Mechanisms of isotopic control of precipitation in the Yellow River source region

The study of water vapour sources and water cycle patterns in the Yellow River source region is of great significance for ensuring water resource security in the arid and semi-arid regions of northern China. We established a precipitation stable isotope observation system in the Yellow River source region for three consecutive years (2020–2022), systematically analysed the spatial and temporal distribution characteristics of precipitation stable isotopes ²H and ¹⁸O in the Yellow River source region and their interrelationships with environmental factors and topography, and explored the regional water vapour transport pathways by using the HYSPLIT model and combining with the global reanalysis data. The results show that: (1) the δ¹⁸O and δ²H values of precipitation in the Yellow River source region follow the seasonal pattern, with the first half of the year being richer than the second half of the year; (2) the spatial variations of δ¹⁸O of precipitation in the Yellow River source region show a low in the southwest and a high in the northeast; (3) the water vapour source in the source area is basically stable, and the complex transport paths and the cross-effects of the local factors determine the stable isotope characteristics of the water, and the stable isotope characteristics of the water are determined by the cross-effects of the local factors, because the source of the water vapour and the local factors such as the height will not change significantly in the short term. Since the source of water vapour and local elevation factors will not change significantly in the short term, the precipitation pattern in the source area of the Yellow River can be considered to be basically stable.     

Influence of below-cloud evaporation on stable isotopes of precipitation in the Yellow River source region

The study of below-cloud evaporation effects under clouds in the Yellow River source region is of great significance for regional water resource generation as well as for water resource security in the arid and semi-arid regions of northern China. In this study, we quantitatively assessed the evapotranspiration effect in the Yellow River source region from March to November based on the improved Stewart model. The study concluded that: (1) below-cloud evaporation was slightly higher in summer than in other seasons (residual fractions of raindrop evaporation were 80.57% in summer, 81.12% in spring, and 84.2% in autumn, respectively); and (2) sub-cloud evaporation diminishes with increasing altitude (residual fractions of raindrop evaporation were 83.09% in the western part of the area, 81.82% in the central part of the area, and 81.36% in the eastern part of the area, respectively). (3) The total linear index between study areas f and ∆d is 2.24, where f > 95%, it is 1.19; that is, the evaporation of raindrops increases by 1% and the reduction in the excess of mercury by about 2‰. (4) Local meteorological factors (temperature, precipitation, and relative humidity) and raindrop diameter have a cross-influence on below-cloud evaporation, with relative humidity having the most significant effect, with the highest correlation coefficient of 3.03 when relative humidity is less than 70%. The results of the study can provide a parameter basis for hydrological and climatic models in the Yellow River Basin.     

东海西湖凹陷平湖组沉积环境演化

东海西湖凹陷ＴＷＴ井位于盆地南部,ＰＨＡ井位于盆地西部斜坡,是目前西湖凹陷揭露平湖组最多的两口钻井,以ＰＨＡ,ＴＷＴ井平滑组沉积特征及古生物资料为依据,以海平面升降控相原理为指导,通过旋回地层学分析,建立了Ａ,Ｂ,Ｃ,Ｄ四个等时沉积旋回,而而旋回间两井对比受相应的地震波组控制。通过对比,建立了Ｄｔ－Ａｐ的具最大地史跨度的平湖组沉积序列;而Ｂｔ,Ｃｔ与Ｂｐ,Ｃｐ之间的沉积旋回对比,揭示了同沉积期空间     

沿海地区风暴潮灾害的脆弱性组合评价及原因探析

以典型海洋灾害风暴潮为研究对象,以国家海洋局统计公报数据、国家统计局和各省市统计数据为数据源,将粗糙集理论(RST)与组合赋权策略(CWM)结合建立了基于RST-CWM的风暴潮灾害脆弱性组合评价模型。利用粗糙集的知识简约属性、投影寻踪组合赋权思想进行沿海各省市地区海洋风暴潮灾害脆弱性的综合评价。测算结果表明:沿海地区基于RST-CWM模型的风暴潮灾害脆弱性呈现出一定的空间差异性,但研究区各省市海洋风暴潮灾害脆弱性与地理位置分布没有必然的联系,说明在沿海地区开展海洋防灾减灾工作,若只注重地理区划并不一定能改善当地风暴潮脆弱程度。研究区各省市海洋灾害脆弱程度大小排序为:山东、天津、福建、广东、广西、辽宁、江苏、浙江、海南、河北、上海,同时,各省市的脆弱性要素即暴露性、敏感性及适应性构成有所差异,说明完备海洋风暴潮防灾减灾机制的驱动力是多样的,风暴潮防治应综合考虑灾害本身和人为因素。     

2002年6月20～24日梅雨锋中尺度对流系统发生发展分析

利用“973”中国暴雨试验获得的加密观测资料 ,首先对 2 0 0 2年 6月 2 0～ 2 4日发生在长江中下游地区的中尺度对流系统发生发展进行了分析 ,有 7个尺度较大的α中尺度对流系统在长江中下游地区发展 ,造成了大范围的强降雨。然后针对安徽南部发生的中尺度对流系统发生发展过程进行了详细分析 :MCS生成于切变线南侧的西南暖湿气流中 ,其源地是大别山区和大别山与九华山之间的长江河谷地带 ;低层西南风的水汽输送是安徽南部对流不稳定和对流有效位能积聚的主要原因 ;在降雨发生前整层可降水量有明显增加 ,开始降雨后则逐渐减小。雷达探测的回波显示α中尺度对流系统中有 β和γ中尺度系统的活动 ,β和γ中尺度系统与整个中尺度对流系统的移动方向不一致 ;中尺度对流系统中的带状回波有地面中尺度辐合线配合 ,对流带随地面的中尺度辐合线移动 ,对流带中的对流单体沿辐合带移动。     

一种改进的降水临近外推预报技术方法研究及效果检验

中尺度模式对于0～2h的预报存在起转问题,因此外推预报成为0～2h临近预报中不可或缺的技术方法。目前INCA(Integrated Nowcasting through Comprehensive Analysis System)降水外推预报中,外推矢量扰动由外推矢量随时间的变化确定,即相邻时次外推矢量差确定,本文统计2017年7月江淮地区(29°～35.5°N,114°～120°E)INCA系统相邻10min外推矢量偏差来代表外推矢量随时间变化。若降水向东北方向移动,则外推矢量方向规定为东北方向。统计结果表明:①对于江淮地区,外推矢量以东北方向和西南方向偏差为主,外推矢量越大,其偏差的大小越大;②从外推矢量方向看,东北方向外推矢量占绝大多数(73%),可能是因为绝大多数降水发生在槽前形势下,引导气流为西南风。基于外推矢量偏差统计样本,随机生成多个符合外推矢量偏差分布的外推矢量扰动,得到多个不确定的外推矢量,将INCA确定性外推预报变为0～2h降水外推集合预报,采用均方误差(MSE)、TS评分、BIAS评分和Brier技巧评分等方法,对集合预报结果检验表明:随着预报时效增加,集合预报比确定性预报的优势更明显。因此,考虑外推矢量的不确定性可以提高降水外推预报准确率。     

古城601井井身结构优化设计

古城地区实钻中存在表层窜冒、却尔却克组大段难钻“黑被子”地层、H2S、卡钻、井漏、溢流、井塌、地层压力温度高等技术难点，导致该区块钻井周期长、钻井成本高。针对古城地区地质特点，结合古城601井钻井目的及完井方式，综合考虑地层压力、必封点等井身结构设计关键点，在保障安全和质量的前提下，对古城601井进行了井身结构优化设计，并经实钻验证该设计思路合理，为古城地区井身结构设计提供了新思路。     

雷达干涉测量在地震形变研究中的应用

合成孔径雷达干涉测量(DInSAR)以厘米乃至毫米的精度和很大的空间覆盖范围实现地表形变观测,它是进行地壳形变观测的重要手段,在地震形变研究中发挥着越来越重要的作用。本文首先简要给出了微波雷达测量的特征,阐述了雷达图像数据处理的基本方法,分析了InSAR技术的主要影响因素和观测精度。结合较新的研究成果,分析了雷达遥感图像研究地震形变的方法,讨论了DInSAR在震间、同震和震后形变观测研究中的最新进展。同时讨论了目前我国应用DInSAR研究地震形变中面临的主要问题,最后阐述了应用雷达干涉测量研究地震形变的发展趋势。     

Relationship between oceanic heat content and sea surface height on interannual time scale

The relationship between heat content and sea surface height (SSH) in the global ocean on the interannual time scale is examined with satellite altimeter measurements, historical hydrography, and model assimilation outputs. Results show that correlation between altimetric SSH and heat content in the upper 700 m calculated from Ishii data is geographically nonuniform. In the tropical ocean, heat content and SSH are strongly correlated and exhibit nearly the same interannual variations. In the polar ocean, their correlation is relatively weak. Further analysis with Simple Ocean Data Assimilation outputs shows that such nonuniform distribution is not from dynamical origin but from the limited integral depth selected to calculate heat content. The integral depth of 700m is inadequate to capture variation of the deep main thermocline in the polar region. The halosteric effect also contributes to the nonuniform pattern of correlation, because saline contraction becomes significant in the polar ocean owing to low temperature.     

老挝万象平原盐丘发育程度与钾盐找矿策略

老挝万象平原不同矿区盐丘构造发育程度不同。由于盐丘控制了钾盐矿层的分布,因此研究盐丘及其发育程度并对其分级,对万象平原及其周边地区的钾盐找矿具有重要参考意义。通过对万象平原大量的钾盐勘查资料研究,将该区域内盐丘构造按发育程度不同分为Ⅲ级(较发育)、Ⅱ级(发育)和Ⅰ级(极发育)三个级别。属Ⅲ级的有通芒盐丘和班海盐丘,属Ⅱ级的有农刀及塔贡盐丘,属Ⅰ级的为农哈湖盐丘。在万象平原进行钾盐勘查时,发育程度不同的盐丘及盐丘的不同部位的工程布设不同,找矿效果也不同。