基于印度洋海温信号的我国西北地区东部夏季降水组合降尺度预测方法研究     

朱晓炜  李清泉  孙银川  王璠  王岱  高睿娜  刘颖 《气象》2024,50(3):357-369

利用国家气候中心第二代气候模式预测业务系统(BCC-CPSv2)预测产品,引入印度洋海温信号,采用组合降尺度方法建立了西北地区东部汛期降水预测模型。该预测模型对1991—2017年西北地区东部夏季降水的回报技巧较BCC-CPSv2预测技巧显著提高,空间相关系数由0.42提高到0.75,均方根误差明显减小,最多下降达80%。预测模型对降水空间分布型的预测能力较好,很好地回报了典型年份（1987年和2010年）夏季的降水距平百分率分布。通过抓住气象变量的空间分布特征,组合降尺度方法可以修正动力模式产品的预测误差,为西北地区东部夏季降水预测提供科学依据和技术支持,具有较好的应用前景。  相似文献   

5月南极涛动对青藏高原西部夏季气温影响的诊断分析     

张宇  李清泉  余锦华  沈新勇  毕淼  吴清源 《气象》2024,50(3):344-356

青藏高原是全球气候变暖最敏感的地区之一,是北半球夏季最大的热源,其气候响应受到广泛关注。然而,有关南极涛动与青藏高原夏季气温的关系和机理知之甚少。为了研究南极涛动与青藏高原夏季气温的关系,基于1979—2020年英国东安哥拉大学气候研究中心（CRU）的逐月气温、美国国家海洋和大气管理局（NOAA）的逐月海表面温度和大气环流再分析数据以及南极涛动指数等数据,采用相关、回归、合成分析等方法进行研究。结果表明,北半球夏季青藏高原西部气温与5月南极涛动存在显著负相关,即当5月南极涛动异常偏弱时,夏季青藏高原西部气温异常偏高。其影响过程为,南极涛动为正位相时,在南印度洋中高纬地区出现“负-正-负”的经向“三极子”海温模态,该模态可持续到夏季,在印度洋形成异常的纬向-垂直环流,相应在热带西印度洋和东印度洋-海洋性大陆之间的降水异常导致热带正“偶极子”降水模态,通过该降水模态在青藏高原西部引起异常反气旋环流和下沉运动,有利于高原西部气温偏高。研究结果显示,海洋的热惯性在“延长”南极涛动影响过程中起着重要的桥梁作用,可为青藏高原夏季气温预测提供科学依据。  相似文献   

Detrital and authigenic(?) baddeleyite (ZrO2) in ferromanganese nodules of Central Indian Ocean Basin     

Bibhuranjan Nayak  Swapan Kumar Das  Kalyan Kumar Bhattacharyya 《地学前缘(英文版)》2011,2(4):571-576

Occurrence of baddeleyite (ZrO2) which is a rare mineral has been recorded in ferromanganese nodules of Central Indian Ocean Basin (CIOB). The mineral occurs either as independent isolated sub-rounded to elliptical grains or in clusters forming fine subhedral crystals (<3 mm) within ferromanganese concretionary growth bands. The mode of occurrence, textural features and chemistry of the mineral suggest detrital and possibly an authigenic origin for baddeleyite. For authigenic origin it is proposed that zirconium might have got released either from the terrigenous sediments or the altered seafloor rocks forming halogen complexes and subsequently it has re-precipitated in the form of baddeleyite within manganese nodules under oxic to sub-oxic conditions.  相似文献   

Surface cyclopoid copepod assemblages in relation to environmental conditions near undisturbed coral reefs of Minicoy,southeastern Arabian Sea,a part of the Indian Ocean     

Radhika Radhakrishnan  Santu Kuzhikandathil Sunny  Bijoy Nandan Sivasankaran  Harikrishnan Mahadevan 《Marine Ecology》2020,41(6):e12619

The cruise conducted in the spring inter-monsoon (pre-monsoon) of April 2015 in the frame of a funded project epitomized an open ocean survey that allowed procuring a quasi-synoptic picture of cyclopoid copepod community structure in 18 open ocean stations of the Minicoy Island, Lakshadweep archipelago, off the southwestern Indian coast, based on the analysis of standing stock and composition in the integrated 0–10 m water column. The main objective was to explore the community structure of cyclopoid copepods prevailing here and which environmental variable influences the same. It is witnessed that sea surface temperature (SST) (30.42 ± 0.19°C), sea surface salinity (SSS) (33.56 ± 1.15 psu), and dissolved oxygen (DO) (4.32 ± 0.06 ml/L) with SSS and DO are the best matching variables diversifying cyclopoid copepod species (av. abundance 700 ± 386 no. of individuals/100 m³). Average zooplankton biomass (0.03 ml/m³) and abundance (8,989 ± 3,866 no. of individuals/100 m³) were also observed. Fifty-one cyclopoid copepod species belonging to four families and seven genera were identified, with the dominance of high saline species such as Sapphirina, Copilia, Farranula, and Oncaea. An abundance biomass curve (ABC) plot analysis indicated an undisturbed community with normal environmental conditions. TAXDTEST (taxonomic distinctness) depicted a diverse condition where all points clustered together within a 95% confidence level. Our results indicate that the cyclopoid copepod assemblage near Minicoy Island is a diverse, undisturbed community and hypothesize that the stable environmental conditions during pre-monsoon (spring inter-monsoon) preferred the diversification of cyclopoid copepods with the prevalence of high saline species. The data evolved could be used as a standard reference/benchmark to detect any deviation from an undisturbed/diverse community status of Minicoy Island in the looming scenario of climate change in and around the Indian Ocean.  相似文献   

卡尔斯伯格脊 60°~61°E洋脊段多波束后向散射特征及其对构造与岩浆作用强度的指示          下载免费PDF全文

杨驰  韩喜球  王叶剑  李洪林  邱中炎  吴招才 《海洋学研究》2018,36(3):37-49

多波束声纳数据可以有效记录海底地形地貌和底质特征信息。本文利用船载多波束数据对慢速扩张的卡尔斯伯格脊60°~61°E洋脊段的典型构造地貌单元的后向散射强度特征进行了研究,在此基础上,分析了该洋脊段的构造和岩浆作用强度特征。结果表明,洋脊段I以构造拉张作用占主导,脊轴及附近后向散射强度为-29 dB左右,裂谷壁高差可达1 200 m以上,裂谷内断裂发育,裂谷侧翼高度与裂谷宽度的比值为78.7~126.2,裂谷两侧翼部线性构造较少,但轴向正断层面更宽,倾角更小;与洋脊段裂谷中段相比,末端火山活动频率较低但喷发规模较大,火山机构数量和体积也更大,且可发育深大断裂获取深部热源。洋脊段II以岩浆作用占主导,脊轴及附近后向散射强度达-35 dB,裂谷内轴向火山脊发育,裂谷壁高差小于500 m,裂谷侧翼高度与裂谷宽度的比值为77.6~116.8,裂谷两侧翼部线性构造数量众多、长宽比较大且呈近似对称,相邻线性构造之间沉积物广泛分布。通过提取挖掘与底质属性密切相关的多波束后向散射强度数据,结合海底地形地貌的分析,可以为洋中脊的构造和岩浆作用强度的定量研究提供有效的证据。  相似文献   

Strategic elements in the Fort Cooper Coal Measures: potential rare earth elements and other multi-product targets     

J. H. Hodgkinson  M. Grigorescu 《Australian Journal of Earth Sciences》2020,67(3):305-319

Abstract

Mineral matter in coals has been found to host valuable elements including germanium, lithium and rare-earth elements (REE), but such content of Australian coals remains under-explored. The aim of this paper is to provide a proof-of-concept study that determines elemental concentrations in the mineral matter of the high-ash, Fort Cooper Coal Measures (FCCM), Bowen Basin, Queensland. Coal in the FCCM has good coking properties but has not been extensively explored owing to its high ash content. This study performs a preliminary assessment of the elements from the coal portion that would typically become waste after washing or combustion. Given that the needs for industrial extraction methods will change over time, cataloguing and documenting the elemental composition of coal may assist future development of multiple products for the benefit of both the coal and mineral industries. This preliminary study has revealed similar elevations of REE and higher-than-average crustal concentrations of lithium, bismuth and scandium in some of the samples. Further analyses will be required on a larger dataset to better understand elemental associations and explore spatial patterns of elemental content that may indicate localised enrichments. Understanding the potential of valuable elements in the FCCM may stimulate interest in multiple-product-coal (or elemental-coal) mining in this under-exploited resource and further encourage the reduction of waste from other Australian coals at the wash-plant stage.  相似文献   

热带东印度洋春季浮游植物群落结构空间特征分析   总被引：2，自引：0，他引：2  

孙萍  李艳  潘玉龙  韦钦胜  袁超  张学雷  王宗灵 《海洋学报》2020,42(8):76-88

基于2013年3月至5月采集的热带东印度洋海域(10.0°S～4.0°N, 83.0°～97.5°E)浮游植物水样样品，分析了其种类组成、优势类群、细胞丰度等群落特征参数，综合比较了水平和垂向上浮游植物种类及丰度的差异性，初步探讨了其成因。结果表明:2013年春季热带东印度洋微型浮游植物共鉴定出306种，主要由硅藻、甲藻、金藻、蓝藻、裸藻和隐藻六大门类组成，其优势类群主要以粒径较小的隐藻、微型甲藻、菱形藻、环沟藻等为主。水平分布上，各水层浮游植物细胞丰度分布趋势相似，但斑块特征明显，其高值区位于88°E断面赤道以南次表层水域(30 m、75 m)，局部区域细胞丰度值可达104 cells/L以上；与其毗邻的东南部、东部水域为低值区，并向赤道延伸。垂直剖面上，硅藻和甲藻广泛分布在各取样深度，但分布特征有明显的空间差异和规律，0 m、30 m大部分站位硅藻种类比例在0.2～0.3甚至更低，甲藻在0.7～0.8，随着水层加深(75 m、100 m、150 m、300 m)，硅藻种类占比上升到0.5～0.6，甲藻降低到0.4～0.5，无论硅藻还是甲藻种类数75 m层最丰富。30 m和75 m水层细胞丰度明显高于其他水层。甲藻是热带东印度洋微型浮游植物种类和细胞丰度的重要贡献者，低生物量海域表现的更为明显，贡献率大于80%。该研究将极大丰富东印度洋浮游植物群落空间特征基础信息较匮乏的现状，为量化、评估该海域的生物资源提供数据支撑。  相似文献   

Late Quaternary record of Indian summer monsoon-induced stratification and productivity collapse in the Andaman Sea     

A. V. Sijinkumar  B. Nagender Nath  Steven Clemens  N. M. Gayathri  P. Miriyala 《第四纪科学杂志》2021,36(2):298-310

During each summer monsoon, the northeastern Indian Ocean receives a huge amount of rain and river discharge, resulting in strong stratification and prevalence of oligotrophic conditions. These water column changes impact upper ocean productivity which is reflected in the planktonic foraminifera distribution, providing an opportunity to study the effect of monsoon forcing and stratification history. Analogous to modern-day stratification, very intense water column stratification and productivity collapse were observed associated with Indian summer monsoon (ISM) evolution. This paper reports significant stratification events during MIS 3 (37.0 to 33 and 27 to 24 cal ka), Bølling/Allerød (B/A), early Holocene (10.0 to 8.0 cal ka) and mid-Holocene (7.0 to 5.0 cal ka) which slowly muted upwelling and productivity. The deglacial intensification of the ISM started in the early stages of the Bølling/Allerød (B/A) followed by slight weakening during the Younger Dryas and regained strength during the early Holocene, coinciding with the highest summer insolation at 30°N. A progressive decline in the abundances of productivity and salinity proxies from 4.2 to 2.0 cal ka suggests a gradual weakening of the ISM. The late Quaternary productivity variations in the Bay of Bengal and the Andaman Sea are primarily controlled by salinity-related stratification.  相似文献   

于家沟地下水反应溶质运移规律数值仿真     

梁冰  王岩 《地球科学与环境学报》2006,28(4):58-63

针对矸石淋滤液对于家沟地区地下水污染的实际情况,分析其在含水层中运移的规律,充分考虑了地下水变密度对浓度分布的影响,建立了多组分溶质在地下水中运移的耦合动力学数学模型,采用Galerkin有限元方法和Picard迭代法相结合对耦合模型进行了离散,通过室内土柱实验求得基本参数并对地下水污染的动态过程进行了仿真模拟,预测了污染浓度的时空分布特征。结果表明:污染面积随时间推移不断向两轴方向扩大,且纵向显著;不同组分由于各自特征的巨大差异,受到地下水密度影响的程度也有很大差别;渗滤液浓度拟合误差小于6%,从而验证了模型的可靠性和实用性。  相似文献   

煤层气藏的储集特征及储层评价   总被引：1，自引：0，他引：1  

杨建业  杜美利  苏小鹏  李慧利 《地球科学与环境学报》1995,(3)

论述了煤层气非常规天然气的特征，指出控制煤储集性能的因素主要是煤岩性质、煤层埋藏深度及地质构造条件等，并综合分析了煤层气储层各种评价参数，指出各种有利于煤层气藏的地质条件和物性条件。  相似文献