The Seasonal Prediction of the Exceptional Yangtze River Rainfall in Summer 2020     

Chaofan LI  Riyu LU  Nick DUNSTONE  Adam A.SCAIFE  Philip E.BETT  Fei ZHENG 《大气科学进展》2021,38(12):2055-2066

During June and July of 2020, the Yangtze River basin suffered from extreme mei-yu rainfall and catastrophic flooding. This study explores the seasonal predictability and associated dynamical causes for this extreme Yangtze River rainfall event, based on forecasts from the Met Office GloSea5 operational forecast system. The forecasts successfully predicted above-average rainfall over the Yangtze River basin, which arose from the successful reproduction of the anomalous western North Pacific subtropical high (WNPSH). Our results indicate that both the Indian Ocean warm sea surface temperature (SST) and local WNP SST gradient were responsible for the westward extension of the WNPSH, and the forecasts captured these tropical signals well. We explore extratropical drivers but find a large model spread among the forecast members regarding the meridional displacements of the East Asian mid-latitude westerly jet (EAJ). The forecast members with an evident southward displacement of the EAJ favored more extreme Yangtze River rainfall. However, the forecast Yangtze River rainfall anomaly was weaker compared to that was observed and no member showed such strong rainfall. In observations, the EAJ displayed an evident acceleration in summer 2020, which could lead to a significant wind convergence in the lower troposphere around the Yangtze River basin, and favor more mei-yu rainfall. The model forecast failed to satisfactorily reproduce these processes. This difference implies that the observed enhancement of the EAJ intensity gave a large boost to the Yangtze River rainfall, hindering a better forecast of the intensity of the event and disaster mitigation.  相似文献   

沿淮地区秋季连阴雨综合指数构建及其变化特征          下载免费PDF全文

朱公群  韩帮军  段春锋  等. 《气象与环境科学》2022,45(1):96-102

基于安徽省沿淮地区10个国家气象站1960-2019年观测资料、灾情资料和7种地方连阴雨监测指标,在评估7种地方指标适用性的基础上,采用加权综合指数法和线性趋势法,构建了沿淮地区秋季连阴雨综合指数,分析了时空变化特征。结果表明:江苏指标对沿淮地区连阴雨监测的适用性最好,连阴雨综合指数由连阴雨总日数、连阴雨总降水量线性组成,权重分别为0.8和0.2。按照综合指数,将连阴雨强度分成重度、中度、轻度3级,分级结果与灾情实况较吻合,重度连阴雨和中度连阴雨TS评分分别为100%、88.9%。秋季连阴雨在20世纪70年代到80年代前期及近10年发生频率高、强度大,尤其是2016年和2017年的连阴雨,强度居历史前2位。沿淮地区连阴雨年数东部和西部的多于中部的,重度连阴雨阜南的最多,五河的最少。  相似文献   

1980－2018年山西省太行山南麓暴雨时空变化特征          下载免费PDF全文

刘强军  宋军芳  马龙. 《气象与环境科学》2022,45(1):30-38

基于1980-2018年山西省太行山南麓晋城市5个站点的降水资料,利用小波分析和Mann-Kendall方法,研究了太行山南麓暴雨时空变化特征。结果表明:39年平均年暴雨日数有0.9个,年际变化幅度较小。暴雨量与暴雨日数的空间分布并不一致,1980、1981、1982、1995和1996年暴雨日数较多。分析50-59、60-69、70-79、80-89、90-99、100以上6个暴雨量区间空间分布发现,暴雨的空间分布在不同区间并没有明显的趋同性。年暴雨降水量有不同程度的增加趋势,晋城市下辖5站暴雨量趋势均存在突变,突变时间存在差异,暴雨量在19811983年和19921995年为两个峰值时段,之后有所缓和。39年暴雨时间序列的小波波谱显示,太行山南麓暴雨呈现0~3 a、3~7 a、8~24 a等3类周期准振荡变化规律,各波动周期稳定性和显著性不同。3~7 a出现5个多少准周期振荡,该周期表现较为显著,8~24 a出现2个准振荡周期,且这两个周期非常稳定,具有全域性的特征。晋城市3~7 a的暴雨振荡周期和8~24 a特大暴雨振荡周期与现实非常吻合。  相似文献   

开封“7·19”大暴雨天气过程的极端性分析     

冀翠华  李姝霞. 《气象与环境科学》2021,44(4):53-62

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2019年许昌市臭氧污染情况及其与气象条件关系     

崔坤  赵慧  刘鹏  等. 《气象与环境科学》2021,44(1):89-95

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Heavy mineral composition and texture of the recently formed fluvial delta sediment of Lake Nasser/Nubia,Egypt and Sudan     

Omran E.Frihy  Essam A.Deabes  Abdelaleem A.Abudia  Ahamed Adawi 《国际泥沙研究》2022,37(1):70-82

Surficial sediment samples collected from the recently formed fluvial delta in Lake Nasser/Nubia (Egypt and Sudan) in conjunction with data on bottom current and depth soundings are examined to interpret hydraulic-sorting processes and transport/depositional patterns.The～500 km long northeastwardtrending lake,lies within Egypt and Sudan,is created as a result of the construction of the Aswan High Dam in 1964.The original grain-size distribution and heavy mineral compositions of these samples hel...  相似文献   

俄罗斯油气钻采废弃物处理及其利用研究          下载免费PDF全文

汤凤林  赵荣欣  周欣  段隆臣  Третьяк А.А. 《探矿工程》2022,49(5):202-207

生态安全和环境保护是世界各国都非常关心的问题。地质钻探和石油天然气钻采工作中产生大量废弃物,直接影响生态安全和环境保护,给经济建设和人民生活带来很大的负面影响。俄罗斯钻探工作者对此进行了研究,取得了一定效果。他们主要采用综合处理方法和磁化处理方法。利用这2种方法,废弃物不仅可以再生,而且还可以二次使用,有一定的创新和实际意义,值得引起我们的重视,建议对此进行研究与讨论。  相似文献   

Crustal Electrical Structure and Deep Metallogenic Potential in Northern Wuyi Area (South China), based on Magnetotelluric Data     

LUO Fan  LU Qingtian  ZHANG Kun  YAN Jiayong  Colin G. FARQUHARSON  ZHANG Chong  FU Guangming 《《地质学报》英文版》2022,96(3):791-805

The northern Wuyi area, which is located in the northern Wuyi metallogenic belt, has superior mineralization conditions. The Pingxiang–Guangfeng–Jiangshan–Shaoxing fault (PSF) extends across the whole region regardless of whether or how the PSF relates to the near-surface mineralization. We carried out an MT survey in the region and obtained a reliable 2D model of the crustal electrical structure to a depth of 30 km. In the resistivity model, we inferred that a continuous high conductivity belt that ranges from the shallow to deep crust is a part of the PSF. Then, we estimated the fluid content and pressure gradient to identify the deep sources of fluid as well as its pattern of motion pattern. Finally, we proposed a model for the deep metallogenic migration processes that combines geological data, fluid content data, pressure gradient data, and the subsurface resistivity model. The model analysis showed that the Jiangnan orogenic belt and the Cathaysia block formed the PSF during the process of com. The deep fluid migrated upward through the PSF to the shallow crust. Therefore, we believe that the PSF is an ore-forming fluid migration channel and that it laid the material basis for large-scale mineralization in the shallow crust.  相似文献   

Identification of Milankovitch Cycles and Calculation of Net Primary Productivity of Paleo-peatlands using Geophysical Logs of Coal Seams     

SHAO Longyi  WEN He  GAO Xiangyu  Baruch SPIRO  WANG Xuetian  YAN Zhiming  David J. LARGE 《《地质学报》英文版》2022,96(6):1830-1841

Individual coal seams formed in paleo-peatlands represent sustained periods of terrestrial carbon accumulation and a key environmental indicator attributed to this record is the rate of carbon accumulation. Determining the rate of carbon accumulation requires a measure of time contained within the coal. This study aimed to determine this rate via the identification of Milankovitch orbital cycles in the coals. The geophysical log is an ideal paleoclimate proxy and has been widely used in the study of sedimentary records using spectral analysis. Spectral analyses of geophysical log from thick coal seams can be used to identify the Milankovitch cycles and to calculate the period of the coal deposition. By considering the carbon loss during coalification, the long-term average carbon accumulation rate and net primary productivity (NPP) of paleo-peatlands in coal seams can be obtained. This review paper presents the procedures of analysis, assessment of results and interpretation of geophysical logs in determining the NPP of paleo-peatlands.  相似文献   

沿阿穆尔板块西边界的活动断层(蒙古领土)     

Vladimir A.SANKOV  Anna V.PARFEEVETS  Andrey I.MIROSHNITCHENKO  Aleksey V.SANKOV  Amgalan BAYASGALAN  Sodnomsambuu DEMBEREL 《地学前缘》2022,29(1):245-265

阿穆尔板块西部边界在蒙古境内的空间位置尚不清楚,并且活动断层构造及其沿线地壳的应力状态研究较少。本文在沿此边界的三个区域——杭爱—肯特构造鞍部、布尔古特地块(鄂尔浑—土拉交汇处)和色楞格地块(包括色楞格凹陷和布伦—努鲁隆起),利用空间图像解译、地形起伏度分析、地质构造资料以及构造压裂和沿裂缝位移资料重建构造古应力,对活动断层进行研究。研究表明,活动断裂继承了古生代和中生代古构造的非均质性。这些断层沿着板块边界并不是单一的带,而是成簇的。它们的运动取决于走向:亚纬向断层是具有一定逆分量的左旋走滑断层,北西向断层是逆断层或逆冲断层,通常具有右旋走滑分量,海底断层是右旋走滑断层,北东向断层是正断层。位于色楞格凹陷和杭爱东部的断裂构造的活动始于上新世。逆断层和走滑断层与上新世情况不符,但多与更新世地貌相符,表明其活动年代较晚,为更新世时期。利用构造断裂和沿断裂的位移,重建活动断裂带变形末阶段的应力应变状态,结果表明断裂在最大挤压轴的北北东和北东方向上以压缩和走滑为主。只有在色楞格凹陷内,以扩张和走滑类型的应力张量为主,且在最小挤压轴的北西走向尤为显著。在南部,杭爱东部(鄂尔浑地堑)内有1个以扩张机制为主的局部区域,说明蒙古中部断裂在更新世—全新世阶段的活动以及现代地震活动主要受与印度斯坦和欧亚大陆汇聚过程相关的东北方向的附加水平挤压的控制。使研究区地壳产生走滑变形、贝加尔湖裂谷发散活动以及阿穆尔板块东南运动的另一个因素是东南方向软流圈流动对岩石圈底部的影响。阿穆尔板块和蒙古地块之间的边界在构造结构上是零碎的,代表了覆盖整个蒙古西部变形带的边缘部分。  相似文献