Anomalies in the Atmospheric Methane Content over Northern Eurasia in the Summer of 2016

Doklady Earth Sciences - Using data from the AIRS satellite instrument for the period of 2003–2016, the correlation between the regional anomalies of methane content in the atmosphere and the...     

北京“7·20”特大暴雨的时空多要素分析

基于高站点密度的场次降雨数据对2016年7月20日发生在北京地区的特大暴雨过程进行分析,明晰其时空演变过程。主要结论如下:(1)暴雨中心降雨总量在350mm以上,大致呈带状分布,主要位于海拔高度在200~400m范围内的山麓平原,说明地形抬升作用对暴雨的形成有明显的促进作用;(2)暴雨中心处发生的是长历时、高强度的降雨过程,而位于怀柔区和密云区交界处的暴雨副中心处发生的是短历时、高强度的降雨过程;(3)暴雨过程为一小一大的双峰雨型,第二阶段是整个降雨过程的主过程,降雨总量达到184.7mm,与北京"7·21"暴雨的降雨总量基本持平,超过20年一遇标准;(4)随着降雨总量的增加,各站点最大1h雨强呈线性增加的趋势,且最大雨强出现时刻有所提前,随着统计时段的增加,最大降雨总量增加的速率逐渐变缓,可由对数函数进行拟合。     

CMIP3模式对未来50a欧亚大陆雪水当量的预估

为研究预估未来50a欧亚大陆雪水当量,基于遥感数据,用误差百分率、空间相关和误差标准差等统计方法,评估了14个CMIP3模式在20C3M的雪水当量产品,诊断各模式对欧亚大陆雪水当量的模拟能力,在此基础上对模拟效果较好的10个模式产品进行多模式集合,分析了A2和B1情景下2002—2060年欧亚大陆雪水当量的变化．结果表...     

古尔班通古特沙漠树枝状沙丘土壤水分时空变异特征

认识沙漠土壤水分的时空变异性,是揭示沙漠生态系统生态-水文格局的基础。利用中子土壤水分仪的实测数据,对古尔班通古特沙漠树枝状沙丘土壤水分时空变异进行了系统分析。研究表明:① 沙丘不同部位土壤水分随时间具有一致性变化规律,上层土壤和下层土壤的变化趋势有所不同。0~1 m土层坡顶>坡中>坡脚,1~2 m土层坡脚>坡中>坡顶。② 土壤水分具有明显的季节变化和分层变化特征。春季是古尔班通古特沙漠土壤水分最丰富、变化最迅速的时期;0~40 cm、40~140 cm、140~200 cm土层土壤水分变异系数分别为13.56%、5.35%和0.80%,与不同土层水分来源和消耗以及植物根系分布相对应;不同土层土壤水分的变异强度要大于不同部位土壤水分的变异强度。③ 植被和地形对土壤水分的空间分异作用明显,沙丘坡脚处以及荒漠灌木梭梭根区始终存在土壤水分相对富集区。     

欧亚大陆春季植被对同年中国西北夏季大气环流和气候的影响研究

利用1982—2006年欧亚大陆月归一化植被指数（NDVI）,NCAR/NCEP月高度场和风场以及中国西北地区248个气象台站的逐日降水、温度资料,通过SVD及合成分析等方法,分析了欧亚大陆春季植被同同年中国西北夏季大气环流乃至干湿特征的关系.结果表明：欧亚大陆春季植被覆盖状况对预测我国西北地区同年夏季的干湿特征具有较...     

Eigenvector analysis of reconstructed Holocene July temperature departures over northern Canada

July temperatures for the past 6000 yr at 11 sites in northern Canada have been predicted by transfer-function equations. Normalized departures from the mean of each time series at 250-yr intervals are analyzed by principal component (eigenvector) analysis. An initial analysis included 9 sites and the first three principal components accounted for 85.7% of the variance. Maps of the loadings on the principal components show broad spatial coherence on all three components. Temporal coefficients (principal component scores) illustrate major regional and local midsummer temperature variations. An additional 2 sites were then included but the spatial pattern of the loadings remained essentially unchanged. A further test of this approach, with a view toward predicting paleoclimates of northern regions, was to use the spatial coefficients (loadings) to estimate the July temperature departures at an “unknown” site (Long Lake, Keewatin). This reconstruction compares favorably with an independent transfer-function reconstruction (Kay, 1979). Power spectrum analysis of the significant principal component scores (temperature departures) over the 6000 yr showed that the temporal fluctuations associated with the first three principal components follow a “red noise” spectrum, indicative of strong persistence in the reconstructed climatic records. The scores on the fourth principal component approximate a “white noise” spectrum. A peak in power between 2000 and 3000 yr occurs in the variance spectrum of the second principal component (significance 10%). We conclude that eigenvector analysis of Holocene paleoclimatic data has considerable power and may be useful for identifying regional and local climatic variations.     

Analysis of changes in tornadogenesis conditions over Northern Eurasia based on a simple index of atmospheric convective instability

Doklady Earth Sciences - A simple index of convective instability (3D-index) is used for analysis of weather and climate processes that favor to the occurrence of severe convective events including...     

Satellite-based monitoring of recent heavy flooding over north-eastern states of India in July 2019

Natural Hazards - South-west monsoon of 2019 advanced towards northern parts of India during the first week of July. Heavy-to-very-heavy rainfall events during July 05–16 resulted in severe...     

欧亚和我国东北冬春季积雪对东北夏季气温的影响

根据我国东北及邻近地区123个气象站的逐日气温和积雪深度资料,欧亚大陆积雪面积以及NCEP/NCAR全球再分析月平均500hPa高度场资料,通过相关、合成分析等方法,研究了东北夏季气温异常对欧亚和我国东北冬春季积雪的响应,并从大气环流的角度出发分析了欧亚和我国东北冬春季积雪对东北夏季气温异常形成的影响机制.结果表明:东北地区夏季气温与欧亚大陆春季积雪面积以及东北冬季累积雪深的异常存在明显的关系.欧亚春季积雪面积的扩大与维持有利于8月我国东北上空500hPa位势高度的偏低,环流上表现出西欧与我国东北地区槽加深,泰梅尔阻塞高压加强的特征.由于欧亚中高纬上空的环流经向度加大,槽后脊前的西北气流加强,诱导冷空气南下,从而造成东北全区8月气温一致偏低;东北冬季累积雪深减少则有利于6月东北全区、7月东北西南部上空的位势高度偏低(负距平),造成相关区域气温偏低.研究结果对于提高东北夏季气温的短期气候预测水平具有重要意义.     

Future of rail container transport in Eurasia

Conclusions Transport via the Siberian railway in trade between West Europe and Japan is clearly advantageous compared with sea transport. Whether the Siberian transport route is productive for the Soviet Union measured by Western standards is difficult to say. Some Western experts at least have expressed their doubts.It is known that some industrial western market-economy countries have been asked to invest in the construction of the Baikal-Amur railway in return for promised supplies of earth gas and oil. The development of the Siberian transit transport route may also be taken as a sign of an opening up of the Soviet Union to Western countries in a wider sense, and her growing interest in forming trade relations with the West.From the start the Siberian transit transport route was intended, in addition to the Soviet's own transport needs, for goods traffic between West Europe and Japan. Since then connections have been made with Hong Kong and the Philippines. In the future connections via Siberia may be made with Taiwan, South Korea and other East Asian countries and Australia. Thus the international significance of the Trans-Siberian railway in trade between the Far East and Europe will increase considerably. This will mean that the Soviet officials will be faced with what may prove a difficult decision concerning the growing demands of international transit traffic in relation to the increasing domestic transport on the same rail network.It seems likely that the Soviet Union will obtain an increasing proportion of the foreign exchange she needs from this growth in transport. In 1975 this sum was estimated at US $ 150.000.000. With the development in traffic the Soviets are also obtaining and developing new technological know-how. The biggest losers are the shipping lines belonging to the Far-Eastern Freight Conference. They are mainly from Western countries, but there are also members from Poland and East Germany who will lose freights to the Siberian transport route.     

Mineralogy of fossil resins in Northern Eurasia

The investigation is focused on identification and origin of fossil resins from the Cretaceous, Tertiary, and Quaternary sediments of Northern Eurasia on the basis of detailed study of their physical and chemical characteristics: morphology; size; mass; density; optical, mechanical, and thermal properties; chemical composition; etc. The composition of amorphous organic minerals with polymeric structure, fossil resins included, is studied with IR spectrometry, the EPR method, derivatography at low heating rates, XRD, chemical analysis, emission spectrometry, etc. The results of investigation summarized for the Baltic-Dnieper, North Siberian, and Far East amber-bearing provinces show some similarity of fossil resins in combination with specific features inherent to each province. Resins from the Baltic-Dnieper province should be termed as amber (succinite). Their variety is the most characteristic of Northern and Eastern Europe. Amber-like fossil resins from the North Siberian and Far East provinces are irrelevant to succinite. They usually occur as brittle resins, namely, retinite and gedanite, without jewelry value. Viscous fossil resin rumänite with an expected high economic value occurs in the Far East, on the shore of Sakhalin Island.     

Geodynamic setting of recent volcanism in North Eurasia

A GIS layout of the map of recent volcanism in North Eurasia is used to estimate the geodynamic setting of this volcanism. The fields of recent volcanic activity surround the Russian and Siberian platforms—the largest ancient tectonic blocks of Eurasia—from the arctic part of North Eurasia to the Russian Northeast and Far East and then via Central Asia to the Caucasus and West Europe. Asymmetry in the spatial distribution of recent volcanics of North Eurasia is emphasized by compositional variations and corresponding geodynamic settings. Recent volcanic rocks in the arctic part of North Eurasia comprise the within-plate alkaline and subalkaline basic rocks on the islands of the Arctic Ocean and tholeiitic basalts of the mid-ocean Gakkel Ridge. The southern, eastern, and western volcanic fields are characterized by a combination of within-plate alkaline and subalkaline basic rocks, including carbonatites in Afghanistan, and island-arc or collision basalt-andesite-rhyolite associations. The spatial distribution of recent volcanism is controlled by the thermal state of the mantle beneath North Eurasia. The enormous mass of the oceanic lithosphere was subducted during the formation of the Pangea supercontinent primarily beneath Eurasia (cold superplume) and cooled its mantle, having retained the North Pangea supercontinent almost unchanged for 200 Ma. Volcanic activity was related to the development of various shallow-seated geodynamic settings and deep-seated within-plate processes. Within-plate volcanism in eastern and southern North Eurasia is controlled, as a rule, by upper mantle plumes, which appeared in zones of convergence of lithospheric plates in connection with ascending hot flows compensating submergence of cold lithospheric slabs. After the breakdown of Pangea, which affected the northern hemisphere of the Earth insignificantly, marine basins with oceanic crust started to form in the Cretaceous and Cenozoic in response to the subsequent breakdown of the supercontinent in the northern hemisphere. In our opinion, the young Arctic Ocean that arose before the growth of the Gakkel Ridge and, probably, the oceanic portion of the Amerasia Basin should be regarded as a typical intracontinental basin within the supercontinent [48]. Most likely, this basin was formed under the effect of mantle plumes in the course of their propagation (expansion, after Yu.M. Pushcharovsky) to the north of the Central Atlantic, including an inferred plume of the North Pole (HALIP).     

Pyrological Situation in the Steppes of Northern Eurasia

Doklady Earth Sciences - The emergence and spreading of grass fires in the steppe regions of Northern Eurasia occurs against the background of spatial heterogeneity of landscapes and differences in...     

Lower Devonian conodont zonation in arctic regions of Eurasia

The evolution of viewpoints on the Lower Devonian conodont zonal stratigraphy in Arctic regions of Eurasia is considered. The morphophylogenetic analysis of the Early Devonian conodonts is used to elaborate the Lower Devonian conodont zonation.     

Simulation of a flood producing rainfall event of 29 July 2010 over north-west Pakistan using WRF-ARW model

Simulation of a flood producing rainfall event of 29 July 2010 over north-west Pakistan has been carried out using the Weather Research and Forecasting (WRF) model. This extraordinary rainfall event was localized over north-west Pakistan and recorded 274 mm of rainfall at Peshawar (34.02°N, 71.58°E), within a span of 24 h on that eventful day where monthly July normal rainfall is only 46.1 mm. The WRF model was run with the triple-nested domains of 27, 9, and 3 km horizontal resolution using Kain–Fritsch cumulus parameterization scheme having YSU planetary boundary layer. The model performance was evaluated by examining the different simulated parameters. The model-derived rainfall was compared with Pakistan Meteorological Department–observed rainfall. The model suggested that this flood producing heavy rainfall event over north-west region of Pakistan might be the result of an interaction of active monsoon flow with upper air westerly trough (mid-latitude). The north-west Pakistan was the meeting point of the southeasterly flow from the Bay of Bengal following monsoon trough and southwesterly flow from the Arabian Sea which helped to transport high magnitude of moisture. The vertical profile of the humidity showed that moisture content was reached up to upper troposphere during their mature stage (monsoon system usually did not extent up to that level) like a narrow vertical column where high amounts of rainfall were recorded. The other favourable conditions were strong vertical wind shear, low-level convergence and upper level divergence, and strong vorticity field which demarked the area of heavy rainfall. The WRF model might be able to simulate the flood producing rainfall event over north-west Pakistan and associated dynamical features reasonably well, though there were some spatial and temporal biases in the simulated rainfall pattern.     

Heat flow in salt-dome basins of Eurasia: A comparative study

The geothermal fields in the Pericaspian, Pripyat, and North German basins are considered. These basins are characterized by widespread Upper Paleozoic evaporite sequences, which underwent halokinesis with the formation of salt domes and plugs owing to tectonic and gravity instability. Heat flow refraction occurs at the boundaries of the domes with country rocks due to the contrast in thermal conductivity of evaporites and terrigenous rocks between the domal zones. This is the main cause of heat flow variation in the lateral and vertical directions in the salt-dome basins. Close correlation between zones of elevated temperature in the sedimentary rocks and petroleum occurrences is confirmed by the results of 2D and 3D modeling of the geothermal field. The previously noted relations of oil and gas fields to the deep faults in the studied basins create prerequisites for consideration of the geothermal field as a genetic factor controlling the tectonic features and petroleum resources of the salt-dome basins.     

The Paleocene and Eocene in the Russian part of West Eurasia

Biostratigraphic charts of marine Paleocene and Eocene in the European and West Siberian parts of Russia include the unified zonations of nannoplankton, planktonic and benthic foraminifers, dinocysts, radiolarians, diatoms, and palynomorphs of higher plants. These regional zonations summarize comprehensive data on the Lower Paleogene, which have been obtained by paleontologists and biostratigraphers in the last century. In the content and resolution degree, they represent a solid basis for geological and paleogeographic consideration and characterize the time succession of diverse biotic and abiotic events. On the other hand, the depicted biotic events have been controlled by successive tectonic, paleogeographic, and paleoclimatic events, because organisms determining contents of biostratigraphic zones changed not only in the course of evolution, but also in response to transformation of surroundings. As elements of general communication systems, epicontinental seas of the Paleogene have been interconnected via straits and seaways, which promoted interchange of water masses and biotas belonging to the Tethys, Atlantic or Arctic oceans, and inner seas. Size and configuration of the seas and seaways changed under influence of tectonic processes and eustatic events of epeirogenic or regional origin. Widening, narrowing, and cessation of communication ways have been responsible for different-scale changes in sedimentation and biotic environments. New materials on the Paleogene in a vast territory of Russian sector of West Eurasia offer an opportunity to revise somewhat the dynamics of climatic changes in the Northern Hemisphere during the Early Cenozoic, which characterize the terminal phase of transition from the warm to cold biosphere of the Earth.     

Variations in the Aboveground Phytomass in Northern Eurasia in the 21st Century

Doklady Earth Sciences - Changes in the phytomass of the ecosystems of Northern Eurasia were traced based on the results of modeling and analysis of multispectral satellite imagery (MODIS archives...