DEM) with computational fluid dynamics (CFD) under isothermal settings, the process was numerically studied at the meso-scale in two-dimensional conditions. A flow network was used to describe fluid behaviour in a continuous domain between particles. Small concrete specimens of a simplified particle mesostructure were subjected to fully coupled hydro-mechanical simulation tests. A simple uniaxial compression test was used to calibrate the pure DEM represented by bonded spheres, while a permeability and sorptivity test for an assembly of spheres was used to calibrate the pure CFD. For simplified specimens of the pure cement matrix, cement matrix with aggregate, and cement matrix with aggregate and ITZ of a given thickness, DEM/CFD simulations were performed sequentially. The numerical results of permeability and sorptivity were directly compared to the data found in the literature. A satisfactory agreement was achieved. Porous ITZs in concrete were found to reduce sorption by slowing the capillary-driven fluid flow, and to speed the full saturation of pores when sufficiently high hydraulic water pressures were dominant.