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351.
过去几十年太湖流域经济社会快速发展,但由于经济增长方式尚未根本转变,流域水循环系统遭到无序干扰和破坏,太湖水污染问题严重,水质型缺水问题突出,流域水安全面临巨大挑战. “引江济太”作为太湖流域水安全保障的关键措施和流域水环境综合治理的重要举措,自2002年启动实施以来,以丰补枯,增加流域水资源供给;以动治静,抑制太湖蓝藻大规模暴发,改善流域区域水环境;科学应对,保障突发水污染事件和重大活动期间供水安全,取得了显著的综合效益,社会各界予以了广泛关注. 本文基于监测数据和大量文献,在综述“引江济太”实践背景、过程和成效的基础上,重点围绕“引江济太”调度模式、水量水质保障、洪旱风险管控、调水事件驱动等进行了研究. 结果表明,“引江济太”通过试验探索回答了流域治理管理的一些关键科学问题,已经成为提升流域水资源和水环境承载能力的重要手段. 面对极端气候变化、流域水循环格局变化、保障长三角一体化高质量发展水安全新需求和挑战,建议“引江济太”实践中,探索多目标统筹协调调度、开展数字孪生太湖调水、促进流域骨干水网建设,实现”引江济太”综合效益最大化. 相似文献
352.
Cornel Olariu Ronald J. Steel Nataleigh K. Vann Eugen P. Tudor Moonsoo Shin René R. Winter Yuqian Gan Eunsil Jung Flavio N. De Almeida Jr. Gabriel Giacomone Daniel Minisini Walter Brinkworth Maria L. Loss Juan Iñigo Raul Gutierrez 《Basin Research》2020,32(2):279-292
Seismic-reflection data show that most deepwater (>200 m water depth) basins are filled by sand and mud dispersed across clinoformal geometries characterized by gently dipping topsets, steeper foresets and gently dipping bottomsets. However, the entire geometry of these ubiquitous clinoforms is not always recognized in outcrops. Sometimes the infill is erroneously interpreted as “layer cake” or “ramp” stratigraphy because the topset-foreset-bottomset clinoforms are not well exposed. Regional 2-D seismic lines show clinoforms in the Lower to Middle Jurassic Challaco, Lajas, and Los Molles formations in S. Neuquén Basin in Argentina. Time equivalent shelf, slope and basin-floor segments of clinoforms are exposed, and can be walked out in hundreds of metres thick and kilometres-wide outcrops. The studied margin-scale clinoforms are not representing a continental-margin but a deepwater shelf margin that built out in a back-arc basin. Lajas-Los Molles clinoforms have been outcrop-mapped by tracing mudstones interpreted as flooding surfaces on the shelf and abandonment surfaces (low sedimentation rate) in the deepwater basin. The downslope and lateral facies variability in the outcrops is also consistent with a clinoform interpretation. The Lajas topset (shelf) is dominated by fluvial and tidal deposits. The shelf-edge rollover zone is occasionally occupied by a 40–50-m-thick coarse-grained shelf-edge delta, sometimes incising into the underlying slope mudstones, producing oblique clinoforms expressing toplap erosion on seismic. A muddy transgressive phase capping the shelf-edge deltas contains tidal sandbodies. Shelf-edge deltas transition downslope into turbidite- and debris flow-filled channels that penetrate down the mud-prone Los Molles slope. At the base-of-slope, some 300m below the shelf edge, there are basin-floor fan deposits (>200 m thick) composed of sandy submarine-fan lobes separated by muddy abandonment intervals. The large-scale outcrop correlation between topset–foreset–bottomset allows facies and depositional interpretation and sets outcrop criteria recognition for each clinoform segment. 相似文献
353.
我国教育事业的核心是立德树人,通过各学科进行学科育人是其重要途径,其中,地理学科有着较强学科育人的学段与学科优势地位。本文以沪教版初中地理“我国的人口”为例进行了基于任务驱动的课堂教学设计。 相似文献
354.
High-resolution Givetian-Frasnian boundary recognition from conodont-chemo-stratigraphic correlation at Liujing, Guangxi, South China 总被引:1,自引:0,他引:1
The Givetian-Frasnian boundary at Liujing, Guangxi, South China is for the first time recognized and correlated in high resolution
using characteristic chemocycles of element abundance fluctuation integrated with conodont biostratignphy. The first appearance
of Ancyrodella rotundiloba early form is as a biomarker, and the boundary of lowering fluctuation of element abundance followed
by a sequence of characteristic chemocycles with a sequence of cmodonts is as an abiotic auxiliary marker. The error is not
more than 0.10 Ma. The study indicates that in a quiet interval, characteristic chemocycles integrated with biomarkers can
be used for boundary recognition and regional cormlation in high resolution, and this method has potential for intercontinental
correlation 相似文献
355.
356.
357.
W.Q. Gan 《Astrophysics and Space Science》2000,274(3):481-488
Investigation of the gamma-ray spectra observed by the GRS/SMM leads to the conclusion that there exist two extreme cases:
electron-dominated spectra and proton-dominated spectra. The observation of different spectra is determined by both the spectral
hardness of non-thermal electrons and the number ratio of protons to electrons. Any viable acceleration mechanism should be
able to explain these differences in accelerating electrons versus protons.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
358.
359.
A. N. Luk’yanov A. Yu. Karpechko V. A. Yushkov L. I. Korshunov S. M. Khaikin A. V. Gan’shin E. Kyro R. Kivi M. Maturilli H. Voemel 《Izvestiya Atmospheric and Oceanic Physics》2009,45(3):294-301
Processes of mass exchange through the tropopause at extratropical latitudes are studied. For this purpose, balloon data on ozone and water vapor obtained during the LAUTLOS field campaign were analyzed and a trajectory model was used to analyze the origin of air masses and to calculate fluxes through the tropopause. The results of observations and trajectory modeling showed that tropospheric air masses penetrated into the stratosphere by no more than ~2.5 km above the tropopause level during the campaign. Both tropospheric and stratospheric particles are present in this mixing layer. Backward trajectories showed that, at the anticyclone boundary, tropospheric air penetrates into the stratosphere in the form of fine fibrous structures (filaments). The fluxes through the tropopause were also quantitatively estimated by the Wei method with the use of forward and backward trajectories. The spatial structure of the fluxes through the tropopause coincides with the regions of the tropopause inclination and its folds. The absolute values of the fluxes calculated with the use of the Wei method decrease, depending on the length of trajectories at the expense of the filtering-out of a shallow reversible exchange. It is shown that the exchange depth can be controlled by both vertical fluxes in the troposphere and changes in the level of the tropopause itself. The use of isentropic and three-dimensional trajectories made it possible to estimate the contribution of nonadiabatic processes to the stratosphere-troposphere exchange. 相似文献
360.
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