Progressive failure leading to the 3 December 2013 rockfall at Puigcercós scarp (Catalonia,Spain)

A detailed analysis of the pre-failure behavior of the 3 December 2013 rockfall (1,012 m³) occurred on Puigcercós pilot study area (Catalonia, Spain) is presented. The exact date of failure was obtained based on a photographic monitoring performed every 4 h. The long-term monitoring (2,217 days) of the rock slope carried out by a Terrestrial LiDAR allowed the early detection of both pre-failure deformation and precursory rockfalls preceding the final failure. By means of the analysis of the pre-failure deformation, four different deformed areas were detected and the tertiary creep phase was observed in three of them. An attempt to predict the time to failure was performed using the Fukuzono’s (1985) method. Furthermore, the temporal evolution of the precursory rockfalls occurred in those four areas during the progressive failure showed a close resemblance with the exponential pattern of the cumulated displacements at tertiary creep stage. Finally, the study of the meteorological conditions did not show any single triggering factor associated with the final failure. Reversely, the increase in the occurrence of precursory rockfalls on several areas of the slope together with the observed acceleration on the deformation pattern reinforce the role of a progressive degradation of the stability conditions, which ultimately leaded to the 3 December rockfall event.     

Refractory Black Carbon Results and a Method Comparison between Solid-state Cutting and Continuous Melting Sampling of a West Antarctic Snow and Firn Core

This work presents the refractory black carbon(rBC)results of a snow and firn core drilled in West Antarctica(79°55'34.6"S,94°21'13.3"W)during the 2014?15 austral summer,collected by Brazilian researchers as part of the First Brazilian West Antarctic Ice Sheet Traverse.The core was drilled to a depth of 20 m,and we present the results of the first 8 m by comparing two subsampling methods—solid-state cutting and continuous melting—both with discrete sampling.The core was analyzed at the Department of Geological Sciences,Central Washington University(CWU),WA,USA,using a single particle soot photometer(SP2)coupled to a CETAC Marin-5 nebulizer.The continuous melting system was recently assembled at CWU and these are its first results.We also present experimental results regarding SP2 reproducibility,indicating that sample concentration has a greater influence than the analysis time on the reproducibility for low rBC concentrations,like those found in the Antarctic core.Dating was carried out using mainly the rBC variation and sulfur,sodium and strontium as secondary parameters,giving the core 17 years(1998?2014).The data show a well-defined seasonality of rBC concentrations for these first meters,with geometric mean summer/fall concentrations of 0.016μg L^?1 and geometric mean winter/spring concentrations of 0.063μg L^?1.The annual rBC concentration geometric mean was 0.029μg L^?1(the lowest of all rBC cores in Antarctica referenced in this work),while the annual rBC flux was 6.1μg m^?2 yr^?1(the lowest flux in West Antarctica records so far).     

Decreasing precipitation occurs in daily extreme precipitation intervals across China in observations and model simulations

Extreme precipitation response to increasing temperature includes not only changes of frequency and intensity, but also changes of extreme precipitation interval (EPIV) and the precipitation during the neighboring daily extreme precipitations interval (EPIP). These changes have not been fully evaluated yet in observations or climate model simulations although they are very useful to understand variations of extreme precipitation. We used daily precipitation data from 669 meteorological stations during the past five decades across China and projections of 19 general circulation models from CMIP5 under the RCP4.5 and RCP8.5 scenarios to investigate variations of EPIV and EPIP. We found the national average annual EPIV increased across China during the last five decades, while annual EPIP significantly decreased. The decreases mainly occurred in southwest China, east China, and southeast China. At national and regional scales, the average annual EPIV and EPIP showed greater decreases under the RCP8.5 scenario than those under the RCP4.5 scenario from 2006 to 2100. Annual EPIP showed a stronger correlation with extreme precipitation intensity than EPIV. The national average annual EPIP had a significant positive correlation with the Western Pacific Subtropical High Area Index. The abnormal geopotential heights over western Mongolia and the western Pacific at 500 hpa as well as the abnormal SSTs in Japan Sea and the western of Pacific in rainy seasons would result in abnormal annual EPIVs and EPIPs in China. This study may provide references for flooding prediction, water resources management, and disaster prevention and mitigation.     

CMIP5 model simulations of warm Arctic-cold Eurasia pattern in winter surface air temperature anomalies

Climate Dynamics - The second empirical orthogonal function mode (EOF2) of winter surface air temperature (SAT) over 0°–180° E, 40°–90° N during 1979–2005 is...     

河南省区域暴雪的天气学分型及应用

普查了1986-2000年冬季河南省70个暴雪的个例资料,分析了河南省暴雪的时空分布特征及其天气形势特征,建立了横槽型和两槽一脊型的暴雪天气学模型.通过对2003年2月9-10日(横槽型)和2003年3月4-5日(两槽一脊型)河南省出现的两场区域性暴雪过程的环流背景、成因特征、物理量等的对比分析发现,暴雪天气一般发生在经向环流与纬向环流相互调整之时,低空急流与低层切变线上气旋性曲率东扩或低涡东移是产生暴雪的重要原因,冷垫是产生暴雪的基本条件,最后给出了两类典型暴雪的具体预报特征.     

西宁曹家堡机场雷暴统计特征分析

基于2006—2015年西宁曹家堡机场的雷暴观测资料,从雷暴日（次）数、持续时间、初现方位、伴随天气现象和雷暴初终日特征方面对该高原机场的雷暴特征进行统计分析。结果表明,曹家堡机场年平均雷暴日数为34.7 d,主要发生在5—9月,夏季是该机场雷暴的集中爆发期;雷暴具有明显的日变化特征,集中发生在午后至夜间（16—22时）,持续时间在2 h以内;雷暴初现方位以偏西、偏北为主,偏西、偏北的对流云团发展是该机场飞行保障的关注重点;雷暴伴随天气现象以干雷暴和小阵雨为主,而少数伴有中、大阵雨的强雷暴主要发生在夏季;雷暴初终日平均间隔为173.2 d,并且初雷能充分体现该机场的典型雷暴特征。     

杭州市钱塘新区地下空间开发地质环境适宜性评价

地下空间地质环境适宜性评价是实现地下空间合理有序开发的重要环节,也是国土空间科学规划的必要前提。通过系统分析杭州市钱塘新区地质环境条件,从地形地貌、工程地质条件、水文地质条件、活动断裂及地震效应、环境地质问题等五个方面选取15个指标构建了地下空间开发地质环境适宜性评价指标体系。在此基础上,采用变权层次分析法和灰色关联分析模型,对浅层(0~ 15m)、次浅层(15~ 30m)、次深层(30~ 50 m)地下空间进行了开发利用地质环境条件适宜性评价。结果表明,研究区浅层和次深层地下空间更适宜开发,而次浅层地下空间适宜性好和适宜性较好的总面积仅占全区的45.7%,地质环境条件复杂,具有一定的开发难度。该结果可为钱塘新区地下空间合理开发提供参考。     

Simulated impacts of afforestation in East China monsoon region as modulated by ocean variability

Using the National Center for Atmospheric Research Community Climate System Model Version 3.5, this paper examines the climatic effects of afforestation in the East China monsoon region with a focus on land–atmosphere interactions and the modulating influence of ocean variability. In response to afforestation, the local surface air temperature significantly decreases in summer and increases in winter. The summer cooling is attributed to enhanced evapotranspiration from increased tree cover. During winter, afforestation induces greater roughness and weaker winds over the adjacent coastal ocean, leading to diminished latent heat flux and increased sea-surface temperature (SST). The enhanced SST supports greater atmospheric water vapor, which is accompanied by anomalous wind, and transported into the East China monsoon region. The increase in atmospheric water vapor favors more cloud cover and precipitation, especially in the eastern afforestation region. Furthermore, the increase in atmospheric water vapor and cloud cover produce a greenhouse effect, raising the wintertime surface air temperature. By comparing simulations in which ocean temperature are either fixed or variable, we demonstrate that a significant hydrologic response in East China to afforestation only occurs if ocean temperatures are allowed to vary and the oceanic source of moisture to the continent is enhanced.